Broadband two-dimensional eight-beam switchable annular magnetoelectric dipole array antenna and design method thereof

Abstract

The invention discloses a broadband two-dimensional eight-beam switchable annular magnetoelectric dipole array antenna and a design method thereof, and relates to the technical field of radio frequency communication, the broadband two-dimensional eight-beam switchable annular magnetoelectric dipole array antenna comprises a first four-beam unit and a second four-beam unit which form an eight-beam array antenna; the array antennas in the four-beam unit are all located on the same horizontal plane and arranged on the dielectric substrates, the array antennas are all in a four-leaf clover shape, the difference between the array antennas and the dielectric substrates is 45 degrees, and the metal floor is arranged at the connected bottom ends of the two dielectric substrates. The short-circuit pin is arranged at the top end of the array antenna blade and sequentially penetrates through the array antenna and the dielectric substrate to be connected with the metal floor; and the coaxial inner conductor metal column is arranged at the junction of the array antenna blades, penetrates through the array antenna, the dielectric substrate and the metal floor, and is connected with the feed port. The invention provides the beam switching antenna which is small and exquisite, wider in coincidence bandwidth during multi-beam switching and more in switching states.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency communication technology, and more particularly to a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna and a design method thereof. Background Art

[0002] At present, beam switching antennas have attracted widespread attention in recent years due to their ability to switch multiple beams, increase channel capacity, and improve communication link stability. These antennas improve the utilization efficiency of the antenna by reconstructing the directional beam to the required angle, so they are widely used in radar systems, satellite communications, vehicle communications, tracking systems, etc.

[0003] However, existing beam switching or scanning antennas generally use phased array antennas or antennas based on beamforming networks (BFN) for beam steering. However, phased array antennas inevitably require expensive transceiver elements and complex radiating element design and layout. In addition, the inevitable large and complex structure of the beamforming network limits its application. In order to meet this demand, many compact beam steering antennas have been studied and reported in the past few decades, such as square ring antennas, four-arm curl antennas, patch array antennas without beamforming networks, low-profile directional pattern reconfigurable antennas with short pins, and diode-loaded directional pattern reconfigurable antennas. With the development of 5G and 6G, broadband characteristics have become a basic requirement for modern wireless communications. However, most of the above antennas operate in narrow bands, and their frequency bands are usually less than 25%. In addition, the existing beam switchable antennas have fewer beam switching states, which may not be sufficient to meet some communication systems requiring high beam accuracy.

[0004] Therefore, how to provide a compact beam switching antenna with a wider overlap bandwidth during multi-beam switching and more switching states is a problem that those skilled in the art need to solve urgently. Summary of the invention

[0005] In view of this, the present invention provides a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna and a design method thereof to solve the problems existing in the background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna, comprising: a first four-beam unit and a second four-beam unit, wherein the first four-beam unit and the second four-beam unit form an eight-beam array antenna; the first four-beam unit comprises a first four-beam switchable annular magneto-electric dipole array, a coaxial inner conductor metal column, a short-circuit pin, a dielectric substrate, a metal floor, and a feeding port; the second four-beam unit comprises a second four-beam switchable annular magneto-electric dipole array, a coaxial inner conductor metal column, a short-circuit pin, a dielectric substrate, a metal floor, and a feeding port; the first four-beam switchable annular magneto-electric dipole array and the second four-beam switchable annular magneto-electric dipole array are in the same horizontal plane and are arranged on the On the dielectric substrate, two dielectric substrates are connected, and the metal floor is arranged at the bottom end of the dielectric substrate; the first four-beam switchable annular magneto-electric dipole array and the second four-beam switchable annular magneto-electric dipole array are both in the shape of four-leaf clover and are 45° apart; the short-circuit pin is arranged at the top of the blade of the four-beam switchable annular magneto-electric dipole array, passes through the four-beam switchable annular magneto-electric dipole array and the dielectric substrate in sequence, and is connected to the metal floor; the coaxial inner conductor metal column is respectively arranged at the junction of the same four-beam switchable annular magneto-electric dipole array blade, passes through the four-beam switchable annular magneto-electric dipole array, the dielectric substrate and the metal floor in sequence, and is connected to the feeding port.

[0008] Preferably, the dielectric substrates used by the first four-beam unit and the second four-beam unit are in the shape of a rectangular parallelepiped, and are both chamfered with the metal floor.

[0009] Preferably, a gap is provided between the metal floors corresponding to the first four-beam unit and the second four-beam unit.

[0010] Preferably, in the corner cutting process, the length of the right-angle side of the corner cutting is 15 mm.

[0011] Preferably, the width of the gap is 2 mm.

[0012] Preferably, the dielectric substrate is made of F4BM320, has a dielectric constant of 3.2, and a dielectric loss of 0.0015.

[0013] A design method for a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna, comprising:

[0014] S01: Determine the working frequency band of the antenna, design a broadband four-beam switchable annular magneto-electric dipole array of the corresponding size in the required frequency band, introduce four short-circuit pins, and use the magnetic current source mode to expand the bandwidth of the antenna;

[0015] S02: keep the first four-beam switchable annular magneto-electric dipole array unchanged, and add a second four-beam switchable annular magneto-electric dipole array, which is 45 degrees different from the first four-beam switchable annular magneto-electric dipole array;

[0016] S03: In order to obtain a beam with higher directivity and low side lobes, a cut-angle design is adopted for the dielectric substrate;

[0017] S04: Slit the metal floor to improve the isolation between the two multi-beam array ports.

[0018] It can be seen from the above technical solution that compared with the prior art, the present invention discloses a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna and a design method thereof, which expands the bandwidth of the antenna by adding short-circuit pins to the annular four-leaf clover antenna and introducing a magnetic current source mode, thereby designing a broadband beam switchable array unit to solve the problem of narrow overlapping bandwidth, and at the same time adopts a reconfigurable unit integration method to expand the number of beams, which can increase the number of beams without greatly increasing the volume of the antenna, and adopts a floor gap method to reduce the coupling between ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 A perspective view of a broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0021] Figure 2 A top view of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0022] Figure 3 A bottom view of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0023] Figure 4 A schematic diagram of beam switching of a broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in eight states;

[0024] Figure 5 A reflection coefficient diagram of each port of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention with or without a short-circuit pin, wherein a represents no short-circuit pin and b represents with a short-circuit pin;

[0025] Figure 6A design flow chart of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0026] Figure 7 A schematic diagram of beam switching of a broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in eight states;

[0027] Figure 8 A simulated current diagram at 5.8 GHz on the floor when the dielectric substrate of the four-beam unit antenna provided by the present invention adopts different side length and angle cutting designs;

[0028] Fig. 9 A schematic diagram of the influence between each element and the port in the two four-port elements provided by the present invention;

[0029] Fig.10 The floor width selection diagram of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention, where a is the Ce5 variation curve at different floor widths, and b is the |S at different floor widths 55 |Change curve;

[0030] Fig.11 The measured data of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention are as follows: 11 |-|S 88 |Figure;

[0031] Fig.12 Simulation of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention 11 |-|S 88 |Figure;

[0032] Fig.13 A gain simulation curve diagram of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0033] Fig.14 A measured curve diagram of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention;

[0034] Fig.15 The simulated and measured directional patterns of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in the phi=45° plane when port 1 is excited at 4.75GHz;

[0035] Fig.16 The simulated and measured directional patterns of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in the phi=45° plane when port 1 is excited at 5.2GHz;

[0036] Fig.17The simulated and measured directional patterns of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in the phi=45° plane when port 1 is excited at 5.65GHz;

[0037] Fig.18 The simulated and measured directional patterns of the broadband eight-beam switchable magneto-electric dipole array antenna provided by the present invention in the phi=45° plane when port 1 is excited at 6.1GHz;

[0038] In the figure: 1 first four-beam switchable annular magneto-electric dipole array; 2 second four-beam switchable annular magneto-electric dipole array; 3 coaxial inner conductor metal column; 4 short-circuit pin; 5 dielectric substrate; 6 gap; 7 feeding port; 8 metal floor. DETAILED DESCRIPTION

[0039] 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.

[0040] The embodiment of the present invention discloses a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna, such as Figure 1 As shown, it includes: a first four-beam unit and a second four-beam unit, and the first four-beam unit and the second four-beam unit form an eight-beam array antenna; the first four-beam unit includes a first four-beam switchable annular magneto-electric dipole array 1, a coaxial inner conductor metal column 3, a short-circuit pin 4, a dielectric substrate 5, a metal floor 8, and a feeding port 7, and the second four-beam unit includes a second four-beam switchable annular magneto-electric dipole array 2, a coaxial inner conductor metal column 3, a short-circuit pin 4, a dielectric substrate 5, a metal floor 8, and a feeding port 7; the first four-beam switchable annular magneto-electric dipole array 1 and the second four-beam switchable annular magneto-electric dipole array 2 are in the same horizontal plane and are arranged on the dielectric substrate 5. On the top, two dielectric substrates 5 are connected, and a metal floor 8 is arranged at the bottom of the dielectric substrate 5; the first four-beam switchable annular magneto-electric dipole array 1 and the second four-beam switchable annular magneto-electric dipole array 2 are both in the shape of four-leaf clover and are 45° apart; the short-circuit pin 4 is arranged at the top of the blade of the four-beam switchable annular magneto-electric dipole array, passes through the four-beam switchable annular magneto-electric dipole array and the dielectric substrate 5 in sequence, and is connected to the metal floor 8; the coaxial inner conductor metal columns 3 are respectively arranged at the junction of the blades of the same four-beam switchable annular magneto-electric dipole array, and pass through the four-beam switchable annular magneto-electric dipole array, the dielectric substrate 5 and the metal floor 8 in sequence, and are connected to the feeding port 7.

[0041] In a specific embodiment, there are 8 feeding ports 7, and the first four-beam switchable annular magneto-electric dipole array 1 can generate four tilted beams with azimuth planes pointing to 45 degrees, 135 degrees, 225 degrees and 315 degrees; the second four-beam switchable annular magneto-electric dipole array 2 is similar thereto, which can be regarded as the first four-beam switchable annular magneto-electric dipole array 1 translated and then rotated 45 degrees around the center, and can generate four tilted beams with azimuth planes pointing to 0 degrees, 90 degrees, 180 degrees and 270 degrees; the coaxial inner conductor metal column can feed the radio frequency signal into the array element to be excited in the annular array to obtain a tilted beam with the desired beam pointing; the short-circuit pin 4 is an introduced magnetic current short-circuit pin, which is used to increase the bandwidth of the annular antenna array.

[0042] The top view and bottom view of the antenna involved in the present invention are as follows Figure 2 and 3 As shown, Figure 3 The eight ports are named 7-1 to 7-8. When ports 7-5, 7-6, 7-7, and 7-8 are excited respectively, tilted beams pointing at 0 degrees, 90 degrees, 180 degrees, and 270 degrees can be generated; when ports 7-1, 7-2, 7-3, and 7-4 are excited respectively, tilted beams pointing at 45 degrees, 135 degrees, 225 degrees, and 315 degrees can be generated. In this way, by switching ports, eight radiation beams pointing in different azimuth planes can be generated, thereby covering users in different intervals, and achieving the effect as shown in the figure. Figure 4 shown.

[0043] Figure 5 (a) and (b) respectively give the reflection coefficients |S of the eight ports of the antenna with and without the short-circuit pin 4. 11 |-|S 88 |,It can be found that after adding the short-circuit pin, a new low-frequency mode is introduced, thereby expanding the -10dB impedance bandwidth, and thus designing a broadband four-beam switchable circular magneto-electric dipole array, such as Figure 6 As shown in step 1. On this basis, by rotating the four-beam magneto-electric dipole array antenna 1 around the center by 45 degrees and then translating it, a broadband eight-beam magneto-electric dipole array antenna can be obtained, as shown in Figure 6 As shown in step 2. However, for the annular magneto-electric dipole array antenna that can generate four beams pointing at 45°, 135°, 225°, and 315°, if a rectangular dielectric substrate is still used, its radiation pattern will deteriorate. In the present invention, the dielectric substrate of the array antenna unit adopts a substrate with an oblique cutting design, which has a better radiation pattern. Taking the state of port 1 (7-1) being mechanism (beam pointing phi=45°) as an example, the two-dimensional radiation pattern in the phi=45° plane when the cutting angle changes at the 5.8GHz frequency point is as follows Figure 7 As shown. Figure 7As shown in the figure, when the two right-angled sides of the cut angle are 15 mm, a tilted beam with better gain and sidelobe level can be obtained. This is because the finite large surface with different tilt angles has different effects on the multi-beam magneto-electric dipole array. At 5.8 GHz, Figure 8 It can be seen that the ground current distribution is more uniform when the length of the right angle side is 15mm than other parameters. The size of the array antenna is finally designed to be 100mm×50mm×8mm. In this way, the multi-wave switching array antenna can not only obtain better radiation characteristics, but also has a lighter weight, which is more conducive to the application in some lightweight wireless systems. Finally, we use the method of slits in the floor to optimize the isolation between the two multi-beam elements, such as Figure 6 As shown in step 4.

[0044] In a specific embodiment, the dielectric substrate 5 used by the first four-beam unit and the second four-beam unit is in the shape of a rectangular parallelepiped, and both the dielectric substrate 5 and the metal floor 8 are cut at corners.

[0045] In a specific embodiment, a gap 6 is provided between the metal floors 8 corresponding to the first four-beam unit and the second four-beam unit, so as to improve the isolation between the ports.

[0046] Specifically, in order to improve the mutual influence between two multi-port components, the present invention adopts the method of opening the floor to improve the isolation between the components and the ports. In order to explain the problem more clearly, the present invention redefines a method for coupling between multi-port integrated networks. It is generally believed that the influence between ports 1 and 8 can be expressed as |S 18 |or|S 81 | is used to characterize the two multi-port elements. However, for two multi-port elements, it is not enough to only look at the influence of one port on the other port. We should look at the influence of all ports of a multi-port element on the other port. Therefore, we define the influence of a multi-port element on a port in another element as a new coupling coefficient Cei (i = 1, 2, 3 ..., n). In the present invention, n = 8. As a representative example, Fig. 9 For example, the normalized influence of element 1 on port 5 can be expressed as

[0047] C e5 =(|S 15 |+|S 25 |+|S 35 |+|S 45 |) / 4;

[0048] Furthermore, if we need to know the sum of the normalized effects of a multi-port element on another multi-port element, we can define it as the sum of the effects of all ports of one element on all ports of another element and then take the average, which is defined as

[0049] Coupling_ele12=(C e5+ C e6+ C e7+ C e8 ) / 4;

[0050] Coupling_ele21=(C e1+ C e2+ C e3+ C e4 ) / 4;

[0051] In order to explore the impact of floor gaps on isolation, we selected port 5 (7-5) as the research object because it is closer to part 1 and more easily affected by element 1. Fig.10 (a) shows the curve of Ce5 changing with frequency when the floor width is selected to different values. Fig.10 (b) shows the |S when the floor width is selected for different values 55 |. From this, we can find that when the gap is wider, the in-band influence of element 1 on port 5 will be smaller, but the gap width will also affect the return loss of port 5. Too large a gap width will cause the -10dB bandwidth of port 5 to become narrower. Therefore, the larger the gap width is within a certain range, the better. Finally, as a compromise, the gap width is selected as 2mm in the present invention.

[0052] In a specific embodiment, during the chamfering process, the length of the right-angle side of the chamfer is 15 mm.

[0053] In a specific embodiment, the width of the gap 6 is 2 mm.

[0054] In a specific embodiment, the dielectric substrate 5 is made of F4BM320, has a dielectric constant of 3.2, and a dielectric loss of 0.0015.

[0055] A broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna design method, such as Figure 6 As shown, including:

[0056] S01: Determine the working frequency band of the antenna, design a broadband four-beam switchable annular magneto-electric dipole array of the size corresponding to the required frequency band, introduce four short-circuit pins 4, and use the magnetic current source mode to expand the bandwidth of the antenna;

[0057] S02: keep the first four-beam switchable annular magneto-electric dipole array 1 unchanged, and add a second four-beam switchable annular magneto-electric dipole array 2, which is 45 degrees different from the first four-beam switchable annular magneto-electric dipole array 1;

[0058] S03: In order to obtain a beam with higher directivity and low side lobes, a cut-angle design is adopted for the dielectric substrate 5;

[0059] S04: Open a gap in the metal floor 8 to improve the isolation between the two multi-beam array ports.

[0060] In order to verify the proposed antenna design, the proposed broadband eight-beam switchable array antenna is designed, physically processed and measured. The standard multi-layer printed circuit board (PCB) process is used for manufacturing.

[0061] Fig.11 and Fig.12 The simulation and measured |S11|-|S88| of the broadband eight-beam switchable magnetoelectric dipole array antenna involved in the present invention are given respectively, from which it can be seen that the simulation and measurement results are consistent with each other. When the basic reflection coefficient is less than -10dB, the common simulation bandwidth of the eight states is 32.5% (4.44GHz~6.16GHz), and the measured bandwidth is 29.9% (4.52GHz~6.11GHz).

[0062] Fig.13 and Fig.14 The gain simulation curve and measured curve of the broadband eight-beam switchable magneto-electric dipole array antenna involved in the present invention are given respectively. The simulation results are consistent with the experimental results, and the error between the simulation results and the actual measured values ​​is less than 2dB. The peak gains of the simulation and measured results are 8.25 and 8.02dBi respectively, which verifies the effectiveness of the antenna.

[0063] Figure 15-18 The simulation and measured directional patterns of the broadband eight-beam switchable magneto-electric dipole array antenna involved in the present invention in the phi=45° plane when port 1 is excited at 4.75, 5.2, 5.65 and 6.1 GHz are given respectively. It can be seen that the simulation and the measured patterns are consistent with each other.

[0064] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna, characterized in that: include: The first four-beam unit and the second four-beam unit form an eight-beam array antenna; the first four-beam unit includes a first four-beam switchable annular magneto-electric dipole array, a coaxial inner conductor metal column, a short-circuit pin, a dielectric substrate, a metal floor, and a feeding port; the second four-beam unit includes a second four-beam switchable annular magneto-electric dipole array, a coaxial inner conductor metal column, a short-circuit pin, a dielectric substrate, a metal floor, and a feeding port; the first four-beam switchable annular magneto-electric dipole array and the second The four-beam switchable annular magneto-electric dipole arrays are in the same horizontal plane and are arranged on the dielectric substrate, the two dielectric substrates are connected, and the metal floor is arranged at the bottom of the dielectric substrate; the first four-beam switchable annular magneto-electric dipole array and the second four-beam switchable annular magneto-electric dipole array are both in the shape of four-leaf clover and differ by 45°; the short-circuit pin is arranged at the top of the blade of the four-beam switchable annular magneto-electric dipole array, passes through the four-beam switchable annular magneto-electric dipole array and the dielectric substrate in sequence, and is connected to the metal floor; The coaxial inner conductor metal columns are respectively arranged at the intersection of the blades of the same four-beam switchable annular magneto-electric dipole array, and sequentially penetrate the four-beam switchable annular magneto-electric dipole array, the dielectric substrate and the metal floor, and are connected to the feeding port.

2. The broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna according to claim 1, characterized in that: The dielectric substrates used by the first four-beam unit and the second four-beam unit are in the shape of a rectangular parallelepiped, and are both chamfered with the metal floor.

3. The broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna according to claim 1, characterized in that: A gap is provided between the metal floors corresponding to the first four-beam unit and the second four-beam unit.

4. The broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna according to claim 2, characterized in that: In the corner cutting process, the length of the right angle side of the corner cutting is 15 mm.

5. The broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna according to claim 3, characterized in that: The width of the gap is 2 mm.

6. The broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna according to claim 1, characterized in that: The dielectric substrate is made of F4BM320, has a dielectric constant of 3.2, and a dielectric loss of 0.0015.

7. A broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna design method, applied to a broadband two-dimensional eight-beam switchable annular magneto-electric dipole array antenna as described in any one of claims 1-6, characterized in that: include: S01: Determine the working frequency band of the antenna, design a broadband four-beam switchable annular magneto-electric dipole array of the corresponding size in the required frequency band, introduce four short-circuit pins, and use the magnetic current source mode to expand the bandwidth of the antenna; S02: keep the first four-beam switchable annular magneto-electric dipole array unchanged, and add a second four-beam switchable annular magneto-electric dipole array, which is 45 degrees different from the first four-beam switchable annular magneto-electric dipole array; S03: In order to obtain a beam with higher directivity and low side lobes, a cut-angle design is adopted for the dielectric substrate; S04: Slit the metal floor to improve the isolation between the two multi-beam array ports.

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