Broadband MIC 4-bit phase shifter to control a phased array antenna

This paper describes the design of a low cost 4-bit switched line phase shifter microwave integrated circuit (MIC) on a 10 mil Alumina substrate. Schiffman coupled lines were used to implement each of the 4 bits. These coupled lines provide a dispersive phase response which can be used to produce a relatively constant phase shift over a large bandwidth. Over the 4–8 GHz frequency range, initial measurements have shown that the bandwidth requirement was met. The dimensions of the 4-bit phase shifter are 5.5 cm × 1.0 cm.