A Ka-Band Circularly Polarized Fixed-Frequency Beam-Scanning Leaky-Wave Antenna Based on Groove Gap Waveguide With Consistent High Gains

A novel fixed-frequency beam-scanning circularly polarized (CP) leaky-wave antenna based on the groove gap waveguide (GGW) structure is presented, operating in the Ka-band. By adopting the serrated ridge, a slow-wave transmission is achieved and used to excite the 80 CP patches on the top of the GGW. The operation states of the patches can be switched between “ON” and “OFF” states by controlling the biasing of the p-i-n diodes. Thus, a beam-scanning antenna with CP characteristic is developed by manipulating the period length of the antenna. Both the simulated and measured results are given as validations of the antenna performance. A measured peak gain of 17 dBic and a beam-scanning range larger than 83° can be achieved, with good CP performance.