Noise Analysis and Optimization of Front-End Circuit in Ultra-High Precision Capacitive Transducer

Capacitive transducers are the core of electrostatic space accelerometers and have been applied in several space science missions. However, the noise of the front-end circuit in a capacitive transducer is a major limitation to capacitance resolution. The current theoretical models cannot accurately and comprehensively describe the performance of the front-end circuit in an ultra-high precision capacitive transducer. In this study, we modified the sensitivity and noise models of the front-end circuit and verified them by precision experiments. Under the guidance of the corrected models, we optimized the total stray capacitance by thickening the insulating layer between the shield and signal from 123 pF to 38 pF, thereby reducing the noise to 0.08 aF/Hz
$^{\text {1/2}}$
. We believe that this work will support the development of an ultrasensitive electrostatic accelerometer for application in space science missions.