A Four-Corner-Fed Double-Layer Waveguide Slot Array With Low Sidelobes Developed for a 40 GHz-Band DDD System

A double-layer waveguide slot array antenna is developed for a 40-GHz-band directional division duplex (DDD) system, which exhibits extremely high utilization efficiency of frequency. To minimize the interference from the surrounding buildings, the Taylor distributions are adopted in both longitudinal and transverse directions over the antenna aperture to suppress the sidelobe levels (SLLs) below -30 dB. A four-corner-fed structure instead of the typical center-feed one is introduced for wideband operation. The perfect magnetic conductor (PMC) terminations are also adopted at the center of feeding waveguides due to the symmetric feed from right-and-left ends. As the predicted antenna performance using HFSS, the antenna gain of more than 31.8 dBi and the reflection of less than -10 dB are estimated over the operating frequency range of 39.5-41.0 GHz. The test antennas are fabricated by diffusion bonding of copper plates. As the measured antenna performance, the antenna gain higher than 30.6 dBi and the reflection lower than -10 dB are achieved over the desired frequency range. The sidelobes are suppressed below -30 dB, and the isolation between two antennas arranged in H-plane is achieved at the level of more than 76 dB.