1. Analysis of a Capacitive Sensing Circuit and Sensitive Structure Based on a Low-Temperature-Drift Planar Transformer.
- Author
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Sui, Yanlin, Yu, Tao, Wang, Longqi, Wang, Zhi, Xue, Ke, Chen, Yuzhu, Liu, Xin, and Chen, Yongkun
- Subjects
DETECTOR circuits ,TEMPERATURE control ,THERMAL noise ,CAPACITIVE sensors ,LOW temperatures ,EARTH temperature - Abstract
In space gravitational-wave-detection missions, inertial sensors are used as the core loads, and their acceleration noise needs to reach 3 × 10 − 15 ms − 2 / Hz at a frequency of 0.1 mHz , which corresponds to the capacitive sensing system; the capacitive sensing noise on the sensitive axis needs to reach 1 aF / Hz . Unlike traditional circuit noise evaluation, the noise in the mHz frequency band is dominated by the thermal noise and the 1 / f noise of the device, which is a challenging technical goal. In this paper, a low-frequency, high-precision resonant capacitor bridge method based on a planar transformer is used. Compared with the traditional winding transformer, the developed planar transformer has the advantages of low temperature drift and low 1 / f noise. For closed-loop measurements of capacitive sensing circuits and sensitive structures, the minimum capacitive resolution in the time domain is about 3 aF , which is far lower than the scientific measurement resolution requirement of 5.8 fF for gravitational wave detection. The capacitive sensing noise is converted to 1.095 aF / Hz in the frequency band of 10 mHz – 1 Hz . Although there is a gap between the closed-loop measurement results and the final index, the measurement environment is an experimental condition without temperature control on the ground; additionally, in China, the measurement integrity and actual measurement results of the capacitive sensing function have reached a domestic leading level. This is the realization of China's future space gravitational wave exploration. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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