Co-Aperture Dual-Circular-Polarized Patch Antenna for Simultaneous Transmit and Receive
Mingcong Xie, Huiwei Yao, Xizhang Wei, Yanqun Tang, Junyu Wang, Dujuan Hu
Abstract
A co-aperture dual-circularly polarized antenna for simultaneous transmit (Tx) and receive (Rx) sensing systems is proposed in this letter. The antenna consists of a radiating patch, a dielectric substrate, and a ground plane. Embedding a rectangular slot in the center of the patch implements left-handed circular polarization for Tx and right-handed circular polarization for Rx. A pair of U-shaped slots (USS) with a 90° phase shift is placed into the ground plane for decoupling. When the USS works, the mutual coupling in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -direction cancels each other at the Rx port. As verification, a prototype with the size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.43{\lambda }_0 \times 0.43{\lambda }_0 \times 0.01{\lambda }_0$</tex-math></inline-formula> is fabricated and measured. The operating bandwidth, in which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$| {{S}_{11}} |$</tex-math></inline-formula> and axial ratio are respectively less than –10 and 3 dB, is 4.32–4.42 GHz. Within this band, the measured peak realized gain is 5.4 dBi, and the isolation is better than 23 dB with a maximum of 34 dB. In comparison with other works, the proposed antenna is competitive in terms of antenna size, aperture efficiency, and total efficiency.