A coupled resonator decoupling network system applied to dual-frequency coupling suppression of MIMO antenna array

Abstract

The application belongs to the technical field of antennas, and discloses a coupled resonator decoupling network system applied to MIMO antenna array double-frequency coupling suppression, which comprises a radiating antenna array, a metal floor, a transmission line structure, a single-branch matching network, a three-port double-frequency CRDN structure and a dielectric substrate; the radiating antenna array, the transmission line structure, the single-branch matching network and the three-port double-frequency CRDN structure are printed on the upper layer of the dielectric substrate, and the metal floor is printed on the lower layer of the dielectric substrate; the application has clear principles, mature technology, stable structure, low cost, simple processing technology and is suitable for large-scale production; the application realizes the suppression of mutual coupling of the antenna array in two frequency bands at the same time in a limited space, is suitable for the double-frequency decoupling demand of a compact space multi-antenna system, does not occupy too much additional volume, has low profile and scalability, and can be popularized to different antenna types and other working frequency bands.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and specifically relates to a coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays. Background Technology

[0002] In modern wireless communication systems, MIMO (Multiple-Input Multiple-Output) antenna systems can achieve greater channel capacity and diversity gain. However, the trend towards integration and miniaturization of wireless communication devices has led to increasingly compact antenna deployment spaces. This reduction in antenna installation space inevitably results in smaller spacing between antenna elements, causing severe mutual coupling problems. Mutual coupling between antennas can significantly degrade various key performance parameters of the antenna system, such as directivity, gain, and efficiency.

[0003] To address the mutual coupling problem between multiple antenna elements, numerous decoupling methods have been proposed. Common decoupling methods include electromagnetic bandgap (EBG) structures, parasitic elements, metamaterial cladding, neutralization lines, and decoupling networks. However, EBG structures typically require large volumes, making them unsuitable for antenna structures with close spacing. Parasitic elements achieve decoupling by introducing new coupling paths on the ground plane between antenna elements to cancel the coupling current of the original paths, but this can easily cause functional changes in the antenna elements, such as reduced bandwidth. Metamaterial cladding is usually placed at a certain height above the antenna radiating elements, achieving decoupling by absorbing or reflecting coupled waves to modulate the electromagnetic wave propagation path, but at the cost of increasing the overall profile height of the antenna system. Neutralization line decoupling lacks systematic theoretical guidance and requires significant electromagnetic computational resources to determine the optimal size and location. Decoupling networks achieve decoupling by introducing circuits to prevent or reduce coupling current and coupled electromagnetic energy between antenna elements. It has attracted much attention due to the clarity of its guiding theory, the independence of its design, and its low profile height; however, most decoupling networks currently available can only suppress mutual coupling between two antenna elements in one frequency band at the same time.

[0004] To address the coupling suppression problem between multiple antenna elements, decoupling networks can be used when antenna deployment space is compact, antenna element spacing is small, and antenna profile height cannot be increased. However, most current decoupling networks can only suppress coupling between two antennas within one frequency band. As the number of antennas increases, the coupling paths between antennas also increase. Furthermore, as the operating frequency bands of the antennas increase, it is necessary to suppress coupling between antenna elements simultaneously in two or more frequency bands. Therefore, multi-frequency decoupling networks need to be designed for coupling in different frequency bands. Multi-frequency decoupling can be implemented in two ways: one is to design a single-frequency decoupling sub-network for each frequency band and then integrate them into a single multi-frequency decoupling network. This approach is less complex but significantly increases the additional space required. The other approach is to design a single, integrated multi-frequency decoupling network that simultaneously decouples antenna elements across multiple frequency bands while minimizing space requirements. However, this increases the difficulty and complexity of the decoupling network design. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies and provides the following solutions:

[0006] A coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays includes: a radiating antenna array, a metal ground plane, a transmission line structure, a single stub matching network, a three-port dual-frequency CRDN structure, and a dielectric substrate;

[0007] The radiating antenna array, the transmission line structure, the single-stub matching network, and the three-port dual-frequency CRDN structure are printed on the upper layer of the dielectric substrate, and the metal ground plane is printed on the lower layer of the dielectric substrate.

[0008] Preferably, by controlling the transmission line structure, the real part of the mutual admittance of the radiating antenna array is converted to 0 in the expected frequency band, and the imaginary part of the mutual admittance of the three-port dual-band CRDN structure cancels out the imaginary part of the radiating antenna array in both frequency bands, thereby suppressing mutual coupling in the radiating antenna array. By adjusting the single-stub matching network, the matching bandwidth of the antenna is improved.

[0009] Preferably, the radiating antenna array is composed of three radiating antenna elements arranged in an equilateral triangle, including: a first radiating antenna element, a second radiating antenna element, and a third radiating antenna element;

[0010] The first radiating antenna unit, the second radiating antenna unit, and the third radiating antenna unit are the three vertices of an equilateral triangle, and are vertically printed on the dielectric substrate with the center of the circular dielectric substrate as the center.

[0011] Preferably, the geometric center distance between any two adjacent radiating antenna elements is 8.7 mm. The geometric center distance is expressed as 0.12λ1 and 0.16λ2 at two different frequencies, where λ1 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 3.5 GHz, and λ2 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 4.9 GHz.

[0012] Preferably, there is strong mutual coupling between the two operating frequency bands of the radiating antenna elements, including S 12 S 13 and S 23 Since the radiating antenna elements are symmetrically arranged, the values ​​of strong mutual coupling are considered equal: S 12 =S 13 =S 23 ;

[0013] The radiating antenna elements have mutual admittance, including: Y 12 Y 13 and Y 23 And there is Y 12 =Y 13 =Y 23 .

[0014] Preferably, the three-port dual-frequency CRDN structure consists of three closely placed and identical triangular open-face resonators, with a triangular block placed at the bottom of the triangular open-face resonators;

[0015] By controlling the size of the triangular open resonator and the size of the triangular block, the desired imaginary part of the cross admittance can be designed in both frequency bands.

[0016] Preferably, the distance from the center of each radiating antenna element to the center of the dielectric substrate is X1=10mm, and the total length of each radiating antenna element is H=H1+H2=18.8mm, wherein the length of the upper sleeve is H1=4.2mm and the length of the lower sleeve is H2=14.6mm.

[0017] Preferably, the total length of the transmission line structure is L. T1 +L T2 +L T3 +L T4 +L T5 +L T6 +L T7 =30.1mm, where L T1 =3.4mm, L T2 =7.7mm, L T3 =2.9mm, L T4 =5.9mm, L T5=3.7mm, L T6 =4.1mm, L T7 =2.4mm;

[0018] Preferably, in the three-port dual-frequency CRDN structure, the side length of the transmission line of the triangular open resonator is L. R1 =9.3mm, width is W R1 =0.3mm; the side length of the top opening is L R2 =5.4mm, width is g1=0.2mm; the gap between each of the triangular open resonators is g2=0.4mm.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention includes a transmission line structure with a characteristic impedance equal to the antenna port impedance, a three-port dual-band CRDN structure, and a single-stub matching network. The radiating antenna array includes three radiating antennas operating simultaneously in two frequency bands. The transmission line structure ensures that the real part of the mutual admittance between the radiating antenna elements is close to zero in both expected frequency bands. The three-port dual-band CRDN structure provides the desired imaginary part of the mutual admittance, achieving mutual cancellation with the imaginary part of the mutual admittance of the radiating antennas in both operating frequency bands, thus achieving the goal of having the imaginary part of the mutual admittance between the radiating antenna elements near zero in both frequency bands. Through the above design, the real and imaginary parts of the mutual admittance between the three radiating antenna elements are close to zero in both expected frequency bands, thereby achieving coupling suppression. The single-stub matching network compensates for the matching phase of the antenna elements and further extends the matching bandwidth of the antenna. The principle of this invention is clear, the technology is mature, the structure is stable, the cost is low, the processing technology is simple, and it is suitable for mass production. This invention achieves the suppression of mutual coupling of antenna arrays in two frequency bands in a limited space, which is suitable for the dual-frequency decoupling requirements of multi-antenna systems in compact space. It does not occupy too much extra volume, has low profile and scalability, and can be extended to different antenna types and other operating frequency bands. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional schematic diagram of a coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays according to an embodiment of the present invention;

[0023] Figure 2 This is an embodiment of the present invention. Figure 1 A schematic diagram of the structure shown in the top view;

[0024] Figure 3 This is an embodiment of the present invention. Figure 1 A schematic diagram of the structure shown in the side view;

[0025] Figure 4 This is an embodiment of the present invention. Figure 1 The diagram shows a schematic of the transmission line and matching network in the top view, as well as a partial enlarged view of the three-port dual-frequency CRDN.

[0026] Figure 5 This is a three-dimensional schematic diagram of a comparative radiating antenna array (reference antenna array) in an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the transmission line and matching network structure introduced on the dielectric substrate in an embodiment of the present invention;

[0028] Figure 7 The radiating antenna array in the embodiments of the present invention and Figure 5 The comparison diagram shows the reflection coefficients of the reference antenna array in the comparative example, where "before decoupling" corresponds to the comparative example and "after decoupling" corresponds to the embodiment of the present invention.

[0029] Figure 8 The radiating antenna array in the embodiments of the present invention and Figure 5 A comparison diagram of the reverse transmission coefficients of the reference antenna array in the comparative example, where "before decoupling" corresponds to the comparative example and "after decoupling" corresponds to the embodiment of the present invention;

[0030] Figure 9 This is an embodiment of the present invention. Figure 5 The reference antenna array in the comparison model and Figure 1 The antenna shown Figure 6 Comparison of the real parts of the mutual admittances of the intermediate structures;

[0031] Figure 10 This is an embodiment of the present invention. Figure 5 The antenna shown is Figure 1 The antenna shown Figure 4 The imaginary part of the mutual admittance corresponding to the three-port dual-frequency CRDN structure;

[0032] Figure 11 The radiating antenna array in the embodiments of the present invention and Figure 5 The comparison diagram shows the radiation pattern of the reference antenna array at 3.5 GHz. (a) represents the radiation pattern of the antenna array in the xoz plane before and after decoupling, and (b) represents the radiation pattern of the antenna array in the xoy plane before and after decoupling. "Before decoupling" corresponds to the comparison diagram, and "after decoupling" corresponds to the embodiment of the present invention.

[0033] Figure 12 The radiating antenna array in the embodiments of the present invention and Figure 5 The comparison diagram shows the radiation pattern of the reference antenna array at 4.9 GHz. (a) represents the radiation pattern of the antenna array in the xoz plane before and after decoupling, and (b) represents the radiation pattern of the antenna array in the xoy plane before and after decoupling. "Before decoupling" corresponds to the comparison diagram, and "after decoupling" corresponds to the embodiment of the present invention.

[0034] Figure 13 The radiating antenna array in the embodiments of the present invention and Figure 5 The comparison chart shows the overall efficiency of the reference antenna array in the comparative example, where "before decoupling" corresponds to the comparative example and "after decoupling" corresponds to the embodiment of the present invention;

[0035] Figure 14 The radiating antenna array in the embodiments of the present invention and Figure 5 A comparison diagram of the envelope correlation coefficients of the reference antenna array in the comparative example, where "before decoupling" corresponds to the comparative example and "after decoupling" corresponds to the embodiment of the present invention;

[0036] Explanation of reference numerals in the attached figures:

[0037] F1, First direction; F2, Second direction; 1, First radiating antenna element; 2, Second radiating antenna element; 3, Third radiating antenna element; 4, Metal ground plane; 5, Transmission line structure; 6, Single stub matching network; 7, Three-port dual-band CRDN structure; 8, Dielectric substrate. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Example

[0041] In this embodiment, Figure 1 , Figure 2As shown, a coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays includes: a radiating antenna array, a metal ground plane 4, a transmission line structure 5 with the same truncated characteristic impedance as the antenna characteristic impedance, a single stub matching network 6, a three-port dual-frequency CRDN structure 7, and a dielectric substrate 8.

[0042] The radiating antenna array, transmission line structure 5, single stub matching network 6, and three-port dual-frequency CRDN structure 7 are printed on the upper layer of the dielectric substrate 8, and the metal ground plane 4 is printed on the lower layer of the dielectric substrate 8.

[0043] In this embodiment, the metal ground plane 4 can be used for soldering test connectors, which are used to connect to antenna testing equipment. The dielectric substrate 8 uses a Rogers 4350 PCB board with a thickness of 0.762 mm and a dielectric constant of 3.66.

[0044] The radiating antenna array consists of three radiating antenna elements arranged in an equilateral triangle: a first radiating antenna element 1, a second radiating antenna element 2, and a third radiating antenna element 3. These three elements, serving as the three vertices of the equilateral triangle, are vertically printed on the circular dielectric substrate 8, with the center of the substrate as the center. The geometric center distance between any two adjacent radiating antenna elements is 8.7 mm, corresponding to 0.12λ1 and 0.16λ2 at two different frequencies. Here, λ1 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 3.5 GHz, and λ2 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 4.9 GHz. Strong mutual coupling exists between the two operating frequency bands of the radiating antenna elements, including S... 12 S 13 and S 23 Since the radiating antenna elements are symmetrically arranged, the values ​​of strong mutual coupling are considered equal: S 12 =S 13 =S 23 In this embodiment, the strong mutual coupling values ​​are approximately -10.2 dB and -11.4 dB, respectively. Mutual admittance exists between the radiating antenna elements, including: Y 12 Y 13 and Y 23 And there is Y 12 =Y 13 =Y 23 .

[0045] The three-port dual-frequency CRDN structure 7 consists of three closely placed and identical triangular open-ended resonators, with a triangular block placed at the bottom of each resonator. By controlling the size of the triangular open-ended resonators and the size of the triangular block, the desired imaginary part of the mutual admittance can be designed in both frequency bands.

[0046] In this embodiment, as Figure 3 , Figure 4 As shown, the distance from the center of each radiating antenna element to the center of the dielectric substrate 8 is X1 = 10 mm, and the total length of each radiating antenna element is H = H1 + H2 = 18.8 mm, where the upper sleeve length is H1 = 4.2 mm and the lower sleeve length is H2 = 14.6 mm; the total length of the transmission line structure 5 is L. T1 +L T2 +L T3 +L T4 +L T5 +L T6 +L T7 =30.1mm, where L T1 =3.4mm, L T2 =7.7mm, L T3 =2.9mm, L T4 =5.9mm, L T5 =3.7mm, L T6 =4.1mm, L T7 =2.4mm; In the three-port dual-frequency CRDN structure 7, the side length of the transmission line of the triangular open resonator is L. R1 =9.3mm, width is W R1 =0.3mm; the side length of the top opening is L R2 =5.4mm, width is g1=0.2mm; the gap between each triangular open resonator is g2=0.4mm.

[0047] Since the mutual admittance of the three-port dual-band CRDN structure 7 is purely imaginary, to achieve decoupling, the real part of the mutual admittance of the radiating antennas must first be made close to 0 in the required frequency band through an effective method. In this embodiment, a transmission line structure 5 is inserted in series at the ports of the three radiating antennas to simultaneously convert the real part of the mutual admittance of the radiating antenna elements to near 0 in both the designed low-frequency and high-frequency bands. Then, by designing the three-port dual-band CRDN structure 7, the imaginary part of the mutual admittance of the radiating antennas is mutually canceled out in both frequency bands, achieving the goal of making the imaginary part of the mutual admittance close to 0 in both frequency bands. Simultaneously, to compensate for the antenna's matching phase and further expand the antenna's matching bandwidth, a single-stub matching network 6 is designed.

[0048] In contrast. Figure 5 A three-dimensional structural diagram containing only the radiating antenna array is given, which is used as the reference antenna array in the comparative example. Figure 6 A structural diagram of the transmission line and the three-port CRDN printed on the dielectric substrate 8 is given.

[0049] See Figure 7 , Figure 7 Given Figure 1 The radiating antenna array shown is Figure 5 The comparison diagram of the reflection coefficients of the comparative reference antenna arrays shows that, under the premise that the reflection coefficient is below -10dB, the reference antenna array in the comparative example can cover the 3.27-3.63GHz frequency band and the 4.70-5.03GHz frequency band, while the radiating antenna array in the embodiment can cover the 3.38-3.61GHz frequency band and the 4.80-5.02GHz frequency band.

[0050] See also Figure 8 , Figure 8 Given Figure 1 The radiating antenna array shown is Figure 5 The comparison chart of the reverse transmission coefficients of the comparative reference antenna array shows that, within the 3.4-3.6 GHz frequency band, the S in the comparative example... 12 Between -10.2 dB and -9.8 dB, with -9.9 dB at the 3.5 GHz frequency point, in the embodiment, the coupling can be reduced overall within the frequency band to below -20.1 dB, with the 3.5 GHz frequency point reduced to -35.6 dB; in the 4.8-5.0 GHz frequency band, the S in the comparative example 12 Between -11.4dB and -10.6dB, with -10.8dB at the 4.9GHz frequency point, in the embodiment, the coupling can be reduced overall within the frequency band to below -20.6dB, with the 4.9GHz frequency point reduced to -29.5dB.

[0051] See also Figure 9 , Figure 9 Given Figure 5 The reference antenna array in the comparison model and Figure 1 The antenna shown Figure 6 A comparison diagram of the real parts of the mutual admittances of the structures shown; wherein, " "The mutual admittance of the response ratio," "The mutual admittance of transmission line structure 5, which corresponds to a three-port dual-frequency CRDN connected in series with a section whose characteristic impedance is equal to that of the antenna port." correspond Figure 1 The mutual admittance between port 1 and port 2 of the antenna shown represents the introduction of three structures based on the comparative example: transmission line, three-port dual-band CRDN, and matching network. Subscripts indicate the relationship between port 1 and port 2. It can be seen that in the 3.4-3.6 GHz frequency band, in the comparative reference antenna array, Between 0.0056 and 0.0062, the real part of the mutual admittance is relatively far from the target of 0. The real part of the mutual admittance of a dual-band CRDN structure with a transmission line structure 5 connected in series with a section whose characteristic impedance is the same as the antenna port impedance is... Between -0.0065 and -0.0048, Figure 1The real part of the cross-conductance of the antenna array in the illustrated embodiment Between 0.00125 and 0.00129, the real part of the cross-admittance is near 0. In the 4.8-5.0 GHz band, in the comparative reference antenna array, Between 0.0118 and 0.0122, Figure 6 Real part of the mutual admittance of the structure shown In this frequency band, between -0.0141 and -0.0123, the real part of the cross-conductance of the antenna array in the embodiment... Between -0.0020 and -0.0011, the real part of the mutual admittance is close to 0. Note: Re represents the real part.

[0052] See also Figure 10 , Figure 10 Given Figure 5 The comparative antenna array shown is Figure 1 The antenna shown Figure 4 The imaginary parts of the three different mutual admittances corresponding to the three-port dual-frequency CRDN structure 7 are shown; among them, correspond Figure 1 The mutual admittance between port 1 and port 2 of the antenna shown is... correspond Figure 4 The mutual admittance between port 1 and port 2 in the three-port dual-frequency CRDN structure 7 shown is illustrated. It can be seen that... Figure 5 The imaginary part of the mutual admittance of the antenna array shown is positive in both frequency bands, while the imaginary part of the mutual admittance provided by the three-port dual-band CRDN is negative in both expected frequency bands, achieving a mutual cancellation effect. Figure 1 The target shown in this embodiment is that the imaginary part of the cross-inductance of the antenna array is close to 0 in both frequency bands.

[0053] See also Figure 11 , Figure 11 Given Figure 1 The radiating antenna array shown is Figure 5 The radiation pattern of the reference antenna array in the comparative example is shown in the comparison diagram at the 3.5 GHz frequency point. It can be seen that the antenna array in this embodiment maintains relatively excellent radiation performance, with a radiation pattern that is not much different from that of the comparative example, and the overall performance is improved.

[0054] See also Figure 12 , Figure 12 Given Figure 1 The radiating antenna array shown is Figure 5 A comparison of the radiation pattern of the reference antenna array at 4.9 GHz in the comparative example. Compared to the comparative example, the concave phenomenon of the antenna radiation pattern in this embodiment is restored, and the radiation performance is also improved.

[0055] See also Figure 13 , Figure 13 Given Figure 1 The radiating antenna array shown is Figure 5 A comparison chart showing the overall efficiency of the reference antenna array in the comparative example. This chart demonstrates that, compared to... Figure 5 Compared with the comparative example, the overall efficiency of this embodiment is significantly improved in both the 3.4-3.6GHz band and the 4.8-5.0GHz range.

[0056] See also Figure 14 , Figure 14 Given Figure 1 The radiating antenna array shown is Figure 5 A comparison chart of the envelope correlation coefficients of the reference antenna array in the comparative example. This chart shows that, compared to... Figure 5 Compared to the comparative example, the envelope correlation coefficient between ports in this embodiment is significantly reduced in both expected frequency bands.

[0057] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A decoupling network system for coupled resonators applied to dual-frequency coupling suppression in MIMO antenna arrays, characterized in that, include: Radiation antenna array, metal ground plane, transmission line structure with characteristic impedance the same as antenna port impedance, single stub matching network, three-port dual-frequency CRDN structure and dielectric substrate; The radiating antenna array, the transmission line structure, the single stub matching network, and the three-port dual-frequency CRDN structure are printed on the upper layer of the dielectric substrate, and the metal ground plane is printed on the lower layer of the dielectric substrate. The radiating antenna array is composed of three radiating antenna elements arranged in an equilateral triangle, including: a first radiating antenna element, a second radiating antenna element, and a third radiating antenna element; The first radiating antenna unit, the second radiating antenna unit, and the third radiating antenna unit are the three vertices of an equilateral triangle, and are vertically printed on the dielectric substrate with the center of the circular dielectric substrate as the center. The three-port dual-frequency CRDN structure consists of three closely placed and identical triangular open-face resonators, with a triangular block placed at the bottom of each triangular open-face resonator. By controlling the size of the triangular open resonator and the size of the triangular block, the desired imaginary part of the mutual admittance can be designed in both frequency bands. By controlling the transmission line structure, the real part of the mutual admittance of the radiating antenna array is converted to 0 in the expected frequency band. The imaginary part of the mutual admittance of the three-port dual-frequency CRDN structure cancels out the imaginary part of the radiating antenna array in both frequency bands, thus suppressing mutual coupling in the radiating antenna array. By adjusting the single-stub matching network, the matching bandwidth of the antenna is improved.

2. The coupling resonator decoupling network system for dual-frequency coupling suppression in MIMO antenna arrays according to claim 1, characterized in that, The geometric center distance between any two adjacent radiating antenna elements is 8.7 mm. The geometric center distance is expressed as 0.12λ1 and 0.16λ2 at two different frequencies, where λ1 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 3.5 GHz, and λ2 represents the wavelength of the electromagnetic wave in vacuum when the radiating antenna element operates at a center frequency of 4.9 GHz.

3. The coupling resonator decoupling network system for dual-frequency coupling suppression in MIMO antenna arrays according to claim 2, characterized in that, There is strong mutual coupling between the two operating frequency bands of the radiating antenna elements, including S 12 S 13 and S 23 Since the radiating antenna elements are symmetrically arranged, the values ​​of strong mutual coupling are considered equal: S 12 =S 13 =S 23 ; The radiating antenna elements have mutual admittance, including: Y 12 Y 13 and Y 23 And there is Y 12 =Y 13 =Y 23 .

4. The coupling resonator decoupling network system for dual-frequency coupling suppression in MIMO antenna arrays according to claim 3, characterized in that, The distance from the center of each radiating antenna element to the center of the dielectric substrate is X1=10mm, and the total length of each radiating antenna element is H=H1+H2=18.8mm, wherein the length of the upper sleeve is H1=4.2mm and the length of the lower sleeve is H2=14.6mm.

5. The coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays according to claim 4, characterized in that, The total length of the transmission line structure is L. T1 +L T2 +L T3 +L T4 +L T5 +L T6 +L T7 =30.1mm, where L T1 =3.4mm, L T2 =7.7mm, L T3 =2.9mm, L T4 =5.9mm, L T5 =3.7mm, L T6 =4.1mm, L T7 =2.4mm.

6. The coupling resonator decoupling network system for dual-frequency coupling suppression of MIMO antenna arrays according to claim 4, characterized in that, In the three-port dual-frequency CRDN structure, the side length of the transmission line of the triangular open resonator is L. R1 =9.3mm, width is W R1 =0.3mm; the side length of the top opening is L R2 =5.4mm, width is g1=0.2mm; The gap between each of the triangular open resonators is g2 = 0.4 mm.

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