A Dual-Band Circularly Polarized Antenna With Shared Aperture for Satellite-Assisted Internet of Things Communications
Zhichao Sun, Xiaojing Lv, Xuyi Zhu, Zhenxi Liang, Yang Yang
Abstract
A low-profile and dual-wideband circularly polarized (CP) shared aperture antenna is demonstrated for satellite-assisted Internet of Things (SATA-IoT) communications. It comprises an X-band antenna and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> Ka-band antenna array, both magnetoelectric (ME) dipole structures with complementary structures, and only have <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.08{\lambda }_{\mathrm { low}}$ </tex-math></inline-formula> thickness. Four mesh-structure dipole arms are utilized for the X-band antenna to integrate the X/Ka band antenna into the limited aperture while maintaining good isolation. Meanwhile, stubs and a sequential rotation feeding (SRF) network are adopted to improve the axial ratio (AR) performance of the two antennas, respectively. The measured results indicate that the antenna achieves an overlapped bandwidth (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$|S_{11}|\lt -10$ </tex-math></inline-formula> dB, AR ¡ 3) of 10.8% (8.7–9.7 GHz) and 29.32% (25.73–34.57 GHz), with isolations greater than 20 dB in both bands. The measured peak realized gains are 8.9 and 15 dBi, respectively. The proposed antenna realized exceptional low-profile and dual-wideband CP performance, making it a promising candidate for SATA-IoT communications.