Multibeam-switching millimeter-wave antenna using beam-tilting design in perpendicular plane to feeding line of microstrip comb-line antenna

A beam-switching antenna which is composed of several independent antennas with different beam directions is one of the realistic solutions of an electronic beam-scanning antenna, because it does not need any special feeding circuits. Excitation phases of radiating elements in traveling wave antennas are controlled by changing the connection point along the feeding line. As the radiating elements are connected on the both sides of the feeding line, the effective element spacing in the perpendicular direction of the feeding line of the comb-line antenna can be almost a half of the spacing of the feeding lines. The amplitude distribution is also designed for low-sidelobe characteristic. In this paper, a five-beam switching antenna composed of five independent microstrip comb-line antennas with five different beams is proposed. The performance of the proposed antenna is demonstrated by simulation and measurement in this work.