Dual-Mode Transduction–Induced Noise Correlation for Enhanced Fused Resolution in A Single Resonant Accelerometer

Signal fusion between various sensors has been explored to enhance the robustness and resolution, leveraging their complementary characteristics. In general, a higher correlation between sensors leads to more efficient fusion. This work presents a silicon resonant accelerometer (SRA) that enables tunable noise correlation between capacitive and piezoresistive dual transductions. The accelerometer comprises a double clamped beam resonator with piezoresistive gauges and capacitive electrodes, allowing simultaneous transduction outputs of both signals. Through tuning the thermal bias applied to the piezoresistive gauges, the transduction gain of the piezoresistive signal can be tuned, enabling real-time control of the correlation between the two signals. The real-time frequencies demodulated from the signals with variable correlation are fused by using a general 2nd-order Kalman filter algorithm. Experimental results demonstrate that the fused output achieves a resolution of 0.49 µg/√Hz. This represents an improvement of approximately 10.45 dB compared with capacitive detection alone. Meanwhile, the fused signal preserves the broad bandwidth of ∼1150 Hz provided by piezoresistive detection. This highlights the effectiveness of noise correlation manipulation for enhancing sensor performance by output signal fusion.