SIW Cavity-Backed Self-Quadruplexing Antenna for Compact RF Front Ends

Abstract

A compact quarter-mode substrate integrated waveguide (QMSIW)-based self-quadruplexing antenna is proposed for compact radio frequency (RF) front ends. The QMSIW-based self-quadruplexing antenna has four unequal resonators resonating at the Industrial, Scientific, and Medical (ISM) band (2.45 GHz), fifth-generation (5G) band (3.5 GHz), wireless local area network (WLAN) band (4.9 GHz), and wireless fidelity band (5.4 GHz). All four resonators radiate through the open-ended wall of the QMSIW resonator and the arc-shaped slot inside the cavity. By properly optimizing the locations and dimensions of the resonators, higher isolation ( $>$ 29.9 dB) is gained. In fact, all four resonators operate on a common grounded substrate with negligible interference. A dummy rectangular device is used to keep the printed circuit board (PCB) and antenna in it to measure the S -parameters and radiation properties. The proposed antenna has a lower circuit size (0.23 $\lambda _{g}^{2}$ ), reasonable gain ( $>$ 3.85 dBi), high efficiency ( $>$ 82.7 %), and high isolation ( $>$ 29.9 dB). Based on the above-mentioned attributes, it is a good candidate for compact RF front ends.