CN114924129A - Dielectric constant measuring device and method - Google Patents

Abstract

The embodiment of the application provides a dielectric constant measuring device and method, and is suitable for the technical field of terahertz. The method comprises the following steps: the dielectric constant of a dielectric material is measured in a terahertz frequency band through a dielectric sensor structure based on an artificial plasmon waveguide with an improved structure, specifically, the function of the waveguide is changed from transmission to sensing through changing the geometric parameters of a metal layer of a specific part of the waveguide, then the resonance peak central frequency of the dielectric sensor can be shifted according to samples with different dielectric constants, and the dielectric constant of a sample to be measured is calculated through the shift of the resonance peak central frequency. The device for implementing the method comprises the artificial plasmon waveguide based on the method, and has the advantages of simple structure, easiness in processing, good sensitivity and the like. The method for measuring the dielectric constant can be used for simply, conveniently and quickly measuring the dielectric constant of a trace small sample.

Description

Dielectric constant measuring device and method

Technical Field

The application belongs to the technical field of terahertz, and particularly relates to a dielectric constant measuring device and method.

Background

An artificial surface plasmon is an electromagnetic wave that propagates along metal and dielectric surfaces and is strongly bound to the surface of the device with an exponential decay in the direction perpendicular to the wave. In order to popularize the concept of surface plasmon to a low frequency band (such as microwave and terahertz wave band) and realize high-constraint propagation of surface electromagnetic waves in the microwave and terahertz frequency bands, artificial surface plasma can be obtained by digging holes or grooving on the metal surface.

Terahertz waves, which generally refer to electromagnetic radiation having a frequency between 0.1THz and 10THz, have long been limited by the lack of effective terahertz generation sources and detection means, and this band is also referred to as the terahertz gap. At present, the application of artificial plasma in terahertz dielectric sensing is not fully explored and developed.

In a terahertz frequency band, the structure of the existing artificial surface plasmon-based dielectric sensor is generally non-planar, so that the system obtained by integrating an artificial surface plasmon waveguide and a vector network analyzer is not high in compactness.

Disclosure of Invention

The embodiment of the application provides a dielectric constant measuring device and a dielectric constant measuring method, the dielectric constant measuring device changes the function of a waveguide from transmission to sensing by changing the size of a central unit of the waveguide dielectric sensor, the dielectric constant of a sample to be measured is calculated according to the resonance peak central frequency offset of the sample to be measured, and the problem of simply, conveniently and quickly measuring the dielectric constant of a trace small sample is solved.

In a first aspect, there is provided a structure of a dielectric constant measuring apparatus, including: a waveguide dielectric sensor comprising a first port and a second port, a first transition region on a side of the first port, a second transition region on a side of the second port, a central cell region, a first transmission region between the first port and the first transition region, a second transmission region between the second port and the second transition region; the vector network analyzer comprises a third port and a fourth port, the first port of the waveguide dielectric sensor is connected with the third port of the vector network analyzer, and the second port of the waveguide dielectric sensor is connected with the fourth port of the vector network analyzer.

With reference to the first aspect, in certain implementations of the first aspect, the first transition region and the second transition region are symmetrical with respect to a central position of the waveguide dielectric sensor, the central unit region is located at a central region of the waveguide dielectric sensor, the first transition region, the second transition region, and the central unit region respectively include a plurality of metal grids, and a length of the metal grid located at the central position is greater than lengths of other metal grids; the lengths of the metal grids at the first transition region become uniformly smaller in a direction from the central position toward the first port, and the lengths of the metal grids at the second transition region become uniformly smaller in a direction from the central position toward the second port.

With reference to the first aspect, in certain implementations of the first aspect, a length of the metal grid located at the central position is set to any one of a length greater than 150 micrometers and less than 300 micrometers.

With reference to the first aspect, in certain implementations of the first aspect, lengths of the metal grids located in the first and second transmission regions and the metal grids located in the central cell region except for the central position are set to any one of lengths greater than 0 micron and less than 100 microns.

With reference to the first aspect, in certain implementations of the first aspect, a length of the metal grid located at the first transition region becomes uniformly smaller in a direction pointing from the central location to the first port until the length of the metal grid reaches a first threshold; and the length of the metal grid at the second transition region becomes smaller uniformly in a direction from the central position toward the second port until the length of the metal grid reaches the first threshold.

With reference to the first aspect, in certain implementations of the first aspect, the waveguide dielectric sensor includes a substrate, and a metal grid array periodically distributed along a length direction of the waveguide dielectric sensor on an upper surface of the substrate, where the metal grid array includes a plurality of metal grids having one-dimensional trench structures therebetween.

With reference to the first aspect, in certain implementations of the first aspect, the material of the substrate of the waveguide dielectric sensor is silicon and/or sapphire.

With reference to the first aspect, in certain implementations of the first aspect, the metal grid is made of gold and/or copper.

With reference to the first aspect, in certain implementations of the first aspect, the first port of the waveguide dielectric sensor is connected to the third port of the vector network analyzer, and the second port of the waveguide dielectric sensor is connected to the fourth port of the vector network analyzer.

In a second aspect, there is provided a dielectric constant measuring method applied to a dielectric constant measuring apparatus including a waveguide dielectric sensor and a vector network analyzer, the method including: placing a sample to be tested in a central unit area of the waveguide dielectric sensor; receiving a transverse electromagnetic wave signal fed in from a third port of a vector network analyzer through a first port of the waveguide dielectric sensor; the second port of the waveguide dielectric sensor outputs a transverse magnetic wave signal to the fourth port of the vector network analyzer; acquiring a resonance curve corresponding to the sample to be detected, wherein the corresponding frequency when the transmission efficiency of the resonance curve reaches the minimum value is the central frequency of a resonance peak, and the central frequency of the resonance peak corresponds to the dielectric constant of the sample to be detected one by one; and acquiring the dielectric constant of the sample to be detected according to the resonance peak of the sample to be detected and the resonance peak of a preset standard sample.

With reference to the first aspect, in certain implementation manners of the first aspect, dielectric constants and resonant peak center frequencies of the preset multiple standard samples are measured, so as to obtain multiple resonant peak center frequencies when the dielectric constants of the multiple standard samples are changed, where the resonant peak center frequencies have a one-to-one correspondence relationship with the dielectric constants of the standard samples; obtaining a frequency deviation rule according to the corresponding relation; and calculating the dielectric constant of the sample to be detected according to the frequency deviation rule and the numerical value of the center frequency of the resonance peak of the sample to be detected.

Drawings

Fig. 1 is a top view structural diagram of a waveguide dielectric sensor of a dielectric constant measuring device according to an embodiment of the present application.

Fig. 2 is a side view structural diagram of a waveguide dielectric sensor of a dielectric constant measuring device according to an embodiment of the present application.

Fig. 3 is a schematic diagram of various dimensional parameters of a single metal grid of a waveguide dielectric sensor of a dielectric constant measurement apparatus according to an embodiment of the present application.

Fig. 4 is a transmission spectrum of a waveguide dielectric sensor of a dielectric constant measuring apparatus according to an embodiment of the present application, in which the metal grids at the center of the central unit are 80 micrometers and 300 micrometers, respectively.

Fig. 5 is a schematic diagram of a dielectric constant measurement apparatus and method according to an embodiment of the present disclosure for measuring a rate of change of a frequency offset of a sample with a refractive index.

Fig. 6 is a schematic workflow diagram of a dielectric constant measuring system based on a dielectric constant measuring device and method according to an embodiment of the present disclosure.

Fig. 7 is a transmission spectrum when different dielectric constant samples are measured based on the dielectric constant measuring device and method provided in the embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should also be understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

As used in this specification and the appended claims, the term "if" may be interpreted contextually as "when", "upon" or "in response to" determining "or" in response to detecting ". Similarly, the phrase "if it is determined" or "if a [ described condition or event ] is detected" may be interpreted contextually to mean "upon determining" or "in response to determining" or "upon detecting [ described condition or event ]" or "in response to detecting [ described condition or event ]".

Furthermore, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used for distinguishing between descriptions and not necessarily for describing or implying relative importance.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather mean "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically stated.

The present invention is further described with reference to the accompanying drawings, it is to be understood that the specific embodiments described herein are for purposes of illustration only and not for purposes of limitation, and that various equivalent modifications of the invention will occur to those skilled in the art upon reading the disclosure and are intended to be within the scope of the invention as defined in the appended claims.

In combination with the introduction of the background art, in addition to non-planar artificial surface plasmon dielectric sensors, there are also planar structures based on artificial surface plasmon dielectric sensors, such as metamaterial resonant rings. However, the input signal of such a planar plasmon dielectric sensor is based on terahertz light excited by a quasi-optical system in free space, and this process requires complicated and precise instruments such as a terahertz time-domain spectrometer and stable environmental conditions such as inert gas, temperature, humidity, etc., so that the method for sensing and measuring a terahertz frequency band dielectric material by using the planar plasmon dielectric sensor is complicated.

Aiming at the problems, the invention provides a dielectric constant measuring device and a method, the method measures the resonance peak curves of different samples by changing the geometric parameters of the metal unit of the waveguide dielectric sensor, acquires the information of the resonance peak central frequencies of different materials by the resonance peak curves, and realizes the dielectric sensing function of the waveguide.

Illustratively, as shown in fig. 1, a schematic top-view structure diagram of a waveguide dielectric sensor 100 provided in an embodiment of the present application is shown.

The waveguide dielectric sensor 100 may be based on an artificial surface plasmon waveguide, among others.

In some embodiments, the waveguide dielectric sensor 100 includes first and second coplanar waveguide regions 102 and 108, first and second transition regions 103 and 107, first and second transmission regions 104 and 106, a central cell region 105, and a substrate 200. The coplanar waveguide region 102 is provided with a metal linear groove pointing to the central direction of the waveguide, and the first transition region 103, the second transition region 107, the first transmission region 104, the second transmission region 106 and the central unit region 105 are provided with a metal grid 110. The metal grid 110 includes a plurality of metal units 111, the metal units 111 are periodically arranged along a central axis of the waveguide in a length direction, lengths of the metal units 111 disposed in the first transition region 103 and the second transition region 107 in a direction toward a center of the waveguide are sequentially increased, lengths of the metal units 111 disposed in the first transmission region 104 and the second transmission region 106 are maintained, and a length of the metal grid 112 disposed at a center position of the center unit region 105 is greater than lengths of the other metal units 111 disposed in the center unit region 105. The length hl of the metal cell 112 located at the central position within the central cell area 105 may be set to range from 150 micrometers to 300 micrometers, for example, in order to fit the operating range of the vector network analyzer. The lengths of the metal units in the first and second transmission regions 104 and 106 and the central unit region 105 may determine an operating frequency of the device, and the smaller the length is, the higher the operating frequency is, so that the operating frequency of the whole device may be controlled by changing the lengths of the metal units 111 (except the metal unit 112 at the central position of the central unit region) in the first and second transmission regions 104 and 106 and the central unit region 105, in practical applications, the length range of the metal units 111 may be set as required, and for example, the length of the metal units 111 may be set to any length greater than 0 micron and less than 100 microns.

For example, as shown in fig. 1, the metal grid array may include N (N is an odd number greater than 1) metal grids, for example, the number of the metal grids may be 41, but this is not limited in this embodiment of the application.

Unlike the prior art designs, the length hl of the metal cell 112 located at the center of the center cell region 105 is greater than the lengths of the other metal cells 111 located in the center cell region 105. By setting the length hl of the metal unit 112 to be greater than the lengths of the other metal units 111, the momentum of the propagating electromagnetic waves is mismatched, so that the electromagnetic waves are locally limited in the central unit area, the resonance curve generates a resonance peak, the waveguide function can be changed from electromagnetic wave transmission to electromagnetic wave sensing, and the function of measuring the dielectric constant of the material is further realized.

Illustratively, as shown in fig. 2, a schematic side view of a waveguide dielectric sensor 100 according to an embodiment of the present application is provided.

In some embodiments, the upper surface of the substrate of the waveguide dielectric sensor 100 has a metal grid array periodically distributed along the length direction of the waveguide dielectric sensor, the metal grid array including a plurality of metal grids having a one-dimensional trench structure.

In some embodiments, the metal layer may be processed by photolithography or additive manufacturing of the integrated circuit, for example, photolithography or additive manufacturing may be performed on the metal layer covering the first coplanar waveguide region 102 and the second coplanar waveguide region 108, so that the first coplanar waveguide region 102 and the second coplanar waveguide region 108 have a metal wire-shaped trench structure pointing to the center direction of the waveguide dielectric sensor; for another example, a photolithography process or an additive manufacturing process is performed on metal layers covered on the first transition region 103 and the second transition region 107, the first transmission region 104 and the second transmission region 106, and the central unit region 105, so that the transition region 103 and the second transition region 107, the transmission region 104 and the second transmission region 106, and the central unit region 105 have a one-dimensional trench structure, and the metal grid array of the one-dimensional trench structure is symmetrical along the width direction and the length direction of the substrate. The metal layer covering the surface of the waveguide substrate can be made of metal materials with high conductivity and low loss, such as gold and copper. The material of the base can be a substrate material of a semiconductor process, such as silicon, sapphire and the like. The thicknesses of the metal layer and the substrate are on the order of less than micrometers, and as thin as possible under the conditions allowed by the process, the thickness may be set to any length less than 0.2 micrometers, for example, the thickness of the metal layer may be set to 0.2 micrometers, and the thickness of the substrate may be set to 0.2 micrometers, but the embodiment of the present application is not limited thereto.

In order to better explain the dielectric sensing function of the waveguide provided by the embodiments of the present application, a specific waveguide dielectric sensor structure is taken as an example, and the implementation principle of the dielectric sensing function of the waveguide is described below.

For example, in one possible implementation, the substrate material of the waveguide dielectric sensor may be silicon, and the metal layer material may be gold. Illustratively, as shown in fig. 3, the arrangement period p of the metal grid array in the waveguide dielectric sensor may be, for example, 100 micrometers, the groove width a of the individual metal grid may be 35 micrometers, and the width g of the transverse strips in the individual metal grid may be 25 micrometers. The metal grids in the first and second transmission regions 104 and 106, and the metal grids in the central cell region 105 except for the central position may have a length h of 80 micrometers, the length hl of the metal grids in the central position in the central cell region 105 may be set to 300 micrometers, the longitudinal lengths of the metal grids in the first and second transition regions 103 and 107 may be uniformly decreased from the center of the waveguide toward the first and second ports 101 and 109 of the waveguide, respectively, the number of the metal grids of the first transition region 103 and the second transition region 107 can be respectively set to 8, the length h of the metal grids from the center position of the waveguide to the first port 101 of the waveguide and the direction of the second port 109 of the waveguide become smaller uniformly, and the lengths are changed uniformly from 80 micrometers, and each time, the lengths are reduced by 10 micrometers until the length h of the metal grid of the waveguide dielectric sensor reaches 10 micrometers.

In order to more clearly understand the feasibility and the effect of the dielectric constant of the material can be measured by increasing the length of the metal grid at the central position of the central unit area of the waveguide. Fig. 4 shows transmission spectra of the metal grids at the center of the central unit area 105 of a waveguide dielectric sensor provided by the present application at 80 micrometers and 300 micrometers, respectively.

As shown in fig. 4, when the length of the metal grid 112 at the center position of the central unit area 105 is 80 μm, the transmission coefficient does not fluctuate significantly in the frequency range of 0THz to 0.25THz, and the resonance curve appears as a line gentle in the horizontal direction without generating a significant resonance peak. When the length of the metal grid 112 at the center of the central unit area 105 is 300 micrometers, the momentum of the transmitted electromagnetic waves is mismatched because the length of the metal grid is greater than the lengths of other metal grids positioned in the central unit area, so that the electromagnetic waves are locally limited in the central unit area, the resonance curve obviously fluctuates within 0.15-0.20 THz, the transmission efficiency of the resonance curve reaches the maximum value when the frequency of the resonance curve is 0.175THz, the resonance curve generates a resonance peak, and the central frequency of the resonance peak can be obtained, so that the function of the artificial surface plasmon is changed from transmission to sensing, the dielectric sensing function is realized, and a device basis is provided for a method for measuring the dielectric constant of the dielectric material.

Most of the existing artificial surface plasmons have large structure sizes and are limited in use, compared with the prior art, the artificial surface plasmon waveguide provided by the invention has a sensing function because the length of the metal grid 112 at the central position of the central unit area 105 of the waveguide dielectric sensor is changed, and compared with a dielectric sensing measurement method needing a precise instrument, the instrument structure required by the dielectric constant measurement method provided by the embodiment of the invention is simpler, has no strict requirement on environmental conditions, can realize the sensing function under the conditions, has the advantages of portability, light weight, easy integration, high sensitivity and the like, FIG. 5 shows the sensitivity of the waveguide dielectric sensor measurement in this example, and as can be seen from the calculation of the slope of the resonant frequency-refractive index curve in FIG. 5, the sensitivity of the waveguide dielectric sensor reached 27.4 MHz/RIU.

In some embodiments, the present application provides a dielectric constant measurement method, which is described in detail below with reference to the accompanying drawings.

Fig. 6 shows a schematic workflow diagram of a dielectric constant measuring system of a dielectric constant measuring device and a dielectric constant measuring method according to an embodiment of the present application, the dielectric constant measuring device includes a waveguide dielectric sensor and a vector network analyzer, the vector network analyzer has a two-port network including a third port 201 and a fourth port 202, an excitation electromagnetic wave signal is output from the third port 201 of the vector network analyzer through a coaxial cable, the excitation electromagnetic wave signal is fed from the first port of the waveguide dielectric sensor 101, after passing through the waveguide dielectric sensor, a signal is output from the second port 109 of the waveguide, and the signal is transmitted to the fourth port 202 of the vector network analyzer through the coaxial cable. Illustratively, in some embodiments, the vector network analyzer excites a transverse electromagnetic wave, which is fed into the first coplanar waveguide region 102 of the waveguide dielectric sensor from the first port 101 of the waveguide dielectric sensor, and is converted into a transverse magnetic wave through the first transition region 103, wherein the electromagnetic wave is strictly bound on the metal grating in the form of a surface wave due to the surface plasmon propagating along the metal and dielectric surfaces and exponentially decaying in the direction perpendicular to the wave propagation, and propagates through the first transmission region 104, and the metal grating 112 with different lengths is introduced into the central unit region 105, so that the momentum of the propagating electromagnetic wave is mismatched, and the electromagnetic wave is locally confined in the central unit region, and appears as a resonance peak on the resonance curve, and the information of the center frequency of the resonance peak of different samples can be collected through the resonance peak curve, the waveguide dielectric sensor thus converts from a transmitting function to a sensing function. The dielectric constant measuring device comprises a vector network analyzer and a waveguide dielectric sensor, wherein the vector network analyzer is provided with a two-port network structure, two symmetrical ports are shown, the two symmetrical ports are marked as a third port 201 and a fourth port 202, each port can excite signals and can also receive signals, the structure of the waveguide dielectric sensor integrated with the vector network analyzer is also in a symmetrical structure due to the two-port network characteristic of the vector network analyzer, and the two ports of the waveguide dielectric sensor are marked as a first port 101 and a second port 109. When the dielectric constant is measured, electromagnetic waves are excited through the third port 201 of the vector network analyzer, are fed in through the first port 101 of the waveguide dielectric sensor, flow out through the second port 109 of the waveguide dielectric sensor to the fourth port 202 of the vector network analyzer after passing through the waveguide dielectric sensor, and the vector network analyzer receives signals to obtain the transmission coefficient. Because the two-port network structure of the vector network analyzer has symmetry, when the electromagnetic wave is excited by the second port 202 of the vector network analyzer and passes through the waveguide dielectric sensor, the third port 201 of the vector network analyzer receives the signal, and the transmission coefficient can also be obtained. In the prior art, for a terahertz dielectric sensor applied in measurement of dielectric constant, although the terahertz dielectric sensor has a planar geometric structure, such as a metamaterial resonant ring, an input signal of the terahertz dielectric sensor is based on terahertz light excited by a quasi-optical system in a free space, a complex precise instrument, such as a terahertz time-domain spectrometer, is required, a measurement process is complicated, and the process requires stable environmental conditions, such as inert gas, temperature, humidity and the like. The main instrument of the dielectric constant measuring system has the advantages of simple structure and low requirement on environmental conditions, and the vector network analyzer has a mature instrument platform, so that the dielectric constant of a sample can be conveniently and quickly measured.

Fig. 7 shows the shift of the resonance peak of the resonance curve when the waveguide dielectric sensor is loaded with samples of different dielectric constants. When the waveguide dielectric sensor is not provided with a sample, the dielectric constant is 1, the resonance frequency is 0.173THz, and when the waveguide dielectric sensor is provided with a sample with the dielectric constant of 2 to 7, the resonance curve is red shifted along with the increase of the dielectric constant of the measured sample. Therefore, the sample with known dielectric constant is measured, the corresponding resonance peak center frequency can be obtained, the rule of resonance peak frequency deviation is obtained, the frequency deviation amount of the sample with unknown dielectric constant can be calculated by combining the resonance peak center frequency of the sample with known dielectric constant through the position of the resonance peak center frequency of the sample with unknown dielectric constant, the rule of frequency deviation can be obtained, the dielectric constant is calculated through a vector network analyzer, and the function of measuring the dielectric constant is realized.

Further, since the waveguide dielectric sensor in the dielectric constant measuring apparatus provided by the present application is planarized and small in size, the dielectric constant of a sample having a size of micrometer can be measured, compared with the prior art. In measuring the dielectric constant of a sample, a small volume of a solid sample is subjected to a sheeting process, and a thin sheet is placed in the central cell region 105 of the waveguide dielectric sensor described herein; for liquid samples, it is preferable that the liquid sample is fixed with hydrogel and then placed in the central unit area 105 of the waveguide dielectric sensor; receiving a transverse electromagnetic wave signal fed in from a third port of a vector network analyzer through a first port of the waveguide dielectric sensor; the second port of the waveguide dielectric sensor outputs a transverse magnetic wave signal to the fourth port of the vector network analyzer; acquiring a resonance curve corresponding to the sample to be detected, wherein the corresponding frequency when the transmission efficiency of the resonance curve reaches the minimum value is the central frequency of a resonance peak, and the central frequency of the resonance peak corresponds to the dielectric constant of the sample to be detected one by one; and acquiring the dielectric constant of the sample to be detected according to the resonance peak of the sample to be detected and the resonance peak of a preset standard sample. Measuring the dielectric constants and the resonant peak central frequencies of the plurality of preset standard samples to obtain a plurality of resonant peak central frequencies when the dielectric constants of the plurality of standard samples are changed, wherein the resonant peak central frequencies and the dielectric constants of the standard samples have one-to-one correspondence; obtaining a frequency deviation rule according to the corresponding relation; and calculating the dielectric constant of the sample to be detected according to the frequency deviation rule and the numerical value of the center frequency of the resonance peak of the sample to be detected.

Furthermore, compared with the prior art, because the electromagnetic wave is strictly bound on the metal grid, the dielectric sensor provided by the application is combined with the planarization characteristic of the dielectric sensor, so that the dielectric sensor can be highly integrated with a terahertz system or a circuit, and the whole dielectric measurement system has the advantages of portability, light weight and easiness in integration.

Furthermore, the working frequency of the dielectric constant measuring device and the working frequency of the dielectric constant measuring method can be controlled by changing the geometric parameters of the metal grid of the metal layer central unit in the waveguide, and the design is convenient and flexible.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (10)

1. A dielectric constant measuring apparatus, comprising:

a waveguide dielectric sensor and a vector network analyzer, the waveguide sensor comprising a first port and a second port, the vector network analyzer comprising a third port and a fourth port, the first port connected to the third port, the second port connected to a fourth port;

the waveguide dielectric sensor comprises a first transition region at the first port side, a second transition region at the second port side, and a central unit region, wherein the first transition region and the second transition region are symmetrical relative to the central position of the waveguide dielectric sensor, and the central unit region is located in the central region of the waveguide dielectric sensor, wherein:

the first transition region, the second transition region and the central unit region respectively comprise a plurality of metal grids, and the length of the metal grid positioned at the central position is greater than the lengths of other metal grids; the lengths of the metal grids at the first transition region become uniformly smaller in a direction from the central position toward the first port, and the lengths of the metal grids at the second transition region become uniformly smaller in a direction from the central position toward the second port.

2. The dielectric constant measuring apparatus according to claim 1, wherein a length of the metal grid located at the central position is set to any one of a length greater than 150 micrometers and less than 300 micrometers.

3. The dielectric constant measurement device of claim 1, wherein the waveguide dielectric sensor further comprises a first transmission region and a second transmission region, the first transmission region being located between the first port and the first transition region, the second transmission region being located between the second port and the second transition region;

the lengths of the metal grids located in the first and second transmission regions and the metal grids located in the central cell region except for the central position are set to any length greater than 0 micron and less than 100 microns.

4. The dielectric constant measurement device according to claim 1 or 2, wherein a length of the metal grid located at the first transition region becomes smaller uniformly in a direction from the central position toward the first port until the length of the metal grid reaches a first threshold value; and the length of the metal grid at the second transition region becomes smaller uniformly in a direction from the central position toward the second port until the length of the metal grid reaches the first threshold.

5. A dielectric constant measuring device as claimed in claim 1 or 2, wherein the waveguide dielectric sensor comprises a substrate, the upper surface of the substrate is provided with a metal grid array periodically distributed along the length direction of the waveguide dielectric sensor, the metal grid array comprises a plurality of metal grids, and one-dimensional groove structures are arranged among the metal grids.

6. Dielectric constant measuring device according to claim 5, characterized in that the material of the substrate of the waveguide dielectric sensor is silicon and/or sapphire.

7. Dielectric constant measuring device according to claim 5, characterized in that the material of the metal grid is gold and/or copper.

8. A dielectric constant measuring method applied to a dielectric constant measuring apparatus according to any one of claims 1 to 7, the dielectric constant measuring apparatus including a waveguide dielectric sensor and a vector network analyzer, the method comprising:

placing a sample to be tested in a central unit area of the waveguide dielectric sensor;

receiving a transverse electromagnetic wave signal fed in from a third port of a vector network analyzer through a first port of the waveguide dielectric sensor;

the second port of the waveguide dielectric sensor outputs a transverse magnetic wave signal to the fourth port of the vector network analyzer;

acquiring a resonance curve corresponding to the sample to be detected, wherein the corresponding frequency when the transmission efficiency of the resonance curve reaches the minimum value is the central frequency of a resonance peak, and the central frequency of the resonance peak corresponds to the dielectric constant of the sample to be detected one by one;

and acquiring the dielectric constant of the sample to be detected according to the resonance peak of the sample to be detected and the resonance peak of a preset standard sample.

9. The method according to claim 8, wherein the dielectric constants and the center frequencies of the resonance peaks of the predetermined plurality of standard samples are measured to obtain a plurality of center frequencies of the resonance peaks when the dielectric constants of the plurality of standard samples are changed, and the center frequencies of the resonance peaks have a one-to-one correspondence relationship with the dielectric constants of the standard samples;

obtaining a frequency deviation rule according to the corresponding relation;

and calculating the dielectric constant of the sample to be detected according to the frequency deviation rule and the numerical value of the center frequency of the resonance peak of the sample to be detected.

10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 8 or 9.

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