An L ‐band 90° hybrid‐coupled phase shifter using UHF band p‐i‐n diodes

The design, development, and testing of a low‐cost L ‐band hybrid‐coupled 90° phase shifter are presented. The developed phase shifter uses a compact branch line coupler to minimize its size, and employs low‐cost UHF band p‐i‐n switching diodes to minimize its production cost. The diodes in a stand‐alone configuration feature large stray capacitance, which make them a poor‐quality open circuit in the reverse‐bias state. An LC compensation technique is applied to tune out this capacitance and make the diodes applicable to L ‐band. The developed phase shifter exhibits less than 1.0 dB insertion loss, more than 15 dB RL, and ±8° phase deviation over 225 MHz centered at 1.6 GHz. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 51–54, 1999.