CN113640587A - Dual-band lossless dielectric constant measuring sensor based on spiral resonator - Google Patents
Dual-band lossless dielectric constant measuring sensor based on spiral resonator Download PDFInfo
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- CN113640587A CN113640587A CN202110984878.3A CN202110984878A CN113640587A CN 113640587 A CN113640587 A CN 113640587A CN 202110984878 A CN202110984878 A CN 202110984878A CN 113640587 A CN113640587 A CN 113640587A
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- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
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Abstract
The invention discloses a dual-band lossless dielectric constant measuring sensor based on a spiral resonator, which is a two-port device and consists of a dielectric layer, a metal patch layer and a ground layer, wherein the sensor generates two resonance points in the frequency range of 1GHz-4GHz, and can realize the measurement of dielectric constants and dielectric loss tangents in two frequency bands of 1.0GHz-2.0GHz and 2.1GHz-3.1 GHz; the invention has the advantages of simple structure, high Q value, high sensitivity, small processing difficulty and low cost.
Description
Technical Field
The invention belongs to the technical field of microwave sensors, and particularly relates to a dual-band lossless dielectric constant measuring sensor based on a spiral resonator.
Background
The dielectric constant refers to the ability of electrolyte to bind charges, the larger the dielectric constant is, the stronger the ability to bind charges is, and the better the insulating property of the material is; the dielectric loss refers to energy lost by an object due to collision, friction and self heating under the action of an external electric field; with the rapid development of microwave technology, the selection of dielectric materials in practical application becomes more and more important, and the dielectric constant and the dielectric loss are two important parameters for measuring the performance of the dielectric materials; for example, the material for manufacturing the capacitor is required to have a dielectric constant as large as possible and a dielectric loss as small as possible; on the contrary, the material for manufacturing the instrument insulator requires that the dielectric constant and the dielectric loss are both as small as possible; in some special cases, the dielectric loss of the material is required to be large; therefore, by measuring the dielectric constant and the dielectric loss tangent, various factors affecting the dielectric constant and the dielectric loss can be further understood, and a basis is provided for improving the performance of the material.
In practical application, the dielectric constant and the dielectric loss tangent of the characterization material mostly adopt microwave sensors based on SRR or CSRR, but when the microwave sensors of the type are loaded with samples to be tested of different dielectric materials, the test result is greatly influenced by the thickness of the samples to be tested, so that when the thicknesses of the samples to be tested are different, the dielectric constant and the dielectric loss tangent obtained through inversion of the test result are possibly greatly different; in addition, the S21 amplitude at the resonant frequency point of this type of microwave sensor is generally small, and therefore the figure of merit calculated from the S21 amplitude is also small, so that the longitudinal sensitivity of the microwave sensor is limited.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems mentioned in the background technology, the invention provides a dual-band lossless dielectric constant measuring sensor based on a spiral resonator, wherein the sensor generates two resonance points in the frequency range of 1GHz-4GHz, and can realize the measurement of dielectric constant and dielectric loss tangent of two frequency bands of 1.0GHz-2.0GHz and 2.1GHz-3.1 GHz; the invention has the advantages of simple structure, high Q value, high sensitivity, small processing difficulty and low cost.
The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows: a dual-band lossless dielectric constant measuring sensor based on a spiral resonator is a two-port device and consists of a dielectric layer, a metal patch layer and a ground layer, and is characterized in that the sensor sequentially comprises the ground layer (3), the dielectric layer (2) and the metal patch layer (1) from bottom to top; the grounding layer is laid on the lower surface of the dielectric layer and etched with two grooved metal spiral structures; the metal patch layer is laid on the upper surface of the dielectric layer and comprises a section of microstrip transmission line and two square metal patches.
Further, the thickness of the ground layer (3) and the metal patch layer (1) is 0.017mm, and can be floated from 0mm to 0.02mm, and the metal material can be a conductive material with conductivity equivalent to gold, silver and copper.
Furthermore, the dielectric layer (2) has the dimensions of 50mm multiplied by 30mm multiplied by 1.6mm, the FR4 material is adopted, the dielectric constant is 4.3, and the loss tangent value is 0.02.
Furthermore, the size of the left-side grooved metal spiral structure in the ground layer (3) is 6mm multiplied by 6mm, the structure is composed of 8 sections of grooved rectangles, the width of each section of grooved rectangle is 0.5mm, and the distance between adjacent grooved rectangles is 0.5 mm.
Furthermore, the size of the right-side grooved metal spiral structure in the ground layer (3) is 4.2mm multiplied by 4.2mm, the ground layer is composed of 8 sections of grooved rectangles, the width of each section of grooved rectangle is 0.35mm, and the distance between adjacent grooved rectangles is 0.35 mm.
Furthermore, the length of a microstrip transmission line in the metal patch layer is 50mm, the width of the microstrip transmission line is 3mm, and the side length of the square metal patch is 6 mm.
Furthermore, the square metal patch and the grooved metal spiral structure are both square, and the central points of the square metal patch and the grooved metal spiral structure are symmetrical about the dielectric substrate.
Further, the sample to be detected is placed right above the grooved metal spiral structure.
1. The invention has two working frequency ranges of 1.0GHz-2.0GHz and 2.1GHz-3.1GHz respectively, each working frequency range can measure the dielectric constant and the dielectric loss tangent value of a sample to be measured, and the measurement results are almost the same for the samples to be measured with different thicknesses.
2. Compared with the existing microwave sensor, the invention adds two square metal patches on the other side of the dielectric substrate corresponding to the position of the grooved metal spiral structure, improves the transmission efficiency by enhancing the coupling between the microstrip transmission line and the resonator, further obtains a larger quality factor and increases the longitudinal sensitivity of the sensor.
Drawings
Fig. 1 is a schematic three-dimensional structure diagram of a dual-band lossless dielectric constant measuring sensor based on a spiral resonator.
FIG. 2 is a top view of a dual band lossless permittivity measurement sensor based on a spiral resonator according to the present invention.
FIG. 3 is a top view of the ground plane of a dual band lossless permittivity measurement sensor based on a spiral resonator according to the present invention.
FIG. 4 is a comparison of S21 before and after two square metal patches are added to the dual-band lossless dielectric constant measuring sensor based on the spiral resonator.
FIG. 5 is a diagram of the relative dielectric constant and the resonant frequency of a dual-band lossless dielectric constant measuring sensor based on a spiral resonator.
FIG. 6 is a graph of loss tangent and S21 amplitude of a dual-band lossless dielectric constant measuring sensor based on a helical resonator.
FIG. 7 is a linear relationship diagram of the relative dielectric constant and the inverse square of the resonant frequency of the dual-band lossless dielectric constant measuring sensor based on the spiral resonator.
FIG. 8 is a linear relationship diagram of loss tangent and Q-factor minus-plus-minus square of a dual-band lossless dielectric constant measuring sensor based on a spiral resonator when the thickness of the sample to be measured is different.
FIG. 9 is a linear relationship diagram of loss tangent and quality factor minus square of a dual-band lossless permittivity measurement sensor based on a spiral resonator when the permittivity of the sample to be measured is different.
FIG. 10 is a diagram of the relative dielectric constant versus the resonant frequency of a dual-band lossless dielectric constant measuring sensor based on a spiral resonator according to the present invention.
FIG. 11 is a graph of loss tangent and S21 amplitude for a dual-band lossless permittivity measurement sensor based on a helical resonator according to the present invention.
FIG. 12 is a linear relationship of the relative permittivity to the inverse square of the resonant frequency of a dual-band lossless permittivity measurement sensor based on a spiral resonator according to the present invention.
FIG. 13 is a linear relationship diagram of loss tangent and Q-factor minus-plus-minus square of a dual-band lossless permittivity measurement sensor based on a spiral resonator according to the present invention when the thickness of the sample to be measured is different.
FIG. 14 is a linear relationship diagram of loss tangent and quality factor minus square of a dual-band lossless permittivity measurement sensor based on a spiral resonator when the permittivity of the sample to be measured is different.
Fig. 5 to 9 are schematic diagrams of relationships obtained when a sample to be measured is placed right above the grooved metal spiral structure on the left side of fig. 1, namely, the relationship between the frequency bands of 1.0GHz to 2.0 GHz; fig. 10 to 14 are schematic diagrams of relationships obtained when a sample to be measured is placed right above the grooved metal spiral structure on the right side of fig. 1, namely, the relationship between 2.1GHz and 3.1GHz frequency bands.
Detailed Description
The invention relates to a dual-band lossless dielectric constant measuring sensor based on a spiral resonator, which is explained in more detail with reference to the attached drawings and technical schemes.
As shown in fig. 1, which is a schematic diagram of a three-dimensional structure of a dual-band lossless permittivity measurement sensor based on a spiral resonator according to the present invention, as shown in the figure, the dual-band lossless permittivity measurement sensor sequentially includes, from bottom to top, a ground layer (3), a dielectric layer (2), and a metal patch layer (1); the grounding layer is made of conductive materials such as gold, silver, copper and the like, the thickness of the grounding layer is 0.017mm, two spiral structures are etched on the grounding layer in a grooving mode, the size of the left grooving metal spiral structure is 6mm multiplied by 6mm, the width of each section of grooving rectangle is 0.5mm, the distance between every two adjacent grooving rectangles is 0.5mm, the size of the right grooving metal spiral structure is 4.2mm multiplied by 4.2mm, the width of each section of grooving rectangle is 0.35mm, the distance between every two adjacent grooving rectangles is 0.35mm, the distance between the central points of the two grooving metal spiral structures is 30mm, and the grooving depth is 0.017 mm; the medium layer is made of FR4 material and has a thickness of 1.6 mm; the metal patch layer comprises a section of microstrip transmission line and two square metal patches, the length of the microstrip transmission line is 50mm, the width of the microstrip transmission line is 3mm, the length and the width of each square metal patch are both 6mm, and the distance between the central points of the two square metal patches is 30 mm.
FIG. 2 is a top view of a dual-band lossless permittivity measurement sensor based on a spiral resonator according to the present invention;
FIG. 3 is a schematic diagram showing a top view of a ground plane of a dual-band lossless permittivity measurement sensor based on a spiral resonator according to the present invention;
as shown in fig. 4, when two square metal patches are added, the resonance frequency is not substantially shifted, but the amplitude of S21 is effectively increased; when unloaded, the quality factor increases from 164 to 206 at 2GHz and from 110 to 185 at the second resonant frequency, 3GHz, increasing longitudinal sensitivity.
As shown in fig. 5, when the dielectric constant of the sample to be measured gradually increases, the first resonant frequency gradually shifts to a low frequency, and the second resonant frequency remains stable.
As shown in fig. 6, when the dielectric constant of the sample to be measured is kept constant, the dielectric loss tangent is gradually increased, the first resonant frequency is kept stable, the amplitude of S21 is gradually decreased, and the second resonant frequency and the amplitude of S21 are both kept stable.
As shown in fig. 7, when the thickness of the sample to be measured is different, the inverse square of the dielectric constant and the resonant frequency maintains a stable linear relationship, and the linear relationship is almost consistent at different thicknesses.
As shown in fig. 8, when the thickness of the sample to be measured is different, the dielectric tangent and the negative power of the quality factor maintain a stable linear relationship, and the linear relationship is almost consistent at different thicknesses.
As shown in fig. 9, since the dielectric loss tangent and the negative power of the quality factor have a linear relationship and are also affected by the dielectric constant of the sample to be measured, the dielectric constant of the sample to be measured needs to be taken into consideration as a variable when inverting the dielectric loss tangent by the quality factor.
As shown in fig. 10, when the dielectric constant of the sample to be measured gradually increases, the first resonance frequency remains stable, and the second resonance frequency gradually shifts to a low frequency.
As shown in FIG. 11, when the sample to be measured is insertedThe electrical constant is kept constant, the dielectric loss tangent is gradually increased, the first resonance frequency and S21The amplitudes are all kept stable, while the second resonance frequency is kept stable, and the amplitude of S21 is gradually reduced.
As shown in fig. 12, when the thickness of the sample to be measured is different, the dielectric constant and the inverse square of the resonant frequency maintain a stable linear relationship, and the linear relationship is almost consistent at different thicknesses.
As shown in fig. 13, when the thickness of the sample to be measured is different, the dielectric tangent and the negative power of the quality factor maintain a stable linear relationship, and the linear relationship is almost consistent at different thicknesses.
As shown in fig. 14, since the dielectric loss tangent and the negative power of the quality factor have a linear relationship and are also affected by the dielectric constant of the sample to be measured, the dielectric constant of the sample to be measured needs to be taken into consideration as a variable when inverting the dielectric loss tangent by the quality factor.
The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.
Claims (9)
1. A dual-band lossless dielectric constant measuring sensor based on a spiral resonator is a two-port device and consists of a dielectric layer, a metal patch layer and a ground layer, and is characterized in that the sensor sequentially comprises the ground layer (3), the dielectric layer (2) and the metal patch layer (1) from bottom to top; the grounding layer is laid on the lower surface of the dielectric layer and etched with two grooved metal spiral structures; the metal patch layer is laid on the upper surface of the dielectric layer and comprises a section of microstrip transmission line and two square metal patches.
2. The dual-band lossless dielectric constant measurement sensor based on the spiral resonator as claimed in claim 1, wherein the grooved metal spiral structure is coupled with the microstrip transmission line through two square metal patches, which can generate two resonance points in the frequency range of 1GHz-4GHz, and can realize the measurement of dielectric constant and dielectric loss tangent at two frequency bands of 1.0GHz-2.0GHz and 2.1GHz-3.1 GHz.
3. The dual band lossless permittivity measurement sensor based on the spiral resonator of claim 1, wherein the thickness of the ground layer (3) and the metal patch layer (1) is 0.017mm, and can be floated from 0mm to 0.02mm, and the metal material can be a conductive material having conductivity comparable to gold, silver, copper.
4. The dual band lossless permittivity measurement sensor based on a spiral resonator according to claim 1, wherein the dielectric layer (2) has dimensions of 50mm x 30mm x 1.6mm, and is made of FR4 material, and has a permittivity of 4.3 and a loss tangent of 0.02.
5. The dual band lossless permittivity measurement sensor based on spiral resonator of claim 1, wherein the left-side grooved metal spiral structure in the ground layer (3) has a size of 6mm x 6mm, and is formed by 8 grooved rectangles, each grooved rectangle has a width of 0.5mm, and the interval between adjacent grooved rectangles is 0.5 mm.
6. The dual band lossless permittivity measurement sensor based on spiral resonator of claim 1, wherein the right-side grooved metal spiral structure in the ground layer (3) has a size of 4.2mm x 4.2mm, and is formed by 8 grooved rectangles, each grooved rectangle has a width of 0.35mm, and the interval between adjacent grooved rectangles is 0.35 mm.
7. The dual-band lossless permittivity measurement sensor based on the spiral resonator according to claim 1, wherein a microstrip transmission line in the metal patch layer (1) has a length of 50mm, a width of 3mm, and a side length of a square metal patch of 6 mm.
8. The dual-band lossless permittivity measurement sensor based on a spiral resonator of claim 1, wherein the square metal patch and the grooved metal spiral structure are both square, and the central points of the two are symmetrical with respect to the dielectric substrate.
9. The dual-band lossless permittivity measurement sensor based on a spiral resonator of claim 1, wherein a sample to be measured is placed in a region directly above the grooved metal spiral structure.
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