A Megawatt p-i-n Diode Waveguide Phase Shifter

A p-i-n diode waveguide phase shifter (PS) with a power handing capacity over 1 MW and a response time within 100 ns is proposed at the S-band. By inserting a conventional switchable shunt-loaded microstrip circuit into a rectangular waveguide, the signal transmission along the microstrip line can be converted into transmission along the waveguide. This method increases the power handing capacity of the p-i-n diode PS to megawatt level while retaining its nanosecond response time and also reduces the insertion loss (IL) to be comparable to that of a waveguide PS. In order to analyze the microwave characteristics of the p-i-n diode waveguide PS, an equivalent circuit model (ECM) based on rectangular waveguide diaphragms is proposed. For verification purposes, three groups of single-bit PSs with different phase shift angles are designed and simulated. Good agreements between the calculated and simulated S parameters are observed. In order to test the power capacity and verify the feasibility of digital phase shift application, three 2-bit PSs using p-i-n diodes with different capacitances are designed, fabricated, and experimentally demonstrated with cold and high-power tests. The cold test results are in good agreement with the simulation results. IL of all three 2-bit PSs is less than 1 dB, and the phase error is less than 3°. The high-power test results show that the power capacity of the PS exceeds 1 MW.