Bandwidth Improvement for Low-Profile Horizontal Omnidirectional SIW Horn Antenna by Loading with Strips

In this paper, a low-profile, omnidirectional SIW horn antenna is proposed for the application in worldwide interoperability for microwave access (WiMax). The antenna is composed of four horn antennas and four matching vias with a probe centrally located in the substrate as the feeding part. A rectangular microstrip loop with slots is introduced around the antenna to improve the antenna's impedance bandwidth. The antenna has a low-profile of only 1mm (0.018 lambda(0)), omnidirectional radiation pattern on the horizontal plane. The dimension of the modified antenna is 0.72 lambda(0) * 0.72 lambda(0) *0.018 lambda(0), and the bandwidth is 124 MHz from 5.453 to 5.577 GHz, 63.2% wider than the original one, which owns bandwidth of 76MHz from 5.487 to 5.563 GHz. The simulation results verify our expectations and the antenna is a potential candidate for the WiMax application in future.