A high-isolation patch antenna array composed of dual-element sub-arrays and decoupling neutralization lines

Abstract

The present invention discloses a high-isolation patch antenna array composed of dual-element sub-arrays and decoupling neutralization lines, which is mainly used to reduce the mutual coupling between two ports caused by the too-close distance between the dual-element sub-arrays in a MIMO antenna array. The present invention includes two dual-element antenna arrays and a ground plane, where each array includes two antenna elements. The isolation degree (S21 < -20 dB) is achieved by connecting the neutralization lines in a gap-coupling manner at the feeding ports of the two dual-element antenna arrays. In order to avoid conflicts with the layout of the antenna array, the neutralization lines are located at the bottom of the ground plane. The present invention only adds a section of neutralization line on the basis of the original antenna array, so the structure is simple and easy to implement. And compared with other decoupling technologies that only decouple between different antenna elements, the present invention realizes the decoupling between antenna arrays, thus saving the cost of manpower and material resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and relates to a high-isolation patch antenna array composed of a dual-element sub-array and a decoupling neutralization line. Specifically, it is a technology that can achieve high decoupling isolation between dual-element antenna matrices in the frequency band of 2.5 GHz to 3.5 GHz. Background Art

[0002] In the field of radio communication, multi-input multi-output (MIMO) antenna arrays have been widely used in various communication systems. Such arrays have many advantages, such as improving the wireless transmission rate and quality of data, expanding the channel capacity, and enhancing the radiation gain of the antenna. However, when a MIMO antenna array needs to be placed in a small and enclosed space, designers must arrange the antenna elements as compactly as possible. At this time, the mutual coupling between antenna elements and between antenna arrays will increase significantly, thereby seriously affecting the performance of the MIMO antenna array.

[0003] To improve the isolation performance of MIMO antenna arrays, researchers have developed various decoupling technologies, most of which are only used for decoupling between antenna elements. These decoupling technologies include defected ground structure (DGS), decoupling network, etc. The defected ground structure technology is to engrave a periodic gap structure on the ground plane to suppress the generation of coupling current on the ground plane, thereby achieving high isolation between antenna elements. However, some of the gap structures are complex, difficult to manufacture, and expensive to process. The decoupling network is to add a transmission line network between each pair of antenna elements. And the mutual admittance of this network is exactly opposite to the mutual admittance of the coupled antenna elements, so as to eliminate the mutual coupling between the two antenna elements from a narrow band. Later, people further invented a coupled resonator network on this concept, achieving a broadband decoupling effect, but still unable to change the fact that only the mutual coupling between two antenna elements can be eliminated. The array-antenna decoupling surface is a newly emerged decoupling method in recent years. It places a dielectric plate directly above the antenna array for placing metal patches. Each metal patch is located directly above each antenna element and is used to reflect the electromagnetic waves radiated by the antenna. When the electromagnetic waves refracted by the metal patch and the coupled electromagnetic waves between the antenna elements form a 180-degree phase difference and the amplitudes are exactly equal, the two cancel each other out, forming decoupling. This method has a good effect, but adding a dielectric plate above the antenna array will significantly increase the volume occupied in the horizontal direction.

[0004] Therefore, although these decoupling techniques can all achieve the decoupling effect for the MIMO antenna array, they all have their own non-negligible disadvantages. Therefore, it is necessary to develop a technology that is applied to a dual-element subarray, is simple, feasible, easy to process, does not increase the volume, and can achieve good decoupling between subarrays.

[0005] The present invention proposes a decoupling neutralization line technology applied between dual-element antenna arrays. A neutralization line is added at the ports of two antenna arrays. The electromagnetic waves coupled by radiation between the two antenna arrays and the electromagnetic waves coupled by the neutralization line have a phase difference of 180 degrees and equal amplitudes, and the two cancel each other out to achieve the purpose of decoupling between the antenna arrays. In order to control the energy coupled by the neutralization line from being too large, the connection between the neutralization line and the feeding port of the antenna array adopts a gap coupling method. Compared with some other technologies that can only achieve decoupling between antenna elements, this technology can achieve decoupling between antenna arrays. The proposed decoupling method does not increase the volume of the original MIMO antenna array and is easy to process and manufacture. Summary of the Invention

[0006] The purpose of the present invention is to provide a decoupling neutralization line technology applied between dual-element antenna arrays in view of the deficiencies of the prior art.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A high-isolation patch antenna array composed of a dual-element subarray and a novel decoupling network, comprising:

[0009] A dielectric substrate;

[0010] A system floor (1), located above the dielectric substrate;

[0011] Two dual-element antenna arrays (2), located above the system floor, and are axisymmetric about the central axis in the long side direction of the system floor (1); and there is an air layer between the two dual-element antenna arrays (2) and the system floor (1);

[0012] A decoupling neutralization line (3), located below the dielectric substrate;

[0013] Two split feeding networks (4), located below the dielectric substrate;

[0014] Wherein:

[0015] The dual-element antenna array (2) includes two antenna elements (2-1), and the two antenna elements (2-1) are axisymmetric about the central axis in the wide side direction of the system floor (1);

[0016] Two antenna elements (2-1) of the same dual-element antenna array (2) are respectively connected to two feed output ports of one of the split feed networks (4) through a metal cylinder (5) that penetrates the system floor (1) and the dielectric substrate;

[0017] Preferably, the antenna element (2-1) is a metal patch; more preferably, the metal patch is square;

[0018] The decoupling neutralization line (3) includes a first coupling port (3-1), a second coupling port (3-2), a first transmission line (3-3), a second transmission line (3-4), a third transmission line (3-5), and a fourth transmission line (3-6); the first coupling port (3-1) is a T-shaped structure, including a first coupling microstrip line (3-1-1) and a second coupling microstrip line (3-1-2); the second coupling port (3-2) is a T-shaped structure, including a third coupling microstrip line (3-2-1) and a fourth coupling microstrip line (3-2-2); the midpoint of the first coupling microstrip line (3-1-1) is connected to one end of the second coupling microstrip line (3-1-2), the other end of the second coupling microstrip line (3-1-2) is connected to one end of the first transmission line (3-3), the other end of the first transmission line (3-3) is connected to one end of the second transmission line (3-4) and one end of the third transmission line (3-5), the other end of the third transmission line (3-5) is connected to one end of the fourth transmission line (3-6), the other end of the fourth transmission line (3-6) is connected to one end of the third coupling microstrip line (3-2-1), and the other end of the third coupling microstrip line (3-2-1) is connected to the midpoint of the fourth coupling microstrip line (3-2-2). The other end of the second transmission line (3-4) is open-circuited;

[0019] There are gaps between the first coupling port (3-1) and the second coupling port (3-2) and the two split feed networks (4) respectively to achieve gap coupling;

[0020] Preferably, the first transmission line (3-3), the second transmission line (3-4), the third transmission line (3-5), and the fourth transmission line (3-6) each independently adopt partial or all different forms of bends;

[0021] More preferably, the middle section of the third transmission line (3-5) adopts a "U" - shaped bend;

[0022] Preferably, the split - two feeding network (4) includes an input feeder, a first feeder branch, a first output feeder, a second feeder branch, and a second output feeder; one end of the input feeder is connected to the power feed, and the other end is connected to one end of the first feeder branch and one end of the second feeder branch. The other end of the first feeder branch is connected to one end of the first output feeder, and the other end of the first output feeder serves as the power feed output port. The other end of the second feeder branch is connected to one end of the second output feeder, and the other end of the second output feeder serves as the power feed output port; the first feeder branch and the second feeder branch are located on the same straight line;

[0023] More preferably, the first coupled microstrip line (3 - 1 - 1) is parallel to and located on the same straight line as the first feeder branch and the second feeder branch.

[0024] Preferably, the length of the second transmission line (3 - 4) is adjustable to achieve the matching of the center frequency (S11) of the antenna matrix and the tuning of the isolation (S21). More preferably, the length of the second transmission line (3 - 4) is 81.5 mm.

[0025] Preferably, the width of the second transmission line (3 - 4) is adjustable to achieve the matching of the center frequency (S11) of the antenna array and the tuning of the isolation (S21). More preferably, the width of the second transmission line (3 - 4) is 2.72 mm.

[0026] Preferably, the length of the third transmission line (3 - 5) is adjustable to achieve the tuning of the isolation (S21). More preferably, the length of the third transmission line (3 - 5) is 77 mm.

[0027] Preferably, the width of the third transmission line (3 - 5) is adjustable to achieve the tuning of the decoupling effect. More preferably, the width of the third transmission line (3 - 5) is 1.09673 mm.

[0028] Working principle: When two dual - element antenna arrays (2) radiate electromagnetic waves, they will couple with each other through spatial radiation or surface waves on the dielectric substrate surface. This coupling will change the current distribution, amplitude, and phase of the dual - element antenna arrays (2). Specifically, an unnecessary transmission path is generated between the two dual - element antenna arrays (2). To cancel this effect, a new transmission path can be introduced. The voltage amplitude and voltage phase of the new transmission path and the coupling path should satisfy the following relationship:

[0029]

[0030]

[0031] where represents the voltage transfer coefficient of the coupling path, The voltage transfer coefficient represents the newly introduced transmission path, Phase represents the function of taking the phase, and n represents any odd number.

[0032] The meaning expressed by formula (1) is that the voltage amplitudes of the coupling path and the newly introduced path are the same, but the signs are opposite. According to the voltage superposition theorem, the sum of the two is 0, that is, they cancel each other out. According to the above theorem, when designing the decoupling neutral line (3), when in the frequency band with strong mutual coupling, the decoupling neutral line (3) can form a deeper path for canceling mutual coupling, while in the frequency band with very low mutual coupling or no mutual coupling at all, the decoupling neutral line (3) should only generate a shallower path or not generate a path for canceling mutual coupling. The admittance Y between the two ports of the entire antenna array 21 satisfies formula (3):

[0033]

[0034] where ω = 2πf and f is the center frequency; represents the admittance of the coupling path, represents the admittance of the newly introduced transmission path;

[0035] Since the center frequency at which the two dual - element antenna arrays (2) are most strongly coupled is 3 GHz, the decoupling neutral line (3) generates a path for canceling mutual coupling at 3 GHz.

[0036] The beneficial effects of the present invention are as follows: high port isolation is achieved by adding a decoupling neutral line between two dual - element antenna sub - arrays. Compared with other decoupling methods, this structure is simple and easy to implement, does not increase the extra volume, saves labor and material costs. The decoupling neutral line is located at the bottom of the dielectric substrate, making full use of the area. And compared with other decoupling technologies that only decouple between different antenna elements, this technology realizes the decoupling between antenna arrays, expands the antenna impedance bandwidth, and forms a higher port isolation degree. Therefore, it well solves the problem of strong coupling caused by too small antenna spacing in the current wireless communication field. At the same time, compared with the rest of the inventions that can achieve decoupling with high port isolation (S21>20 dB), the antennas are placed closely and symmetrically, which has good feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a top - view of the structure of a MIMO antenna array including two sub - antenna arrays, a total of four antenna elements.

[0038] Figure 2 is a front - view of the structure of a MIMO antenna array including two sub - antenna arrays, a total of four antenna elements.

[0039] Figure 3 is a left - view of the structure of a MIMO antenna array including two sub - antenna arrays, a total of four antenna elements.

[0040] Figure 4 It is a structural bottom view of a MIMO antenna array that includes two sub - antenna arrays, a total of four antenna elements, but without adding a neutralization line.

[0041] Figure 5 It is a structural diagram of the added neutralization line for decoupling.

[0042] Figure 6 It is a structural bottom view of a MIMO antenna array that includes two sub - antenna arrays, a total of four antenna elements, after adding a neutralization line.

[0043] Figure 7 It is an S - parameter diagram of the MIMO antenna before adding the neutralization line. It can be seen that the mutual coupling between the two sub - arrays in the MIMO antenna array is relatively strong.

[0044] Figure 8 It is an S - parameter diagram of the MIMO antenna after adding the neutralization line. It can be seen that after adding the neutralization line, the mutual coupling between the two sub - arrays in the MIMO antenna array is significantly reduced.

[0045] Figure 9 It is a two - dimensional radiation pattern of the MIMO antenna after adding the neutralization line. Detailed implementation manners

[0046] In order to clarify the object, technical solution and advantages of the present invention more clearly, the present invention is further described in detail below by combining specific examples and with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0047] A high - isolation patch antenna array composed of a dual - element antenna array 2 and a novel decoupling network, as Figures 1 - 3 including:

[0048] A dielectric substrate; a system floor 1, located above the dielectric substrate, with a length of 200 mm, a width of 150 mm, and a thickness of 1.65 mm; two dual - element antenna arrays 2, located above the system floor and axisymmetric about the central axis in the long - side direction of the system floor 1; and there is an air layer between the two dual - element antenna arrays 2 and the system floor 1; a decoupling neutralization line 3, located below the dielectric substrate; two feeding networks 4, located below the dielectric substrate;

[0049] The dual - element antenna array 2 includes two antenna elements 2 - 1, and the two antenna elements 2 - 1 are axisymmetric about the central axis in the wide - side direction of the system floor 1; there are a total of 4 antenna elements 2 - 1 in the two dual - element antenna arrays 2. The antenna element 2 - 1 uses a square metal patch, with a length and a width both being 41.7 mm.

[0050] Two antenna elements 2-1 of the same dual-element antenna array 2 are respectively connected to two feed output ports of one of the split feed networks 4 through a metal cylinder 5 passing through the system floor 1 and the dielectric substrate; the height of the metal cylinder 5 is 6.65 mm and the diameter is 1.5 mm.

[0051] Two groups of dual-antenna element arrays are formed with the ground plane, and each group of arrays is composed of two square antenna elements. Antenna array 1 and antenna array 2 are symmetrically distributed along the vertical center line of the ground plane, and the elements within each group of antenna arrays are symmetrically distributed along the horizontal center line of the ground plane. Each group of antenna arrays has only one vertical arm connected to the feed port of the system floor, and the energy transmitted into the feed port will be evenly distributed to the two antenna elements in the antenna array. A neutralization line for decoupling is connected to the feed ports of the two groups of antenna arrays by means of gap coupling.

[0052] Before the neutralization line is added to the described antenna array, there is strong coupling between the antenna arrays. After the neutralization line is added, the coupling between the antenna arrays is significantly reduced (S21 < -20 dB), and all improvements in isolation performance are achieved by adding the neutralization line.

[0053] By means of neutralization line decoupling, decoupling between dual-element antenna arrays can be achieved, not limited to decoupling between individual antenna elements. When the neutralization line is connected to the feed port of the antenna array, gap coupling is used instead of direct coupling.

[0054] The method of decoupling through the neutralization line can decouple antenna arrays not limited to between dual-element antenna arrays, and can reduce the coupling between antenna arrays with any number of elements. The number of antenna array elements decoupled by the neutralization line is determined by the number of neutralization lines. Specifically, the number of antenna array elements to be decoupled is twice the number of neutralization lines.

[0055] Figure 4The elevation view of the MIMO antenna without adding a neutralization line is specifically as follows: At the bottom of the system floor 1 are two feed networks 4, which are exactly the same and symmetric along the vertical center line of the system floor 1. Taking one of the feed networks 4 as an example, after the electromagnetic wave enters from the feed arm on the left side of the feed network 4, it is equally divided into two electromagnetic waves with the same power and respectively enters the two antenna elements 2-1 of the same dual-element antenna array 2. The feed network 4 includes an input feeder, a first feeder branch, a first output feeder, a second feeder branch, and a second output feeder; one end of the input feeder is connected to the feed, and the other end is connected to one end of the first feeder branch and one end of the second feeder branch. The other end of the first feeder branch is connected to one end of the first output feeder, and the other end of the first output feeder serves as the feed output port. The other end of the second feeder branch is connected to one end of the second output feeder, and the other end of the second output feeder serves as the feed output port; the first feeder branch and the second feeder branch are located on the same straight line; the first coupling microstrip line 3-1-1 is parallel to the first feeder branch and the second feeder branch on the same straight line.

[0056] Figure 5 The structure diagram of the neutralization line. The decoupling neutralization line 3 includes a first coupling port 3-1, a second coupling port 3-2, a first transmission line 3-3, a second transmission line 3-4, a third transmission line 3-5, and a fourth transmission line 3-6; the first coupling port 3-1 is of a T-shaped structure and includes a first coupling microstrip line 3-1-1 and a second coupling microstrip line 3-1-2; the second coupling port 3-2 is of a T-shaped structure and includes a third coupling microstrip line 3-2-1 and a fourth coupling microstrip line 3-2-2; the midpoint of the first coupling microstrip line 3-1-1 is connected to one end of the second coupling microstrip line 3-1-2, and the other end of the second coupling microstrip line 3-1-2 is connected to one end of the first transmission line 3-3. The other end of the first transmission line 3-3 is connected to one end of the second transmission line 3-4 and one end of the third transmission line 3-5. The other end of the third transmission line 3-5 is connected to one end of the fourth transmission line 3-6, and the other end of the fourth transmission line 3-6 is connected to one end of the third coupling microstrip line 3-2-1. The other end of the third coupling microstrip line 3-2-1 is connected to the midpoint of the fourth coupling microstrip line 3-2-2. The other end of the second transmission line 3-4 is open-circuited;

[0057] There are gaps between the first coupling port 3-1, the second coupling port 3-2 and the two feed networks 4 respectively to achieve gap coupling, so as to reduce the mutual coupling between the feed ports;

[0058] The first transmission line 3-3, the second transmission line 3-4, the third transmission line 3-5, and the fourth transmission line 3-6 are each independently bent appropriately; preferably, the middle section of the third transmission line 3-5 is bent in a "U" shape;

[0059] Figure 6 It is the structural diagram of the neutralization line and the schematic diagram and dimensions of the structure after adding the neutralization line to the MIMO antenna array. By adjusting the vertical position of the neutralization line, the optimal decoupling effect can be achieved.

[0060] The advantages of the present invention can be further illustrated by the simulation results. The MIMO antenna array after adding the neutralization line to the above specific dimensions is modeled and full-wave simulated to obtain the simulated S-parameter diagram and radiation pattern.

[0061] Figure 7 It is the S-parameter diagram of the MIMO antenna array before adding the neutralization line. It can be seen that at the 3GHz antenna resonance point, S21 is greater than -15dB, and when it is 2.5 - 3.5GHz, S21 is generally greater than -20dB. This shows that the mutual coupling between the two antenna sub-arrays is relatively strong.

[0062] Figure 8 It is the S-parameter diagram of the MIMO antenna array after adding the neutralization line. It can be seen that at the 3GHz antenna resonance point, S21 is reduced to -25dB, and when it is 2.5 - 3.5GHz, S21 is generally less than -20dB. This shows that after adding the neutralization line, the mutual coupling between the antenna arrays is significantly suppressed. At the same time, the resonance bandwidth of the antenna also becomes wider. At 3GHz, S11 is still greater than -16dB, and the performance is more excellent.

[0063] Figure 9 It is the two-dimensional radiation pattern of the MIMO antenna after adding the neutralization line, including the directions of 0 degrees and 90 degrees.

[0064] The present invention is a high-isolation patch antenna array composed of a dual-element antenna array 2 and a novel decoupling network. By adding a decoupling neutralization line between the two antenna arrays, high isolation of the ports is achieved. Compared with other decoupling methods, this structure is simple and easy to implement. And compared with other decoupling technologies that only decouple between different antenna elements, this technology realizes the decoupling between antenna arrays, saves manpower and material costs, expands the antenna impedance bandwidth, and forms a higher port isolation. Therefore, it well solves the problem of strong coupling caused by too small antenna spacing in the current wireless communication field.

[0065] The above is only one embodiment of the present invention, which is only used to help understand the method and core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, the present invention can be improved, and these improvements will also fall within the protection scope of the claims of the present invention. The present invention is not limited to the scope of the specific implementation manner. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

Claims

1. A high-isolation patch antenna array composed of dual-element sub-arrays and a novel decoupling network, characterized in that it includes: a dielectric substrate; a system ground plane (1), located above the dielectric substrate; two dual-element antenna arrays (2), located above the system ground plane, and axially symmetric about the central axis in the long side direction of the system ground plane (1); and there is an air layer between the two dual-element antenna arrays (2) and the system ground plane (1); a decoupling neutralization line (3), located below the dielectric substrate; two split-feed networks (4), located below the dielectric substrate; wherein: the dual-element antenna array (2) includes two antenna elements (2-1), and the two antenna elements (2-1) are axially symmetric about the central axis in the wide side direction of the system ground plane (1); the two antenna elements (2-1) of the same dual-element antenna array (2) are respectively connected to the two feed output ports of one of the split-feed networks (4) through a metal cylinder (5) penetrating the system ground plane (1) and the dielectric substrate; the decoupling neutralization line (3) includes a first coupling port (3-1), a second coupling port (3-2), a first transmission line (3-3), a second transmission line (3-4), a third transmission line (3-5), and a fourth transmission line (3-6); the first coupling port (3-1) is a T-shaped structure, including a first coupling microstrip line (3-1-1) and a second coupling microstrip line (3-1-2); the second coupling port (3-2) is a T-shaped structure, including a third coupling microstrip line (3-2-1) and a fourth coupling microstrip line (3-2-2); the midpoint of the first coupling microstrip line (3-1-1) is connected to one end of the second coupling microstrip line (3-1-2), the other end of the second coupling microstrip line (3-1-2) is connected to one end of the first transmission line (3-3), the other end of the first transmission line (3-3) is connected to one end of the second transmission line (3-4) and one end of the third transmission line (3-5), the other end of the third transmission line (3-5) is connected to one end of the fourth transmission line (3-6), the other end of the fourth transmission line (3-6) is connected to one end of the third coupling microstrip line (3-2-1), and the other end of the third coupling microstrip line (3-2-1) is connected to the midpoint of the fourth coupling microstrip line (3-2-2); the other end of the second transmission line (3-4) is open; a middle section of the third transmission line (3-5) is bent in a "U" shape; there are gaps between the first coupling port (3-1), the second coupling port (3-2) and the two split-feed networks (4) respectively to achieve gap coupling; The split-feed network (4) includes an input feeder, a first feeder branch, a first output feeder, a second feeder branch, and a second output feeder; one end of the input feeder is connected to the power supply, and the other end is connected to one end of the first feeder branch and one end of the second feeder branch. The other end of the first feeder branch is connected to one end of the first output feeder, and the other end of the first output feeder serves as the power supply output port. The other end of the second feeder branch is connected to one end of the second output feeder, and the other end of the second output feeder serves as the power supply output port; the first feeder branch and the second feeder branch are located on the same straight line; The first coupled microstrip line (3-1-1) is parallel to the first feeder branch and the second feeder branch on the same straight line.

2. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to claim 1, characterized in that, the antenna element (2-1) uses a metal patch.

3. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to claim 2, characterized in that, the metal patch is square.

4. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to claim 1, characterized in that, the first transmission line (3-3), the second transmission line (3-4), the third transmission line (3-5), and the fourth transmission line (3-6) each independently adopt partial or all different forms of bends.

5. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to claim 1, characterized in that, the length and width of the second transmission line (3-4) are adjustable to achieve the matching of the center frequency of the antenna matrix and the tuning of the isolation.

6. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to claim 1, characterized in that, the length and width of the third transmission line (3-5) are adjustable to achieve the tuning of the isolation.

7. The high isolation patch antenna array composed of a dual-element subarray and a novel decoupling network according to any one of claims 1-6, characterized in that, when the two dual-element antenna arrays (2) radiate electromagnetic waves, they will be coupled to each other through the way of space radiation or surface waves on the dielectric substrate surface. This coupling will change the current distribution, amplitude, and phase of the dual-element antenna array (2); therefore, an unnecessary transmission path is generated between the two dual-element antenna arrays (2). To offset this influence, a new introduced transmission path generated by introducing a decoupling neutralization line (3) is introduced. The voltage amplitude and voltage phase of the new introduced transmission path and the coupling path satisfy the following relationship: ； ； wherein represents the voltage transfer coefficient of the coupling path, represents the voltage transfer coefficient of the newly introduced transmission path, Phase represents the function of taking the phase, and n represents any odd number; Admittance of the entire antenna array Satisfies Equation (3): ； Among them , is the center frequency; represents the admittance of the coupling path, represents the admittance of the newly introduced transmission path.

Images