An antenna unit

Abstract

The invention relates to the research field of radar antenna technology, and in particular to an antenna unit, comprising a PCB dielectric substrate, a metal ground, a feeding structure, a radiation wall and an impedance adjustment structure, wherein the metal ground is arranged on the PCB dielectric substrate, the feeding structure, the radiation wall and the impedance adjustment structure are arranged on the metal ground, a plurality of metal vias of the radiation wall surround the feeding structure, and a plurality of metal vias of the radiation wall in an electric polarization direction are connected to each other through a metal sheet; the impedance adjustment structure is located between the feeding structure and the radiation wall, and is used to make the parallel impedance of the radiation resistance and the conduction impedance of the antenna unit much smaller than the coupling impedance between the antenna unit and an external adjacent antenna, and utilizes the principle that current always tends to flow to a low impedance location to convert a surface wave that should flow to the outside of the antenna into effective radiation inside the antenna, thereby achieving better surface wave suppression and radiation enhancement effects, and maintaining the compactness of the antenna.

Description

Technical Field

[0001] The invention relates to the research field of radar antenna technology, and in particular to an antenna unit that realizes surface wave self-suppression and high isolation. Background Art

[0002] With the development of communication technology, the distance between antenna and wireless system (including chip) is closer than ever before, and phased array antenna has been widely used in commercial systems. Figure 1 As shown in the figure, the surface wave interference of the antenna has become the main factor affecting the performance of the wireless system. The impact of surface wave interference mainly includes the following three points: surface waves will reduce the isolation of adjacent antenna units; surface waves will deteriorate the performance of the directional pattern; and surface waves flowing into the system will reduce the communication throughput of the system. Figure 1-Figure 3 As shown in the figure, there are two traditional methods to improve the isolation between antenna array units: physical blocking and active suppression. The physical blocking method is to block the interference of surface waves through certain physical structures (such as metal walls, EBG, etc.). In order to achieve the ideal effect, this method usually requires a larger size and a longer isolation distance; the active suppression method is to construct a suppression signal. The suppression signal and the surface wave signal have the same amplitude and opposite phase to form a cancellation. The limitations of this method are: 1. Usually, the bandwidth of active suppression is narrow, and it is impossible to form an effective suppression signal within the broadband; 2. For some complex antennas, there are multiple surface wave propagation paths, and it is difficult to construct a suppression signal. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that the physical blocking method and the active suppression method in the prior art cannot effectively block the propagation of surface waves due to their limitations, and to provide a surface wave self-suppression high-isolation antenna unit.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] An antenna unit comprises a PCB dielectric substrate, a metal ground 1, a feed structure 5, a radiating wall and an impedance adjustment structure 2, wherein the metal ground 1 is arranged on the PCB dielectric substrate, the feed structure 5, the radiating wall and the impedance adjustment structure 2 are arranged on the metal ground 1, a plurality of metal vias of the radiating wall surround the feeding structure 5, and a plurality of metal vias of the radiating wall in an electric polarization direction are interconnected through a metal sheet; the impedance adjustment structure 2 is located between the feeding structure 5 and the radiating wall; and a plurality of metal vias of the impedance adjustment structure 2 are interconnected through a grounded radiating metal sheet.

[0006] The antenna unit of the present invention designs an impedance adjustment structure inside the antenna so that the equivalent impedance of the antenna unit's own conduction impedance and radiation resistance in parallel is much smaller than the coupling impedance between the antenna unit and the external adjacent antenna. Then, the surface waves that should flow to the outside of the antenna are converted into effective radiation inside the antenna by using the principle that current always tends to flow to low impedance, thereby achieving better surface wave suppression and radiation enhancement effects and ensuring the compactness of the antenna. On the other hand, since the surface wave suppression effect is achieved inside the antenna, no additional isolation structure is needed outside the antenna, which is conducive to saving production and manufacturing costs, keeping the antenna small in size, and facilitating array applications.

[0007] Preferably, the radiating wall includes a first opposing side wall 3 and a second opposing side wall 4, a plurality of metal vias of the first opposing side wall 3 and a plurality of metal vias of the second opposing side wall 4 surround the feeding structure 5, and a plurality of metal vias of the radiating wall connected to each other by metal sheets in the polarization direction are the second opposing side wall 4.

[0008] Preferably, the impedance adjustment structure 2 is located between the feeding structure 5 and the first opposite side wall 3 of the radiation wall.

[0009] Preferably, the first opposing side walls 3 and the second opposing side walls 4 form a quadrilateral.

[0010] Preferably, the quadrilateral is a square, a rectangle or a trapezoid.

[0011] Preferably, in the second opposite side walls 4 , the numbers of metal vias on two opposite sides are equal.

[0012] Preferably, in the second opposite side walls 4 , the center distances between adjacent metal vias are all 0.45 mm.

[0013] Preferably, in the first opposing side walls 3 , the center distance between adjacent metal vias is 0.8 mm.

[0014] Preferably, in the impedance adjustment structure 2, the center distance between adjacent metal vias is 1.1 mm.

[0015] Preferably, the diameter of the metal via is 0.3 mm.

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

[0017] 1. The present invention proposes a surface wave self-suppression and high-isolation antenna unit. By designing an impedance adjustment structure inside the antenna, the equivalent impedance of the antenna unit's own conduction impedance and radiation resistance in parallel is much smaller than the coupling impedance between the antenna unit and the external adjacent antenna. Then, by using the principle that current always tends to flow to low impedance, the surface waves that should flow to the outside of the antenna are converted into effective radiation inside the antenna, thereby achieving better surface wave suppression and radiation enhancement effects and ensuring the compactness of the antenna.

[0018] 2. Since the present invention realizes the effect of surface wave suppression inside the antenna, there is no need to add an additional isolation structure outside the antenna, which is beneficial to saving production costs, keeping the antenna small in size, and facilitating array applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of surface wave interference between adjacent antennas.

[0020] Figure 2 The figure is a schematic diagram showing the principle of suppressing surface wave interference by physical blocking in the prior art.

[0021] Figure 3 The figure is a schematic diagram of the principle of suppressing surface wave interference by using active suppression method in the prior art.

[0022] Figure 4 The figure is a schematic diagram showing the principle of suppressing surface wave interference by adjusting equivalent impedance according to the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of the surface wave self-suppression high isolation array antenna unit in Example 1.

[0024] Figure 6 This is a schematic diagram of the structure of the surface wave self-suppression high isolation array antenna unit in Example 2.

[0025] Figure 7 This is the isolation simulation result of the surface wave self-suppression high isolation array antenna unit in Example 2.

[0026] Figure numerals: 1 - metal ground, 2 - impedance adjustment structure, 3 - first opposite side wall, 4 - second opposite side wall, 5 - feeding structure, 6 - matching structure. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0028] Example 1

[0029] An antenna unit that realizes high isolation of surface wave self-suppression, such as Figure 4 As shown, it includes a PCB dielectric substrate, a metal ground 1, a feeding structure 5 and a radiation wall, wherein the metal ground is arranged on the PCB dielectric substrate, and the feeding structure 5, the radiation wall and the impedance adjustment structure 2 are arranged on the metal ground 1;

[0030] The plurality of metal vias of the radiation wall surround the feeding structure 5, and the radiation wall is Figure 4 The multiple metal vias in the X-axis direction are connected to each other through metal sheets; the impedance adjustment structure 2 is located between the feeding structure 5 and the radiation wall; the multiple metal vias of the impedance adjustment structure 2 are connected to each other through the grounded radiation metal sheet.

[0031] Furthermore, the radiating wall includes a first opposing side wall 3 and a second opposing side wall 4, the first opposing side wall 3 includes two rows of metal vias arranged opposite to each other, the second opposing side wall 4 includes two rows of metal vias arranged opposite to each other, the first opposing side wall 3 and the second opposing side wall 4 form a square and surround the feeding structure 5, and the plurality of metal vias of the radiating wall connected to each other by metal sheets in the polarization direction are the second opposing side wall 4, and in the direction perpendicular to the polarization direction, the metal vias of the radiating wall are no longer connected to each other by other media except for being connected by metal ground.

[0032] Furthermore, the impedance adjustment structure 2 is located between the feeding structure 5 and the first opposite side wall 3 of the radiation wall.

[0033] like Figure 5 As shown, the impedance adjustment structure 2 is used to make the radiation resistance R of the antenna unit (antenna 1) S And the conduction impedance R 1 The parallel impedance is much smaller than the coupling impedance R between the antenna unit and the external adjacent antenna (antenna 2). 2 .

[0034] The metal vias of the present invention may be hollow or solid, without affecting the isolation effect. The solid metal vias may be filled with resin material.

[0035] The principle of the present invention is to design a distributed impedance adjustment structure inside the antenna so that the equivalent impedance of the antenna unit's own conductive impedance and radiation resistance in parallel is much smaller than the coupling impedance between the antenna unit and the external adjacent antenna. Then, by utilizing the principle that current always tends to flow to low impedance, the surface wave energy is guided to flow into the antenna and be converted into effective radiation instead of coupling outward, thereby achieving better surface wave suppression and radiation enhancement effects and ensuring the compactness of the antenna.

[0036] Reference again Figure 4On the one hand, the current flows from the feeding structure 5 to the first opposite side wall 3 of the radiation wall through the metal ground. On the other hand, since the first opposite side wall 3 of the radiation wall is used as the radiator of the antenna, the end is open when working, which is equivalent to infinite impedance. The metal ground between the feeding structure 5 and the first opposite side wall 3 is connected with an impedance adjustment structure 2. The first opposite side wall 3 and the impedance adjustment structure 2 together constitute an open-ended transmission line. Therefore, the equivalent resistance of the conduction impedance of the antenna unit itself in parallel with the radiation resistance is much smaller than the coupling impedance between the antenna unit and the external adjacent antenna, thereby forming the following Figure 5 The equivalent circuit shown in Figure 5 The coupling impedance R2 between the middle antenna unit and the external adjacent antenna is an infinite open-circuit impedance, so the surface wave energy radiates outward from the gap formed by the first opposing side wall 3 and the impedance adjustment structure 2, while reducing the propagation outward across the first opposing side wall 3, and converting the surface waves that should flow to the outside of the antenna into effective radiation inside the antenna, thereby achieving better surface wave suppression and radiation enhancement effects and maintaining the compactness of the antenna.

[0037] Since the present invention realizes the surface wave suppression function inside the antenna, no additional isolation structure needs to be added outside the antenna, which is beneficial to saving production costs.

[0038] Example 2

[0039] The PCB dielectric substrate of the antenna unit of this embodiment is implemented by a four-layer board, the dielectric material is Rogers4350B, and the feeding structure 5 is a strip line.

[0040] like Figure 6 As shown, the first opposite side walls 3 of the radiation wall have two groups of metal vias facing each other, one group has 15 metal vias and the other group has 14 metal vias, the hole diameter is 0.3 mm, and the hole spacing (the distance between the centers of the two holes) is 0.8 mm.

[0041] The second opposite side walls 4 have two groups of metal vias facing each other, each group having 33 metal vias, arranged in a left bracket "[" shape and a right bracket "]" shape, with a hole diameter of 0.3mm and a hole spacing (center distance between two holes) of 0.45mm.

[0042] The straight lines where the two groups of metal vias of the first opposing side wall 3 are located are perpendicular to the straight lines where the two groups of metal vias of the second opposing side wall 4 are located, respectively, forming a “mouth” shape, surrounding the feeding structure 5 .

[0043] An impedance adjustment structure 2 is provided between the feed structure 5 and the two groups of metal vias of the first opposing side wall 3. The impedance adjustment structure 2 includes a first subsection and a second subsection. The first subsection is located between the feed structure 5 and one group of metal vias of the first metal via array, and has 6 metal vias. One end of the 6 metal vias is connected to the metal ground 1, and the other ends are connected to each other through a grounded radiation metal sheet. The second subsection is located between the feed structure 5 and another group of metal vias of the first opposing side wall 3, and has 4 metal vias. The diameter of the metal vias is 0.3 mm, and the hole spacing (the center distance between the two holes) is 0.45 mm. One end of the 4 metal vias is connected to the metal ground 1, and the other ends are connected to each other through a grounded radiation metal sheet.

[0044] In this embodiment, the matching structure 6 is a plurality of metal vias, which are used to achieve impedance matching of the antenna unit.

[0045] The results of the simulation of the isolation of two antenna units of this embodiment at about one wavelength are as follows: Figure 7 As shown, it can be seen that, compared with conventional phased array antennas at the same array spacing, the antenna unit using the surface wave self-suppression of the present invention achieves an isolation level higher than 40 dB, and the isolation is improved by 20 dB (100 times).

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An antenna unit, It is characterized in that It comprises a PCB dielectric substrate, a metal ground (1), a feeding structure (5), a radiating wall and an impedance adjustment structure (2), wherein the metal ground (1) is arranged on the PCB dielectric substrate, the feeding structure (5), the radiating wall and the impedance adjustment structure (2) are arranged on the metal ground (1), a plurality of metal vias of the radiating wall surround the feeding structure (5), and a plurality of metal vias of the radiating wall in the electric polarization direction are connected to each other through a metal sheet; The impedance adjustment structure (2) is located between the feeding structure (5) and the radiation wall; a plurality of metal vias of the impedance adjustment structure (2) are interconnected through a grounded radiation metal sheet; The radiation wall comprises a first opposing side wall (3) and a second opposing side wall (4); a plurality of metal vias of the first opposing side wall (3) and a plurality of metal vias of the second opposing side wall (4) surround the feeding structure (5); a plurality of metal vias of the radiation wall connected to each other by metal sheets in the electric polarization direction are the second opposing side wall (4); The straight lines where the two groups of metal vias of the first opposing side walls (3) are located are respectively perpendicular to the straight lines where the two groups of metal vias of the second opposing side walls (4) are located, forming a "mouth" shape, surrounding the feeding structure (5); The impedance adjustment structure (2) is located between the feeding structure (5) and two groups of metal vias of the first opposite side wall (3); The impedance adjustment structure (2) comprises a first subsection and a second subsection; The first subsection is located between the feeding structure (5) and one group of metal vias of the first opposing side wall (3); the second subsection is located between the feeding structure (5) and another group of metal vias of the first opposing side wall (3); The first sub-section and the second sub-section have a plurality of metal vias, one end of the metal vias is connected to the metal ground (1), and the other end is connected to each other through a grounded radiation metal sheet.

2. An antenna unit as claimed in claim 1, It is characterized in that The first opposing side walls (3) and the second opposing side walls (4) form a quadrilateral.

3. An antenna unit as claimed in claim 2, It is characterized in that The quadrilateral is a square, a rectangle or a trapezoid.

4. An antenna unit as claimed in claim 3, It is characterized in that In the second opposite side walls (4), the numbers of metal vias on two opposite sides are equal.

5. An antenna unit as claimed in claim 4, It is characterized in that In the second opposing side walls (4), the center distances between adjacent metal vias are all 0.45 mm.

6. An antenna unit as claimed in claim 5, It is characterized in that In the first opposing side walls (3), the distance between the centers of adjacent metal vias is 0.8 millimeters.

7. An antenna unit as claimed in claim 6, It is characterized in that In the impedance adjustment structure (2), the distance between the centers of adjacent metal vias is 1.1 millimeters.

8. An antenna unit according to any one of claims 1 to 7, It is characterized in that The diameter of the metal via is 0.3 mm.

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