Design approach for microstrip PIN-diode phase shifters with equalized losses

The paper describes the design procedure for microstrip PIN-diode C-band phase shifters with equalized (flattened) losses in all discrete states over a wide relative bandwidth of 13%. Particular attention is paid to the problems of wideband Lange couplers and controllable reflective loads development. The structure of 4-finger Lange coupler was synthesized using full-wave analysis of coupled microstrip lines in spectral domain. Measurement results of PS test prototype are presented and discussed.