Wideband Circularly Polarized Phased Array Antenna System for Wide Axial Ratio Scanning

Abstract

This communication proposes the wideband circularly polarized (CP) phased array antenna system for wide axial ratio scanning. For mobile satellite communication, the low-profile CP antenna with a wide axial ratio scanning region in wide frequency bandwidth is necessary, but the antenna with the required axial ratio performance is rarely reported. In this communication, the proposed CP phased array antenna system with an axial ratio control scheme has a wide axial ratio scanning region in the wide frequency bandwidth. In the proposed axial ratio control scheme, the amplitude and phase of the received signals are controlled to compensate for the difference between dual polarizations. The proposed antenna system is designed at 5.8 GHz and has a fractional frequency bandwidth of 20%. In a simulation, the axial ratio is under 1 dB at the elevation scanning region from -60 degrees to 60 degrees at every 360 degrees azimuth angle in the operating frequency bandwidth. For validation, the 1 x 8 CP phased array antenna system was implemented. The measured axial ratio is under 2 dB at the elevation scanning region from -57 degrees to 57 degrees in the operating frequency bandwidth.