Investigation of active array geometries to improve performance for 30 GHz portable satellite communications terminals

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Mekelburg, Theresa R.
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This thesis describes, based on certain design specifications, the research and development of a cavity array antenna that improves the performance of the existing EHF active phased array of cavity elements presented in (1). The best array lattice candidate was found to be an offset gridded hexagonal array lattice with a simulated directivity of D$\sb{\rm o}$ = 34.60 dB, a symmetrical beamwidth of $\Theta\sb{\rm 3dB}$ 2.3$\sp\circ$, and all sidelobes and grating lobes approximately 15 dB down from the main beam peak in all $\phi$ planes. A new cavity element architecture design was proposed to include vias to provide for a continuous, common ground plane for the antenna. A study to determine the appropriate number of vias to use for optimal cavity element performance was inconclusive due to manufacturing problems and a study to determine the repeatability of the manufacturing process suggested that the manufacturing process is not repeatable. As a means of improving the radiation performance of the elements, a brief study of the grounding of a cavity element was carried out. The cavity element was found to suffer from improper grounding. The final array lattice and feed network represent an improvement over the original antenna of (1) in terms of an increased directivity and simplified feed network complexity with approximately the same symmetrical beamwidth and sidelobe/grating lobe levels. (Abstract shortened by UMI.)