Design of a Compact D-Band All-Metal Antenna Fed by a Circular Waveguide

The commercialization of D-band wireless systems calls for compact, low-cost, and low-loss antennas. This paper presents a D-band metallic resonant cavity antenna fed by a circular waveguide. The total antenna thickness above the feed is only 1.16 mm. Analysis of the antenna gain shows the aperture size should be optimized to achieve an optimum aperture efficiency. The radiation pattern of the resultant antenna has a much lower sidelobe level (−25.3 dB) compared with the feed antenna pattern due to the edge tapering of the radiating aperture. In addition to the linear polarization operation, we show preliminary results of circular polarization performance by applying an ideal excitation to the feed.