A far-field pattern analysis method for patch antennas based on equivalent surface magnetic current spacing

Abstract

The present invention discloses a patch antenna far-field pattern analysis method based on equivalent surface magnetic flux spacing, including determining design parameters and material parameters of the patch antenna, calculating analysis parameters of the patch antenna; combining the analysis parameters with the theoretical assumptions of the patch antenna transmission line analysis method, determining the radiation of a single equivalent surface magnetic flux, determining the pattern function of the transmission line analysis method, obtaining the equivalent coefficient of the material, and then obtaining the equivalent relative dielectric constant of the microstrip line, and finally obtaining the equivalent surface magnetic flux spacing; according to the equivalent surface magnetic flux spacing and the theoretical assumptions of the transmission line analysis method, obtaining the patch antenna far-field pattern based on the equivalent surface magnetic flux spacing, and analyzing the radiation characteristics of the patch antenna. The present invention can accurately analyze the radiation characteristics of the patch antenna, and has a strong engineering significance for the electrical performance analysis of the patch antenna in actual work.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and specifically relates to a far-field pattern analysis method of a patch antenna based on an equivalent surface magnetic current spacing, which can be used to guide the electrical performance analysis of the patch antenna in actual work. Background Art

[0002] With the increase in the amount of data transmitted in modern communications, higher requirements are placed on the overall performance of antennas, such as multi-band, high gain, etc. Among the various types of antennas, patch antennas, as an important component, have developed rapidly in the past 50 years. Patch antennas have been loved by researchers for their many advantages such as small weight, small size, low cost, and easy manufacturing, and have great potential.

[0003] There are many methods for patch antenna far-field pattern analysis. The most widely used one is the transmission line analysis method proposed by Mangsen in 1974. This method can provide a clear physical explanation, and the analysis is direct and simple, easy to understand and remember. It is a one-dimensional approximate calculation method. But the disadvantage is that it is less accurate than other methods and difficult to perform coupled modeling. The cavity model theory proposed by Luo Yuanzhi in 1979 is a two-dimensional approximate analysis method, and it is applicable to all regular shapes, but its disadvantage is that it cannot analyze patches of larger thickness. The most accurate are various full-wave analysis methods such as the finite element method, the finite difference time domain method, and the moment method, but their disadvantages are huge calculations and relatively complex processes. Summary of the invention

[0004] In order to solve the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a patch antenna far-field pattern analysis method based on the equivalent surface magnetic current spacing. This method improves the spacing of the equivalent surface magnetic current in the transmission line analysis method, and can accurately analyze the far-field pattern of the patch antenna, which is of great significance for the prediction of the radiation performance of the patch antenna in actual work.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a patch antenna far-field pattern analysis method based on equivalent surface magnetic current spacing, comprising the following steps:

[0007] (1) Determine the design parameters and material parameters of the patch antenna based on the actual design requirements of the patch antenna;

[0008] (2) Calculate the analysis parameters of the patch antenna based on the design parameters of the patch antenna;

[0009] (3) Based on the analysis parameters of the patch antenna and the theoretical assumptions of the patch antenna transmission line analysis method, determine the radiation of a single equivalent surface magnetic flux and determine the directional pattern function of the transmission line analysis method;

[0010] (4) According to the material parameters of the patch antenna, the equivalent coefficient of the material is obtained, and then the equivalent relative dielectric constant of the microstrip line is obtained, and finally the equivalent surface magnetic current spacing is obtained;

[0011] (5) According to the theoretical assumptions of the equivalent surface magnetic flux spacing and transmission line analysis method, the far-field radiation pattern of the patch antenna based on the equivalent surface magnetic flux spacing is obtained, and the radiation characteristics of the patch antenna are analyzed.

[0012] Preferably, the patch antenna design parameters include the antenna resonant frequency and the thickness of the dielectric substrate; and the material parameter is the relative dielectric constant of the dielectric substrate.

[0013] Preferably, in step (2), the analysis parameters of the patch antenna are calculated including the width of the patch, the effective dielectric constant of the microstrip line, and the effective length of the patch antenna.

[0014] Preferably, step (3) is performed as follows:

[0015] (3a) Determine the radiation field of a single equivalent surface magnetic flux;

[0016] (3b) Determine the directional pattern function of the transmission line analysis method based on the radiation field of the single equivalent surface magnetic current in step (3a) and the effective length of the patch antenna in step (2c).

[0017] Preferably, step (4) is performed as follows:

[0018] (4a) calculating the equivalent coefficient according to the relative dielectric constant of the dielectric substrate material in step (1);

[0019] (4b) Calculate the equivalent dielectric constant of the microstrip line based on the equivalent coefficient obtained in step (4a);

[0020] (4c) Based on the equivalent dielectric constant of the microstrip line obtained in step (4b), calculate the equivalent surface magnetic current spacing.

[0021] Preferably, step (5) is performed according to the following steps:

[0022] (5a) According to the equivalent surface magnetic current spacing calculated in step (4c), replace the effective length of the directional pattern function of the transmission line analysis method in step (3b):

[0023] (5b) According to step (5a), the far-field pattern of the patch antenna is calculated to obtain the beam pointing direction and beam width.

[0024] The present invention adopts the above technical solution, which has the following beneficial effects:

[0025] 1. The present invention adopts the method of replacing the effective length in the transmission line analysis method with the equivalent surface magnetic current spacing, which solves the disadvantage of insufficient accuracy compared with the traditional transmission line analysis method.

[0026] 2. The present invention is based on the traditional transmission line analysis method. Compared with the cavity mode theory analysis method, it solves the shortcoming that it cannot analyze the thickness of a large dielectric substrate.

[0027] 3. Compared with the full-wave analysis method, the present invention solves the shortcomings of huge calculation amount and relatively complicated process.

[0028] 4. Comparing the two main-surface beam widths calculated by the transmission line analysis method of the present invention and the HFSS software, the maximum directivity coefficient error of the patch antenna is no more than 0.2dBi; the E-surface beam width error is no more than 3°; and the H-surface beam width error is no more than 4°. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is a flow chart of a patch antenna far-field pattern analysis method based on equivalent surface magnetic current spacing of the present invention;

[0031] Figure 2 It is a schematic diagram of the model of the patch antenna;

[0032] Figure 3 This is a comparison diagram of the E surface of the simulation results of the present invention, the transmission line analysis method and the numerical software HFSS in Example 1;

[0033] Figure 4 This is an H-plane comparison diagram of simulation results of Example 1 using the present invention, the transmission line analysis method and the numerical software HFSS.

[0034] Figure 5 This is a comparison diagram of the E surface of the simulation results of Example 2 using the present invention, the transmission line analysis method and the numerical software HFSS;

[0035] Figure 6 This is an H-plane comparison diagram of simulation results of Example 2 using the present invention, the transmission line analysis method and the numerical software HFSS.

[0036] Figure 7 This is a comparison diagram of the E surface of the simulation results of the transmission line analysis method and the numerical software HFSS using the present invention in Example 3;

[0037] Figure 8 This is an H-plane comparison diagram of simulation results of Example 3 using the present invention, the transmission line analysis method and the numerical software HFSS. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0039] Reference Figure 1 The present invention is a patch antenna far-field pattern analysis method based on equivalent surface magnetic current spacing, and the specific steps are as follows:

[0040] Step 1: Determine the design parameters of the patch antenna

[0041] According to the actual requirements of the patch antenna, the design parameters of the patch antenna include the antenna resonant frequency and the thickness of the dielectric substrate; the material parameter is the relative dielectric constant of the dielectric substrate.

[0042] Step 2: Determine the analysis parameters of the patch antenna

[0043] Calculate the analysis parameters of the patch antenna according to the design parameters of the patch antenna in step 1. The analysis parameters of the patch antenna include the width of the patch antenna, the effective dielectric constant of the microstrip line, and the effective length of the patch antenna. Follow the steps below:

[0044] (2a) The width of the patch antenna is calculated as follows:

[0045]

[0046] Among them, C 0 is the speed of light, f r Antenna resonant frequency, ε r The relative dielectric constant of the material;

[0047] (2b) Determine the effective dielectric constant of the microstrip line and calculate it according to the following formula:

[0048]

[0049] Where, h is the thickness of the dielectric substrate;

[0050] (2c) Determine the effective length of the patch antenna and calculate it according to the following formula:

[0051]

[0052] Step 3: Determine the directivity diagram function of the transmission line analysis method

[0053] According to the analysis parameters of the patch antenna in step 2, determine the radiation of a single equivalent surface magnetic flux, and then determine the directional pattern function of the transmission line analysis method, and proceed as follows:

[0054] (3a) Determine the radiation field of a single surface magnetic flux and calculate it according to the following formula:

[0055]

[0056] Among them, k 0 =2πf r / C 0 is the propagation constant, is the far-field normalized pattern function of a single equivalent surface magnetic current.

[0057] (3b) Determine the directivity pattern function of the transmission line analysis method, which is calculated according to the following formula:

[0058]

[0059] in, is the far-field normalized pattern function of the patch antenna based on the transmission line analysis method.

[0060] Step 4, solving the equivalent coefficient, equivalent dielectric constant and equivalent surface magnetic current spacing;

[0061] According to the relative dielectric constant of the patch antenna dielectric substrate material in step 1, the equivalent coefficient of the material is calculated, and then the equivalent dielectric constant of the microstrip line is calculated, and finally the equivalent surface magnetic current spacing is calculated. Follow the steps below:

[0062] (4a) According to the relative dielectric constant of the dielectric substrate material obtained in step (1), the equivalent coefficient is calculated according to the following formula:

[0063] S=1.0696ε r -0.634

[0064] (4b) Based on the equivalent coefficient obtained in step (4a), calculate the equivalent dielectric constant of the microstrip line according to the following formula:

[0065]

[0066] (4c) Based on the equivalent dielectric constant of the microstrip line obtained in step (4b), the equivalent surface magnetic current spacing is calculated according to the following formula:

[0067] Step 5: Far-field normalized pattern based on equivalent surface magnetic flux spacing

[0068] According to the equivalent surface magnetic current spacing in step 4, replace the effective length in the transmission line pattern function to obtain the far-field pattern of the patch antenna based on the equivalent surface magnetic current spacing. Follow the steps below:

[0069] (5a) According to the equivalent surface magnetic current spacing calculated in step (4c), replace the effective length in the transmission line analysis method directional diagram function in (3b):

[0070]

[0071] In the formula, is the far-field normalized pattern function of the patch antenna based on the equivalent surface magnetic current spacing;

[0072] (5b) According to step (5a), the far-field radiation pattern of the patch antenna is calculated to obtain electrical parameters such as beam pointing and beam width.

[0073] The advantages of the present invention can be further illustrated by the following simulation case:

[0074] 1. Simulation parameters

[0075] Simulation Example 1: Taking a patch antenna with a central operating frequency of f=3 GHz, a relative dielectric constant of 2.2, and a dielectric substrate thickness of 2.87 mm as an analysis case, its radiation performance is analyzed.

[0076] Simulation Example 2: Taking a patch antenna with a central operating frequency of f=10 GHz, a relative dielectric constant of 2.2, and a dielectric substrate thickness of 1.588 mm as an analysis case, its radiation performance is analyzed.

[0077] Simulation Example 3: Taking a patch antenna with a central operating frequency of f=2.45 GHz, a relative dielectric constant of 4.4, and a dielectric substrate thickness of 1.6 mm as an analysis case, its radiation performance is analyzed.

[0078] 2. Simulation content and results

[0079] Figure 2 is a schematic diagram of the patch antenna structure; Figure 3 and Figure 4 The E-plane and H-plane directional diagrams calculated by the method in Example 1, and the comparison of the simulation results calculated by the transmission line analysis method and the numerical software HFSS are given respectively; Table 1 gives the comparison results of the two main surface beam widths calculated by the present invention, the transmission line analysis method and the HFSS software in Example 1.

[0080] Table 1 Comparison of electrical performance parameters of Example 1

[0081] Electrical performance parameters The present invention Transmission Line Analysis Methods HFSS Maximum directivity coefficient / dBi 7.99 6.91 8.16 <![CDATA[Main beam pointing θ / ° > 0 0 0 E-plane beamwidth BW / ° 74 90 76.11 H-plane beamwidth BW / ° 73 73 69.2

[0082] It can be seen that the far-field pattern of the patch antenna analyzed by the present invention is not much different from the calculation result of the numerical software HFSS, and is basically consistent, and the accuracy is greatly improved compared with the transmission line analysis method. The maximum directivity coefficient error between this method and the simulation result is 0.16dBi; the E-plane beam width error is 2.11°; and the H-plane beam width error is 3.8°.

[0083] Figure 5 and Figure 6 The E-plane and H-plane directional diagrams calculated by the method in Example 2, and the comparison of the simulation results calculated by the transmission line analysis method and the numerical software HFSS are given respectively; Table 2 gives the comparison results of the two main surface beam widths calculated by the present invention, the transmission line analysis method and the HFSS software in Example 2.

[0084] Table 2 Comparison of electrical performance parameters of Example 2

[0085] Electrical performance parameters The present invention Transmission Line Analysis Methods HFSS Maximum directivity coefficient / dBi 7.82 7.28 7.96 <![CDATA[Main beam pointing θ / ° > 0 0 0 E-plane beamwidth BW / ° 76.1 91.2 78.28 H-plane beamwidth BW / ° 75.2 75.2 71.33

[0086] It can be seen that the far-field pattern of the patch antenna analyzed by the present invention is not much different from the calculation result of the numerical software HFSS, and is basically consistent, and the accuracy is greatly improved compared with the transmission line analysis method. The maximum directivity coefficient error between this method and the simulation result is 0.14dBi; the E-plane beam width error is 2.18°; and the H-plane beam width error is 3.87°.

[0087] Figure 7 and Figure 8 The E-plane and H-plane directional diagrams calculated by the method in Example 3, and the comparison of the simulation results calculated by the transmission line analysis method and the numerical software HFSS are given respectively; Table 3 gives the comparison results of the two main surface beam widths calculated by the present invention, the transmission line analysis method and the HFSS software in Example 3.

[0088] Table 3 Comparison of electrical performance parameters of Example 3

[0089]

[0090]

[0091] It can be seen that the far-field pattern of the patch antenna analyzed by the present invention is not much different from the calculation result of the numerical software HFSS, and is basically consistent, and the accuracy is greatly improved compared with the transmission line analysis method. The maximum directivity coefficient error between this method and the simulation result is 0.15dBi; the E-plane beam width error is 2.8°; and the H-plane beam width error is 3.5°.

[0092] From the comparison of the above embodiments, it can be seen that the transmission line analysis method of the present invention is compared with the two main plane beam widths calculated by HFSS software, and the maximum directivity coefficient error of the patch antenna is no more than 0.2dBi; the E plane beam width error is no more than 3°; and the H plane beam width error is no more than 4°. Therefore, the effectiveness of the method of the present invention is verified.

[0093] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for analyzing far-field patterns of patch antennas based on equivalent surface magnetic current spacing, characterized in that: The steps include: (1) Determine the design parameters and material parameters of the patch antenna based on the actual design requirements of the patch antenna; (2) Calculate the analysis parameters of the patch antenna based on the design parameters of the patch antenna; (3) Based on the analysis parameters of the patch antenna and the theoretical assumptions of the patch antenna transmission line analysis method, determine the radiation of a single equivalent surface magnetic flux and determine the directional pattern function of the transmission line analysis method; (4) According to the material parameters of the patch antenna, the equivalent coefficient of the material is obtained, and then the equivalent relative dielectric constant of the microstrip line is obtained, and finally the equivalent surface magnetic current spacing is obtained; (5) According to the theoretical assumptions of the equivalent surface magnetic flux spacing and transmission line analysis method, the far-field pattern of the patch antenna based on the equivalent surface magnetic flux spacing is obtained, and the radiation characteristics of the patch antenna are analyzed; The step (4) is carried out as follows: (4a) Based on the relative dielectric constant of the dielectric substrate material in step (1), the equivalent coefficient is calculated according to the following formula: S=1.0696e r -0.634 Among them, ε r is the relative dielectric constant of the material; (4b) Based on the equivalent coefficient obtained in step (4a), calculate the equivalent dielectric constant of the microstrip line according to the following formula: (4c) Based on the equivalent dielectric constant of the microstrip line obtained in step (4b), the equivalent surface magnetic current spacing is calculated according to the following formula: Where C0 is the speed of light, f r is the antenna resonant frequency; In the step (5), according to the equivalent surface magnetic current spacing, the effective length of the transmission line pattern function is replaced to obtain the far-field pattern function of the patch antenna based on the equivalent surface magnetic current spacing; The step (5) is carried out according to the following steps: (5a) According to the equivalent surface magnetic current spacing calculated in step (4c), replace the effective length of the directional pattern function of the transmission line analysis method in step (3b): (5b) According to step (5a), the far-field pattern of the patch antenna is calculated to obtain the beam pointing direction and beam width.

2. According to the method for analyzing far-field pattern of patch antenna based on equivalent surface magnetic current spacing of claim 1, it is characterized in that: The patch antenna design parameters include the antenna resonant frequency and the thickness of the dielectric substrate; the material parameter is the relative dielectric constant of the dielectric substrate.

3. The method for analyzing far-field patterns of patch antennas based on equivalent surface magnetic current spacing according to claim 1 is characterized in that: In the step (2), the analysis parameters of the patch antenna are calculated including the width of the patch, the effective dielectric constant of the microstrip line, and the effective length of the patch antenna; Determine the width of the patch and calculate according to the following formula: Determine the effective dielectric constant of the microstrip line and calculate it according to the following formula; Where, h is the thickness of the dielectric substrate; Determine the effective length of the patch antenna and calculate according to the following formula; 4. The method for analyzing far-field patterns of patch antennas based on equivalent surface magnetic current spacing according to claim 3 is characterized in that: The step (3) is carried out as follows: (3a) Determine the radiation field of a single equivalent surface magnetic flux: where k0 = 2πf r / C0 is the propagation constant, is the far-field normalized pattern function of a single equivalent surface magnetic current; (3b) According to the radiation field of a single equivalent surface magnetic flux combined with the effective length of the patch antenna, the directional pattern function of the transmission line analysis method is determined: in, is the far-field normalized pattern function of the patch antenna based on the transmission line analysis method.

5. The method for analyzing far-field patterns of patch antennas based on equivalent surface magnetic current spacing according to claim 1, characterized in that: The effective length of the transmission line analysis method pattern function in the replacement step (3b) is calculated according to the following formula: In the formula, is the far-field pattern function of the patch antenna based on the equivalent surface magnetic current spacing, D r is the equivalent surface magnetic flux distance.

6. A patch antenna far-field pattern analysis method based on equivalent surface magnetic current spacing according to any one of claims 1 to 5, characterized in that: The maximum directivity coefficient error of the patch antenna is no more than 0.2dBi; the E-plane beam width error is no more than 3°; the H-plane beam width error is no more than 4°.

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