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You searched for subject:(Sinuous antennas). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Crocker, Dylan Andrew. Numerical and experimental evaluation of sinuous antennas for remote sensing applications.

Degree: PhD, Electrical and Computer Engineering, 2019, Georgia Tech

The objective of the research presented in this dissertation is to analyze the operation of the sinuous antenna and seek to overcome practical design challenges when utilizing the antenna in radar applications. The sinuous antenna can operate over ultra-wide bandwidths while producing polarization diversity, which makes the antenna an attractive candidate for polarimetric radar. However, the sinuous antenna may suffer from unintended resonant modes which distort the radiation and will produce ringing when the antenna is used to transmit pulses. An investigation was performed to determine the correlation between design parameters and these resonant modes. Design guidance is presented, which mitigates the excitation of these modes. A new sinuous antenna outer truncation technique is also presented, which prevents low-frequency resonances. Dispersion in sinuous antennas is another undesirable characteristic when radiating pulses.Since the active region on the antenna moves with frequency, the spectral content of the radiation is spread out over time. The original pulse may be reconstructed by applying a phase correction that compensates the dispersive effects. A simple dispersion model that is suitable for a fieldable system is proposed and implemented, which allows the antenna to transmit and receive temporally short pulses successfully. With these design challenges overcome, a new sinuous antenna was developed for the detection of targets close to the ground surface with ground-penetrating radar (GPR). GPR systems often employ a bistatic antenna configuration; however, this leads to extreme bistatic angles when attempting to detect targets close to the ground surface, which often reduces system performance. The operation of the sinuous antenna as an array of closely spaced yet independent arms is investigated as a potential quasi-monostatic antenna with a low height profile. The quasi-monostatic configuration dramatically reduces the bistatic angles, which significantly improves performance for close-in targets while keeping the isolation to a manageable level. A prototype antenna is fabricated and integrated into a GPR testbed. The polarimetric nature of the antenna allows for the discrimination between linear and circular targets, which is demonstrated with measured data. Advisors/Committee Members: Scott, Waymond R. (advisor).

Subjects/Keywords: Antennas; Sinuous antennas; Radar; Ground-penetrating radar

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APA (6th Edition):

Crocker, D. A. (2019). Numerical and experimental evaluation of sinuous antennas for remote sensing applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62321

Chicago Manual of Style (16th Edition):

Crocker, Dylan Andrew. “Numerical and experimental evaluation of sinuous antennas for remote sensing applications.” 2019. Doctoral Dissertation, Georgia Tech. Accessed December 02, 2020. http://hdl.handle.net/1853/62321.

MLA Handbook (7th Edition):

Crocker, Dylan Andrew. “Numerical and experimental evaluation of sinuous antennas for remote sensing applications.” 2019. Web. 02 Dec 2020.

Vancouver:

Crocker DA. Numerical and experimental evaluation of sinuous antennas for remote sensing applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2020 Dec 02]. Available from: http://hdl.handle.net/1853/62321.

Council of Science Editors:

Crocker DA. Numerical and experimental evaluation of sinuous antennas for remote sensing applications. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62321


Stellenbosch University

2. Du Toit, Zainodean. Wideband low loss feed integration with a pyramidal sinuous antenna.

Degree: MEng, Electrical and Electronic Engineering, 2020, Stellenbosch University

ENGLISH ABSTRACT: In this thesis, a pyramidal sinuous antenna is designed to be integrated with a balun. This system is to be used as the feed of a shaped, offset Gregorian reflector. Initially, a previously designed Marchand balun is chosen due to its maximum amplitude and phase unbalance of ±0.2 dB and 1.5◦ , respectively. The balun matched the antennas 300 Ω real input impedance component across a 4.5:1 band. A new descrambling network is also designed to allow for the integration of two baluns, yielding a dual polarised sinuous antenna. Using this descrambling network, simulations showed that the antenna and balun integration matched a previous, single polarised integration. The simulated reflection coefficient remained below -10 dB across the majority of the band, reaching a maximum of -7.5 dB. The simulated radiation pattern also showed symmetry across the band, with a BOR1 (body of revolution type 1) efficiency above 90% and a reflector aperture efficiency above 70%. While the measured radiation pattern also showed symmetry, the reflection coefficient reached a maximum of -6 dB. Due to the measured reflection coefficient of the integrated balun and antenna, a Phelan balun is designed and suggested as an improvement. This balun was chosen for its inherent 4:1 impedance transformation. Balun simulations showed a maximum amplitude unbalance of 0.02 dB, and a maximum phase unbalance of 3.5% across a 0.26-1.8 GHz range. The simulated and measured reflection coefficient for this balun remained well below -10 dB across the same range.

AFRIKAANSE OPSOMMING:In hierdie tesis is ’n piramidiese sinusvormige antenna ontwerp om met ’n balun geïntegreer te word. Hierdie stelsel moet dan gebruik word as voer vir ’n gevormde, gekompenseerde Gregoriaanse weerkaatser. Aanvanklik word ’n voorheen ontwerpte Marchand-balun gekies as gevolg van sy maksimum amplitude en fase-onbalans van onderskeidelik ±0.2 dB en 1.5◦. Die balun pas by die antenna se 300 Ω reële invoerimpedansie-komponent oor ’n band van 1.05-4.7 GHz.’n Nuwe ontknopingsnetwerk is ook ontwerp om die inskakeling van twee baluns moontlik te maak, wat ’n dubbele gepolariseerde sinusvormige antenna lewer. Met behulp van hierdie ontknopingsnetwerk het simulasies getoon dat die antenna- en balun-integrasie ooreenstem met ’n vorige, enkel gepolariseerde integrasie. Die gesimuleerde weerkaatskoëffisiënt bly onder -10 dB oor die grootste deel van die band, en bereik ’n maksimum van -7.5 dB. Die gesimuleerde stralingspatroon het ook simmetrie oor die hele band getoon, met ’n BOR1 doeltreffendheid bo 90% en ’n reflektoropening doeltreffendheid bo 70%. Terwyl die gemete stralingspatroon ook simmetrie getoon het, bereik die weerkaatskoëffisiënt ’n maksimum van -6 dB. As gevolg van die gemete weerkaatskoëffisiënt van die geïntegreerde balun en antenna, word ’n Phelan-balun ontwerp en voorgestel as verbetering. Hierdie balun is gekies vir die inherente 4:1 impedansie transformasie. Simulasies het ’n maksimale amplitude-onbalans van 0.02 dB getoon, en ’n maksimum…

Advisors/Committee Members: Van Niekerk, C., De Villiers, D. I. L., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering..

Subjects/Keywords: Marchand-balun; Pyramidal sinuous antenna; Ultra-wideband antennas; Antennas (Electronics); UCTD

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

APA (6th Edition):

Du Toit, Z. (2020). Wideband low loss feed integration with a pyramidal sinuous antenna. (Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/107860

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Du Toit, Zainodean. “Wideband low loss feed integration with a pyramidal sinuous antenna.” 2020. Thesis, Stellenbosch University. Accessed December 02, 2020. http://hdl.handle.net/10019.1/107860.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Du Toit, Zainodean. “Wideband low loss feed integration with a pyramidal sinuous antenna.” 2020. Web. 02 Dec 2020.

Vancouver:

Du Toit Z. Wideband low loss feed integration with a pyramidal sinuous antenna. [Internet] [Thesis]. Stellenbosch University; 2020. [cited 2020 Dec 02]. Available from: http://hdl.handle.net/10019.1/107860.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Du Toit Z. Wideband low loss feed integration with a pyramidal sinuous antenna. [Thesis]. Stellenbosch University; 2020. Available from: http://hdl.handle.net/10019.1/107860

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.