Wideband Microwave Waveguide Pillbox Antenna with Fan-Beam Radiation Pattern and Optimized Matching Performance

A wideband waveguide pillbox antenna for microwave range was analyzed and developed in this paper. Design of the antenna includes feeding transition from coaxial transmission line to waveguide, parabolic mirror made from a conductor, and a radiating aperture limited by sidewalls of the mirror and two parallel conducting plates. Two types of feeding were compared. The first type consists of a coaxial probe, which is short-circuited in the focus point of parabolic mirror surface of the antenna. The second type is based on a coaxial probe, which is also located in the focus point of parabolic mirror surface of the antenna, but it is isolated from the opposite conducting plate. Developed antenna operates in the octave band of frequencies from 6 to 12 GHz. Antenna provides VSWR less than 2.5 and gain higher than 11 dB.