The design of a shielded, dual patch antenna array element for mobile satellite communications

An investigation into a dual patch, shielded antenna array element suitable for use in land vehicle satellite communication has been carried out. To reduce the cost of the antenna elements, configurations with minimal use of the substrate dielectric have been considered. For configurations which use an air dielectric for the lower patch, it has been found that, to achieve a large operational bandwidth, series capacitive compensation for the probe feed was required. Two methods of compensation, one which uses the disc ended probe directly connected to the patch and another which uses the disc ended probe electromagnetically coupled to the patch, were tested. The first design results in a 12% bandwidth and the second in a 33% bandwidth (voltage standing wave ratio < 2). The effect of shielding on the input impedance of the antenna element was also studied. It was found that the housing mainly influenced the resonant frequency of the upper element.<>