CN-121783056-B - High-sensitivity linearity compensation type thickness sensor based on interdigital groove structure

CN121783056BCN 121783056 BCN121783056 BCN 121783056BCN-121783056-B

Abstract

The invention discloses a high-sensitivity linearity compensation type thickness sensor based on an interdigital groove structure, which relates to the field of microwave sensing and comprises a dielectric substrate, a coplanar waveguide, an interdigital groove resonant structure and a stacking boundary structure, wherein the coplanar waveguide is arranged on the surface of the dielectric substrate, the interdigital groove resonant structure is etched on a grounding strap of the coplanar waveguide, the stacking boundary structure is positioned above the interdigital groove resonant structure, and the stacking boundary structure comprises an insulating gasket and a metal reflecting layer which are arranged in a stacked mode from bottom to top. The high-sensitivity linear-holding type microwave resonance thickness sensor provided by the invention has the advantages that the high sensitivity is realized, the phenomenon that the sensitivity is rapidly attenuated along with the increase of the thickness of a sample to be measured is effectively inhibited, the response linearity and uniformity of the sensor are obviously improved, the stability and reliability of measurement are maintained, and the structure is simple.

Inventors

ZHANG QINGCHENG
XU YANGQING
Ye Qirong
LI LIN

Assignees

浙江理工大学

Dates

Publication Date: 20260508
Application Date: 20260309

Claims (6)

1. The high-sensitivity linearity compensation type thickness sensor based on the interdigital groove structure is characterized by comprising a dielectric substrate, a coplanar waveguide, an interdigital groove resonance structure and a stacked boundary structure, wherein the coplanar waveguide is arranged on the surface of the dielectric substrate, the interdigital groove resonance structure is etched on a grounding strap of the coplanar waveguide, the stacked boundary structure is positioned above the interdigital groove resonance structure, and the stacked boundary structure comprises an insulating gasket and a metal reflecting layer which are arranged in a stacked mode from bottom to top.
2. The interdigital structure-based high sensitivity linearity compensation type thickness sensor of claim 1, wherein the coplanar waveguide comprises a central conductor strip and grounding strips positioned at both sides of the central conductor strip, a signal transmission gap is arranged between the central conductor strip and the grounding strips, and the structure of the coplanar waveguide is distributed in mirror symmetry about a central axis of the central conductor strip.
3. The interdigital structure-based high sensitivity linearity compensation type thickness sensor of claim 1, wherein the interdigital resonant structure comprises interdigital structures cascaded at equal intervals along a propagation direction of the microwave signal, each pair of interdigital structures comprises a finger metal arm extending inward from the ground strap and a meandering slot between the finger metal arms, and the interdigital structures form a Defective Ground Structure (DGS) on the ground strap.
4. The interdigital structure-based high sensitivity linearity compensation type thickness sensor of claim 1, wherein the insulating pad is directly covered on the interdigital resonant structure, and a projected area of the metal reflective layer in a vertical direction covers the interdigital resonant structure and the insulating pad.
5. The interdigitated structure based high sensitivity linearity compensation type thickness sensor of claim 1, wherein a test area is formed between the stacked border structure and the dielectric substrate.
6. The interdigital structure-based high sensitivity linearity compensation type thickness sensor of claim 1, wherein the metal reflection layer is configured to reflect electromagnetic waves radiated from the coplanar waveguide back to the sensing region, and a quasi-closed electromagnetic coupling domain is formed between the dielectric substrate and the metal reflection layer.

Description

High-sensitivity linearity compensation type thickness sensor based on interdigital groove structure Technical Field The invention relates to the technical field of microwave sensing, in particular to a high-sensitivity linearity compensation type thickness sensor based on an interdigital groove structure. Background In the radio frequency and microwave test scene, high-precision real-time measurement of the thickness of a material is urgently required in the fields of industrial quality control, intelligent manufacturing, nondestructive detection and the like. The microwave resonant sensor is an effective technical path for realizing the requirements due to the characteristics of high resolution, quick response and easy planar integration. The basic working principle of the sensor is that when a material to be measured is placed in a resonance field of the sensor, the equivalent dielectric constant and electromagnetic field distribution of the material to be measured are changed, so that the change of parameters such as resonance frequency, quality factor or insertion loss is caused, and the thickness of the material can be inverted by detecting the change of the parameters. Therefore, the development of microwave sensors with high sensitivity and good response linearity has become a key requirement for current scientific and engineering applications. The existing microwave planar sensor mainly adopts microstrip lines or coplanar waveguides and other transmission line structures. The conventional microstrip line structure sensor is widely used because of simple manufacturing process, however, because the signal line is positioned on the top layer of the dielectric substrate and the ground plane is positioned on the bottom layer of the substrate, the electromagnetic field is mainly restrained in the dielectric between the signal line and the ground plane below. This means that at the most important media interface of the sensor (i.e. above the signal line), the electric field distribution available for coupling with the externally loaded media is very weak, resulting in a sensor that is less sensitive to changes in the external media thickness or dielectric constant and less pronounced zero drift. In order to improve the sensitivity, many researchers have made various works, and many sensors having high sensitivity characteristics have been proposed. The Aiza team utilizes the CPW structure to place the ground plane on both sides of the center conductor, and the exposed part of the electromagnetic field is increased, so that the influence of the electromagnetic field on the externally loaded substances is more sensitive. Morteza et al introduce a defected ground structure DGS that more intensively distributes the electromagnetic field energy in the slot region between the conductor and the ground strap, thereby increasing the sensitivity. While the above-described structures have made significant advances in sensitivity, the sensitivity of these structures is highly dependent on the electromagnetic field that enhances the interface between the sensor and the medium under test. Once the thickness of the material increases, a non-linear rapid drop in sensing sensitivity will occur, directly limiting the sensing range of these thickness sensors. Disclosure of Invention The invention aims to provide a high-sensitivity linearity compensation type thickness sensor based on an interdigital structure, which realizes high sensitivity, effectively inhibits the phenomenon that the sensitivity is rapidly attenuated along with the increase of the thickness to be measured, remarkably improves the response linearity and uniformity of the sensor, keeps the stability and reliability of measurement, and has simple structure. The invention provides a high-sensitivity linearity compensation type thickness sensor based on an interdigital structure, which comprises a dielectric substrate, a coplanar waveguide, an interdigital resonant structure and a stacking boundary structure, wherein the coplanar waveguide is arranged on the surface of the dielectric substrate, the interdigital resonant structure is etched on a grounding strap of the coplanar waveguide, the stacking boundary structure is positioned above the interdigital resonant structure, and the stacking boundary structure comprises an insulating gasket and a metal reflecting layer which are arranged in a stacked manner from bottom to top. Preferably, the coplanar waveguide includes a center conductor strip and ground strips on either side of the center conductor strip. Preferably, the interdigital resonating structures comprise interdigital structures cascaded at equal intervals along the propagation direction of the microwave signal, each pair of interdigital structures comprising finger metal arms extending inward from the ground strip and a meandering slot between the finger metal arms, the interdigital structures forming a defective ground structure DGS on the ground