Electret based mems electric field sensor

Abstract

The invention belongs to the technical field of sensors, in particular to an MEMS electric field sensor based on an electret. The MEMS electric field sensor based on the electret is mainly used for measuring a low-and-medium-frequency alternating-current electric field in a space. The MEMS electric field sensor comprises an insulating substrate, a thin strip, a thin wire, a supporting surface and the electret, wherein the thin wire is arranged above the insulating substrate in parallel, and a capacitor is formed by the thin wire and the conductive thin strip on the substrate. An electrostatic field formed by the electret adhering to the supporting surface provides appropriate bias for the metal thin wire located in the electrostatic field. When an alternating-current electric field is externally added, the metal thin wire can generate vibration with the corresponding frequency and amplitude. The MEMS electric field sensor based on the electret measures the magnitude of the externally added alternating-current electric field by detecting changes of the capacitor formed by the metal thin wire and the conductive thin strip on the substrate. The MEMS electric field sensor based on the electret is manufactured through the MEMS micromachining technology, small in size, convenient to carry, simple in device, and much lower in cost compared with an existing optical fiber measuring system.

Description

technical field [0001] The invention belongs to the technical field of sensors, in particular to an electret-based MEMS electric field sensor. Background technique [0002] Electric field sensors are widely used in industrial production and scientific research projects, such as railway automatic systems, electric field environment detection for aircraft and spacecraft operations, high-voltage transmission line power frequency electric field distribution, electromagnetic shielding and compatibility of precision electronic equipment, etc. The size of the electric field in the above environment directly affects the normal work and research, so the measurement of the electric field is very important. [0003] The electric field has two characteristics of frequency and field strength. In terms of frequency, there are mainly electrostatic fields, low-frequency electric fields and high-frequency electric fields. In each type of frequency, there are strong electric fields and weak ...

AI Technical Summary

Problems solved by technology

At present, the low-frequency band mainly uses the electromagnetic induction principle of the antenna to measure, and the high-frequency band mostly uses the electro-optical effect of the crystal to measure the electric field; both of them must be transmitted through the optical fiber system and then processed. The system is complex and the sensitivity is not high. Generally, the volume is large, which is not conducive to integration, and the cost is high

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