A Differential Dual-Polarized SIW Cavity-Backed Slot Antenna

Abstract

A compact, low-profile, and dual-polarized differential slot antenna with high isolation and high common-mode rejection is presented in this communication. The antenna is composed of a cross-shaped slot backed by a square substrate integrated waveguide (SIW) cavity. The two differential pairs of grounded coplanar waveguide are used for the excitation of the differential signals. These differential signals excite the diagonal TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">120</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">210</sub> modes of the SIW cavity. The proposed antenna offers a differential gain of 7.4 dBi with a front-to-back ratio of 22 dB. A prototype of the designed differential antenna is fabricated as a proof of concept. The experimental results show that the proposed antenna is a good candidate for various X-band applications.