PLL application research of a broadband MEMS phase detector: Theory, measurement and modeling

- The application of a broadband MEMS phase detector in PLL is presented through equivalent-circuit modeling.
- Broadband performance is realized through cascaded transmission line structure.
- Power handling and phase detection ability for large signals up to 1 W are measured and studied.
- The modeling mechanism relies on analogies between thermal variables and electrical variables.

This paper evaluates the capability of a broadband MEMS phase detector in the application of phase locked loops (PLLs) through the aspect of theory, measurement and modeling. For the first time, it demonstrates how broadband property and optimized structure are realized through cascaded transmission lines and ANSYS simulations. The broadband MEMS phase detector shows potential in PLL application for its dc voltage output and large power handling ability which is important for munition applications. S-parameters of the power combiner in the MEMS phase detector are measured with S11 better than −15 dB and S23 better than −10 dB over the whole X-band. Compared to our previous works, developed phase detection measurements are performed and focused on signals at larger power levels up to 1 W. Cosine tendencies are revealed between the output voltage and the phase difference for both small and large signals. Simulation approach through equivalent circuit modeling is proposed to study the PLL application of the broadband MEMS phase detector. Synchronization and tracking properties are revealed.