Microstrip antenna and microstrip antenna array

Abstract

The present invention discloses a microstrip antenna and a microstrip antenna array, comprising a dielectric substrate, a radiation patch, a ground patch and a feeding microstrip line; the radiation patch is arranged on the front of the dielectric substrate, the radiation patch is connected to the feeding microstrip line, and is fed through the feeding microstrip line; the ground patch is arranged on the back of the dielectric substrate, a calabash groove is provided in the middle of the ground patch, the opening side of the calabash groove is located on the upper side of the ground patch, and there is an arc cut angle between the upper side and the left and right sides of the ground patch. The present invention realizes ultra-wideband and omnidirectional radiation and reception covering L, S, C, X, Ku, and K frequency bands by introducing an arc cut angle and a central calabash groove on the ground patch.

Description

Technical Field

[0001] The invention relates to antenna design technology, and in particular to a microstrip antenna and a microstrip antenna array suitable for electromagnetic compatibility measurement in an electromagnetic radiation emission site. Background Art

[0002] In the field of electromagnetic compatibility measurement at most radiation emission sites, the antennas usually used are directional antennas with narrow bandwidth and large size. In a specific complex field environment, it is necessary to collect electromagnetic interference signals from multiple directions and multiple working frequencies based on a specific electromagnetic signal processing algorithm. However, environmental electromagnetic interference signals are difficult to predict and prone to sudden emergencies. In order to receive unpredictable interference electromagnetic waves in all directions and frequency bands, an omnidirectional ultra-wideband electromagnetic compatibility antenna with a wide bandwidth and a wide radiation coverage range is required. At present, in the field of realizing ultra-wideband antennas, there are mainly the following types:

[0003] Dielectric resonator antenna: Dielectric resonator antennas are easy to obtain longer bandwidths by selecting appropriate resonant parameters such as the shape, size, and dielectric constant of the dielectric resonator, and are often used in the field of wireless communications. Although dielectric resonator antennas have excellent performance in terms of bandwidth and gain, most of them are three-dimensional structures with high profiles. Antennas used for electromagnetic compatibility measurements are generally large in size and difficult to carry and transport.

[0004] Planar tapered slot antenna: By designing a tapered slot line on the metal surface of a given dielectric substrate, such as an exponentially tapered Vivaldi antenna, electromagnetic waves are transmitted and radiated along the slot, thereby achieving ultra-wideband. Planar tapered slot antennas are widely used in wireless communication systems, automotive radar remote sensing imaging, etc. However, planar tapered slot antennas require the design of a longer slot tapered radiation structure, which increases the size of the antenna and the manufacturing cost of the antenna.

[0005] Microstrip antenna: Microstrip antenna can widen the frequency band to achieve ultra-wideband by increasing the thickness of the dielectric substrate or reducing its dielectric constant, loading metamaterials, adding matching networks, and forming antenna arrays. Microstrip antennas are easy to process and have low production costs, so they have broad application prospects. Among them, the microstrip antenna with a fractal structure is a very promising ultra-wideband antenna in recent years. The fractal structure is mainly based on the symmetry of different specified limits, and is defined and designed through recursive and iterative mathematical principles, and ultra-wideband is achieved through mathematical optimization methods. However, the structure of the microstrip antenna patch with a fractal structure is sometimes too complicated, and some difficulties will be encountered in actual processing. The conventional design of microstrip patch antennas generally has a narrow frequency band, and its relative bandwidth is about 1% to 7%; there are conductor and dielectric losses, which will excite surface waves and have low efficiency. Summary of the invention

[0006] In view of the problems in the prior art that the electromagnetic compatibility measurement receiving antenna currently working in the L and S bands is large in size (greater than 1 working wavelength), weak in omnidirectional performance (small signal coverage receiving range), complex in structure, narrow in bandwidth (relative bandwidth is about 20%, which makes it difficult to cover multiple working frequencies of electromagnetic interference sources), and low in radiation gain (<2dB, low radiation efficiency), the purpose of the present invention is to provide a microstrip antenna and a microstrip antenna array.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0008] In one aspect, the present invention provides a microstrip antenna, comprising a dielectric substrate, a radiation patch, a ground patch, and a feeding microstrip line;

[0009] The radiation patch is arranged on the front side of the dielectric substrate, the radiation patch is connected to the feeding microstrip line, and is fed through the feeding microstrip line;

[0010] The ground patch is arranged on the back of the dielectric substrate, a calabash groove is provided in the middle of the ground patch, the opening side of the calabash groove is located on the upper side of the ground patch, and an arc-shaped cut angle is provided between the upper side and the left and right sides of the ground patch.

[0011] As a preferred embodiment of the present invention, the dielectric substrate is rectangular or square, the ground patch is rectangular, the dielectric substrate, radiation patch and ground patch are all axisymmetric structures, and the symmetry axes of the dielectric substrate, radiation patch and ground patch coincide.

[0012] As a preferred solution of the present invention, the radiation patch and the ground patch are both metal patches.

[0013] As a preferred embodiment of the present invention, the radiation patch is a semi-circular metal patch. The semi-circular radiation patch is obtained by cutting off a small semi-circular metal patch above a semi-circular metal patch. The first end of the feed microstrip line is connected to the middle of the bottom arc outer edge of the semi-circular metal patch, and the second end of the feed microstrip line extends vertically to the lower side of the dielectric substrate.

[0014] As a preferred solution of the present invention, the radius of the two arc-shaped cut corners of the ground patch affects the working bandwidth of the antenna. As the radius of the two arc-shaped cut corners increases, the working frequency band in the low frequency band becomes narrower, and there is no obvious change trend in the high frequency band.

[0015] On the other hand, the present invention provides a microstrip antenna array, comprising a plurality of any of the above-mentioned microstrip antennas.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The invention realizes ultra-wideband and omnidirectional radiation and reception covering L, S, C, X, Ku and K frequency bands by introducing arc-shaped cut corners and a central gourd groove on a ground patch.

[0018] The present invention greatly improves the bandwidth of the microstrip antenna, the bandwidth reaches 180.6%, and realizes the miniaturization and omnidirectionality of the microstrip antenna.

[0019] The invention has a novel and simple structure, reduces the cost and is easy to process and manufacture compared with the existing disclosed documents. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front structural schematic diagram of an embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the back structure of an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the side structure of an embodiment of the present invention;

[0023] Figure 4 A graph of antenna reflection coefficient according to an embodiment of the present invention;

[0024] Figure 5 The E-plane and H-plane radiation patterns of the antenna of one embodiment of the present invention are at different frequency points, wherein: (a) represents the E-plane and H-plane radiation patterns of the antenna when it is at 2 GHz; (b) represents the E-plane and H-plane radiation patterns of the antenna when it is at 5 GHz; (c) represents the E-plane and H-plane radiation patterns of the antenna when it is at 10 GHz; (d) represents the E-plane and H-plane radiation patterns of the antenna when it is at 15 GHz; (e) represents the E-plane and H-plane radiation patterns of the antenna when it is at 20 GHz; (f) represents the E-plane and H-plane radiation patterns of the antenna when it is at 25 GHz.

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The electromagnetic compatibility measurement receiving antenna currently working in the L and S bands is large in size (greater than 1 working wavelength), has weak omnidirectional performance (small signal coverage receiving range), complex structure, narrow bandwidth (relative bandwidth is about 20%, which makes it difficult to cover multiple working frequencies of electromagnetic interference sources), and low radiation gain (<2dB, low radiation efficiency). The ultra-wideband omnidirectional electromagnetic compatibility antenna (1.4GHz-27.5GHz) designed by the present invention can achieve the miniaturization, omnidirectionality and ultra-wideband working characteristics of the antenna by introducing arc-shaped corners and gourd-shaped metamaterial structures in a circular ring radiating patch and on the back floor, and can cover the radiation source signals and electromagnetic interference signals in the L, S, C, X, Ku, and K bands, and has high gain and radiation efficiency.

[0032] The present invention is currently mainly designed for use in the field of electromagnetic compatibility measurement in electromagnetic radiation emission sites. While the antenna achieves omnidirectionality, it achieves miniaturization and ultra-wideband by loading a metamaterial structure, and has high radiation efficiency. It can also be promoted and applied to fields such as the Internet of Things and radar.

[0033] Reference Figure 1 , Figure 2 and Figure 3 In one embodiment of the present invention, a microstrip antenna is provided, and the microstrip antenna has an axisymmetric structure as a whole.

[0034] The microstrip antenna comprises a dielectric substrate 1, a radiation patch 2, a ground patch 3 and a feeding microstrip line 4. The dielectric substrate 1, the radiation patch 2, the ground patch 3 and the feeding microstrip line 4 are all axisymmetric structures, and the symmetry axes of the dielectric substrate 1, the radiation patch 2, the ground patch 3 and the feeding microstrip line 4 coincide.

[0035] The dielectric substrate 1 is a rectangular dielectric substrate with a length of l and a width of w.

[0036] The radiation patch 2 is a semi-circular metal patch. The semi-circular radiation patch is obtained by cutting off a small semi-circular metal patch (with a radius of R1) above a semi-circular metal patch (with a radius of R2). The radius of the outer arc of the semi-circular metal patch is R2, and the radius of the inner arc of the semi-circular metal patch is R1.

[0037] The radiation patch 2 is arranged on the front of the dielectric substrate 1, and the radiation patch 1 is connected to the rectangular feeding microstrip line 4, and is fed through the feeding microstrip line 4. The first end of the feeding microstrip line 4 is connected to the middle of the arc-shaped outer edge of the bottom of the semi-circular metal patch, and the second end of the feeding microstrip line 4 extends vertically to the lower side of the dielectric substrate 1. The length of the rectangular feeding microstrip line 4 is l s , with a width of w d .

[0038] The open end of the radiation patch 2 faces the upper side of the dielectric substrate 1. The surface current of the radiation patch 2 is mainly distributed near the outer arc edge 5 of the radiation patch 2 and near the left and right edges of the feeding microstrip line 4. The place where the surface current is most dense is also the place where the radiation is strongest. The signal is coupled to the outer arc edge of the radiation patch 2 along the left and right edges of the feeding microstrip line 4, and gradually radiates along the arc edges on both sides of the radiation patch 2. This is the key factor for it to produce omnidirectional radiation and broadband operation. There is almost no distributed surface current above the radiation patch 2, so the semi-circular radiation patch is obtained by cutting off a small semi-circular metal patch (radius R1) above a semi-circular metal patch (radius R2), which can minimize the use of metal, thereby saving costs, and does not affect the overall radiation performance of the antenna.

[0039] The ground patch 3 is a rectangular metal patch, and its length is the same as that of the dielectric substrate 1, which is l, and its width is g. The ground patch 3 is arranged on the back of the dielectric substrate 1, and the lower long side of the ground patch 3 coincides with the lower side of the dielectric substrate 1. A gourd groove 6 is provided in the middle of the ground patch 3, and the opening side of the gourd groove 6 is located on the upper side of the ground patch 3. There is an arc-shaped cut corner 7 between the upper side and the left and right sides of the ground patch 3, and the radius of the arc-shaped cut corner 7 is R3. The radius of the two arc-shaped cut corners 7 of the ground patch 3 affects the bandwidth of the antenna. As the radius of the two arc-shaped cut corners increases, the working frequency band in the low frequency band becomes narrower, and there is no obvious change trend in the high frequency band.

[0040] The gourd groove 6 is composed of two or more circular gourd groove units connected in series, wherein the radius of the circular gourd groove unit located on the outermost side is the largest, and the radius of the circular gourd groove unit decreases linearly from the outer side to the inner side. Figure 2 In the embodiment shown, the gourd groove 6 is composed of three circular gourd groove units connected in series, i.e., a three-stage gourd groove. The radius of the circular gourd groove unit located on the outermost side is the largest, followed by the middle, and the radius of the circular gourd groove unit located on the innermost side is the smallest, and the radii are R4, R5, and R6 respectively, wherein R4>R5>R6.

[0041] Setting a gourd groove on the ground patch, and designing the order of the gourd groove (i.e., the number of circular gourd groove units in the gourd groove) and the depth (the depth of the gourd groove, i.e., the depth from the upper side of the ground patch to the bottom of the gourd groove) is another important factor affecting the antenna bandwidth. Unlike the rectangular slotting method of the back floor of most planar monopole antennas at present, the gourd groove can significantly optimize the high-frequency impedance mismatch and greatly expand the working frequency band to high frequency. Preferably, the order of the gourd groove is preferably 3rd order. After simulation optimization, it is found that the gourd groove is from 1st order, 2nd order to 3rd order, and as the order of the gourd groove increases and the depth increases, the impedance matching of the microstrip antenna is better. However, when the gourd groove starts from the 4th order, the impedance matching will deteriorate, and the impedance matching will become worse. Therefore, the order of the gourd groove is selected as 3rd order, so that the impedance matching of the antenna is optimized and the working bandwidth of the antenna is maximized. This is because etching the gourd groove in the center of the ground patch can introduce the surface current into the gourd groove, increase the current path, and thus greatly improve the matching and increase the working bandwidth.

[0042] In another embodiment of the present invention, the front side is as follows Figure 1 As shown, the back side Figure 2 As shown, the side Figure 3As shown, the dielectric substrate is Rogers RT6002, with a relative dielectric constant of 2.94, a length of 60 mm, a width of 44 mm, and a thickness of 3.048 mm. The radiation patch 2 and the ground patch 3 are both metal patches with a thickness of 0.018 mm. The specific parameters of this embodiment are as follows: l = 60 mm, w = 44 mm, R1 = 10 mm, R2 = 26.6 mm, w d =7.76mm, l s =16.44mm, g=15mm, R3=5mm, R4=4mm, R5=3mm, R6=2mm. The structure of the microstrip antenna in this embodiment is simulated and improved by simulation software, the influence of the main parameters on the antenna performance is studied and analyzed, and the antenna performance is further optimized by parameter scanning. Figure 4 The impedance matching characteristic of the antenna is characterized by the reflection coefficient, which is usually required to be no more than -10dB. Figure 4 It can be seen that the impedance matching of the microstrip antenna provided by the present invention is good, S 11 The parameters are all below -10dB, indicating that the signal energy is reflected very little (less than 30%) and is basically radiated. 11 The frequency band with parameters below -10dB is considered the working frequency band, and the working frequency band is very wide (1.4GHz-27.5GHz), which proves that the antenna is an ultra-wideband antenna.

[0043] Figure 5 The E-plane and H-plane radiation patterns of the antenna at different frequencies, where: (a) represents the E-plane and H-plane radiation patterns of the antenna at 2 GHz, where the E-plane gain is 1.11 dB; (b) represents the E-plane and H-plane radiation patterns of the antenna at 5 GHz, where the E-plane gain is 1.94 dB; (c) represents the E-plane and H-plane radiation patterns of the antenna at 10 GHz, where the E-plane gain is 5.79 dB; (d) represents the E-plane and H-plane radiation patterns of the antenna at 15 GHz, where the E-plane gain is 5.34 dB; (e) represents the E-plane and H-plane radiation patterns of the antenna at 20 GHz, where the E-plane gain is 4.38 dB; (f) represents the E-plane and H-plane radiation patterns of the antenna at 25 GHz, where the E-plane gain is 2.42 dB. Figure 5 It can be seen that the microstrip antenna provided by the present invention has good omnidirectionality, and the H-plane radiation pattern is approximately circular, that is, omnidirectional radiation.

[0044] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A microstrip antenna, characterized in that: It includes a dielectric substrate, a radiation patch, a ground patch and a feeding microstrip line; The radiation patch is arranged on the front side of the dielectric substrate, the radiation patch is connected to the feeding microstrip line, and is fed through the feeding microstrip line; The ground patch is arranged on the back of the dielectric substrate, a calabash groove is provided in the middle of the ground patch, the opening side of the calabash groove is located on the upper side of the ground patch, and an arc-shaped cut angle is provided between the upper side and the left and right sides of the ground patch.

2. The microstrip antenna according to claim 1, characterized in that: The dielectric substrate, the radiation patch and the ground patch are all axisymmetric structures, and the symmetry axes of the dielectric substrate, the radiation patch and the ground patch coincide with each other.

3. The microstrip antenna according to claim 2, characterized in that: The dielectric substrate is a rectangular or square metal patch, and the ground patch is a rectangular metal patch.

4. The microstrip antenna according to claim 3, characterized in that: The radiation patch is a semi-annular metal patch.

5. The microstrip antenna according to claim 4, characterized in that: The semi-circular radiation patch is obtained by cutting off a small semi-circular metal patch above a semi-circular metal patch.

6. The microstrip antenna according to claim 4 or 5, characterized in that: The first end of the feeding microstrip line is connected to the middle of the arc-shaped outer edge of the bottom of the semi-annular metal patch, and the second end of the feeding microstrip line vertically extends to the lower side of the dielectric substrate.

7. The microstrip antenna according to claim 6, characterized in that: The radius of the two arc-shaped cut corners of the ground patch affects the bandwidth of the antenna. As the radius of the two arc-shaped cut corners increases, the operating frequency band becomes narrower in the low frequency band, and there is no obvious change trend in the high frequency band.

8. The microstrip antenna according to claim 1, 2, 3, 4, 5 or 7, characterized in that: The gourd trough is composed of more than two circular gourd trough units connected in series.

9. The microstrip antenna according to claim 8, characterized in that: The radius of the circular gourd groove unit located at the outermost side of the gourd groove is the largest, and the radius of the circular gourd groove unit decreases linearly from the outside to the inside.

10. A microstrip antenna array, characterized in that: The invention comprises a plurality of microstrip antennas as described in claims 1, 2, 3, 4, 5, 7 or 9.

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