CN116430124B

CN116430124B - Method, device, equipment and medium for testing complex dielectric constant of bumper material

Info

Publication number: CN116430124B
Application number: CN202310700254.3A
Authority: CN
Inventors: 王俊涛; 何凌强; 黄志强; 李旭阳; 周恺
Original assignee: Saien Lingdong Shanghai Intelligent Technology Co ltd
Current assignee: Saien Lingdong Shanghai Intelligent Technology Co ltd
Priority date: 2023-06-14
Filing date: 2023-06-14
Publication date: 2023-09-22
Anticipated expiration: 2043-06-14
Also published as: CN116430124A

Abstract

The application provides a method, a device, equipment and a medium for testing complex dielectric constants of bumper materials, and relates to the technical field of microwave testing. The method comprises the steps of obtaining a test template, and sequentially measuring S parameters of a preset test position on the test template and the material thickness of each dielectric material at the preset test position; calculating at least one return loss of each dielectric material at the preset test position in a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position; and calculating loss tangent and dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range. The layered measurement of the dielectric materials is realized by measuring and calculating the dielectric constants of the dielectric materials of each layer on the multilayer template, and the measurement accuracy of the dielectric constants of different dielectric materials is improved.

Description

Method, device, equipment and medium for testing complex dielectric constant of bumper material

Technical Field

The application relates to the technical field of microwave testing, in particular to a method, a device, equipment and a medium for testing complex dielectric constants of a bumper material.

Background

Millimeter wave radar is a main sensor of ADAS system due to its features of long detection distance, high detection precision, and strong angular resolution. The millimeter wave radar is generally arranged behind an automobile bumper, and whether the design of the bumper is reasonable or not has a larger influence on the performance of the millimeter wave radar, so that the influence of the bumper on the performance of the millimeter wave radar is particularly important to analyze in the early stage of the design of the bumper. The automobile bumper is generally composed of four layers of materials including a base material, a primer, a colored paint and a varnish, the arrangement of the materials of each layer of the bumper directly has a great influence on the millimeter wave radar performance, and complex dielectric constants of the materials of each layer of the bumper in a 77GHz frequency band must be accurately known to properly design the parameters of the materials of each layer of the bumper.

There are two ways of doing so in common use: one is to manufacture a flat bumper sample according to the actual bumper technology, directly test the insertion loss and reflection loss of the bumper sample by using a network analyzer, and the equivalent complex dielectric constant; the second method is to directly use radar to test the influence of the bumper on radar performance, but the two methods cannot obtain complex dielectric constants of materials of each layer of the bumper, and the second method can only use an actual bumper to test after the design of the bumper is completed, so that the influence of the actual bumper on radar performance is not beneficial to simulation analysis in the early stage of the design of the bumper.

Therefore, it is highly desirable to find a method for conveniently, efficiently and accurately measuring complex dielectric constants of various layers of materials of a bumper.

Disclosure of Invention

The application provides a method, a device, equipment and a storage medium for testing the complex dielectric constant of a bumper material, and aims to improve the accuracy of measuring and calculating the complex dielectric constant of each layer of material of the bumper.

In a first aspect, the present application provides a method for testing the complex permittivity of a bumper material, the method comprising:

acquiring a test template, and sequentially measuring S parameters of a preset test position on the test template and the material thickness of each dielectric material at the preset test position; wherein the test template comprises a multi-layer template, and the multi-layer template comprises at least one layer of the dielectric material;

calculating at least one return loss of each dielectric material at the preset test position in a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position;

and calculating loss tangent and dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range.

Further, before calculating at least one return loss of each dielectric material at the preset test position in the preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, the method further includes:

acquiring a transmission matrix of the dielectric material;

acquiring a return loss calculation formula based on the conversion relation between the transmission matrix and the S parameter;

wherein, the transmission matrix is:

wherein t is the number of layers of dielectric materials,for the equivalent electrical length of the i-th dielectric material layer,/or->For the thickness of the dielectric material of the i-th layer, +.>Is of electromagnetic wave wavelength->C/f, c is the speed of light, f is the electromagnetic wave frequency, +.>Is the complex dielectric constant of the dielectric material of the i-th layer, < ->θ is the angle, j is the imaginary unit, +.>Is the dielectric constant of the dielectric material of the i-th layer, < ->Loss tangent of dielectric material of the i-th layer, < >>Is normalized by the dielectric material of the ith layer relative to the free spaceEquivalent characteristic impedance:

the conversion relation between the transmission matrix and the S parameter is as follows:

wherein, the return loss calculation formula is:

wherein, RL is return loss.

Further, the calculating, based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, at least one return loss of each dielectric material in a preset frequency range at the preset test position includes:

dividing the S parameter into at least one frequency band based on the corresponding relation between the frequency in the preset frequency range and the S parameter to obtain at least one sub-frequency range, wherein the sub-frequency range comprises at least one frequency point;

and calculating the return loss corresponding to each frequency point in the sub-frequency range based on the return loss calculation formula and the material thickness of each dielectric material.

Further, the calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range includes:

calculating an initial value of loss tangent and an initial value of dielectric constant corresponding to the sub-frequency range based on the return loss corresponding to each frequency point in the sub-frequency range and the actual measurement value of return loss corresponding to each frequency point;

Performing curve fitting on the initial value of the loss tangent and the initial value of the dielectric constant corresponding to the sub-frequency range to obtain a fitting value of the loss tangent and a fitting value of the dielectric constant corresponding to each frequency point;

and calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on the loss tangent fitting value and the dielectric constant fitting value corresponding to each frequency point.

Further, the calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on the loss tangent fitting value and the dielectric constant fitting value corresponding to each frequency point includes:

acquiring the loss tangent fitting value and the dielectric constant fitting value which are calculated corresponding to each preset test position;

calculating the average value of the loss tangent fitting values corresponding to the same frequency point to obtain the loss tangent of the dielectric material;

and calculating the average value of the dielectric constant fitting values corresponding to the same frequency point to obtain the dielectric constant of the dielectric material.

Further, the dielectric materials include substrates, primers, paints, and varnishes;

the test panels include substrate panels, substrate-primer-paint panels, and substrate-primer-paint-varnish panels.

Further, the calculating, based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, at least one return loss of each dielectric material at the preset test position in a preset frequency range includes:

when the test template comprises multiple layers of dielectric materials, calculating at least one return loss of the dielectric material to be tested in the preset frequency range at the preset test position based on the dielectric constant and the loss tangent of the dielectric material to be tested, the material thickness of the dielectric material to be tested and the S parameter corresponding to the preset test position.

In a second aspect, the present application also provides a device for testing the complex dielectric constant of a bumper material, the device comprising:

the template measurement module is used for acquiring a test template and sequentially measuring S parameters of a preset test position on the test template and the material thickness of each dielectric material at the preset test position; wherein the test template comprises a multi-layer template, and the multi-layer template comprises at least one layer of the dielectric material;

The return loss calculation module is used for calculating at least one return loss of each dielectric material in a preset frequency range at the preset test position based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position;

and the dielectric constant calculation module is used for calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range.

In a third aspect, the present application also provides a computer device comprising a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein the computer program when executed by the processor implements the steps of the method for testing the complex permittivity of a bumper material as described above.

In a fourth aspect, the present application also provides a computer readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method for testing the complex permittivity of a bumper material as described above.

The application provides a test method, a device, equipment and a storage medium for complex dielectric constants of bumper materials, wherein the method comprises the steps of obtaining a test template, and sequentially measuring S parameters of a preset test position on the test template and the material thickness of each medium material at the preset test position; wherein the test template comprises a multi-layer template, and the multi-layer template comprises at least one layer of the dielectric material; calculating at least one return loss of each dielectric material at the preset test position in a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position; and calculating loss tangent and dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range. By the method, the return loss of each dielectric material in the preset frequency range is sequentially calculated by measuring the S parameter of the preset test position on the test template and the material thickness of each dielectric material, and the loss tangent and the dielectric constant of each layer of dielectric material are calculated according to the return loss of each dielectric material. The layered measurement of the dielectric materials is realized by measuring and calculating the dielectric constants of the dielectric materials of each layer on the multilayer template, and the measurement accuracy of the dielectric constants of different dielectric materials is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic flow chart of a first embodiment of a method for testing complex dielectric constant of a bumper material according to the present application;

fig. 2 is a signal transmission schematic diagram of a passive two-port network transmission channel of S parameter according to an embodiment of the present application;

FIG. 3 is a schematic diagram showing connection between a test template, a test fixture and a network analyzer according to an embodiment of the present application;

fig. 4 is a schematic flow chart of a return loss calculation formula obtaining method provided by the application;

FIG. 5 is a schematic flow chart of a second embodiment of a method for testing complex dielectric constant of a bumper material according to an embodiment of the present application;

FIG. 6 is a schematic flow chart of a third embodiment of a method for testing complex dielectric constant of a bumper material according to an embodiment of the present application;

FIG. 7 is a graph showing the dielectric constant of a paint according to the method for testing complex dielectric constant of a bumper material according to an embodiment of the present application;

FIG. 8 is a graph showing the loss tangent of a paint, which is measured by the method for testing the complex dielectric constant of a bumper material according to an embodiment of the present application;

FIG. 9 is a schematic structural diagram of a device for testing complex dielectric constant of a bumper material according to the present application;

fig. 10 is a schematic block diagram of a computer device according to an embodiment of the present application.

The achievement of the objects, functional features and advantages of the present application will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The flow diagrams depicted in the figures are merely illustrative and not necessarily all of the elements and operations/steps are included or performed in the order described. For example, some operations/steps may be further divided, combined, or partially combined, so that the order of actual execution may be changed according to actual situations.

Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

Referring to fig. 1, fig. 1 is a flow chart of a first embodiment of a method for testing complex dielectric constant of a bumper material according to the present application.

As shown in fig. 1, the method for testing the complex dielectric constant of the bumper material includes steps S101 to S103.

Step S101, acquiring a test template, and sequentially measuring S parameters of a preset test position on the test template and the material thickness of each dielectric material at the preset test position; wherein the test template comprises a multi-layer template, and the multi-layer template comprises at least one layer of the dielectric material;

in one embodiment, the dielectric material includes a substrate, a primer, a paint, and a varnish; the test panels include substrate panels, substrate-primer-paint panels, and substrate-primer-paint-varnish panels.

In one embodiment, the bumper is generally composed of four layers, including a base material, a primer, a color paint and a varnish, sequentially from inside to outside, and the same process of the vehicle bumper is adopted to manufacture four types of flat-plate sample pieces (b is more than or equal to 5) of base material sample plate PC, base material+primer sample plate PD, base material+primer+color paint sample plate PE, base material+primer+color paint+varnish sample plate PF with proper sizes (such as 100mm x 100 mm), and the flat-plate sample pieces are respectively numbered as PC 1-PCb, PD 1-PDb, PE 1-PEb and PF 1-PFb.

In one embodiment, a network analyzer and a Swiss to 12 Materials Characterization Kit test device (hereinafter referred to as MCK) are connected, and each of the four flat-panel samples is tested for S-parameters in the frequency range of f_down, f_up after calibration.

The S parameter is defined under the condition that terminals are arranged at two ends of a transmission line. As shown in fig. 2, the transmission channel is considered as a black box, and the S parameter describes the frequency domain characteristics of the black box itself. Almost all characteristics of the transmission channel, such as reflection of the signal, crosstalk, loss, etc., can be seen by the S-parameters.

Wherein, the S parameter can be expressed as:

in one embodiment, as shown in fig. 3, two ports of a network analyzer are correspondingly connected with two ports of an MCK respectively, a computer is connected with the network analyzer by using a network cable, a control program of the MCK on the computer is opened, a preset frequency range [ f_down, f_up ] to be tested is set, a metal calibration sheet is placed into a clamp for calibrating the MCK and clamped, S11 of the MCK is calibrated, then the metal calibration sheet is taken out, two ports of the MCK clamp are directly and tightly connected, and S21 of the MCK is calibrated.

In one embodiment, the substrate templates PC 1-PCb are sequentially placed into an MCK clamp and clamped, each template is tested for S parameter S_PCip at different positions, and the test results are marked in one-to-one correspondence with the test positions on the template. Wherein S_PCip represents the S parameter measured at the p-th position of the substrate template numbered PCi.

In one embodiment, a micrometer may be used to measure the thickness h_pcip of each test location of each substrate template, where h_pcip represents the thickness of the p-th location of the substrate template numbered PCi.

In an embodiment, each test template may be tested by selecting four preset test positions, recording the measured S parameter s_tes, identifying each test position, and slicing to test the thickness h1, the primer thickness h2, the paint thickness h3, and the varnish thickness h4 of the substrate at each test position, where if a certain type of template lacks a certain layer of material, the corresponding material thickness is recorded as 0, for example, the sample PC has only the substrate, and the thicknesses of other layers of materials are recorded as 0.

Further, as shown in fig. 4, before the step S101, the method further includes:

step S201, acquiring a transmission matrix of the dielectric material;

Step S202, acquiring a return loss calculation formula based on the conversion relation between the transmission matrix and the S parameter.

Wherein, the transmission matrix is:

wherein t is the number of layers of dielectric materials,for the equivalent electrical length of the i-th dielectric material layer,/or->For the thickness of the dielectric material of the i-th layer, +.>Is of electromagnetic wave wavelength->C/f, c is the speed of light, f is the electromagnetic wave frequency, +.>Is the complex dielectric constant of the dielectric material of the i-th layer, < ->θ is the angle, j is the imaginary unit, +.>Is the dielectric constant of the dielectric material of the i-th layer, < ->Loss tangent of dielectric material of the i-th layer, < >>Normalized equivalent characteristic impedance of the dielectric material of the i layer relative to free space:

wherein, the return loss calculation formula is:

wherein, RL is return loss.

Step S102, calculating at least one return loss of each dielectric material at the preset test position within a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position.

In an embodiment, when the test template includes multiple layers of the dielectric material, at least one return loss of the dielectric material to be tested in the preset frequency range at the preset test position is calculated based on the dielectric constant and the loss tangent of the dielectric material to be tested, the material thickness of the dielectric material to be tested, and the S parameter corresponding to the preset test position.

In an embodiment, according to the S parameter obtained by the test, the data substituted into the return loss calculation formula is different according to the difference of the dielectric materials in the test template. For the substrate template, only the S parameter and the thickness are substituted into the return loss calculation formula, while for other test templates including multiple layers of different dielectric materials, the current S parameter, the thickness of the dielectric material, and the dielectric constant and loss tangent of the measured dielectric material are substituted into the return loss calculation formula to calculate the return loss of the multiple layers of dielectric materials in the current test template.

Among these, return loss is one way to represent the reflection coefficient in logarithmic form (dB). Return loss is the number of dB of reflected signal below incident signal. The return loss is always negative, between 0dB (total reflection) and negative infinity (ideal match).

Step S103, calculating loss tangent and dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range.

In this embodiment, the S parameter is divided according to frequency according to a preset frequency range, then the return loss of each frequency segment is calculated, for each frequency segment, the loss tangent and the dielectric constant in which the return loss is minimized are taken as initial values, and then the initial value average value of each dielectric material calculated by a plurality of templates is calculated as the loss tangent and the dielectric constant of the dielectric material.

The embodiment of the application provides a test method for complex dielectric constants of bumper materials, which sequentially calculates the return loss of each dielectric material in a preset frequency range by measuring S parameters of preset test positions on a test sample plate and the material thickness of each dielectric material, and calculates the loss tangent and the dielectric constants of each layer of dielectric material according to the return loss of each dielectric material. The layered measurement of the dielectric materials is realized by measuring and calculating the dielectric constants of the dielectric materials of each layer on the multilayer template, and the measurement accuracy of the dielectric constants of different dielectric materials is improved.

Referring to fig. 5, fig. 5 is a flow chart of a second embodiment of a method for testing complex dielectric constant of a bumper material according to an embodiment of the application.

In this embodiment, based on the embodiment shown in fig. 1, the step S102 specifically includes:

step S301, dividing the S parameter into at least one frequency band based on the correspondence between the frequencies in the preset frequency range and the S parameter, to obtain at least one sub-frequency range, where the sub-frequency range includes at least one frequency point.

In one embodiment, for the S parameter measured at each test position on the test template, the first column of the S parameter is a column vector Sf composed of a plurality of discrete frequency points in the range of [ f_down, f_up ], and the S parameter is divided into m frequency bands according to frequencies, and n frequency points of each frequency band.

The S parameter measured for each test position on the substrate template PC may be denoted s_pcip, which represents the S parameter measured at the p-th position of the substrate template numbered PCi.

The S parameter measured for each test location on the substrate + primer template PD may be referred to as s_pdip, representing the S parameter measured at the p-th location of the substrate template numbered PDi.

The S parameter measured for each test location on the substrate + primer + paint template PE may be denoted s_peip, representing the S parameter measured at the p-th location of the substrate template numbered PEi.

The S parameter measured for each test location on the substrate + primer + paint + varnish template PF can be noted as s_pfip, representing the S parameter measured at the p-th location of the substrate template numbered PFi.

Step S302, calculating the return loss corresponding to each frequency point in the sub-frequency range based on the return loss calculation formula and the material thickness of each dielectric material.

In an embodiment, the S parameter and the thickness corresponding to each test position are substituted into the return loss calculation formula, and when each frequency band is very small, the Dk and Df of the material used by the base material template PC are considered to be unchanged in the frequency band range, so that the return loss of each frequency point in each frequency range is calculated by performing parameter scanning on Dk and Df.

For the base material template PC, the thickness measured at each test position on the base material template PC is denoted as h_pcip, and represents the thickness at the p-th position of the base material template numbered PCi.

For the substrate+primer template PD, each substrate+primer template PD was sliced at each test location, and then the substrate thickness h1_pdip and the primer thickness h2_pdip at each test location were measured using an image tester, where h1_pdip and h2_pdip represent the substrate thickness and the primer thickness at the p-th location of the substrate+primer template numbered PDi, respectively.

For the substrate+primer+color template PE, each substrate+primer+color template PE is sliced at each test position, and then the substrate thickness h1_peip, the primer thickness h2_peip and the color thickness h3_peip at each test position are measured by using an image tester, wherein h1_peip, h2_peip and h3_peip respectively represent the substrate+primer+color template p-th position of the substrate, the primer thickness and the color thickness numbered PEi.

For the substrate+primer+color+varnish template PF, each substrate+primer+color+color template PF was sliced at each test location, and then the substrate thickness h1_pfip, the primer thickness h2_pfip, the color thickness h3_pfip, and the varnish thickness h4_pfip at each test location were measured using an image tester, wherein h1_peip, h2_peip, h3_peip, and h4_pfip represent the substrate thickness, the primer thickness, the color thickness, and the varnish thickness at the p-th location of the substrate+primer+color+varnish template numbered PFi, respectively.

Further, as shown in fig. 6, based on the embodiment shown in fig. 5, the step S103 includes:

step S401, calculating an initial value of loss tangent and an initial value of dielectric constant corresponding to the sub-frequency range based on the return loss corresponding to each frequency point in the sub-frequency range and the actual measurement value of return loss corresponding to each frequency point.

In this embodiment, for the S parameter measured at each preset test position on the test template, the S parameter is divided into m frequency bands according to the frequency, n frequency points in each frequency band, and the thickness of the dielectric material measured at the preset test position is substituted into the return loss calculation formula to calculate the return loss. The return loss of each frequency point in each frequency range is calculated in a parameter scanning mode, and for the p-th frequency range, the dielectric constant and the loss tangent with the smallest RL_del are the initial value of the dielectric constant and the initial value of the loss tangent of the base material PC in the frequency range:

wherein, the liquid crystal display device comprises a liquid crystal display device,a calculated return loss value representing the ith frequency point in the frequency range of the p-th segment, +.>Representing the p-th band frequencyThe return loss measured value of the ith frequency point in the range,/->S11_tes_p_i represents the s11 actual measurement value of the ith frequency point in the p-th frequency range.

And step S402, performing curve fitting on the initial value of the loss tangent and the initial value of the dielectric constant corresponding to the sub-frequency range to obtain a fitting value of the loss tangent and a fitting value of the dielectric constant corresponding to each frequency point.

In one embodiment, the obtained m×n Dk and Df are then smoothed by fitting to obtain a dielectric constant fit and a loss tangent fit of the dielectric material used for the test template in the frequency range of [ f_down, f_up ].

Step S403, calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on the fit value of the loss tangent and the fit value of the dielectric constant corresponding to each frequency point.

Further, obtaining each loss tangent fitting value and each dielectric constant fitting value which are calculated correspondingly to each preset test position; calculating the average value of the loss tangent fitting values corresponding to the same frequency point to obtain the loss tangent of the dielectric material; and calculating the average value of the dielectric constant fitting values corresponding to the same frequency point to obtain the dielectric constant of the dielectric material.

In one embodiment, dielectric constants and loss tangents of dielectric materials used for the test templates are obtained by respectively calculating average values of dielectric constants and loss tangents at each frequency point according to dielectric constant fitting values and loss tangents corresponding to a plurality of identical test templates at different preset test positions.

In an embodiment, in order to facilitate a clearer understanding of the technical solution of the present application for a person skilled in the art, the embodiment of the present application describes in detail a complete test procedure of a test template including different dielectric materials, the test procedure is as follows:

in one embodiment, for a substrate template PC, which has only one layer of dielectric material, the transmission matrix is:

wherein, the liquid crystal display device comprises a liquid crystal display device,for the equivalent electrical length of the dielectric layer, j is the imaginary unit, d is the dielectric thickness, +.>Is of electromagnetic wave wavelength->C/f, c is the speed of light, f is the electromagnetic wave frequency, +.>The complex permittivity of the medium, Z is the normalized equivalent characteristic impedance relative to free space;

wherein the method comprises the steps ofθ is the angle of incidence.

Wherein Z is the normalized equivalent characteristic impedance with respect to free space:

where θ is the angle of incidence.

Further, for the S parameter s_pcip measured at each test position on the substrate template PC, the first column of S parameters is a column vector Sf composed of a plurality of discrete frequency points within the range of [ f_down, f_up ], and the S parameters are divided into m frequency bands according to frequencies, and n frequency points for each frequency band.

Where s_pcip represents the S parameter measured at the p-th position of the substrate template numbered PCi, and h_pcip represents the thickness of the p-th position of the substrate template numbered PCi.

Further, the thickness h_PCip corresponding to the preset test position is brought into a return loss calculation formula. And calculating the return loss of each frequency point in each frequency range by means of parameter scanning on Dk and Df.

It will be appreciated that when each band is small, it is believed that both Dk and Df of the material used for the base template PC are constant over that band.

Further, for the p-th frequency range, dk and Df with the smallest RL_del_p values are the initial dielectric constant Dk_pc_p and the initial loss tangent Df_pc_p of the base material used by the base material template PC in the frequency range;

wherein, the liquid crystal display device comprises a liquid crystal display device,a calculated return loss value representing the ith frequency point in the frequency range of the p-th segment, +.>Representing the actual measured value of return loss of the ith frequency point in the frequency range of the p-th section, +.>S11_tes_p_i represents the s11 actual measurement value of the ith frequency point in the p-th frequency range.

Thus, two curves of the initial value Dk_pcip_init and the initial value Df_pcip_init of the loss tangent of the base material for the PC template at the preset test position in the frequency range of [ f_down, f_up ] can be obtained.

Wherein Dk_pcip_init and Df_pcip_init respectively represent the dielectric constant initial value and the loss tangent initial value of the substrate obtained at the p-th test position of the substrate template with the number PCi.

Further, two curves of the initial dielectric constant Dk_pcip_init and the initial loss tangent Df_pcip_init are firstly subjected to curve fitting by using a polynomial function polyfit (x, y, n) respectively, so as to obtain two curves Dk1_poly and Df1_poly of the dielectric constant and the loss tangent of the substrate after fitting with respect to frequency. The fitted dielectric constant Dk_pcip_poly and the fitted loss tangent Df_pcip_poly for each frequency bin in Sf are then calculated using the function polyval.

Wherein x corresponds to each frequency point of the column vector Sf, y corresponds to the initial value Dk_pcip_init of the dielectric constant or the initial value Df_pcip_init of the loss tangent, and n is the highest fitting order.

Further, a total of 4*b pieces of PC templates are calculated, wherein the fitting values Dk_pcip_poly and the fitting values Df_pcip_poly of the dielectric constants of the base materials are in the frequency range of [ f_down, f_up ], and the dielectric constants and the average values of the loss tangent are respectively calculated on each frequency point of the column vector Sf, so that the dielectric constants Dk_pc and the loss tangent Df_pc of the base materials used for the PC templates are obtained in the frequency range of [ f_down, f_up ].

Wherein b is the number of base material PC templates, and more than 5 base material templates can be used for ensuring the test result.

In another embodiment, for the substrate and primer template PD, a computer, an MCK and a network analyzer are connected, after calibration is completed, the substrate and primer templates PD 1-PDb are sequentially placed into an MCK fixture and clamped, each template can test S parameter s_pdip at different positions, and the test results and the test positions on the templates are marked in a one-to-one correspondence.

Where s_pdip represents the S parameter measured at the p-th position of the PD template numbered PDi.

Further, for each substrate+primer template PD, dicing was performed at each test position, and then the substrate thickness h1_pdip and the primer thickness h2_pdip at each test position were measured using an image tester, wherein h1_pdip and h2_pdip represent the substrate thickness and the primer thickness at the p-th position of the substrate+primer template numbered PDi, respectively.

It will be appreciated that for the substrate + primer template PD, it has 2 layers of media, the transmission matrix for the i-th layer of media is:

wherein, the liquid crystal display device comprises a liquid crystal display device,for the equivalent electrical length of the i-th dielectric layer, < >>For the thickness of the i-th layer medium,/a>Is of electromagnetic wave wavelength->C/f, c is the speed of light, f is the electromagnetic wave frequency, +.>Is the complex dielectric constant of the i-th layer medium, < ->θ is the incident angle, < >>Is the dielectric constant of the dielectric material of the i-th layer, < ->The loss tangent of the dielectric material of the i-th layer is j, and j is an imaginary unit.

Wherein, the normalized equivalent characteristic impedance of the i-th layer medium relative to the free space is as follows:

then the total transmission matrix for the t-layer medium is:

for the substrate + primer template PD, t is 2.

By using the conversion relation between the transmission matrix and the S parameter, the calculation formula of the return loss RL can be obtained as follows:

Further, for the S parameter s_pdip measured at each test position on the substrate+primer template PD, the first column of S parameters is a column vector Sf composed of a plurality of discrete frequency points within the range of [ f_down, f_up ], and the S parameters are divided into m frequency bands according to frequencies, and n frequency points for each frequency band. Wherein s_pdip represents the S parameter measured at the p-th position of the substrate template numbered PDi.

Further, the substrate thickness h1_pdip, the primer thickness h2_pdip, and the dielectric constant dk_pc and the loss tangent df_pc of the substrate measured based on the substrate PC template corresponding to the preset test position are brought into the return loss calculation formula.

It will be appreciated that when each band is small, it is considered that the dielectric constant Dk_pd and loss tangent Df_pd of the primer used for the substrate+primer template PD are constant over that band.

Further, the return loss of each frequency point in each frequency range is calculated by means of parameter scanning of the dielectric constant Dk_pd and the loss tangent Df_pd of the primer.

Further, for the p-th frequency range, dk_pd and Df_pd with the smallest RL_del_p values are the initial dielectric constant Dk_pd_p and the initial loss tangent Df_pd_p of the base material+primer used by the primer template PD in the frequency range;

/>

Thereby, two curves of the initial value dk_pdip_init and the initial value df_pdip_init of the loss tangent of the primer used for the template PD at the preset test position in the frequency range of [ f_down, f_up ] are obtained with respect to the column vector Sf.

Wherein Dk_pdip_init and Df_pdip_init represent the base material numbered PDi+primer template p-th test position to obtain the initial value of the dielectric constant and the initial value of the loss tangent of the primer, respectively.

Further, two curves of the initial dielectric constant value Dk_pdip_init and the initial loss tangent value Df_pdip_init are subjected to curve fitting by using a polynomial function polyfit (x, y, n) respectively, so as to obtain two curves Dk2_poly and Df2_poly of the fitted dielectric constant and loss tangent with respect to frequency. The fitted dielectric constant Dk_pdip_poly and the fitted loss tangent Df_pdip_poly for each frequency bin in Sf are then calculated using the function polyval.

Wherein x corresponds to each frequency point of the column vector Sf, y corresponds to the initial value Dk_pdip_init of the dielectric constant or the initial value Df_pdip_init of the loss tangent, and n is the highest fitting order.

Further, a total of 4*b primer dielectric constant fitting values Dk_pdip_poly and loss tangent fitting values Df_pdip_poly in the frequency range of [ f_down, f_up ] are summed up, and dielectric constants and loss tangent average values are respectively calculated on each frequency point of the column vector Sf, so that the dielectric constants Dk_pd and the loss tangent Df_pd of the primer used for the PD template in the frequency range of [ f_down, f_up ] can be obtained.

Wherein b is the number of base materials and primer templates PD, and may be 5 or more base material templates to ensure the test result.

In another embodiment, for the base material, the primer and the color paint template PE, a computer, an MCK and a network analyzer are connected, after calibration is completed, the base material, the primer and the color paint templates PE 1-PEb are sequentially placed into an MCK clamp and clamped, each template is tested for S parameter S_PEip at different positions, and the test results and the test positions on the templates are marked in a one-to-one correspondence.

Wherein S_PEip represents the S parameter measured at the p-th position of the substrate template numbered PEi.

Further, for each substrate+primer+color paint template PE, slicing is carried out at each test position, and then an image tester is used for measuring the thickness of the substrate h1_PEip, the thickness of the primer h2_PEip and the thickness of the color paint h3_PEip at each test position; wherein h1_peip, h2_peip and h3_peip represent the substrate thickness, primer thickness and paint thickness at the p-th position of the substrate + primer + paint template numbered PEi, respectively.

It can be understood that the calculation formula of the return loss can be obtained according to the conversion relation between the multi-layer medium transmission matrix and the S parameter:

further, for the S parameter s_peip measured at each test position on the substrate+primer+color paint template PE, the first column of S parameters is a column vector Sf composed of a plurality of discrete frequency points within the range of [ f_down, f_up ], and the S parameters are divided into m frequency bands according to the frequency, and n frequency points for each frequency band.

Further, the substrate thickness h1_peip, the primer thickness h2_peip, the color paint thickness h3_peip, the dielectric constant dk_pc and the loss tangent df_pc of the substrate measured based on the substrate PC template, and the primer dielectric constant dk_pd and the loss tangent df_pd measured based on the PD template corresponding to the preset test position are brought into the return loss calculation formula. The return loss of each frequency point in each frequency range is calculated by means of parameter scanning of the dielectric constant Dk_pe and the loss tangent Df_pe of the color paint.

It will be appreciated that when each band is small, it is considered that the dielectric constant Dk_pe and loss tangent Df_pe of the paint used for the substrate + primer + paint template PE are constant over that band.

Further, for the p-th frequency range, dk_pe and Df_pe with the smallest RL_del_p values are the initial dielectric constant Dk_pe_p and the initial loss tangent Df_pe_p of the color paint used for the base material+primer+color paint template PE in the frequency range;

Thus, as shown in fig. 7 and 8, two curves of the initial value dk_peip_init and the initial value df_peip_init of the dielectric constant of the paint used for the template PE at the preset test position with respect to the column vector Sf can be obtained in the frequency range of [ f_down, f_up ].

Wherein Dk_peip_init and Df_peip_init respectively represent a base material numbered PEi+primer+paint template p-th test position to obtain a dielectric constant initial value and a loss tangent initial value of the paint.

Further, two curves of the initial dielectric constant value Dk_peip_init and the initial loss tangent value Df_peip_init are firstly subjected to curve fitting by using a polynomial function polyfit (x, y, n) respectively, so that two curves Dk2_poly and Df2_poly of the dielectric constant and the loss tangent relative to frequency after fitting are obtained. The fitted dielectric constant Dk_peip_poly and the fitted loss tangent Df_peip_poly for each frequency bin in Sf are then calculated using the function polyval.

Wherein x corresponds to each frequency point of the column vector Sf, y corresponds to the dielectric constant initial value Dk_peip_init or the loss tangent initial value Df_peip_init, and n is the highest fitting order.

Further, a total of 4*b pieces of PE templates are subjected to dielectric constant fitting value Dk_peip_poly and loss tangent fitting value Df_peip_poly in the frequency range of [ f_down, f_up ], and dielectric constants and loss tangent average values are respectively calculated on each frequency point of the column vector Sf, so that the dielectric constants Dk_pe and the loss tangents Df_pe of the color paint used for the PE templates in the frequency range of [ f_down, f_up ] can be obtained.

Wherein b is the number of base material, primer and color paint template PE, and more than 5 PE templates can be used for ensuring the test result.

In another embodiment, for the base material, the primer, the color paint and the varnish template PF, a computer, an MCK and a network analyzer are connected, after calibration is completed, the base material, the primer and the color paint templates PF 1-PFb are sequentially placed into an MCK clamp and clamped, each template is tested for S parameter S_PFip at different positions, and the test results and the test positions on the template are marked in a one-to-one correspondence.

Wherein S_PFip represents the S parameter measured at the p-th position of the substrate template numbered PFi.

Further, each substrate+primer+paint+paint template PF is sliced at each preset test position, and then the substrate thickness h1_pfip, the primer thickness h2_pfip, the paint thickness h3_pfip, and the varnish thickness h4_pfip at each test position are measured using an image tester.

Wherein h1_peip, h2_peip, h3_peip, and h4_pfip represent the substrate thickness, primer thickness, paint thickness, and varnish thickness at the p-th position of the substrate + primer + paint + varnish template numbered PFi, respectively.

It can be understood that, according to the conversion relation between the multi-layer medium transmission matrix and the S parameter, a return loss calculation formula can be obtained:

further, for the S parameter s_pfip measured at each test position on the substrate+primer+paint+varnish template PF, the first column of S parameters is a column vector Sf composed of a plurality of discrete frequency points within the range of [ f_down, f_up ], and the S parameter is divided into m frequency bands according to the frequency, n frequency points for each frequency band.

Further, the substrate thickness h1_pfip, the primer thickness h2_pfip, the paint thickness h3_pfip, the varnish thickness h4_pfip, the dielectric constants dk_pc and loss tangent df_pc of the substrate measured based on the PC board, the primer dielectric constants dk_pd and loss tangent df_pd measured based on the PD board, and the paint dielectric constants dk_pe and loss tangent df_pe measured based on the PE board are brought into a return loss calculation formula, and the return loss of each frequency point in each frequency range is calculated by performing parameter scanning on the dielectric constants dk_pf and loss tangent df_pf of the varnish.

It will be appreciated that when each band is small, it is considered that the dielectric constant Dk_pf and loss tangent Df_pf of the varnish used for the substrate + primer + paint + varnish template PF are constant over that band.

Further, for the p-th frequency range, dk_pf and Df_pf with the smallest RL_del_p value are the initial dielectric constant Dk_pf_p and the initial loss tangent Df_pf_p of the base material, the primer, the color paint and the color paint used for the varnish template PF in the frequency range;

wherein, the liquid crystal display device comprises a liquid crystal display device,a calculated return loss value representing the ith frequency point in the frequency range of the p-th segment, +.>Indicating the real return loss of the ith frequency point in the p-th frequency rangeMeasuring value of->S11_tes_p_i represents the s11 actual measurement value of the ith frequency point in the p-th frequency range of the PF template.

Thus, two curves of the initial value Dk_pfip_init and the initial value Df_pfip_init of the loss tangent of the varnish for the template PF at the preset test position with respect to the column vector Sf in the frequency range of [ f_down, f_up ] can be obtained.

Wherein Dk_pfip_init and Df_pfip_init represent the substrate+primer+color paint+varnish template p-th test position numbered PFi, respectively, to obtain the initial value of the dielectric constant and the initial value of the loss tangent of the varnish.

Further, two curves of the initial dielectric constant Dk_pfip_init and the initial loss tangent Df_pfip_init are firstly subjected to curve fitting by using a polynomial function polyfit (x, y, n) respectively, so as to obtain two curves Dk2_poly and Df2_poly of the dielectric constant and the loss tangent with respect to frequency after fitting. The fitted dielectric constant Dk_pfip_poly and the fitted loss tangent Df_pfip_poly for each frequency bin in Sf are then calculated using the function polyval.

Wherein x corresponds to each frequency point of the column vector Sf, y corresponds to the dielectric constant initial value Dk_pfip_init or the loss tangent initial value Df_pfip_init, and n is the highest fitting order.

Further, a total of 4*b pieces of the b PF templates are subjected to fitting values Dk_pfip_poly and loss tangent fitting values Df_pfip_poly of primer dielectric constants in the frequency ranges of [ f_down, f_up ], and dielectric constants and loss tangent average values are respectively calculated on each frequency point of the column vector Sf, so that the varnish for the PF template can be obtained, wherein the dielectric constants Dk_pf and the loss tangent Df_pf of the varnish are in the frequency ranges of [ f_down, f_up ].

Wherein b is the number of base materials, primer, color paint and varnish templates PF, and more than 5 PF templates can be used for ensuring the test result.

Referring to fig. 9, fig. 9 is a schematic structural diagram of a device for testing complex dielectric constant of a bumper material according to the present application, where the device for testing complex dielectric constant of a bumper material is used for executing the method for testing complex dielectric constant of a bumper material. The device for testing the complex dielectric constant of the bumper material can be configured in a server.

As shown in fig. 9, the test device 300 for complex dielectric constant of a bumper material includes: a flow orchestration execution module 301, a target node selection module 302, and an event flow generation module 303.

The template measurement module 301 is configured to obtain a test template, and sequentially measure an S parameter of a preset test position on the test template and a material thickness of each dielectric material at the preset test position; wherein the test template comprises a multi-layer template, and the multi-layer template comprises at least one layer of the dielectric material;

a return loss calculation module 302, configured to calculate at least one return loss of each of the dielectric materials at the preset test location in a preset frequency range based on the S parameter corresponding to the preset test location and a material thickness of each of the dielectric materials corresponding to the preset test location;

and a dielectric constant calculation module 303, configured to calculate a loss tangent and a dielectric constant corresponding to each of the dielectric materials based on at least one return loss of each of the dielectric materials in a preset frequency range.

In one embodiment, the test device 300 for complex dielectric constant of the bumper material further includes a return loss formula acquisition module for acquiring a transmission matrix of the dielectric material; and acquiring a return loss calculation formula based on the conversion relation between the transmission matrix and the S parameter.

In one embodiment, the return loss calculation module 302 is further configured to divide the S parameter into at least one frequency band based on a correspondence between frequencies in the preset frequency range and the S parameter, to obtain at least one sub-frequency range, where the sub-frequency range includes at least one frequency point; and calculating the return loss corresponding to each frequency point in the sub-frequency range based on the return loss calculation formula and the material thickness of each dielectric material.

In one embodiment, the dielectric constant calculating module 303 is further configured to calculate an initial value of loss tangent and an initial value of dielectric constant corresponding to the sub-frequency range based on the return loss corresponding to each frequency point in the sub-frequency range and an actual measurement value of return loss corresponding to each frequency point; performing curve fitting on the initial value of the loss tangent and the initial value of the dielectric constant corresponding to the sub-frequency range to obtain a fitting value of the loss tangent and a fitting value of the dielectric constant corresponding to each frequency point; and calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on the loss tangent fitting value and the dielectric constant fitting value corresponding to each frequency point.

In one embodiment, the dielectric constant calculating module 303 is further configured to obtain each of the loss tangent fit value and the dielectric constant fit value calculated corresponding to each of the preset test positions; calculating the average value of the loss tangent fitting values corresponding to the same frequency point to obtain the loss tangent of the dielectric material; and calculating the average value of the dielectric constant fitting values corresponding to the same frequency point to obtain the dielectric constant of the dielectric material.

In one embodiment, the return loss calculation module 302 is further configured to calculate, when the test template includes multiple layers of the dielectric material, at least one return loss of the dielectric material to be tested in the preset frequency range at the preset test position based on the dielectric constant and the loss tangent of the dielectric material to be tested, the material thickness of the dielectric material to be tested, and the S parameter corresponding to the preset test position.

It should be noted that, for convenience and brevity of description, the specific operation of the apparatus and the modules described above may refer to the corresponding process in the embodiment of the method for testing the complex dielectric constant of the bumper material, which is not described herein.

The apparatus provided by the above embodiments may be implemented in the form of a computer program which may be run on a computer device as shown in fig. 10.

Referring to fig. 10, fig. 10 is a schematic block diagram of a computer device according to an embodiment of the present application. The computer device may be a server.

With reference to FIG. 10, the computer device includes a processor, memory, and a network interface connected by a system bus, where the memory may include a non-volatile storage medium and an internal memory.

The non-volatile storage medium may store an operating system and a computer program. The computer program includes program instructions that, when executed, cause the processor to perform any one of a plurality of methods for testing a complex permittivity of a bumper material.

The processor is used to provide computing and control capabilities to support the operation of the entire computer device.

The internal memory provides an environment for the execution of a computer program in the non-volatile storage medium, which when executed by the processor, causes the processor to perform any one of the methods for testing the complex permittivity of the bumper material.

The network interface is used for network communication such as transmitting assigned tasks and the like. It will be appreciated by those skilled in the art that the structure shown in FIG. 10 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the computer device to which the present inventive arrangements may be applied, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.

It should be appreciated that the processor may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field-programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. Wherein the general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

Wherein in one embodiment the processor is configured to run a computer program stored in the memory to implement the steps of:

In one embodiment, before implementing the calculating, based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, at least one return loss of each dielectric material in a preset frequency range at the preset test position, the processor is further configured to implement:

acquiring a transmission matrix of the dielectric material;

wherein, the transmission matrix is:

/>

wherein, the return loss calculation formula is:

wherein, RL is return loss.

In one embodiment, when the processor calculates at least one echo loss of each dielectric material at the preset test position in a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, the processor is configured to implement:

In one embodiment, the processor is configured to, when implementing the calculating the loss tangent and the dielectric constant corresponding to each of the dielectric materials based on at least one return loss of each of the dielectric materials in a preset frequency range, implement:

In one embodiment, the processor is configured to, when implementing the calculation of the loss tangent and the dielectric constant corresponding to each dielectric material based on the loss tangent fit value and the dielectric constant fit value corresponding to each frequency point, implement:

In one embodiment, when the processor calculates at least one echo loss of each of the dielectric materials at the preset test location in a preset frequency range based on the S parameter corresponding to the preset test location and the material thickness of each of the dielectric materials corresponding to the preset test location, the processor is configured to implement:

The embodiment of the application also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, the computer program comprises program instructions, and the processor executes the program instructions to realize the method for testing the complex dielectric constant of any bumper material provided by the embodiment of the application.

The computer readable storage medium may be an internal storage unit of the computer device according to the foregoing embodiment, for example, a hard disk or a memory of the computer device. The computer readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), or the like, which are provided on the computer device.

While the application has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. A method for testing the complex permittivity of a bumper material, the method comprising:

Calculating at least one return loss of each dielectric material at the preset test position in a preset frequency range based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, specifically including:

calculating the return loss corresponding to each frequency point in the sub-frequency range based on a return loss calculation formula and the material thickness of each dielectric material;

calculating loss tangent and dielectric constant corresponding to each dielectric material based on at least one return loss of each dielectric material in a preset frequency range, wherein the method specifically comprises the following steps: calculating an initial value of loss tangent and an initial value of dielectric constant corresponding to the sub-frequency range based on the return loss corresponding to each frequency point in the sub-frequency range and the actual measurement value of return loss corresponding to each frequency point;

Calculating the loss tangent and the dielectric constant corresponding to each dielectric material based on the loss tangent fitting value and the dielectric constant fitting value corresponding to each frequency point;

the test panels include a substrate panel, a substrate-primer-paint panel, and a substrate-primer-paint-varnish panel;

the dielectric material comprises a substrate, a primer, a color paint and a varnish;

2. The method for testing the complex permittivity of a bumper material according to claim 1, wherein before calculating at least one return loss of each of the dielectric materials in a predetermined frequency range at the predetermined test position based on the S parameter corresponding to the predetermined test position and the material thickness of each of the dielectric materials corresponding to the predetermined test position, further comprises:

Acquiring a transmission matrix of the dielectric material;

wherein, the transmission matrix is:

wherein t is the number of layers of dielectric materials,for the equivalent electrical length of the i-th dielectric material layer,/or->For the thickness of the dielectric material of the i-th layer, +.>Is of electromagnetic wave wavelength->C/f, c is the speed of light, f is the electromagnetic wave frequency, +.>Is the complex dielectric constant of the dielectric material of the i-th layer, < ->θ is the incident angle, j is the imaginary unit, +.>Is the dielectric constant of the dielectric material of the i-th layer, < ->Loss tangent of dielectric material of the i-th layer, < >>Normalized equivalent characteristic impedance of the dielectric material of the i layer relative to free space:

wherein, the return loss calculation formula is:

wherein, RL is return loss.

3. The method according to claim 1, wherein the calculating the loss tangent and the dielectric constant for each of the dielectric materials based on the loss tangent fit value and the dielectric constant fit value for each of the frequency points, comprises:

4. A device for testing the complex permittivity of a bumper material, the device comprising:

the return loss calculation module is configured to calculate, based on the S parameter corresponding to the preset test position and the material thickness of each dielectric material corresponding to the preset test position, at least one return loss of each dielectric material at the preset test position in a preset frequency range, and specifically includes: dividing the S parameter into at least one frequency band based on the corresponding relation between the frequency in the preset frequency range and the S parameter to obtain at least one sub-frequency range, wherein the sub-frequency range comprises at least one frequency point;

the dielectric constant calculation module is configured to calculate, based on at least one return loss of each dielectric material in a preset frequency range, loss tangent and dielectric constant corresponding to each dielectric material, and specifically includes:

5. A computer device comprising a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein the computer program when executed by the processor performs the steps of the method for testing the complex permittivity of a bumper material according to any one of claims 1 to 3.

6. A computer-readable storage medium, on which a computer program is stored, wherein the computer program, when being executed by a processor, implements the steps of the method for testing the complex permittivity of a bumper material according to any one of claims 1 to 3.