A Compact Dual-Polarized Co-Aperture Endfire SIW Antenna for Mm-wave Communication

This manuscript presents a novel compact co-aperture endfire antenna with a dual-polarized performance. The proposed antenna is composed of a vertical-polarized (VP) element adopting a substrate integrated waveguide (SIW) cavity and a horizontal-polarized (HP) element utilizing a dipole structure fed by a stripline. The SIW cavity is designed as an open-ended structure to serve as the VP radiation aperture. To achieve low-profile structure, the SIW is designed to work in TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</inf> mode. A microstrip-to-metal-via transition is introduced above the first metallic layer for feeding. A microstrip stub is incorporated into the microstrip line to mitigate the inductive reactance and improve the impedance bandwidth of the VP element. The HP element is integrated into the VP element by loading a dipole on the SIW. The dipole is designed as a dual-layer structure, integrated at the end of the SIW, thereby enabling co-aperture without affecting the VP mode. To achieve compact structure, A stripline is introduced within SIW for feeding dipole. Meanwhile, a H-shaped slot is etched on the first metallic layer for reducing the backward-propagated energy, thus improving the front-to-back ratio level. Simulation results demonstrate that the VP element achieves a −10 dB impedance bandwidth of 32.4–34.4 GHz with a peak gain of 4.85 dBi, Besides, the horizontal polarization (HP) realizes an ultra-wide −10 dB impedance bandwidth spanning 25.6–40.7 GHz and a peak gain of 5.8 dBi.