Monolithic 6-18 GHz 3 Bit Phase Shifter

A 6-18 GHz 3 bit GaAs MMIC phase shifter is described. It incorporates novel high-pass/low-pass circuit structures, with 0.7 µm gate length MESFETs as switching elements. MESFET off-state capacitances are incorporated as. circuit elements, and need not be resonated, thus broadband performance is readily achieved. Each of the 3 bits (45°, 90°, and 180°) has a unique topology, chosen for optimal performance for its specific phase shift. The total FET gate periphery for all 3 bits is 4.9 mm. The 3 bit chip measures only 49 by 87 mils, and is on a 4 mil GaAs substrate.