Tracking error of phased array antenna

A steerable phased array antenna developed for satellite communications is now being testing on a Boeing 747 cargo jet that has transoceanic flight route between Narita and Anchorage. The antenna can track the satellite by electrical beam scanning within +or-60 degrees with respect to the axis of the aircraft. The experimental results show that the antenna has tracking errors between receiving and transmitting frequencies. Experimental results and a theoretical analysis of the tracking error are given, and a method to eliminate this effect is proposed. It is suggested that the adoption of frequency-dependent phase shifters can completely eliminate the beam tracking errors between transmitting and receiving frequencies.<>