A Low-Cost Ultra Low Profile Phased Array System for Mobile Satellite Reception Using Zero-Knowledge Beamforming Algorithm

In this paper, a stair-planar phased array antenna system for mobile broadcast satellite reception in Ku-band will be introduced. The height of the antenna is only 6 cm and the system has two-dimensional electronic scanning capability. The design procedures of low profile high gain microstrip sub-array antennas, low noise amplifiers, hybrid analog phase shifters, along with a novel fast electronic beamforming algorithm will be discussed in this paper. The mobile phased array antenna receives LHCP and RHCP signals simultaneously. For each polarization 496 microstrip elements have been used to provide a radiation gain of 31.5 dBi. This phased array system scans +/- 2.8 degrees in azimuth and +/- 20 degrees in elevation with less than 3 dB scanning loss. The main objective of this design is to develop a Ku-band phased array system with very low cost components and a minimum number of tracking sensors. A novel beamforming algorithm compensates for the fabrication inaccuracies of the microwave components and variations in their characteristics due to ambient changes. Neither a priori knowledge of the satellite's direction, nor the phase-voltage characteristic of the phase shifters are required in this algorithm which results in eliminating an expensive laborious calibration procedure. The real time field tests verify that the developed mobile antenna system can nullify the base vehicle yaw disturbances up to 60 deg/s and 85 deg/s(2).