A conformal SHF phased array for aircraft satellite communication

A receive-only 7.5 GHz microstrip phased array has been developed by Ball Aerospace Systems Division (BASD). This 256 radiating element array provides a gain of 20 dBic over a conical scan region of 120 deg. Two arrays with one on either side of an aircraft would provide near hemispherical coverage. The array consists of four subarrays and can be expanded to achieve higher gain when required. The array is left-hand circularly polarized and has three-bit digital PIN diode phase shifters for steering the beam. A microprocessor-based beam steering controller is used for calculating the phase shifter settings for each beam position. Each subarray includes radiating elements, quadrature hybrids, phase shifters, corporate feed, R.F. chokes in microstrip medium and hybrid PIN diode drivers. The array is approximately 1.5 inches thick and is conformal to the aircraft skin. It is a bolt on assembly only requiring aircraft skin entries for the R.F. output and for control lines. Transmit capability can be provided by merely changing the artwork to go to 8.5 GHz.