A Compact Wideband SIW-Fed Dielectric Antenna With End-Fire Radiation Pattern

In this communication, a triangular-shaped dielectric antenna fed by substrate-integrated waveguide (SIW) is proposed and researched. The effect of the extended substrate's length on performance of the proposed antenna is first researched. In order to reduce sidelobe level (SLL) at high frequency as well as increase the adjustability of the proposed antenna while maintaining its planar structure, air vias are periodically perforated into the loaded substrate to modify the permittivity. The variation trend of modifying permittivity with changing performance of the proposed antenna is studied, followed by analyzing function of the transition stage(s) of the extended substrate. Through optimizing the dielectric length and modifying the diameters of air vias to change the permittivity, the proposed antenna with wide operating bandwidth and low SLL can be realized. Measured results indicate that the proposed antenna works from 17.6 to 26.7 GHz, which almost covers the whole K band. Besides, stable end-fire radiation patterns in the whole operating band are obtained. Moreover, at least 8.3-dBi peak gains with low SLL are achieved as well.