A single‐layer substrate‐integrated waveguide filtering antenna with three independently controllable radiation nulls

Abstract

AbstractIn this paper, a single‐layer substrate‐integrated waveguide (SIW) filtering antenna with three independently controllable radiation nulls is presented. The antenna consists of a single‐layer SIW loaded with two radiation gaps, four metallization columns, and folded‐type slots etched on the chip. The back‐cavity double slots are responsible for extending the bandwidth and realizing the radiation function. Three radiation nulls are generated by analyzing the current distribution of the radiation chip, radiation gap, and folded slots. By adjusting the radiation gap distance, the length of the radiation gap, and the folded slot, three broadside radiation nulls are independently controlled without influence on each other. Therefore, flexible out‐of‐band suppression characteristic is obtained. For demonstration, a prototype is fabricated and tested. The measurements match the simulation results better. The filtering antenna operates at 3.70 GHz with a bandwidth of 5.68% (3.59–3.80 GHz), achieving an average realized gain of 5.10 dBi in a flat passband. The out‐of‐band rejection level exceeds 20 dB.