Microwave sensor based on double-entry resonant cavity and microfluidic technology

Abstract

A microwave sensor based on a dual-entry resonant cavity and microfluidic technology, comprising a substrate-integrated waveguide dual-entrant resonant cavity and a microfluidic chip embedded in the resonant cavity; the resonant cavity consists of a stacked The upper cover plate and the lower base plate are combined, and the upper cover plate and the lower base plate both include a top metal layer, an intermediate medium layer and a bottom metal layer. Both the upper cover plate and the middle dielectric layer of the lower bottom plate include several metal through holes, which connect the top layer and the bottom metal layer. The lower bottom plate has an annular groove, and two symmetrical capacitance columns are arranged in the groove. In the present invention, the microchannel chip is embedded in the substrate-integrated waveguide dual-entry resonant cavity, the liquid dielectric medium to be measured is accurately loaded in the microchannel, and the three-band strong induced electric field excited by the resonant cavity interacts with the polarization of the dielectric medium. The mechanism of action realizes a non-invasive, reusable, high-sensitivity, multi-band liquid medium dielectric property sensor that is easy to integrate with other planar circuits.

Description

technical field [0001] The invention belongs to the field of sensors, in particular to a microwave sensor suitable for detecting liquid media. Background technique [0002] The current microwave sensing and detection methods for liquid media are usually divided into non-resonant transmission method and resonance method. Compared with the non-resonant transmission method, the resonance method has significant advantages such as high Q value and controllable resonance frequency. The point offset and the phase amplitude change of the scattering parameter can realize the accurate measurement of the dielectric constant of the medium. Therefore, the detection technology scheme based on the microwave resonance mechanism has become a research hotspot and has attracted extensive attention from scholars at home and abroad. [0003] However, with the continuous development of modern detection technology, the microwave sensor test system tends to be miniaturized and integrated, and has ...

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Problems solved by technology

For the single-frequency point measurement method, because different mixtures may have the same frequency shift, the measurement at a fixed frequency can only distinguish chemicals by frequency shift, which limits the reliability of measurement identification, that is, because different chemicals in the same Measurements within a frequency band may have the same frequency shift, so it is not reliable to judge chemicals based only on the shift of frequency points within a frequency band

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