K/Ka Dual-Band Dual-Circular-Polarized Coplanar Phased Array Antenna with High Isolation for Satellite Communication

A K/Ka dual-band dual-circular-polarized coplanar phased array antenna with high isolation is presented in this paper. The antenna is capable of receiving the right-handed circularly polarized (RHCP) signal at K-band while transmitting the left-handed circularly polarized (LHCP) signal at Ka-band. The circularly polarized (CP) radiation is realized by loading a linear-to-circular polarizer on the K/Ka dual-band dual-linear-polarized array antenna. The K- and Ka-band arrays are arranged with separate radiating apertures in a coplanar support. Each array is composed of 8×4 elements. Simulated results show the K-band array operating from 19.7 GHz to 21 GHz with the scanning angle of ±40°, and the Ka-band array operating from 29.5 GHz to 31 GHz with the scanning angle of ±40°. Then, by use of a one-to-eight microstrip power divider with the desired phase shifting, the K/Ka-band antenna loaded with the circular polarizer can scan to ±40° with the axial ratio (AR) below 3 dB. Since the K/Ka-band array antennas are separately placed and have orthogonal linear polarizations, the inter-band isolation between the transmit (Tx) and receive (Rx) arrays can be effectively improved. The simulated results show the inter-band isolation is better than 45 dB in K-band and 32 dB in Ka-band.

I. Introduction

Satellite communication (SatCom) has received widespread attention and applications due to its advantages of wide coverage and no geographical restrictions. With the increasing popularity of the commercial satellite communication market, satellite communication mobile terminals have become increasingly important. In order to ensure the good transmission of millimeter-wave high-throughput satellites during the movement of the carrier platform, it is significant to design a SatCom on-the-move (SOTM) terminal device. Phased array antenna is one solution for this application. Due to the current space limitation of SatCom platforms, placing the transceiver array in coplanar can effectively improve the space utilization. However, it is a challenge to improve the isolation between the transmit (Tx) and receive (Rx) arrays when the arrays are placed close to each other in coplanar [1]-[4].