A Dual-Band Dual-Circular-Polarized Planar Antenna System with Low Side-Lobe

In this paper, a dual-band dual-circular polarized and low side-lobe planar antenna based on the horn antenna is realized. The antenna is mainly composed of an orthogonal mode transducers(OMT) and a power divider with Chebysheff distribution and an underlying feed network. The antenna feeding network consists of duplexer, directional mode coupler, which main function is high and low frequency separation and phase shift. Antennas have two feeding ports respectively at high frequency and low frequency. Through different ports, circularly polarized electromagnetic wave with different rotations can be excited. The maximum axial ratio(AR) of the antenna is 1.38dB. The side-lobe level is less than -18.5 dB in both dimensions. Cross-polarization is below 21 dB. Low-frequency gain greater than 31dB. High-frequency gain greater than 33dB.

I. Introduction

Antenna is an indispensable device in modern wireless communication. With the rapid development of wireless communication technology, it is reasonable and inevitable that a large amount of information is transmitted and anti-interference technologies coexist in an antenna [1]. As a consequence, designing dual-band, dual-circular-polarization antenna with low side-lobe level has become a challenge.