Electrical Interconnect Loss Cancellation for MEMS Gyroscopic Resonators via In Situ Integrated Virtual Negative Resistance

Electrical interconnect loss degrades the intrinsic high Q-factor of MEMS gyroscopic resonators and alters their phase response. This paper proposes, for the first time, a loss cancellation approach utilizing an in-situ integrated negative impedance converter (NIC), which requires no additional tuning structures or electrodes. Controllable positive feedback is embedded into the conventional transimpedance amplifier (TIA), yielding a virtual negative resistance (NR) that cancels the interconnect loss or even the intrinsic loss of the resonator itself. We further demonstrate that through proper zero-pole arrangement of the Opam and its feedback network, the NIC can be degenerated into a single-pole system, thereby eliminating stability risk. Serving as the front-end of a split-mode MEMS gyroscope, this scheme recovers the sense Q-factor from a damped value of 2.8k to its intrinsic value of 42k and passively reduces its thermal variation from 52% to 2.1%. Furthermore, it corrects the gyrof’s phase shift from 1.25deg to 0.06deg, corresponding to a reduction in the quadrature leakage coefficient from 2.2% to 0.1% and maintaining a variation of 40ppm over a 100°C-temperature range, even without the use of a high-accurate active stabilization loop.