Dual‐band beam scanning filtering antenna using dual‐eighth mode substrate integrated waveguide‐based metamaterial structure

Abstract

In this article, a dual-band beam scanning antenna with filtering capability is proposed by using novel dual-eighth mode substrate integrated waveguide-based dual-band metamaterial (DB-MTM) structure. The novel DB-MTM structure consists of two interconnected modified eighth mode substrate integrated waveguide (EMSIW) structures, which is designed by etching four interdigital fingers on the upper ground, and has two balanced composite right/left-handed (CRLH) passbands. Taking advantage of the continuous phase constant changing from negative to positive values within the two CRLH passbands of the DB-MTM structure, a beam scanning antenna, which is composed of 11 dB-MTM unit cells, is designed to achieve continuous beam scanning from backward to forward directions within dual operating frequency bands. For verification, the proposed dual-band antenna is fabricated and measured. According to the measurements, the fabricated antenna can scan its main beam from −72° to +57° and −70° to +38° over the two operating frequency bands of 3.40-4.95 GHz and 5.85-6.80 GHz, respectively; and exhibits very sharp transitions at the band edges over the two operating frequency bands. Besides, the measured peak gains in the two operating bands are 14.0 dB at 4.5 GHz and 14.5 dB at 6.4 GHz. Moreover, the measurements show good agreement with the simulations, proving the validity of the design method, and further expanding the applications of EMSIW.