Low-cost microstrip phased array antenna for use in mobile satellite telephone communication service

A design for a low-cost phased array antenna used in a car-top application for a satellite communications link is presented. Microstrip stacked patch elements provide good pattern coverage over the 7% bandwidth. Three-bit distributed element microstrip phase shifters provide beam steering over a range of 30 to 70 degrees from boresight. Microstrip technology is also used in the corporate power divider and polarization hybrids. A hybrid tracking system consisting of an inertial sensor for open loop tracking and a sequential lobing scheme for closed loop tracking provides accurate tracking of the signal through brief signal outages. A novel scheme is used to eliminate the effects of varying multipath on closed-loop tracking accuracy. A single board PC-compatible computer is used in conjunction with an interface board to steer the antenna and interface with the transceiver.