Novel Millimeter-Wave Slow-Wave Phase Shifter Using MEMS Technology

A novel mm-wave MEMS phase shifter based on a slow wave structure is introduced. The phase shifter uses co-planer wave guide that has the signal line loaded with inductors through capacitive coupling. The inductor and the capacitive coupling capacitor are designed to work for the mm-wave frequency range. Integrated metal to metal RF MEMS switches are designed such that inductors can be shortened to ground to obtain a normal CPW when the switches are closed. When the switches are open, the signal is traveling in the slow wave structures and a phase shift is obtained. Unlike other phase shifters, the proposed design can handle higher power and does not have neither MEMS capacitive nor metal to metal switches on the signal line. The measured pull-in voltage is 45 volt. The phase shifter is designed, modeled, fabricated and tested. The phase shift per length is 355 degrees/cm. The phase shifter exhibits high resolution of phase shift while maintaining a return loss of 20 dB and a worst insertion loss of 3.21 dB at 60 GHz.