An improved c-band pin-diode phase shifter

The design and test results of an improved C-band four-bit PIN-diode phase shifter are described. Exceptional wideband performance is achieved through the use of a novel planar, stripline hybrid coupler that is used in the 90-degree and 180-degree phase bits. The measured amplitude and phase flatness versus frequency of these phase bits exceeds the theoretical bandwidth characteristics of a conventional hybrid ring by itself. For BITE implementation, the PIN diodes are mounted to allow bias voltage and current of each diode to be monitored individually.