Wideband Dual-Polarized Patch Antenna with Capacitive Coupling for mm-Wave Bands

This paper presents a planar wideband dual-polarized antenna structure integrated on PCB (Printed Circuit Board). The patch itself is fed by a capacitive coupling with two smaller patches, one for each polarization. Whereas the simulations predicts 24-40 GHz, -10 dB impedance bandwidth. The measured one shows 24.75-42.75 GHz bandwidth. The results are corresponding to 50% relative -10 dB impedance bandwidth. The patch antenna is on the ground plane of size 4.7 mm x 4.7 mm, and the corners of the ground plane are cut to gain better XPD (cross polarization discrimination). The manufactured prototype antenna is measured and simulated with a $50 \Omega$ coaxial line. Simulated total efficiency and XPD are presented as a function of frequency. The total efficiency is better than -0.8 dB (83%) efficiency, whereas the simulated XPD is better than 14 dB. The simulated 3D radiation patterns are presented at 24 GHz, 32 GHz, and 40 GHz with gains of 2.8 dBi, 5.0 dBi, and 4.3 dBi, respectively.