+publisher:"University of Oklahoma" +contributor:("Sigmarsson, Hjalti")

University of Oklahoma

1. Chakraburtty, Manisha. IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION.

Degree: PhD, 2016, University of Oklahoma

► IV-VI semiconductors, with direct gap conduction and valence band extrema at the L-point in k-space, are characterized by four-fold L-valley degeneracy. Prior work [1] has… (more)

▼ IV-VI semiconductors, with direct gap conduction and valence band extrema at the L-point in k-space, are characterized by four-fold L-valley degeneracy. Prior work [1] has shown that this degeneracy can be removed with quantum confinement in the [111] direction. The first half of this dissertation demonstrates the beneficial effects that this degeneracy removal can have on the performance of thermophotovoltaic (TPV) devices. PbSe quantum wells (QWs) with Pb1-xSrxSe barriers were evaluated. Using Schrodinger’s equation and the two different effective masses for charge carriers in the degeneracy split normal (or longitudinal) L-valley and the higher energy three-fold degenerate oblique L-valleys, the largest possible degeneracy splitting energies for three different normal valley subband energy gaps of 450 meV, 550 meV and 650 meV were found to be 21.7 meV, 37.1 meV, and 43.9 meV, respectively. Intrinsic carrier concentrations were calculated for these QWs using density of states functions and Fermi-Dirac statistics. It was found that thermally generated intrinsic carrier density can be reduced by more than an order of magnitude as compared to that of a bulk IV-VI semiconductor material with the same bandgap energy. Dark current and open circuit voltages for TPV devices made from IV-VI materials were also calculated. Results show that use of optimal QW designs can increase open circuit voltages by almost a factor of two as compared to a bulk material having the same band gap energy. With a doubling of open circuit voltages, the incorporation of QW designs in IV-VI semiconductor TPV devices is predicted to enable a 100% increase in optical-to-electrical power conversion efficiencies. The second half of this dissertation discusses the experimental results and analysis of data obtained from characterization of pn junction devices fabricated from a bulk Pb0.93Sr0.07Se active layer. The pn junction layer, which consisted of a 2 μm thick n-type layer doped with bismuth to give an electron density of n=4x1018 cm-3 and a 2 μm thick p-type layer with a selenium overpressure during growth to give a hole density of p=4x1017 cm-3, was grown by molecular beam epitaxy (MBE) on silicon, transferred to copper using a novel flip-chip eutectic bonding method, and fabricated into mesa-etched device structures with sizes of 200 x 200 μm2 and 400 x 400 μm2. Current-versus-voltage characterization was performed with and without broadband illumination at different heatsink temperatures to assess the performance of these devices as TPV cells. Measured reverse bias saturation current densities at -26 mV were observed to increase from 7.5 mA/cm2 to 26.9 mA/cm2 as the lattice temperature was increased from 10°C to 50°C. After accounting for band gap temperature dependence and thermal generation effects, these values were consistent with an increase in minority carrier lifetime from 10 ns at 10°C to 100 ns at 50°C. These data show a clear lifetime enhancing thermal re-excitation effect and confirm the high quality of these IV-VI… Advisors/Committee Members: McCann, Patrick (advisor), Santos, Michael (committee member), Sluss, James (committee member), Grady, Brian (committee member), Sigmarsson, Hjalti (committee member).

Subjects/Keywords: Renewable energy; thermophotovoltaic; nanotechnology; quantum device; IV-VI material

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chakraburtty, M. (2016). IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/46947

Chicago Manual of Style (16^th Edition):

Chakraburtty, Manisha. “IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION.” 2016. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/46947.

MLA Handbook (7^th Edition):

Chakraburtty, Manisha. “IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION.” 2016. Web. 22 Jan 2021.

Vancouver:

Chakraburtty M. IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION. [Internet] [Doctoral dissertation]. University of Oklahoma; 2016. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/46947.

Council of Science Editors:

Chakraburtty M. IV-VI MATERIALS & DEVICES FOR THERMOPHOTOVOLTAIC (TPV) POWER GENERATION. [Doctoral Dissertation]. University of Oklahoma; 2016. Available from: http://hdl.handle.net/11244/46947

University of Oklahoma

2. Mancini, Alessio. A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/316777

► The purpose of this dissertation is to provide a detailed study of the effect of water accumulated on wet radomes. To accomplish this goal, a… (more)

Subjects/Keywords: Radar; Radome; Water; Absorption; Phase array

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mancini, A. (2018). A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/316777

Chicago Manual of Style (16^th Edition):

Mancini, Alessio. “A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/316777.

MLA Handbook (7^th Edition):

Mancini, Alessio. “A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS.” 2018. Web. 22 Jan 2021.

Vancouver:

Mancini A. A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/316777.

Council of Science Editors:

Mancini A. A NEW RESEARCH METHOD TO EVALUATE THE IMPACT OF WET RADOMES ON DUAL-POLARIZED WEATHER RADARS AND COMMUNICATION SYSTEMS. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/316777

University of Oklahoma

3. Atash Bahar, Sattar. RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging.

Degree: PhD, 2017, University of Oklahoma

URL: http://hdl.handle.net/11244/52941

► Magnetic Resonance Imaging (MRI) has become a generally accepted medical procedure and it is estimated that all the U.S. population will have at least one… (more)

▼ Magnetic Resonance Imaging (MRI) has become a generally accepted medical procedure and it is estimated that all the U.S. population will have at least one MRI scan in their lifetime. Unlike common radiography and computed tomography, MRI has many advantages including its nonionizing nature and the capability to distinguish soft tissues. However, the substantial benefits of MRI are often not available to patients with implanted medical devices, such as a pacemaker, an implantable cardiovascular device, a deep brain stimulator, or a neurostimulator. MRIs utilize three powerful fields in the process of producing images, static field, gradient field and Radio Frequency (RF) field that coexist during the scanning. The interaction between the implantable device and the RF electromagnetic field is the main hazard during MRI scanning for most active implantable medical devices. The conductive parts, mainly, the lead wire, act like antennas that pick up the available incident energy. This may result in excessive heating with the capacity for tissue damage . Moreover, the RF power delivered to the Implantable Pulse Generator (IPG) is another concern as it can damage the internal circuitry . In this research, a comprehensive model of the implant in the presence of MRI RF waves is presented. This circuit model represents the induced current and is used to design a lead that minimizes the coupled power to the IPG. This model significantly simplifies designing a new lead by removing Electromagnetic (EM) simulation of implantable devices inside the human body. Also, a circuit model is introduced that extracts the transfer function from the measured parameters of the lead. A miniaturized RF power measurement setup that conforms to the IPG case is designed and used to measure the coupled RF power to the IPG without using external components. This method of measurement, improves the accuracy of the measurement and can be used to measure RF coupled power to the antenna. For communication to the implant using Bluetooth technology, an antenna is designed and the effectiveness of the new measurement setup for the coupled MRI RF waves to the antenna port is demonstrated. Advisors/Committee Members: Sigmarsson, Hjalti (advisor), Salazar-Cerreño, Jorge (committee member), Zhang, Rockee (committee member), Fulton, Caleb (committee member), Floyd, Royce (committee member).

Subjects/Keywords: RF modeling; Antenna; Implantable device

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Atash Bahar, S. (2017). RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/52941

Chicago Manual of Style (16^th Edition):

Atash Bahar, Sattar. “RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging.” 2017. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/52941.

MLA Handbook (7^th Edition):

Atash Bahar, Sattar. “RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging.” 2017. Web. 22 Jan 2021.

Vancouver:

Atash Bahar S. RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging. [Internet] [Doctoral dissertation]. University of Oklahoma; 2017. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/52941.

Council of Science Editors:

Atash Bahar S. RF Modeling and Electromagnetic Analysis of Implantable Devices in Magnetic Resonance Imaging. [Doctoral Dissertation]. University of Oklahoma; 2017. Available from: http://hdl.handle.net/11244/52941

University of Oklahoma

4. Peccarelli, Nicholas. Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/324399

► Modern radar (military, automotive, weather, etc.) and communication systems seek to leverage the spatio-spectral efficiency of phased arrays. Specifically, there is an increasingly large demand… (more)

▼ Modern radar (military, automotive, weather, etc.) and communication systems seek to leverage the spatio-spectral efficiency of phased arrays. Specifically, there is an increasingly large demand for fully-digital arrays, with each antenna element having its own transmitter and receiver. Further, in order to makes these systems realizable, low-cost, low-complexity solutions are required, often sacrificing the system's linearity. Lower linearity paired with the inherent lack of RF spacial filtering can make these highly digital systems vulnerable to high-power interferering signals – potentially introducing spectral regrowth and/or gain compression, distorting the signal-of-interest. Digital linearization solutions such as Digital Pre-Distiortion (DPD) and Nonlinear Equalization (NLEQ) have been shown to effectively mitigate nonlinearities for transmitters and receivers, respectively. Further, DPD and NLEQ seek to extend the effective dynamic range of digital arrays, helping the systems reach their designed dynamic range improvement of 10log₁₀(N)~dB, where N is the number of transmitters/receivers. However, the performance of these solutions is ultimately determined by training model and waveform. Further, the nonlinear characteristics of a system can change with temperature, frequency, power, time, etc., requiring a robust calibration technique to maintain a high-level of nonlinear mitigation. This dissertation reviews the different types of nonlinear models and the current NLEQ and DPD algorithms for digital array systems. Further, a generalized calibration waveform for both NLEQ and DPD is proposed, allowing a system to maximize its dynamic range over power and frequency. Additionally, an it{in-situ} calibration method, leveraging the inherent mutual coupling in an array, is proposed as a solution to maintaining a high level of performance in a fielded digital array system over the system's lifetime. The combination of the proposed training waveform and it{in-situ} calibration technique prove to be very effective at adaptively creating a generalized solution to extending the dynamic range of future low-cost digital array systems. Advisors/Committee Members: Fulton, Caleb (advisor), Goodman, Nathan (committee member), Sigmarsson, Hjalti (committee member), McDaniel, Jay (committee member), Grigo, Alexander (committee member).

Subjects/Keywords: Nonlinear Equalization; Phased Array; Radar; Signal Processing

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Peccarelli, N. (2020). Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/324399

Chicago Manual of Style (16^th Edition):

Peccarelli, Nicholas. “Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/324399.

MLA Handbook (7^th Edition):

Peccarelli, Nicholas. “Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems.” 2020. Web. 22 Jan 2021.

Vancouver:

Peccarelli N. Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/324399.

Council of Science Editors:

Peccarelli N. Nonlinear Equalization and Digital Pre-Distortion Techniques for Future Radar and Communications Digital Array Systems. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/324399

University of Oklahoma

5. Hinkey, Robert. MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS.

Degree: PhD, 2013, University of Oklahoma

URL: http://hdl.handle.net/11244/7906

► Interband cascade photovoltaic (IC PV) structures are an attractive alternative to the conventional long-absorber diode structures currently used for mid-infrared photovoltaic devices. The unique feature… (more)

▼ Interband cascade photovoltaic (IC PV) structures are an attractive alternative to the conventional long-absorber diode structures currently used for mid-infrared photovoltaic devices. The unique feature of IC PV devices is that they utilize a multiple-stage architecture. This sort of design is made possible by the type-II broken-gap alignment between InAs and GaSb. In a multiple-stage device, electrons must be excited several times by above-bandgap photons in order to pass between the device contacts. Although counterintuitive, this transport feature can be beneficial for both energy-conversion and infrared detector technology. In particular, the interband cascade approach should be useful for improving the performance of narrow-bandgap optoelectronic devices operating at high temperature by ensuring a more efficient usage of the incident photons. The aim of this dissertation is to identify and demonstrate the advantages that interband cascade photovoltaic devices offer, both theoretically and experimentally. A theoretical framework for studying signal and noise in multiple-stage interband photovoltaic devices is presented. The theory flows from a general picture of electrons transitioning between thermalized reservoirs. Making the assumption of bulk-like absorbers, we show how the standard semiconductor transport and recombination equations can be extended to the case of multiple-stage devices. The electronic noise arising from fluctuations in the transition rates between reservoirs is derived using the Shockley-Ramo and Weiner-Khintchine theorems. This provides a unified noise treatment accounting for both the Johnson and shot noise. In this framework, we derive consistent analytic expressions for the quantum efficiency and thermal noise in terms of the design parameters and macroscopic material properties of the absorber. The theory is then applied in order to quantify the potential performance improvement that can be gained from the use of multiple stages. We show that multiple-stage detectors can achieve higher sensitivities for applications requiring a very fast temporal response. This is shown by deriving an expression for the optimal number of stages in terms of the absorption coefficient and absorber thicknesses for a multiple-stage detector with short absorbers. The multiple-stage architecture may also be useful for improving the sensitivity of high operating temperature detectors, if a short diffusion length limits the quantum efficiency. The potential sensitivity improvement offered by a multiple-stage architecture can be judged from the product of the absorption coefficient, α, and diffusion length, Ln, of the absorber material. For detector designs where the absorber lengths in each of the stages is equal, the multiple-stage architecture offers the potential for significant detectivity improvement when αLn ≤ 0.2. We also explore the potential of multiple-stage detectors with photocurrent-matched absorbers. In this architecture, the absorbers are designed to absorb and collect an… Advisors/Committee Members: Santos, Michael (advisor), Yang, Rui (committee member), Mullen, Kieran (committee member), Murphy, Sheena (committee member), Sigmarsson, Hjalti (committee member), Abraham, Eric (committee member).

Subjects/Keywords: Physics; Optics.

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hinkey, R. (2013). MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/7906

Chicago Manual of Style (16^th Edition):

Hinkey, Robert. “MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS.” 2013. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/7906.

MLA Handbook (7^th Edition):

Hinkey, Robert. “MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS.” 2013. Web. 22 Jan 2021.

Vancouver:

Hinkey R. MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2013. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/7906.

Council of Science Editors:

Hinkey R. MULTIPLE-STAGE INTERBAND CASCADE PHOTOVOLTAIC DEVICES USING 6.1 Å SEMICONDUCTOR MATERIALS. [Doctoral Dissertation]. University of Oklahoma; 2013. Available from: http://hdl.handle.net/11244/7906

University of Oklahoma

6. Lucking, David. Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/320358

► A sensor's performance is constrained by the amount of resources at its disposal and the utilization of those resources. A radar system, for example, has… (more)

▼ A sensor's performance is constrained by the amount of resources at its disposal and the utilization of those resources. A radar system, for example, has a limited amount of transmit power-aperture per unit time to track a multitude of targets. A typical approach when tracking multiple dynamic targets is to time interleave the update intervals until all the radar tasks are performed. The advent of more agile sensors, such as digital-at-every-element apertures, opens the possibility for dynamic sensor resource allocation strategies to achieve better tracking performance in target-dense, resource-constrained scenarios. With proper research into aperture allocation, such as the analysis provided in this dissertation, an all-digital radar can intelligently exploit the degrees of freedom offered by all-digital radars to increase tracking performance. In this dissertation, we investigate adaptive aperture allocation for tracking a large number of targets. The strategies are first introduced with a parallel, linear channel model, then increased in realism with a non-linear measurement model, and finally applied to a full tracking system. We derive various strategies for allocating power and aperture, and compare their performance based on tracking related metrics. Finally, we investigate the relationship between the aperture allocation strategies and the target locations for multiple scenarios designed to represent the environment for a radar tracking system. This research provides groundbreaking strategies for optimal radar aperture allocation using the digital-at-every-element architectures to reduce the overall system uncertainty and decrease the uncertainty on a per-target basis. Integrating aperture allocation with the management of other degrees of freedom will increase multi-target tracking performance well beyond the current state of the art. Advisors/Committee Members: Goodman, Nathan (advisor), Fulton, Caleb (committee member), Yeary, Mark (committee member), Antonio, John (committee member), Sigmarsson, Hjalti (committee member).

Subjects/Keywords: Digital Arrays; Multi-Target Tracking; Radar Modeling; Radar Resource Management; Radar Signal Processing

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lucking, D. (2019). Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/320358

Chicago Manual of Style (16^th Edition):

Lucking, David. “Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/320358.

MLA Handbook (7^th Edition):

Lucking, David. “Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking.” 2019. Web. 22 Jan 2021.

Vancouver:

Lucking D. Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/320358.

Council of Science Editors:

Lucking D. Digital-At-Every-Element Radar Resource Allocation for Multi-Target Tracking. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/320358

University of Oklahoma

7. Bhowmik, Lal Mohan. Applications of Floquet Analysis to Modern Phased Array Antennas.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/321405

► Next generation radar technology is based on phased array technology and provides remarkable scanning flexibility and spatial search capability for the multifunction weather and air… (more)

▼ Next generation radar technology is based on phased array technology and provides remarkable scanning flexibility and spatial search capability for the multifunction weather and air surveillance radar systems. The future weather radar is comprised of thousands of antenna elements and requires strict polarization purity, grating lobe free system, low sidelobe levels, suppressed surface waves, low cross-polarization, with beam shape requirements. To address these demands is a serious challenge. Over the past few decades, phased array radar technology has been a tremendous advancement in search for future radar technology. With the blessing of modern computational electromagnetic tools, the theory behind the electromagnetic and circuit-level behavior of large-scale phased array system opened the door to analyze the wide variety of multi-layered, complex system of large arrays. However, numerous challenges still remained unsolved for large scale development. One such challenge in integrating a large phased array is the threat of grating lobes that are introduced by unavoidable disturbances to the periodic structure at the seams between mechanical sub-array modules. In particular, gaps in the ground plane may interrupt the natural currents between elements, leading to radiation from periodic sources that are spaced at regular distances that are typically many wavelengths apart. In order to quantify these grating lobe effects, an appropriate analysis framework and accurate model are of utmost importance. The model must capture all surface wave and mutual coupling between elements, and the analysis must have a clear formulation that allows for the calculation of worst-case grating lobe levels as well as differences in active reflection as a function of location within a sub-array. To accurately predict those effects, this dissertation work applied a modern method called Floquet framework, coupling with full wave solver to explore the grating lobe effects in infinite arrays of sub-arrays, with each physical sub-array potentially separated from the others by a gap or discontinuity in the ground plane. Calculations are then performed to extract active reflection coefficients and grating lobe levels from the resulting Floquet mode scattering parameters. Additionally, this Floquet framework is expanded from broadside to any scan angles in space. In the mathematical framework, the surface equivalence theorem based on Huygens’s equivalence principle is applied to authenticate its findings. From the simulation results, it is evident that the grating lobe amplitude level emerged to around 30 dB in the E-plane scan and E- plane grating lobes for a patch array. This is due to natural current disruption in between sub-arrays in the ground plane gap and it is very strong in the E-plane, leading to the potential for low-level grating lobe effects. The other planes and scan angles show less significant effects. It was found that the measurements qualitatively follow the simulated results. The Floquet-based method may therefore be used… Advisors/Committee Members: Fulton, Caleb (advisor), Remling, Christian (committee member), Bluestein, Howard (committee member), Goodman, Nathan (committee member), Sigmarsson, Hjalti (committee member), Ruyle, Jessica (committee member).

Subjects/Keywords: Scan blindness; Creeping waves; Cylindrical Electromagnetic Bandgap (EBG) structures; Floquet analysis; Grating lobe; MPAR; CPPAR; Phased array

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bhowmik, L. M. (2019). Applications of Floquet Analysis to Modern Phased Array Antennas. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/321405

Chicago Manual of Style (16^th Edition):

Bhowmik, Lal Mohan. “Applications of Floquet Analysis to Modern Phased Array Antennas.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/321405.

MLA Handbook (7^th Edition):

Bhowmik, Lal Mohan. “Applications of Floquet Analysis to Modern Phased Array Antennas.” 2019. Web. 22 Jan 2021.

Vancouver:

Bhowmik LM. Applications of Floquet Analysis to Modern Phased Array Antennas. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/321405.

Council of Science Editors:

Bhowmik LM. Applications of Floquet Analysis to Modern Phased Array Antennas. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/321405

University of Oklahoma

8. Rassel, SM Shazzad. CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/299799

► Interband cascade lasers (ICLs) are efficient source of mid-infrared light for many applications that require low power consumption and continuous wave (cw) operation at room… (more)

▼ Interband cascade lasers (ICLs) are efficient source of mid-infrared light for many applications that require low power consumption and continuous wave (cw) operation at room temperature. In the last decade, remarkable progress has been made in developing ICLs on GaSb substrates, mainly in the 3 to 4μm wavelength region, but room temperature (RT) cw operation at the longer wavelength region beyond 6μm has not been achieved. Based on the characterization of earlier grown ICLs, InAs-based plasmon-waveguide ICLs were designed and fabricated to achieve improved performance near or beyond 6μm. These lasers were extensively characterized, investigated and analyzed in terms of various performance features and compared to other state-of-the-art lasers. One laser demonstrated a threshold current density (Jth) as low as 333A/cm2 at 300K for emission at 6003nm. This Jth is the lowest ever reported for a mid-infrared semiconductor laser in this wavelength range. These ICLs lased at temperatures up to 293K in cw mode and up to 357K in pulsed mode. A narrow-ridge laser operated in cw at 293K with a threshold input power as low as 0.66W, and was able to generate 3mW/facet output power at 280K, without accounting for beam divergence loss. These results are very encouraging examples of efficient ICLs at long wavelengths with low power consumption. To investigate the quality of the laser beam of these InAs-based ICLs, the far-field patterns were studied and analyzed for both broad-area and narrow-ridge geometries. In the growth direction, near diffraction-limited single-mode beams were obtained. As expected, multi-mode lasing was observed in the lateral direction because the stripe widths were much longer than the lasing wavelength. Also, as expected, these multi-modes were found to be dependent on applied bias current. These far-field profiles were compared to simulations and reasonable agreement was obtained. Beam propagation factors were plotted against the laser stripe sizes and the values were found close to unity along the growth direction -indicating better beam quality, and below 18 along lateral direction -indicating room for improvement. This methodology can be applied to previously fabricated ICLs to better understand their beam optics. In a related research project, single mode operation of ICLs was obtained by designing and fabricating a cleaved-coupled-cavity (CCC) laser. In our case, rather than cleaving to fabricate two cavities, we successfully demonstrated two ion-milling recipes, using a focused ion beam (FIB) to fabricate our CCC lasers. One recipe separated the two sections of CCC lasers electrically and the other recipe milled a narrow slot (air-gap) into the mesa. Based on the optical power from the fabricated cavities, the quality of the milled facet was found to be comparable to that of an as-cleaved facet. This CCC laser demonstrated a single mode operation at ~3109nm at room temperature with a reasonable side-mode-suppression-ratio (SMSR) of 24dB. A continuous tuning range of ~1.1nm and… Advisors/Committee Members: Yang, Rui (advisor), Johnson, Matthew (committee member), Santos, Michael (committee member), Sigmarsson, Hjalti (committee member), Fulton, Caleb (committee member).

Subjects/Keywords: interband cascade laser; high-frequency; coupled cavity laser; far field beam; carrier transport

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rassel, S. S. (2018). CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/299799

Chicago Manual of Style (16^th Edition):

Rassel, SM Shazzad. “CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/299799.

MLA Handbook (7^th Edition):

Rassel, SM Shazzad. “CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES.” 2018. Web. 22 Jan 2021.

Vancouver:

Rassel SS. CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/299799.

Council of Science Editors:

Rassel SS. CHARACTERIZATION AND DEVELOPMENT OF SEMICONDUCTOR CASCADE DEVICES. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/299799

University of Oklahoma

9. Mirmozafari, Mirhamed. DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/299910

► Multifunction Phased Array Radar (MPAR) was defined to investigate the feasibility of integrating weather observation and air surveillance radars into a single network. Weather radars… (more)

▼ Multifunction Phased Array Radar (MPAR) was defined to investigate the feasibility of integrating weather observation and air surveillance radars into a single network. Weather radars require dual polarization capability which may be also beneficial to aircraft characterization. Research activities have begun to identify challenges, mitigate risk, and demonstrate polarimetric technologies. Ten-panel, developed by MIT’s Lincoln Laboratory, was the first dual-polarized planar phased array demonstrator. Alternatively, a cylindrical polarimetric phased array radar (CPPAR) was developed at the Advanced Radar Research Center of the University of Oklahoma to resolve the intrinsic limitations of planar arrays in making accurate polarimetric measurements. The current CPPAR employs a frequency scanning patch array antenna. Since the radar’s performance would be the most important driver, the future operational CPPAR, suitable for long-range weather measurement, will utilize a new antenna with higher performance. It is the purpose of this research to propose a new dual-polarized phased array antenna for MPAR application. A crossed dipole antenna with sufficient operational frequency bandwidth is designed. A high polarization purity is achieved by using a group of efficient techniques in element scale. This element was modified to obtain a higher match between copolar beams. The modified element is utilized as an embedded element to form a cylindrical and a planar array antenna. It is demonstrated that suppressed azimuthal surface wave and consequently highly matched copolar beams can be achieved in a cylindrical array of proposed crossed dipole. In order to compensate for the electrical and geometrical asymmetry of the element, an imaged arrangement of the elements with respect to the center of the array is utilized. It is shown that a planar array of the modified crossed dipole, arranged in a specific configuration, proposes zero cross-polarization in the principal planes without increased side lobe problem. The experimental verification demonstrates that the proposed phased array antennas are promising candidates for multi-mission applications. Advisors/Committee Members: Zhang, Guifu (advisor), Hong, Yang (committee member), Doviak, Richard (committee member), Sigmarsson, Hjalti (committee member), Zhang, Yan (committee member).

Subjects/Keywords: Phased Array Antenna; Dual Polarization; Crossed Dipole; High Isolation

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mirmozafari, M. (2018). DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/299910

Chicago Manual of Style (16^th Edition):

Mirmozafari, Mirhamed. “DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/299910.

MLA Handbook (7^th Edition):

Mirmozafari, Mirhamed. “DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS.” 2018. Web. 22 Jan 2021.

Vancouver:

Mirmozafari M. DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/299910.

Council of Science Editors:

Mirmozafari M. DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/299910

University of Oklahoma

10. Saeidi Manesh, Hadi. HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/319597

► There are interest and practical value in utilizing polarization diversity for a radar to obtain more target information or for a communication system to carry… (more)

▼ There are interest and practical value in utilizing polarization diversity for a radar to obtain more target information or for a communication system to carry more signal information without occupying more frequency band. This is because frequency bands are getting crowded in microwave frequencies due to the recent advancements in cellular communications. For example, the Spectrum Efficient National Surveillance Radar Program (SENSR) is started to study the feasibility of replacing the four radar networks that service the U.S with a single network of Multifunction Phased Array Radar (MPAR). Candidates being considered for future MPAR include Cylindrical Polarimetric Phased Array Radar (CPPAR), and Planar Polarimetric Phased Array Radar (PPPAR). To have the desired accurate weather measurements with a PPPAR or CPPAR, a high-performance phased array antenna with dual-polarization capability is required. The array antenna is required to possess matched main beams, high input isolation, and low cross-polarization level at broadside and scan angles up to 45◦. The beam mismatch should be within 5% of the beamwidth, the input isolation needs to be better than 40 dB, and to have ZDR bias of less than 0.2 dB, the cross-polarization level along beam axis needs to be lower than -20 dB and -40 dB for alternate and simultaneous transmission, respectively. These are very stringent requirements for antenna design and development. The primary objective of this dissertation is to propose high-performance dual-polarized antenna arrays with high input isolation and low cross-polarization level for multifunction phased radar application. To do so, four different types of dual-polarized microstrip patch antenna arrays are presented. In the proposed patch antennas, different feeding techniques such as, aperture coupling method, balanced feed method and the combination of these methods which is called hybrid feeding technique are used. The proposed antenna arrays in this dissertation are configured according to image configuration for improving the cross-polarization level. The issues and challenges of implementing image arrangement is discussed, and precise procedure for design and predicting the final array radiation characteristics is proposed. The CPPAR demonstrator antenna is redesigned to achieve matched horizontal and vertical polarization beam pointing angels. A method of beam matching between two linearly polarized radiation patterns of a dual-polarized frequency scanning antenna is proposed, implemented, and tested. A meticulous phase match process between the outputs of both individual cells and the whole corresponding horizontal and vertical feed lines is carried out. To verify the simulation results and to take the coupling effect into account, the radiation patterns of an isolated column, as well as those of three columns, are measured. In agreement with the design and simulation results, horizontal and vertical polarization beams with a pointing angle mismatch of less than ±0.2◦ within the resonant frequency… Advisors/Committee Members: Zhang, Guifu (advisor), Hong, Yang (committee member), Sigmarsson, Hjalti (committee member), Doviak, Richard (committee member), Zhang, Yan (committee member).

Subjects/Keywords: Engineering, Electronics and Electrical.; Dual Polarization; Antenna; Phased Array Radar; Microstrip Patch Antenna

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Saeidi Manesh, H. (2019). HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/319597

Chicago Manual of Style (16^th Edition):

Saeidi Manesh, Hadi. “HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/319597.

MLA Handbook (7^th Edition):

Saeidi Manesh, Hadi. “HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION.” 2019. Web. 22 Jan 2021.

Vancouver:

Saeidi Manesh H. HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/319597.

Council of Science Editors:

Saeidi Manesh H. HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/319597

University of Oklahoma

11. Lake, John. Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/319666

► The microwave band is well suited to wireless applications, including radar, communications, and electronic warfare. While radar operations currently have priority in a portion of… (more)

▼ The microwave band is well suited to wireless applications, including radar, communications, and electronic warfare. While radar operations currently have priority in a portion of the microwave band, wireless companies are lobbying to change that; such a change would force current operators into a smaller total bandwidth. Interference would occur, and has already occurred at the former National Weather Radar Testbed Phased Array Radar. The research in this dissertation was motivated by this interference – it occurred even without a change to radar's primacy in the microwave band. If microwave operations had to squeeze into a smaller overall bandwidth, such interference, whether originating from other radars or some other source, would only become more common. The radio frequency interference (RFI) present at the National Weather Radar Testbed Phased Array Radar altered the statistical properties at certain locations, causing targets to be erroneously detected. While harmless enough in clear air, it could affect National Weather Service decisions if it occurred during a weather event. The initial experiments, covered in Chapter 2, used data comprised of a single channel of in-phase and quadrature (IQ) data, reflecting the resources available to the National Weather Service's weather radar surveillance network. A new algorithm, the Interference Spike Detection Algorithm, was developed with these restrictions in mind. This new algorithm outperforms several interference detection algorithms developed by industry. Tests on this data examined algorithm performance quantitatively, using real and simulated weather data and radio frequency interference. Additionally, machine learning classification algorithms were employed for the first time to the RFI classification problem and it was found that, given enough resources, machine learning had the potential to perform even better than the other temporal algorithms. Subsequent experiments, covered in Chapter 3, used spatial data from phased arrays and looked at methods of interference mitigation that leveraged this spatial data. Specifically, adaptive beamforming techniques could be used to mitigate interference and improve data quality. A variety of adaptive digital beamforming techniques were evaluated in terms of their performance at interference mitigation for a communications task. Additionally, weather radar data contaminated with ground clutter was collected from the sidelobe canceller channels of the former National Weather Radar Testbed Phased Array Radar and, using the reasoning that ground clutter is simply interference from the ground, adaptive digital beamforming was successfully employed to mitigate the impact of ground clutter and restore the data to reflect the statistics of the underlying weather data. Tests on digital equalization, covered in Chapter 4, used data from a prototype receiver for Horus, a digital phased array radar under development at the University of Oklahoma. The data suffered from significant channel mismatch, which can… Advisors/Committee Members: Yeary, Mark (advisor), Fulton, Caleb (committee member), Goodman, Nathan (committee member), Sigmarsson, Hjalti (committee member), Homeyer, Cameron (committee member).

Subjects/Keywords: radio frequency interference; adaptive digital beamforming; digital equalization; radar

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lake, J. (2019). Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/319666

Chicago Manual of Style (16^th Edition):

Lake, John. “Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/319666.

MLA Handbook (7^th Edition):

Lake, John. “Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality.” 2019. Web. 22 Jan 2021.

Vancouver:

Lake J. Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/319666.

Council of Science Editors:

Lake J. Temporal and Spatial Interference Mitigation Strategies to Improve Radar Data Quality. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/319666

University of Oklahoma

12. Irazoqui, Robin. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/319751

► Fully digital arrays offer significant advantages in terms of flexibility and performance, however they suffer from dynamic range issues when used in the presence of… (more)

Subjects/Keywords: Radar; Spatial Interference Mitigation; RF Spatial Filtering; Nulling the Embedded Element Pattern

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Irazoqui, R. (2019). An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/319751

Chicago Manual of Style (16^th Edition):

Irazoqui, Robin. “An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/319751.

MLA Handbook (7^th Edition):

Irazoqui, Robin. “An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays.” 2019. Web. 22 Jan 2021.

Vancouver:

Irazoqui R. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/319751.

Council of Science Editors:

Irazoqui R. An Investigation and Solution to Spatial Interferers Before RF Front End for Phased Arrays. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/319751

University of Oklahoma

13. McDaniel, Jay. Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/301298

► The method in which the frequency spectrum is currently allocated is unsustainable. An increasing number of devices are becoming wireless, overcrowding an already crowded spectrum… (more)

▼ The method in which the frequency spectrum is currently allocated is unsustainable. An increasing number of devices are becoming wireless, overcrowding an already crowded spectrum (e.g., the ISM band). Therefore, future systems will be forced to move to higher frequencies in order to be allocated an unused slice of the spectrum and accumulate the desired/required bandwidth. Furthermore, with the continued desire to implement a multitude of sensors on unmanned aerial vehicles (UAVs), as well as the need for conformal small-cell repeaters for 5G communications, next generation systems will have to achieve unprecedented reductions in size, weight, power, and cost (SWaP-C). In order for future systems to become practical, several fundamental technological hurdles must be overcome including the development of low loss and highly integrated components used to build next generation systems. The RF/microwave filter is of particular interest, as it is not only crucial for conditioning the signal for transmission and/or digitization, but can also affect critical system parameters based on it's placement in the system. Due to the increased attenuative nature of the environment at microwave frequencies, the systems dynamic range will have to be maximized requiring an exceptionally low loss filter if placed close to the antenna in the receiver (Rx) chain, which is necessary for defense and adaptive/re-configurable systems. While low loss microwave filtering can be easily achieved using waveguide design techniques, it is much more difficult in a highly integrated planar design due to increased radiation and dielectric losses. A promising solution which minimizes these losses and offers a planar solution is the suspended integrated stripline (SISL) filter. In this research, a low loss fully-board integrated lowpass and highpass filter, using the suspended integrated stripline technology, are designed and studied, pushing the stat-of-the-art in planar filtering technologies. A multi-layer board stack-up, with internally buried hollowed cavities, is used to create the suspended stripline. The embedded filter is accessed through a co-planar waveguide-to-stripline vertical via transition and vice-versa. Simulated and measured results show that insertion losses of less than 1 dB are obtainable including the vertical via transition and associated trace losses. Compared to it's suspended substrate stripline (SSS) predecessor, the SISL filter is one order of magnitude smaller and lighter while achieving identical performance. Beyond the proposed filters, this technological solution can be applied to several other passive microwave components such as couplers, power dividers, and gain equalizers. The capabilities demonstrated in this research will be crucial to the design and integration of modern and next generation systems as it requires no mechanical housing, connectors, or assembly, resulting in a light weight, compact size, and low cost solution. Advisors/Committee Members: Sigmarsson, Hjalti (advisor), Yeary, Mark (committee member), Goodman, Nathan (committee member), Fulton, Caleb (committee member), Basara, Jeffrey (committee member).

Subjects/Keywords: Chebyshev; lowpass filter; suspended integrated stripline; suspended substrate stripline

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

McDaniel, J. (2018). Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/301298

Chicago Manual of Style (16^th Edition):

McDaniel, Jay. “Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/301298.

MLA Handbook (7^th Edition):

McDaniel, Jay. “Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems.” 2018. Web. 22 Jan 2021.

Vancouver:

McDaniel J. Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/301298.

Council of Science Editors:

McDaniel J. Self-Packaged and Low-Loss Suspended Integrated Stripline Filters for Next Generation Systems. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/301298

University of Oklahoma

14. Dower, William. Advances in Synthetic Aperture Radar from a Wavenumber Perspective.

Degree: PhD, 2017, University of Oklahoma

URL: http://hdl.handle.net/11244/52722

► This dissertation examines the wavenumber domain of Synthetic Aperture Radar (SAR) images. This domain is the inverse Fourier transform domain of a SAR image. The… (more)

Subjects/Keywords: synthetic aperture radar; image resolution; back projection; bistatic radar

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dower, W. (2017). Advances in Synthetic Aperture Radar from a Wavenumber Perspective. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/52722

Chicago Manual of Style (16^th Edition):

Dower, William. “Advances in Synthetic Aperture Radar from a Wavenumber Perspective.” 2017. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/52722.

MLA Handbook (7^th Edition):

Dower, William. “Advances in Synthetic Aperture Radar from a Wavenumber Perspective.” 2017. Web. 22 Jan 2021.

Vancouver:

Dower W. Advances in Synthetic Aperture Radar from a Wavenumber Perspective. [Internet] [Doctoral dissertation]. University of Oklahoma; 2017. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/52722.

Council of Science Editors:

Dower W. Advances in Synthetic Aperture Radar from a Wavenumber Perspective. [Doctoral Dissertation]. University of Oklahoma; 2017. Available from: http://hdl.handle.net/11244/52722

University of Oklahoma

15. Li, Zhe. CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/325311

► A desirable candidate for future weather observation is a polarimetric phased array radar (PPAR), which is capable of both using polarimetry for multi-parameter measurements and… (more)

▼ A desirable candidate for future weather observation is a polarimetric phased array radar (PPAR), which is capable of both using polarimetry for multi-parameter measurements and the fast-scan proficiency of the PAR. However, it is challenging to collect high-quality polarimetric radar data of weather with a planar PPAR (PPPAR), whose beam and polarization characteristics change with the electronic beam direction, causing geometrically induced cross-polarization coupling, sensitivity losses, and measurement biases when the PPPAR beam is steered away from the broadside. As an alternative to PPPAR, the concept of cylindrical polarimetric phased array radar (CPPAR) was proposed, which has scan-invariant beam characteristics in azimuth and polarization purity in all directions using commutating scan, thus enables high quality polarimetric weather measurements. To validate the CPPAR concept, a small-scale CPPAR demonstrator has been jointly developed by the Advanced Radar Research Center (ARRC) at the University of Oklahoma (OU) and the National Severe Storms Laboratory (NSSL) of NOAA. This dissertation presents the results of initial weather measurements, shows the performance of the CPPAR demonstrator, and evaluates the polarimetric data quality that has been achieved. The system specifications and field tests of the CPPAR demonstrator are provided, including system overview, waveform design and verification, pattern optimization and far-field tests. In addition, three methods of system calibration are introduced and compared, including calibration with an external source, calibration with weather measurements of mechanical scan, and calibration with ground clutter. It is found that calibration with weather measurements of mechanical scan has the best performance and it is applied on the CPPAR demonstrator for the first time, which effectively improved the beam-to-beam consistency and radar data quality in commutating beam electronic scan by minimizing gain and beamwidth variations. Performance of the CPPAR is assessed through system simulation and weather measurements. The CPPAR is evaluated through an end-to-end phased array radar system simulator (PASIM). The simulation framework, weather returns modeling, antenna pattern, channel electronics, and simulation results of CPPAR, as well as comparison with those that would be obtained with a PPPAR, are provided. Also, weather measurements of a few convective precipitation cases and a stratiform precipitation case made with the CPPAR, employing the single beam mechanical scan and commutating beam electronic scan respectively, are presented. First, a qualitative comparison is made between the CPPAR and a nearby operational NEXRAD. Then a quantitative comparison is conducted between the mechanical scan and electronic scan, and error statistics are estimated and discussed. In addition, a theoretical explanation of a feature of the commutating beam electronic scan in clutter detection that is different from mechanical scan is presented and verified by measurements in clear… Advisors/Committee Members: Zhang, Guifu (advisor), Sigmarsson, Hjalti (committee member), Zrnić, Dusan (committee member), Zhu, Meijun (committee member), Zhang, Yan (committee member).

Subjects/Keywords: Engineering, Electronics and Electrical.; Weather Radar; Cylindrical Polarimetric Phased Array Radar

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Li, Z. (2020). CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/325311

Chicago Manual of Style (16^th Edition):

Li, Zhe. “CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/325311.

MLA Handbook (7^th Edition):

Li, Zhe. “CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS.” 2020. Web. 22 Jan 2021.

Vancouver:

Li Z. CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/325311.

Council of Science Editors:

Li Z. CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/325311

University of Oklahoma

16. Perera, Sudantha. Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems.

Degree: PhD, 2016, University of Oklahoma

URL: http://hdl.handle.net/11244/47142

► The development of a large-scale phased array radar system such as the future MPAR will need a cost-effective tool for predicting electromagnetic characteristics of antennas.… (more)

Subjects/Keywords: Phased Array Antennas; Computational Electromagnetics; Finite Difference Time Domain Method

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Perera, S. (2016). Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/47142

Chicago Manual of Style (16^th Edition):

Perera, Sudantha. “Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems.” 2016. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/47142.

MLA Handbook (7^th Edition):

Perera, Sudantha. “Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems.” 2016. Web. 22 Jan 2021.

Vancouver:

Perera S. Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems. [Internet] [Doctoral dissertation]. University of Oklahoma; 2016. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/47142.

Council of Science Editors:

Perera S. Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems. [Doctoral Dissertation]. University of Oklahoma; 2016. Available from: http://hdl.handle.net/11244/47142

University of Oklahoma

17. Ji, Guomin. Many-Body Delocalization and Evidential Study in Power Grid.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/326579

► Complex energy flow dynamics following an untoward event has a direct impact on the responses of the protective and stabilization control systems of the power… (more)

▼ Complex energy flow dynamics following an untoward event has a direct impact on the responses of the protective and stabilization control systems of the power grid, in defending the power grid against from large-scale cascading failures or network fragmentation. In this dissertation, a non-classic view and an analytical framework on electro-mechanical dynamics are proposed, which is different from the electric circuit-based ones built up classic physics. Inspired from some recent advances in port-Hamiltonian formulism in control systems and random work interpretation of energy flows in electric circuit, a hypothetical but well-grounded unitary view on power grid is postulated, which leads to the new concept of many-body delocalization. The power grid with n ports of synchronized components can be transformed into a unitary electromagnetic field, which can be mathematically described by a complete graph that couples the active and passive resources and boundaries. Thus, the energy flow becomes the manifestation of an underlying unitary electromagnetic field. A quantum number-based analytical framework is built based on several principles related to the unitary field view, such as Hermitian symmetry, Heisenberg uncertainty principles and general relativistic effect. With the intrinsic properties of the quantum number-based model, a new network property is developed, namely z-direction radical distance. This is a new concept about the projection of angular quantum number and the unit reference potential. This novel radical distance concept describes the fundamental connection between the energy flow in a complex network and its structure: it stands for the fraction of system energy surging at various spots as the result of l-motions along the z-direction, later found very useful for understanding the energy flow in power grid. An evidential experiment is carried out using a real world power grid model of electro-mechanical stability. With mathematical tools from tensor analysis of network, the estimation of distribution of network energy flow in the power grid is derived. By comparing the radical distance based estimation of electromagnetic waves in the power grid to the one calculated with the complete dynamic system model of the power grid, a remarkable consistency is observed. This dissertation presents a unique perspective for complex network analysis, which is drastically different from the current “small-world” one. Based on its analytical root and the evidential experiments, we discover that radical distance is a metric that penetrates the boundary between the microscopic quantum world and real-world macroscopic power and energy systems. Such a discovery suggests the possibility of the coupling of active resources of power grid could be of the entangled particles type, authoring the usage of quantum effects in explaining and dealing with the states at a macroscopic scale, at least from a modeling/analytical perspective. Advisors/Committee Members: Jiang, John (advisor), Wu, Xingru (committee member), Moses, Paul (committee member), Barnes, Ronald (committee member), Sigmarsson, Hjalti (committee member).

Subjects/Keywords: Power Grid; Dynamic Stability; Transient Energy Influx

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ji, G. (2020). Many-Body Delocalization and Evidential Study in Power Grid. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/326579

Chicago Manual of Style (16^th Edition):

Ji, Guomin. “Many-Body Delocalization and Evidential Study in Power Grid.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/326579.

MLA Handbook (7^th Edition):

Ji, Guomin. “Many-Body Delocalization and Evidential Study in Power Grid.” 2020. Web. 22 Jan 2021.

Vancouver:

Ji G. Many-Body Delocalization and Evidential Study in Power Grid. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/326579.

Council of Science Editors:

Ji G. Many-Body Delocalization and Evidential Study in Power Grid. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/326579

University of Oklahoma

18. Islam, Shajid. Probe-based, quasi-near-field phased array calibration.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/326668

► Phased array technology provides remarkable scanning flexibility and spatial search capability for the multifunction radar system, airborne radar system, and many other applications. Recent years… (more)

Subjects/Keywords: Phased Array Calibration; Fast Calibration Technique; Quasi-Near-Field; Mutual Coupling

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Islam, S. (2020). Probe-based, quasi-near-field phased array calibration. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/326668

Chicago Manual of Style (16^th Edition):

Islam, Shajid. “Probe-based, quasi-near-field phased array calibration.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/326668.

MLA Handbook (7^th Edition):

Islam, Shajid. “Probe-based, quasi-near-field phased array calibration.” 2020. Web. 22 Jan 2021.

Vancouver:

Islam S. Probe-based, quasi-near-field phased array calibration. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/326668.

Council of Science Editors:

Islam S. Probe-based, quasi-near-field phased array calibration. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/326668

University of Oklahoma

19. Winniford, Paul. Reconfigurable and multiband antennas with resonant and reactive loads.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/326683

► Reactive and resonant loads have been used from the very beginning of antenna design to improve impedance matching, bandwidth, and current distributions on antennas, and… (more)

Subjects/Keywords: Antennas; Reconfigurable Antennas; Multifrequency Antennas; Loaded Antennas

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Winniford, P. (2020). Reconfigurable and multiband antennas with resonant and reactive loads. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/326683

Chicago Manual of Style (16^th Edition):

Winniford, Paul. “Reconfigurable and multiband antennas with resonant and reactive loads.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/326683.

MLA Handbook (7^th Edition):

Winniford, Paul. “Reconfigurable and multiband antennas with resonant and reactive loads.” 2020. Web. 22 Jan 2021.

Vancouver:

Winniford P. Reconfigurable and multiband antennas with resonant and reactive loads. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/326683.

Council of Science Editors:

Winniford P. Reconfigurable and multiband antennas with resonant and reactive loads. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/326683

University of Oklahoma

20. Lei, Lin Jr. Mid-wavelength and long-wavelength interband cascade infrared photodetectors.

Degree: PhD, 2017, University of Oklahoma

URL: http://hdl.handle.net/11244/52405

► Interband cascade (IC) devices are a family of infrared optoelectronic devices that includes interband cascade lasers (ICLs), interband cascade infrared photodetectors (ICIPs) and interband cascade… (more)

▼ Interband cascade (IC) devices are a family of infrared optoelectronic devices that includes interband cascade lasers (ICLs), interband cascade infrared photodetectors (ICIPs) and interband cascade infrared thermophotovoltaics (ICTPVs). They are unique due to their multiple-stage architecture based on type-II heterostructures. In IC devices, the carrier transport is rectified with two unipolar barriers (injectors), namely the electron barrier (hole injector) and hole barrier (electron injector). The series connection between cascade stages is realized by employing the type-II broken-gap alignment between InAs and GaSb layers. While a conventional single stage detector is limited by the short diffusion length and carrier lifetime at high temperatures and long wavelengths, an ICIP with a series of thin discrete absorbers can circumvent these limitations with high device performance. Although the responsivity of ICIPs is reduced by the thin absorbers, noise is also reduced significantly by the series connected cascade stages so that a large signal to noise ratio is retained. Most of the interest for IR detector applications is focused on the mid-wavelength (MW) infrared (IR) and long-wavelength (LW) IR bands. However, most of them require a cooling system to achieve high device performance. ICIPs are one of the most promising candidates for meeting the high-performance and uncooled requirements of these applications. MW ICIPs based on InAs/GaSb type-II superlattice (T2SL) and bulk GaInAsSb absorbers are discussed in detail. High temperature operation and high device performance are demonstrated with Johnson-noise limited detectivities over 1.0×10⁹ cmˑHz¹/2/W at 300 K. LW ICIPs with current-matching and non-current matching architectures were systematically studied. These ICIPs are capable of operating at high temperatures up to 340 K. They exhibited a high device performance with a detectivity (D*) higher than 1.0×10⁹ and 1.0×10⁸ cmˑHz¹/2/W at 200 and 300 K, respectively. While current-matching is necessary for maximizing photon absorption to achieve optimal responsivity, the lower responsivity in the non-current matched ICIPs is attributed to light attenuation in the optically deeper stages. Meanwhile, the responsivity in the non-current matched ICIPs is enhanced by the significantly higher electrical gain, along with the much higher resistances, so that their device performance is comparable or even slightly higher than the current matched ICIPs. Multi-stage ICIPs show superior performance over conventional one-stage detectors at high temperatures in both the MWIR and LWIR regions. The presence of high electrical gain in the both MW and LW ICIPs may be related to two mechanisms: one is the photoconductive gain due to a shorter transit time than carrier lifetime, the other is the compensation of dark current to maintain current continuity. The observed multiple negative differential conductance (NDC) features in the LW ICIPs at high temperatures are related to the sequential turn-off of intraband… Advisors/Committee Members: Yang, Rui Q. Jr (advisor), Santos, Michael Jr (committee member), Johnson, Matthew Jr (committee member), Mullen, Kieran Jr (committee member), Kao, Chung Jr (committee member), Sigmarsson, Hjalti Jr (committee member).

Subjects/Keywords: infrared detectors; interband cascade; mid-wavelength and long wavelength; high operating temperature

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lei, L. J. (2017). Mid-wavelength and long-wavelength interband cascade infrared photodetectors. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/52405

Chicago Manual of Style (16^th Edition):

Lei, Lin Jr. “Mid-wavelength and long-wavelength interband cascade infrared photodetectors.” 2017. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/52405.

MLA Handbook (7^th Edition):

Lei, Lin Jr. “Mid-wavelength and long-wavelength interband cascade infrared photodetectors.” 2017. Web. 22 Jan 2021.

Vancouver:

Lei LJ. Mid-wavelength and long-wavelength interband cascade infrared photodetectors. [Internet] [Doctoral dissertation]. University of Oklahoma; 2017. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/52405.

Council of Science Editors:

Lei LJ. Mid-wavelength and long-wavelength interband cascade infrared photodetectors. [Doctoral Dissertation]. University of Oklahoma; 2017. Available from: http://hdl.handle.net/11244/52405

University of Oklahoma

21. Ortiz, Javier Alejandro. Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/325369

► An analytical model is proposed to characterize and quantify the effects that diffracted fields have on the performance of phased array antennas. The work involves… (more)

▼ An analytical model is proposed to characterize and quantify the effects that diffracted fields have on the performance of phased array antennas. The work involves the combination of diffraction theory techniques and how each can be used to analyze this phenomena with the use of antenna elements as sources. As these antenna elements are placed along a ground plane of relatively large size in terms of λ diffracted fields can perturb the expected cross-polarization radiation performance of the element. As the element is moved along the ground plane and at different relative distances from the edges, depending on the electromagnetic radiation nature of the antenna structure, these edges produce diffracted fields that can affect the performance of the co- as well as the cross-polarized fields of the antenna. This is of great importance when working with highly pure polarized elements for applications that require low cross-polarization. The expansion of an equivalent current model is proposed where the antenna element can be expressed at a distance from the edges and the diffracted fields generated from such edges are calculated from these equivalent currents. Every element position over the ground plane will generate a theoretical equivalent current that would radiate the diffracted fields, which then contribute to the overall array pattern. This work shows a successful implementation of the proposed technique and how this can be combines with finite element method (FEM) analysis in order to predict the radiated fields from different element positions providing an advantage over resource hungry simulations. This proves to be an effective tool by reducing the calculation time substantially for scalable applications where the phased array can be over thousands of elements and extremely difficult to gather resources to produce a predicted pattern. Advisors/Committee Members: Salazar, Jorge (advisor), Aboserwal, Nafati (committee member), Sigmarsson, Hjalti (committee member), Palmer, Robert (committee member), Yu, Tian-You (committee member), Marino, Alberto (committee member).

Subjects/Keywords: Phased Array Antennas; Antennas; Diffraction; Dual-Polarization

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ortiz, J. A. (2020). Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/325369

Chicago Manual of Style (16^th Edition):

Ortiz, Javier Alejandro. “Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/325369.

MLA Handbook (7^th Edition):

Ortiz, Javier Alejandro. “Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas.” 2020. Web. 22 Jan 2021.

Vancouver:

Ortiz JA. Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/325369.

Council of Science Editors:

Ortiz JA. Impact of Edge Diffraction in Dual-Polarized Phased Array Antennas. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/325369

University of Oklahoma

22. Hosseini, Seyed Hossein. REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS.

Degree: PhD, 2014, University of Oklahoma

URL: http://hdl.handle.net/11244/13388

► In this dissertation we provide a novel estimation framework designed and structured on duality theory for estimation of some key parameters in electricity markets. Specifically,… (more)

Subjects/Keywords: Engineering; Electronics and Electrical.

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hosseini, S. H. (2014). REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/13388

Chicago Manual of Style (16^th Edition):

Hosseini, Seyed Hossein. “REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS.” 2014. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/13388.

MLA Handbook (7^th Edition):

Hosseini, Seyed Hossein. “REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS.” 2014. Web. 22 Jan 2021.

Vancouver:

Hosseini SH. REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2014. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/13388.

Council of Science Editors:

Hosseini SH. REVEALING ADDITIONAL INFORMATION ABOUT ELECTRICITY MARKET UNDERLYING POWER SYSTEM USING POWER SYSTEM PRINCIPLES AND PUBLISHED MARKET RESULTS. [Doctoral Dissertation]. University of Oklahoma; 2014. Available from: http://hdl.handle.net/11244/13388

23. Mirković, Djordje. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.

Degree: PhD, 2015, University of Oklahoma

URL: http://hdl.handle.net/11244/21720

► The primary topics of this dissertation are issues existing in the current ensemble scattering procedures. These procedures are failing to quantitatively reproduce polarimetric signatures from… (more)

▼ The primary topics of this dissertation are issues existing in the current ensemble scattering procedures. These procedures are failing to quantitatively reproduce polarimetric signatures from resolution volumes filled with ensembles of resonant size precipitation, biota, and anthropogenic scatterers. Sources of these failures are traced to the constraints on the topology that is admissible to the different modeling procedures. The dissertation evaluates in a systematic manner the current modeling procedures focusing on limitation sources and their effects on the overall process of polarimetric variable simulation. It re-evaluates limitations of the widely used T-Matrix approach and discusses sources of instability. Based on the identified limitations, a novel computational electromagnetics (CEM) approach to scatterer modeling and polarimetric variable calculation is introduced to mitigate the current limitations. Detailed overview of the process as well as guidance on applying the CEM to the polarimetric variable calculation is presented. This is the first systematic exploration of a specific CEM solver to modeling of polarimetric radar signatures from precipitation and biota. Finally, to demonstrate meteorological application the CEM approach is evaluated by comparison with some polarimetric radar observations of hail. Of main significance is modeling of large and giant hail having surface protuberances, or rough, irregular shape. Additionally, radar observations of biota and radar cross section (RCS) measurements are considered for aeroecology applications. As an example, the precise size and shape model of Brazilian Free-tailed bat (Tadarida brasiliensis) is created and compared to the RCS measurements, as well as to radar observations of bat emergence in Texas plains. Advisors/Committee Members: Zhang, Yan (advisor), Zrnic, Dusan (committee member), Doviak, Richard (committee member), Chilson, Phillip (committee member), Sigmarsson, Hjalti (committee member), Kelly, Jeffrey (committee member).

Subjects/Keywords: Computational Electromagnetics; Polarimetric Radar; Radar Cross Section

11 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mirković, D. (2015). Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/21720

Chicago Manual of Style (16^th Edition):

Mirković, Djordje. “Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.” 2015. Doctoral Dissertation, University of Oklahoma. Accessed January 22, 2021. http://hdl.handle.net/11244/21720.

MLA Handbook (7^th Edition):

Mirković, Djordje. “Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.” 2015. Web. 22 Jan 2021.

Vancouver:

Mirković D. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. [Internet] [Doctoral dissertation]. University of Oklahoma; 2015. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/11244/21720.

Council of Science Editors:

Mirković D. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. [Doctoral Dissertation]. University of Oklahoma; 2015. Available from: http://hdl.handle.net/11244/21720

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations