Humidity sensor based on substrate integrated waveguide reentrant resonant cavity

Abstract

A humidity sensor based on a substrate integrated waveguide reentrant resonant cavity comprises a substrate integrated waveguide reentrant resonant cavity and a coplanar waveguide feeder line. The reentrant resonant cavity is formed by vertically stacking four dielectric substrates, and an intermediate dielectric layer of each dielectric substrate is etched with a plurality of metallized through holes that are uniformly distributed outside the resonant cavity and on both sides of the feeder line. The intermediate dielectric layers of the second dielectric substrate and the third dielectric substrate are both etched with fan-shaped grooves, and the bottom metal layer of the second dielectric substrate and the top metal layer of the third dielectric substrate are etched with L-shaped strip grooves. In the invention, a stacking technique is applied in the substrate integrated waveguide reentrant resonant cavity, so as to ensure high quality factor of the resonant cavity and greatly reducerelative size of the resonant cavity, and introduce a sensing region at the strong induced electric field of the resonant cavity to excite strong interaction between the induced electric field and wet air media in the resonant cavity. The humidity sensor of the invention is compact in structure and easy to process and integrate.

Description

technical field [0001] The invention belongs to the field of sensors, in particular to a microwave passive sensor suitable for detecting air relative humidity. Background technique [0002] Humidity is an important indicator in environmental quality monitoring. Monitoring and controlling humidity is very important in many application scenarios. For example, the relative humidity of the air in a greenhouse will directly affect the growth and health of crops. When storing food, it is necessary to control the relative humidity of the environment at an appropriate level to delay the spoilage of the food. Other fields, such as material handling, machinery manufacturing, and large-scale equipment operation, all have higher requirements on ambient humidity. Therefore, the development of high-performance humidity sensors has high practical value in many fields. [0003] Traditional humidity sensors such as resistive sensors, capacitive sensors and piezoelectric sensors all work at...

AI Technical Summary

Problems solved by technology

[0004] The present invention proposes a humidity sensor based on a substrate-integrated waveguide re-entrant resonant cavity. The purpose is to apply the folding technology to the substrate-integrated waveguide re-entrant resonant cavity, and greatly reduce the relative size of the resonant cavity while ensuring a high quality factor. volume, to solve the defects of existing microwave passive sensors such as large volume and low quality factor

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