| This research focuses on the development of a high-power waveguide-fed microwave antenna that has a reduced level of lateral radiation---radiation that travels along the supporting ground plane, potentially causing serious coupling, interference, and diffraction problems. A particular design has been proposed, and a set of specifications for the antenna is established. This antenna design capitalizes on a horizontal metallic disk that were positioned above the supporting metallic ground plane, which according to image theory will not produce lateral radiation in the far-field. The antenna is fed via an aperture located in the top broad wall of the waveguide.The behavior of this antenna design was studied using full-wave simulated results and also using a simple CAD circuit model developed for the antenna. Antenna configurations having varied disk and aperture radii were simulated, providing results for tradeoff analyses, in which the relative lateral radiation level, the input impedance, the impedance bandwidth, as well as the electric field at critical edges are the determining parameters.The electric breakdown strength of the antenna was optimized by minimizing the maximum antenna near-field, achieved by structurally smoothing out sharp edges at the disk and feed aperture. A pressurized gas was also assumed, which allows the antenna to handle high power levels.The reduced lateral wave (RLW) antenna was integrated into a uniform planar triangular array that is designed to avoid grating lobes in the E plane, and offers reduced lateral radiation. The array experiences low mutual coupling thanks to the reduced levels of lateral radiation in the single RLW antenna. Matching networks were also proposed for the array to minimize reflected power.The RLW antenna, by itself or in an array format, realizes low levels of lateral radiation while being able to handle high levels of peak power. However, in terms of impedance bandwidth, the RLW antenna array (with seven elements) has a much narrower bandwidth than does the single element. |
