A microwave circuit band-stop filter device based on artificial magnetic conductor

Abstract

The application relates to a microwave circuit band-stop filtering device based on an artificial magnetic conductor, and belongs to the fields of artificial magnetic conductors and filtering technologies, which solves the problem that a microstrip line causes electromagnetic interference on a circuit board and the surrounding environment in the prior art. The device comprises a shell and a microwave circuit board; the microwave circuit board is arranged in the shell, and a microstrip line is arranged on the microwave circuit board; an artificial magnetic conductor array is arranged on the lower surface of the top cover of the shell, the artificial magnetic conductor array is formed by arranging a plurality of same artificial magnetic conductor structure units, and is used for filtering electromagnetic interference caused by the microstrip line. The microwave circuit band-stop filtering device based on the artificial magnetic conductor is realized.

Description

Technical Field

[0001] This invention relates to the fields of artificial magnetic conductors and filtering technology, and in particular to a microwave circuit band-stop filtering device based on artificial magnetic conductors. Background Technology

[0002] With the development of novel electromagnetic materials technology, metamaterials have become one of the research hotspots in the microwave field. Among them, artificial magnetic conductor structures have in-phase reflection characteristics and magnetic conductor properties within a suitable frequency range, which can significantly improve the performance of microwave circuits, microwave antennas, and laser cavities.

[0003] Currently, artificial magnetic conductor structures mainly focus on improving antenna gain and transmission efficiency, with limited applications in circuits. In microwave circuits, although microstrip lines have the advantage of high integration, they are prone to radiation loss in the high-frequency band, leading to reduced transmission efficiency and causing electromagnetic interference to surrounding circuits. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a microwave circuit bandstop filter based on artificial magnetic conductors to solve the problem of electromagnetic interference caused by existing microstrip lines to nearby circuits in the high-frequency band.

[0005] This invention provides a microwave circuit bandstop filter based on artificial magnetic conductors. The device includes a housing and a microwave circuit board. The microwave circuit board is disposed inside the housing and has microstrip lines disposed on it. An artificial magnetic conductor array is disposed on the lower surface of the housing top cover. The artificial magnetic conductor array is formed by arranging multiple identical artificial magnetic conductor structural units and is used to filter electromagnetic interference caused by the microstrip lines.

[0006] Furthermore, each artificial magnetic conductor structural unit is obtained through the following steps: In a spatial rectangular coordinate system, on the z=0 plane, by three straight lines x=0, x=1.5, y=0 and the curve y=0.4e 0.4x A planar figure is formed, which is then rotated 90° about the positive z-axis with the line y=0 as the axis to form a solid figure. In a spatial rectangular coordinate system, the solid figure is cut with two planes, y=0.6 and z=0.6, to remove the first corner piece with y>0.6 and the second corner piece with z>0.6, resulting in the remaining solid figure. The remaining solid figure is then cut with two planes, z=0.3 and y=0.3, to remove the third triangular piece with z>0.3 and y>0.3, forming a notch, thus obtaining an artificial magnetic conductor structure unit with the notch.

[0007] Furthermore, the gaps of every four artificial magnetic conductor structural units are arranged to form an artificial magnetic conductor unit combination, and the distance between two adjacent artificial magnetic conductor structural units in each artificial magnetic conductor unit combination is 0.3mm.

[0008] Furthermore, multiple identical artificial magnetic conductor units are arranged in an array with their outer surfaces interlocked, and the fan-shaped bottom surface of each artificial magnetic conductor unit in the array is in contact with the top cover of the housing.

[0009] Furthermore, the artificial magnetic conductor array is 3D printed using copper powder as a consumable material, and the artificial magnetic conductor array and the shell top cover are an integrated structure.

[0010] Furthermore, the distance between the lower surface of the artificial magnetic conductor array and the upper surface of the microwave circuit board is 1.0 mm.

[0011] Furthermore, the device also includes connectors, which include a signal input connector and an output connector; the left and right sides of the housing have through holes, and the signal input connector and the output connector are respectively arranged in the two through holes on the left and right sides of the housing. The signal input connector is connected to the input end of the microstrip line on the microwave circuit board, and the output connector is electrically connected to the output end of the microstrip line on the microwave circuit board.

[0012] Furthermore, the connector is an SMP radio frequency coaxial connector.

[0013] Furthermore, the bandstop filter has a bandstop frequency band of 33GHz-36GHz and a center frequency of 35GHz.

[0014] Furthermore, the casing material is copper; the casing dimensions are 22mm × 22mm × 5.75mm.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0016] 1. This invention discloses a microwave circuit band-stop filter based on an artificial magnetic conductor. An artificial magnetic conductor structure is formed on the lower surface of the housing's top cover. A microwave circuit board with microstrip lines is placed inside the housing. The housing has through holes on both sides, and the signal input connector and output connector are respectively arranged in the two through holes on the left and right sides of the housing. The signal input connector is connected to the input end of the microstrip line on the microwave circuit board, and the output connector is electrically connected to the output end of the microstrip line on the microwave circuit board. The artificial magnetic conductor structure is used to perform band-stop filtering on the radio frequency signals transmitted on the circuit board containing the microstrip lines. Applying an artificial magnetic conductor array to the design of the housing containing the microwave circuit board enables selection of the microstrip line transmission band and effectively filters out some high-order harmonics. Simultaneously, the complex structure of the housing top cover is fabricated using 3D printing technology, resulting in low cost and simple manufacturing process.

[0017] 2. In this invention, each artificial magnetic conductor structural unit of a microwave circuit band-stop filter based on artificial magnetic conductors consists of three straight lines (x = 0, x = 1.5, y = 0) and a curve (y = 0.4e).0.4x A planar figure is rotated 90° around the positive z-axis with the line y=0 as the axis to form a solid figure. In a Cartesian coordinate system, the solid figure is cut using planes y=0.6 and z=0.6 to remove the first corner piece (y>0.6) and the second corner piece (z>0.6), resulting in the remaining solid figure. The remaining solid figure is then cut using planes z=0.3 and y=0.3 to remove the third triangular piece (z>0.3 and y>0.3), forming a notch, thus obtaining an artificial magnetic conductor structure unit with the notch. Every four artificial magnetic conductor structure units with their notches facing each other form an artificial magnetic conductor unit combination. The spacing between any two adjacent artificial magnetic conductor structure units in each combination (top / bottom and left / right) is 0.3 mm. Multiple identical artificial magnetic conductor unit combinations are arranged in an array with their outer surfaces touching each other. The fan-shaped bottom surface of each artificial magnetic conductor structure unit in the array contacts the top cover of the housing. The artificial magnetic conductor structure of the band-stop filter device exhibits a 0° reflection phase at 35 GHz, demonstrating excellent band-stop filtering characteristics.

[0018] 3. The housing of the microwave circuit band-stop filter device based on artificial magnetic conductor of the present invention is made of copper, which has a good electromagnetic shielding effect.

[0019] 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 may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 This is a schematic diagram of the structure of a microwave circuit band-stop filter based on an artificial magnetic conductor.

[0022] Figure 2 This is a schematic diagram of an artificial magnetic conductor array structure for a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0023] Figure 3 This is a schematic diagram of an artificial magnetic conductor structure unit for a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0024] Figure 4 This is a schematic diagram of the artificial magnetic conductor unit combination structure of a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0025] Figure 5 The phase angle curve of the reflection coefficient of an artificial magnetic conductor is shown in the image of a microwave circuit bandstop filter based on an artificial magnetic conductor.

[0026] Figure 6 The parameter curve of S21 is shown for a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0027] Figure 7 This is a schematic diagram of the side surface dimensions of an artificial magnetic conductor structural unit in a microwave circuit bandstop filter device based on an artificial magnetic conductor.

[0028] Figure 8 This is a schematic diagram showing the dimensions of the L-shaped top surface of an artificial magnetic conductor structural unit in a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0029] Figure 9 This is a planar pattern in the formation step of an artificial magnetic conductor structural unit for a microwave circuit band-stop filter device based on artificial magnetic conductors.

[0030] Figure label:

[0031] 1-Microstrip line;

[0032] 2-Signal input connector;

[0033] 3-Microwave circuit board;

[0034] 4-Top cover;

[0035] 5-Artificial magnetic conductor array;

[0036] 6- Output connector;

[0037] 7-Shell. Detailed Implementation

[0038] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application 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.

[0039] A specific embodiment of the present invention discloses a microwave circuit band-stop filter based on an artificial magnetic conductor, such as... Figure 1 As shown. The device includes a housing 7 and a microwave circuit board 3; the microwave circuit board 3 is disposed inside the housing 7, and a microstrip line 1 is disposed on the microwave circuit board 3; an artificial magnetic conductor array 5 is disposed on the lower surface of the housing top cover 4, the artificial magnetic conductor array 5 is formed by arranging multiple identical artificial magnetic conductor structural units, and is used to filter the electromagnetic interference caused by the microstrip line 1.

[0040] Specifically, the microstrip line 1 is a microwave transmission line consisting of a single conductor strip disposed on the microwave circuit board 3. The microstrip line 1 is used to transmit high-frequency signals, and it often has multiple branches on the circuit board. Therefore, it is necessary to cover the entire circuit board, i.e., the lower surface of the housing top cover 4, with an array of artificial magnetic conductors 5.

[0041] Each artificial magnetic conductor structural unit is obtained through the following steps: In a spatial rectangular coordinate system, on the z=0 plane, by three straight lines x=0, x=1.5, y=0 and the curve y=0.4e 0.4x A planar figure is formed, which is then rotated 90° about the positive z-axis with the line y=0 as the axis to form a solid figure. In a spatial rectangular coordinate system, the solid figure is cut with two planes, y=0.6 and z=0.6, to remove the first corner piece with y>0.6 and the second corner piece with z>0.6, resulting in the remaining solid figure. The remaining solid figure is then cut with two planes, z=0.3 and y=0.3, to remove the third triangular piece with z>0.3 and y>0.3, forming a notch, thus obtaining an artificial magnetic conductor structure unit with the notch.

[0042] The planar diagrams in the steps of forming artificial magnetic conductor structural units are as follows: Figure 9 As shown.

[0043] A schematic diagram of the artificial magnetic conductor structural unit is shown below. Figure 3 As shown.

[0044] Specifically, each artificial magnetic conductor unit has an L-shaped top surface and a sector-shaped bottom surface with a central angle of 90°.

[0045] A schematic diagram of the side surface dimensions of the artificial magnetic conductor structural unit is shown below. Figure 7 As shown.

[0046] A schematic diagram of the L-shaped top surface dimensions of the artificial magnetic conductor structural unit is shown below. Figure 8 As shown.

[0047] Specifically, w = 0.6 mm, h = 1.5 mm, and s = 0.3 mm. The volume occupied by each artificial magnetic conductor unit assembly is 1.5 mm × 1.5 mm × 1.5 mm.

[0048] A schematic diagram of the artificial magnetic conductor unit assembly structure is shown below. Figure 4 As shown.

[0049] Every four artificial magnetic conductor structural units are arranged in pairs to form an artificial magnetic conductor unit combination. The distance between two adjacent artificial magnetic conductor structural units in each artificial magnetic conductor unit combination is 0.3 mm.

[0050] The band-stop filter has a band-stop frequency band of 33GHz-36GHz and a center frequency of 35GHz.

[0051] Specifically, the artificial magnetic conductor array 5 of the present invention has a spacing of 0.3 mm and a height of 1.5 mm, which produces a band-stop filtering effect with a band-stop frequency band of 33 GHz-36 GHz and a center frequency of 35 GHz.

[0052] The S21 parameter curve of the band-stop filtering effect is as follows: Figure 6 As shown.

[0053] Multiple identical artificial magnetic conductor units are arranged in an artificial magnetic conductor array 5 with their outer surfaces interlocked. The fan-shaped bottom surface of each artificial magnetic conductor unit in the artificial magnetic conductor array 5 is in contact with the top cover of the housing 7.

[0054] A schematic diagram of the artificial magnetic conductor array 5 structure is shown below. Figure 2 As shown.

[0055] Specifically, the four L-shaped corners of the upper surface of each artificial magnetic conductor unit assembly are in contact with the upper cover of the housing 7.

[0056] The phase angle of the reflection coefficient of the artificial magnetic conductor array 5 structure was simulated, and the phase angle curve of the reflection coefficient of the artificial magnetic conductor was obtained as follows: Figure 5 As shown, Figure 5 This reflects that the artificial magnetic conductor array 5 structure at a frequency of around 35 GHz has a 0° reflection phase.

[0057] The artificial magnetic conductor array 5 is 3D printed using copper powder as the consumable material, and the artificial magnetic conductor array 5 and the shell top cover 4 are an integrated structure.

[0058] The distance between the lower surface of the artificial magnetic conductor array 5 and the upper surface of the microwave circuit board 3 is 1.0 mm.

[0059] The device also includes connectors, which include a signal input connector 2 and an output connector 6. The housing 7 has through holes on the left and right sides. The signal input connector 2 and the output connector 6 are respectively arranged in the two through holes on the left and right sides of the housing 7. The signal input connector 2 is connected to the input end of the microstrip line 1 on the microwave circuit board 3, and the output connector 6 is electrically connected to the output end of the microstrip line 1 on the microwave circuit board 3.

[0060] The connector is an SMP radio frequency coaxial connector.

[0061] Specifically, the external radio frequency signal is connected to the input end of the SMP radio frequency coaxial connector via a radio frequency coaxial cable, and then connected to the output end of the SMP radio frequency coaxial connector after passing through microstrip line 1, thus obtaining the radio frequency signal after band-stop filtering by the band-stop filter device.

[0062] The casing 7 is made of copper; the dimensions of casing 7 are 22mm × 22mm × 5.75mm.

[0063] Specifically, the use of copper in the casing 7 provides better shielding compared to other metals.

[0064] In practical engineering applications, the microwave circuit board 3 is bonded to the bottom of the housing 7 using conductive adhesive. The microwave circuit board 3 measures 15mm*15mm*1.5mm and is made of FR4 substrate material. Both the top and bottom of the substrate are metal layers, with microstrip lines 1 arranged on the upper layer and a metal ground layer on the lower layer. SMP connectors are soldered to the ports on both sides of the microstrip lines 1 as the input and output interfaces of the microwave circuit board 3, enabling band-stop filtering at a center frequency of 35GHz.

[0065] Compared with existing technologies, this embodiment provides a microwave circuit bandstop filter device based on artificial magnetic conductors. An artificial magnetic conductor structure is generated on the lower surface of the top cover 4 of the housing. A microwave circuit board 3 with a microstrip line 1 is placed inside the housing 7. The housing 7 has through holes on both sides. The signal input connector 2 and the output connector 6 are respectively arranged in the two through holes on the left and right sides of the housing 7. The signal input connector 2 is connected to the input end of the microstrip line 1 on the microwave circuit board 3, and the output connector 6 is electrically connected to the output end of the microstrip line 1 on the microwave circuit board 3. Bandstop filtering is performed on the circuit board containing the microstrip line 1 through the artificial magnetic conductor structure. Applying the artificial magnetic conductor array 5 to the design of the housing 7 containing the microwave circuit board 3 enables the selection of the transmission band of the microstrip line 1, effectively filtering out some high-order harmonics. Simultaneously, the housing top cover 4, despite its complex structure, is fabricated using 3D printing technology, resulting in low cost and simple manufacturing process. Each artificial magnetic conductor structure unit of the microwave circuit bandstop filter device based on artificial magnetic conductors provided in this embodiment consists of three straight lines (x = 0, x = 1.5, y = 0) and a curve (y = 0.4e). 0.4xA planar figure is rotated 90° around the positive z-axis with the line y=0 as the axis to form a three-dimensional figure. In a spatial rectangular coordinate system, the three-dimensional figure is cut using two planes, y=0.6 and z=0.6, to remove the first corner piece (y>0.6) and the second corner piece (z>0.6), resulting in the remaining three-dimensional figure. The remaining three-dimensional figure is then cut using two planes, z=0.3 and y=0.3, to remove the third triangular piece (z>0.3) and y>0.3, forming a notch, thus obtaining an artificial magnetic conductor structure unit with the notch. Every four artificial magnetic conductor structure units with their notches facing each other form an artificial magnetic conductor unit combination. The distance between two adjacent artificial magnetic conductor structure units in each combination is 0.3mm. Multiple identical artificial magnetic conductor unit combinations are arranged with their outer surfaces touching each other to form an artificial magnetic conductor array 5. The fan-shaped bottom surface of each artificial magnetic conductor structure unit in the artificial magnetic conductor array 5 is in contact with the top cover of the shell 7. The band-stop filter described herein has a 0° reflection phase at 35GHz, with a center frequency of 33GHz-36GHz, and exhibits excellent band-stop filtering characteristics. The housing 7 of the microwave circuit band-stop filter based on an artificial magnetic conductor provided in this embodiment is made of copper, providing excellent electromagnetic shielding.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A microwave circuit band-stop filter based on an artificial magnetic conductor, characterized in that, The device includes a housing and a microwave circuit board; the microwave circuit board is disposed inside the housing and has microstrip lines disposed on it; an artificial magnetic conductor array is disposed on the lower surface of the housing top cover, the artificial magnetic conductor array being formed by arranging multiple identical artificial magnetic conductor structural units, used to filter electromagnetic interference caused by the microstrip lines.

2. The band-stop filter device according to claim 1, characterized in that, Each artificial magnetic conductor structural unit is obtained through the following steps: In a spatial rectangular coordinate system, on the z=0 plane, by three straight lines x=0, x=1.5, y=0 and the curve y=0.4e 0.4x A planar figure is formed, which is then rotated 90° about the positive z-axis with the line y=0 as the axis to form a solid figure. In a spatial rectangular coordinate system, the solid figure is cut with two planes, y=0.6 and z=0.6, to remove the first corner piece with y>0.6 and the second corner piece with z>0.6, resulting in the remaining solid figure. The remaining solid figure is then cut with two planes, z=0.3 and y=0.3, to remove the third triangular piece with z>0.3 and y>0.3, forming a notch, thus obtaining an artificial magnetic conductor structure unit with the notch.

3. The band-stop filter device according to claim 2, characterized in that, Every four artificial magnetic conductor structural units are arranged in pairs to form an artificial magnetic conductor unit combination. The distance between two adjacent artificial magnetic conductor structural units in each artificial magnetic conductor unit combination is 0.3 mm.

4. The band-stop filter device according to claim 3, characterized in that, Multiple identical artificial magnetic conductor units are arranged in an array with their outer surfaces joined together. The fan-shaped bottom surface of each artificial magnetic conductor unit in the array is in contact with the top cover of the shell.

5. The band-stop filter device according to claim 4, characterized in that, The artificial magnetic conductor array is 3D printed using copper powder as the consumable material, and the artificial magnetic conductor array and the shell top cover are an integrated structure.

6. The band-stop filter device according to claim 5, characterized in that, The distance between the lower surface of the artificial magnetic conductor array and the upper surface of the microwave circuit board is 1.0 mm.

7. The band-stop filter device according to claim 1, characterized in that, The device also includes connectors, which include a signal input connector and an output connector; the left and right sides of the housing have through holes, and the signal input connector and the output connector are respectively arranged in the two through holes on the left and right sides of the housing. The signal input connector is connected to the input end of the microstrip line on the microwave circuit board, and the output connector is electrically connected to the output end of the microstrip line on the microwave circuit board.

8. The band-stop filter device according to claim 7, characterized in that, The connector is an SMP radio frequency coaxial connector.

9. The band-stop filter device according to claim 1, characterized in that, The band-stop filter has a band-stop frequency band of 33GHz-36GHz and a center frequency of 35GHz.

10. The band-stop filter device according to claim 1, characterized in that, The casing is made of copper; the casing dimensions are 22mm × 22mm × 5.75mm.

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