Microstrip feed horn antenna

Abstract

The utility model relates to a microstrip feed horn antenna, belongs to the technical field of antennas, and solves the technical problem that the gain and directivity of a conventional microstrip feed antenna are difficult to optimize and adjust according to actual requirements. The microstrip feed horn antenna comprises a horn cavity, a feed waveguide cavity and a feed printed board, the horn cavity is arranged on the feed waveguide cavity, the feed waveguide cavity bears the feed printed board, the distance between the feed printed board and the bottom of the feed waveguide cavity can be adjusted, the feed printed board comprises a first patch and a second patch which are connected with each other, and the first patch and the second patch are connected with each other. The first patch is connected to the feed network to realize feed, and the second patch is used for realizing impedance matching of the antenna; by adopting the technical scheme that the distance between the feed printed board and the bottom of the feed waveguide cavity can be adjusted, the distance between the first patch and the bottom of the feed waveguide cavity is also adjusted, so that the gain and directivity of the antenna can be optimized and adjusted according to actual requirements in the actual operation process.

Description

TECHNICAL FIELD

[0001] The utility model relates to antenna technical field especially relates to a horn antenna of microstrip feed. BACKGROUND

[0002] Millimeter wave holographic imaging security system is an advanced security technology, which uses electromagnetic waves in the millimeter wave frequency band (usually between 30GHz and 300GHz) to generate high-resolution three-dimensional images of the object being inspected. This system can penetrate clothing and other non-metallic materials, but cannot penetrate metal or water, so it is very suitable for human security, and can detect hidden metal and non-metal objects such as weapons, explosives, liquids, plastics and ceramics.

[0003] In the millimeter wave holographic imaging security system, the antenna system is one of the core components, responsible for transmitting and receiving millimeter wave signals, so as to realize high-resolution three-dimensional imaging of the object being inspected, and the design and performance of the antenna directly affect the efficiency, accuracy and user experience of the entire security system.

[0004] The existing microstrip feed antenna cannot adjust the distance between the bottom of the metal cavity and the feed printed board, and the fixed distance leads to poor impedance matching and limited bandwidth; the fixed distance makes it difficult to optimize and adjust the gain and directivity of the antenna according to actual needs. SUMMARY

[0005] In view of the above analysis, the utility model aims to provide a horn antenna of microstrip feed to solve the technical problem that the gain and directivity of the existing microstrip feed antenna are difficult to optimize and adjust according to actual needs.

[0006] The purpose of the utility model is mainly realized through the following technical schemes:

[0007] A horn antenna of microstrip feed for a millimeter wave holographic imaging security system, comprising a horn cavity, a feed waveguide cavity and a feed printed board, the horn cavity is arranged on the feed waveguide cavity, the feed waveguide cavity carries the feed printed board, and the distance between the feed printed board and the bottom of the feed waveguide cavity can be adjusted.

[0008] The feed printed board comprises a first patch and a second patch connected to each other, the first patch is also connected to a feed network to realize feeding, and the second patch is used to realize impedance matching of the horn antenna of microstrip feed.

[0009] Further, the horn antenna of microstrip feed further comprises a waveguide cavity pad block, the waveguide cavity pad block is arranged at the bottom of the feed waveguide cavity to adjust the distance between the bottom of the feed waveguide cavity and the feed printed board, and the waveguide cavity pad block and the feed waveguide cavity are made of the same material.

[0010] Further, a part of the feeding printed board is arranged inside a side cavity wall of the feeding waveguide cavity, and another part of the feeding printed board is overlapped on another side cavity wall of the feeding waveguide cavity.

[0011] Further, a containing groove for containing a part of the feeding printed board is arranged on the side cavity wall of the feeding waveguide cavity.

[0012] Further, the containing groove is located at different depths of the side cavity wall of the feeding waveguide cavity, and the distance between the bottom of the feeding waveguide cavity and the feeding printed board is adjusted by the part of the feeding printed board cooperating with the containing groove at different depths.

[0013] Further, the width of the containing groove is not less than the thickness of the feeding printed board.

[0014] Further, the horn cavity is provided with a first opening and a second opening, the opening size of the first opening is larger than that of the second opening to radiate or receive electromagnetic waves outwardly, and the second opening is connected to the feeding waveguide cavity to receive the fed electromagnetic waves.

[0015] Further, a bearing convex strip is fixedly arranged on the other side cavity wall of the feeding waveguide cavity, and the other part of the feeding printed board is fixedly arranged on the bearing convex strip.

[0016] Further, the first patch is a rectangular patch.

[0017] Further, the second patch is an isosceles trapezoidal patch.

[0018] The technical scheme of the utility model can at least realize one of the following effects:

[0019] (1) The horn antenna with microstrip feed adopts the technical scheme that the distance between the feeding printed board and the bottom of the feeding waveguide cavity can be adjusted, the distance between the first patch and the bottom of the feeding waveguide cavity is also adjusted, so that in the actual operation process, the gain and directivity of the antenna can be optimized and adjusted according to actual requirements, the distance between the feeding printed board and the bottom of the feeding waveguide cavity is adjusted to redistribute the antenna radiation power, so that more energy is concentrated in the main lobe direction, thereby improving the gain of the antenna, in addition, the adjustment of the distance between the feeding printed board and the bottom of the feeding waveguide cavity can change the radiation pattern of the antenna, so that the main lobe width is narrowed or the main lobe direction is deflected, thereby realizing the adjustment of the directivity of the antenna.

[0020] (2) The horn antenna with microstrip feed is provided with a bearing convex strip on the other side cavity wall of the feeding waveguide cavity, and the other part of the feeding printed board is fixed on the bearing convex strip, so that the structure of the feeding printed board is more stable.

[0021] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained from the description and accompanying drawings, which are particularly pointed out. Attached Figure Description

[0022] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0023] Figure 1 This is a schematic cross-sectional view of the microstrip-fed horn antenna in an embodiment of this utility model.

[0024] Figure 2 This is a cross-sectional schematic diagram of the speaker cavity in an embodiment of this utility model;

[0025] Figure 3 This is a schematic diagram of the structure of the power supply printed circuit board in an embodiment of this utility model.

[0026] In the figure, 1-speaker cavity, 11-first opening, 12-second opening, 2-feed waveguide cavity, 21-bearing protrusion, 22-accommodating groove, 3-feed printed circuit board, 31-first patch, 32-second patch, 4-waveguide cavity pad block. Detailed Implementation

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0028] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments.

[0029] like Figure 1 As shown, this utility model embodiment provides a microstrip-fed horn antenna for a millimeter-wave holographic imaging security inspection system. It includes a horn cavity 1, a feeding waveguide cavity 2, and a feeding printed circuit board 3. The horn cavity 1 is disposed on the feeding waveguide cavity 2, which carries the feeding printed circuit board 3. The distance between the bottom of the feeding printed circuit board 3 and the bottom of the feeding waveguide cavity 2 is adjustable. The feeding printed circuit board 3 includes a first patch 31 and a second patch 32 connected to each other. The first patch 31 is also connected to a feeding network to achieve feeding, and the second patch 32 is used to achieve impedance matching of the microstrip-fed horn antenna.

[0030] The first patch 31 on the feeding printed board 3 transmits the radio frequency signal to the feeding waveguide cavity 2. After the signal enters the feeding waveguide cavity 2, a specific electromagnetic field mode is excited in the feeding waveguide cavity 2, and the transmission and distribution are performed according to the shape and size of the feeding waveguide cavity 2 and other factors. The electromagnetic energy output from the feeding waveguide cavity 2 is fed into one end of the horn cavity 1. The horn cavity 1, as a transmission structure, can uniformly transition the electromagnetic energy from one end to the other end and radiate outward. In this process, the distribution of the electromagnetic field in the horn cavity 1 changes accordingly with the change of the shape of the horn cavity 1, thereby forming an electromagnetic beam with a certain directivity and beam width, and realizing effective radiation of energy.

[0031] The horn cavity 1 can be made of metal material, such as aluminum alloy or copper. The good electrical conductivity and mechanical processing performance of the metal material can effectively constrain and guide the electromagnetic field, reduce the loss of electromagnetic energy, and avoid the influence of external interference on the internal electromagnetic field. The feeding waveguide cavity 2 can be made of metal material, such as aluminum alloy. The feeding printed board 3 can be made of insulating material, for example, the dielectric constant of the feeding printed board 3 is 2.2, and the thickness is 0.017 mm.

[0032] The first patch 31 is directly connected to the feeding network and is used to transmit the radio frequency signal from the feeding network to the entire antenna system. In addition, the first patch 31 can also play a role in preliminary impedance matching, helping to adjust the input impedance from the feeding network to the subsequent part. The main function of the second patch 32 is to optimize the impedance matching of the horn antenna with microstrip feed, ensuring that the antenna can maintain efficient energy transfer in the entire working frequency range. At the same time, the cooperation of the first patch 31 and the second patch 32 realizes the effective impedance matching between the horn antenna with microstrip feed and the feeding network, ensures the energy conversion efficiency, and reduces unnecessary reflection. The first patch 31 and the second patch 32 can be made of metal material, such as copper. For example, the first patch 31 can be a rectangular patch with a length of 3 mm and a width of 0.8 mm, and the second patch 32 can be an isosceles trapezoidal patch with an upper base of 1.75 mm, a lower base of 2.2 mm, and a waist of 0.38 mm. The first patch 31 and the second patch 32 can be connected by gold wire bonding.

[0033] The horn cavity 1 can be fixed on the feeding waveguide cavity 2 by conductive glue.

[0034] Since the distance between the feeding printed board 3 and the bottom of the feeding waveguide cavity 2 can be adjusted, the antenna can be fine-tuned according to actual application requirements to achieve the best performance, which is particularly important for the millimeter wave holographic imaging security inspection system, and different parameter settings can be required for the detection of different objects; with the adjustment of the distance, the distance between the first patch 31 and the bottom of the feeding waveguide cavity 2 is also adjusted, thereby the gain and directivity of the antenna can be optimized and adjusted according to actual requirements, and by adjusting the distance, the redistribution of the antenna radiation power is realized, so that more energy is concentrated in the main lobe direction, thereby improving the gain of the antenna; in addition, the adjustment of the distance can change the radiation pattern of the antenna, so that the main lobe width is narrowed or the main lobe direction is deflected, thereby realizing the adjustment of the directivity of the antenna, and solving the technical problem that the gain and directivity are difficult to be optimized and adjusted according to actual requirements in the existing microstrip feeding antenna.

[0035] The horn antenna with microstrip feeding in the embodiment can be applied to security inspection in airports, customs and the like, and industrial nondestructive testing and the like, but is not limited thereto, and through accurate electromagnetic wave transmission and reception, a high-quality three-dimensional image can be generated to help identify hidden articles or structural defects.

[0036] In a preferred embodiment of the utility model, as shown in Figure 1 and Figure 3 part of the feeding printed board 3 is arranged inside one side cavity wall of the feeding waveguide cavity 2, and the other part of the feeding printed board 3 is overlapped on the other side cavity wall of the feeding waveguide cavity 2, so that the feeding printed board 3 is positioned in the feeding waveguide cavity 2 and a certain distance exists between the feeding printed board 3 and the bottom of the feeding waveguide cavity 2, thereby the first patch 31 on the feeding printed board 3 transmits the radio frequency signal into the feeding waveguide cavity 2.

[0037] In a preferred embodiment of the utility model, as shown in Figure 1As shown, the microstrip-fed horn antenna further comprises a waveguide cavity cushion block 4 arranged at the bottom of the feed waveguide cavity 2 to adjust the distance between the bottom of the feed waveguide cavity 2 and the waveguide cavity cushion block 4, wherein the waveguide cavity cushion block 4 is made of the same material as the feed waveguide cavity 2, and the waveguide cavity cushion block 4 can be arranged in one piece or stacked with several waveguide cavity cushion blocks 4; the waveguide cavity cushion block 4 has a structure matched with the bottom of the feed waveguide cavity 2, for example, the waveguide cavity cushion block 4 is a cuboid structure, and the bottom of the feed waveguide cavity 2 has a space for accommodating the cuboid structure; the gap between the bottom of the feed waveguide cavity 2 and the waveguide cavity cushion block 4 is filled with conductive glue to make the waveguide cavity cushion block 4 and the bottom of the feed waveguide cavity 2 form an integral whole; since the waveguide cavity cushion block 4 has a certain height, the distance between the bottom of the feed waveguide cavity 2 and the feed printed board 3 can be adjusted; and a plurality of waveguide cavity cushion blocks 4 with different heights can be arranged to cooperate with the bottom of the feed waveguide cavity 2, so that the gain and direction of the antenna can be optimized and adjusted according to actual needs.

[0038] In a preferred embodiment of the utility model, as shown in the figure, Figure 1 As shown, a containing groove 22 for accommodating a part of the feed printed board 3 is arranged on one side wall of the feed waveguide cavity 2; specifically, a plurality of containing grooves 22 are arranged on one side wall of the feed waveguide cavity 2, and the containing grooves 22 are arranged at different depths of one side wall of the feed waveguide cavity 2; since the containing grooves 22 are arranged at different depths of one side wall of the feed waveguide cavity 2, a part of the feed printed board 3 is matched with different containing grooves 22, so that the distance between the feed printed board 3 and the bottom of the feed waveguide cavity 2 can be adjusted, and thus the gain and direction of the antenna can also be optimized and adjusted according to actual needs.

[0039] On this basis, the groove width of the containing groove 22 is not less than the thickness of the feed printed board 3, so that a part of the feed printed board 3 can be conveniently inserted into the containing groove 22.

[0040] In a preferred embodiment of the utility model, as shown in the figure, Figure 2As shown, the horn cavity 1 is provided with a first opening 11 and a second opening 12, the opening size of the first opening 11 is larger than that of the second opening 12, and the second opening 12 is connected to the feed waveguide cavity 2 to receive the feed of electromagnetic energy of the feed waveguide cavity 2; generally, the horn cavity 1 generally presents a horn-shaped appearance, the smaller second opening 12 is connected to the feed waveguide cavity 2, and the larger first opening 11 is used for radiating or receiving electromagnetic waves, the horn cavity 1 can adopt the shape of a rectangular horn or a circular horn, the rectangular horn cavity is composed of four gradually outwardly expanding sides, and presents a shape of gradually opening and expanding at one end of a cuboid; the circular horn cavity is a structure that gradually expands in diameter around the central axis; in the embodiment, the horn cavity 1 adopts a rectangular horn shape, the length, width and height of the horn cavity 1 are 9.1mm, 9.1mm and 7.3mm respectively, the length and width of the mouth of the first opening 11 at the upper part of the horn cavity 1 are both 7.1mm, and the length and width of the mouth of the second opening 12 at the lower part of the horn cavity 1 are 7.1mm and 4.7mm respectively.

[0041] In a preferred embodiment of the utility model, as shown in Figure 1 As shown, the other side cavity wall of the feed waveguide cavity 2 is fixedly provided with a bearing convex strip 21, and the other part of the feed printed board 3 is fixedly arranged on the bearing convex strip 21; by arranging the bearing convex strip 21 and enabling the other part of the feed printed board 3 to be fixed thereon, the structure of the feed printed board 3 is more stable, and the fixed arrangement can be realized in a welding manner, and the bearing convex strip 21 can be of the same material as the cavity wall of the feed waveguide cavity 2.

[0042] The above is only a preferred specific embodiment of the utility model, but the protection scope of the utility model is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the utility model, which should be covered in the protection scope of the utility model.

Claims

1. A microstrip-fed horn antenna for a millimeter-wave holographic imaging security system, comprising: The microstrip-fed horn antenna comprises a horn cavity (1), a feed waveguide cavity (2) and a feed printed board (3), the horn cavity (1) is arranged on the feed waveguide cavity (2), the feed printed board (3) is carried on the feed waveguide cavity (2), and the distance between the feed printed board (3) and the bottom of the feed waveguide cavity (2) can be adjusted. The feed printed board (3) comprises a first patch (31) and a second patch (32) connected with each other, the first patch (31) is further connected to a feed network to realize feeding, and the second patch (32) is used for realizing impedance matching of the microstrip-fed horn antenna.

2. The microstrip-fed horn antenna of claim 1, wherein, The microstrip-fed horn antenna further comprises a waveguide cavity gasket block (4) arranged at the bottom of the feed waveguide cavity (2) to adjust the distance between the bottom of the feed waveguide cavity (2) and the feed printed board (3).

3. The microstrip-fed horn antenna of claim 1, wherein, Part of the feed printed board (3) is arranged inside one side cavity wall of the feed waveguide cavity (2), and the other part of the feed printed board (3) is overlapped on the other side cavity wall of the feed waveguide cavity (2).

4. The microstrip-fed horn antenna of claim 3, wherein, An accommodating groove (22) for accommodating part of the feed printed board (3) is arranged on one side cavity wall of the feed waveguide cavity (2).

5. The microstrip-fed horn antenna of claim 4, wherein, The accommodating groove (22) is located at different depths of one side cavity wall of the feed waveguide cavity (2), and the distance between the bottom of the feed waveguide cavity (2) and the feed printed board (3) is adjusted by the part of the feed printed board (3) cooperating with the accommodating groove (22) at different depths.

6. The microstrip-fed horn antenna of claim 5, wherein, The groove width of the accommodating groove (22) is not less than the thickness of the feed printed board (3).

7. The microstrip-fed horn antenna of claim 1, wherein, The horn cavity (1) is provided with a first opening (11) and a second opening (12), the opening size of the first opening (11) is larger than that of the second opening (12) to radiate or receive electromagnetic waves outward, and the second opening (12) is connected to the feed waveguide cavity (2) to receive fed electromagnetic waves.

8. The microstrip-fed horn antenna of claim 3, wherein, The other side cavity wall of the feed waveguide cavity (2) is fixedly provided with a bearing convex strip (21), and the other part of the feed printed board (3) is fixedly arranged on the bearing convex strip (21).

9. The microstrip-fed horn antenna of claim 1, wherein, The first patch (31) is a rectangular patch.

10. The microstrip-fed horn antenna of claim 1, wherein, The second patch (32) is an isosceles trapezoidal patch.

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