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Title Three Dimensional Direct Print Additively Manufactured High-Q Microwave Filters and Embedded Antennas
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Publication Date
University/Publisher University of South Florida
Abstract The need for miniaturized, and high performance microwave devices has focused significant attention onto new fabrication technologies that can simultaneously achieve high performance and low manufacturing complexity. Additive manufacturing (AM) has proven its capability in fabricating high performance, compact and light weight microwave circuits and antennas, as well as the ability to achieve designs that are complicated to fabricate using other manufacturing approaches. Direct print additive manufacturing (DPAM) is an emerging AM process that combines the fused deposition modeling (FDM) of thermoplastics with micro-dispensing of conductive and insulating pastes. DPAM has the potential to jointly combine high performance and low manufacturing complexity, along with the possibility of real-time tuning. This dissertation aims to leverage the powerful capabilities of DPAM to come-up with new designs and solutions that meet the requirements of rapidly evolving wireless systems and applications. Furthermore, the work in this dissertation provides new techniques and approaches to alleviate the drawbacks and limitations of DPAM fabrication technology. Firstly, the development of 3D packaged antenna, and antenna array are presented along with an analysis of the inherent roughness of 3D printed structures to provide a deeper understanding of the antenna RF performance. The single element presents a new volumetric approach to realizing a 3D half-wave dipole in a packaged format, where it provides the ability to keep a signal distribution network in close proximity to the ground plane, facilitating the implementation of ground connections (e.g. for an active device), mitigating potential surface wave losses, as well as achieving a modest (10.6%) length reduction. In addition, a new approach of implementing conformal antennas using DPAM is presented by printing thin and flexible substrate that can be adhered to 3D structures to facilitate the fabrication and reduce the surface roughness. The array design leverages direct digital manufacturing (DDM) technology to realize a shaped substrate structure that is used to control the array beamwidth. The non-planar substrate allows the element spacing to be changed without affecting the length of the feed network or the distance to the underlying ground plane. The second part describes the first high-Q capacitively-loaded cavity resonator and filter that is compatible with direct print additive manufacturing. The presented design is a compromise between quality factor, cost and manufacturing complexity and to the best of our knowledge is the highest Q-factor resonator demonstrated to date using DPAM compatible materials and processes. The final version of the single resonator achieves a measured unloaded quality factor of 200-325 over the frequency range from 2.0 to 6.5 GHz. The two pole filter is designed using a coupled-resonator approach to operate at 2.44 GHz with 1.9% fractional bandwidth. The presented design approach simplifies evanescent-mode filter fabrication, eliminating…
Subjects/Keywords 3D-printing; Dipole; Picosecond laser machining; Quality factor; Array; Non-planar; Capacitively-loaded cavity; Evanescent-mode; Stacked structure; Vertically Coupled; Electrical and Computer Engineering; Electromagnetics and Photonics
Country of Publication us
Format application/pdf
Record ID oai:scholarcommons.usf.edu:etd-8362
Repository usf
Date Retrieved
Date Indexed 2020-03-31

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…Figure 4.21 Laterally coupled evanescent-mode cavity filter (all dimensions are in mm) ..................................................................................... 55 Figure 4.22 Post-to-post spacing (px) and opening (y…

…Development of first capacitively-loaded cavity band pass filter (BPF) that is compatible with direct print additive manufacturing: Two proposed designs are described; laterally coupled and vertically coupled filters. The presented design approach…

…an enhanced version of the capacitively-loaded cavity resonator, and two-pole laterally coupled capacitively-loaded cavity band pass filter. The fabrication process, the assembly steps, and tunability are presented as well. Finally, a novel vertically…

…LIST OF TABLES Table 3.1 Dimensions of the 3D antenna in mm. ....................................................................... 16 Table 4.1 Cavity conductive parts and conductive materials vs. the unloaded quality factor at 2.3 GHz…

…Additively manufactured high-Q resonators and filters.......................................... 13 Figure 2.5 Antenna feed system built using selective laser melting fabrication process…

…34 Figure 4.1 Evanescent-mode cavity resonator ......................................................................... 37 Figure 4.2 Evanescent-mode resonator structure ..................................................................... 38…

…Figure 4.3 Evanescent-mode cavity resonator fabrication process .......................................... 39 Figure 4.4 Single resonator simulated vs. measured S21 .......................................................... 40 Figure 4.5 Device under…

…changes vs. resonance frequency and corresponding unloaded quality factor ........................................................................................................... 41 Figure 4.8 Side-view of the capacitively-loaded cavity resonator…

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