Acoustic Frequency Comb-Based QPSK Demodulation Using Nonlinear MEMS Resonators.

This work demonstrates a microelectrome-chanical system (MEMS)-based phase shift keying (PSK) demodulator that leverages nonlinear resonators. In particular, this work employs an internal-resonating MEMS resonator that generates acoustic frequency combs. The spacing of these combs is dynamically modulated by a primary driving signal and an auxiliary signal that carries the phase-encoded information. The discrete variations in comb spacing serve as the demodulation metric, enabling accurate retrieval of the original phase-encoded data. This approach offers a feedforward demodulation structure, which obviates the need for phase-locked loops (PLLs) and mitigates potential I/Q mismatch issues. Through slightly tailored actuation configurations, both simulations and experiments present successful demodulations of binary and quadrature phase-shifted signals. This work presents a promising alternative to transistor-based demodulation systems and marks a significant step toward MEMS-based radio frequency (RF) front-ends.