Hollow-Waveguide Tri-Band Shared-Aperture Full-Corporate-Feed Continuous Transverse Stub Antenna

This article presents a tri-band shared-aperture full-corporate-feed continuous transverse stub (CTS) antenna based on hollow-waveguide. The multiband operation is enabled by a broadband CTS radiator and a novel six-port parallel-plate waveguide (PPW) multiplexer. The CTS radiation slot is fed by a broadband vertical PPW power divider. The six-port multiplexer is composed of three diplexers, which defines the three frequency bands—Ku, K, and Ka. The quasi-TEM mode in the PPW structure is generated by single-layer linear source generators (LSGs). Four such LSGs operating at three different bands are used to feed into the multiplexer. The amplitude and phase precompensation method is applied in the LSG to overcome the imbalance and spurious reflection caused by the metal walls at the terminal ends of the PPW. This has resulted in improved radiation performance in all three bands. A prototype antenna is designed, fabricated, and measured. Good agreement between simulation and measurement has been shown. The peak gains of the antenna over the frequency range of 11.25–15 GHz, 17.7–22 GHz, and 27.5–32 GHz are better than 24.7, 28.2, and 32.1 dBi, respectively. Over 80% antenna efficiency has been achieved in all three frequency bands.