Three-frequency common-caliber differential antenna with adjustable decoupling network and decoupling method

Abstract

The invention discloses a three-frequency common-caliber differential antenna with an adjustable decoupling network and a decoupling method, and belongs to the field of communication, and the three-frequency common-caliber differential antenna comprises a three-frequency-band differential antenna array and common-caliber decoupling network layer, a first dielectric layer, a bonding layer, a ground layer, a second dielectric layer and a differential power divider layer which are sequentially arranged from top to bottom, the three-frequency-band differential antenna array and common-caliber decoupling network layer comprises a three-frequency-band differential antenna unit and an adjustable decoupling network which are integrated in a coplanar mode. By adopting the three-frequency common-caliber differential antenna with the adjustable decoupling network and the decoupling method, through the design of a symmetric residual current offset strategy and a common-caliber adjustable structure, the technical bottlenecks of narrow decoupling bandwidth and complex decoupling structure of a traditional multi-frequency antenna are broken through, and the three-frequency-band collaborative decoupling, wide band, wide band and wide band are realized. The core advantages of high isolation, low size and high integration level are achieved, and a key solution is provided for the next generation of sensing integration technology of 6G, satellite communication and the like.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a triple-band common-aperture differential antenna with an adjustable decoupling network and a decoupling method. Background Art

[0002] With the iterative upgrade of wireless communication technologies, the contradiction between the scarcity of spectrum resources and the demand for multifunctional integration of communication systems has become increasingly prominent. Frontier technologies represented by 6G communication, satellite communication, and radar detection all require the system to have the ability to work in multiple frequency bands. For example, the 6G system needs to cover both the Sub-6GHz and millimeter-wave bands simultaneously to balance wide-area coverage and high-rate transmission; satellite communication needs to support the integration of multiple frequency bands such as Ku / Ka / Q / V to establish interplanetary communication links; radar systems need to operate in multiple frequency bands such as L / S / C / X / Ku to complete multi-target recognition and tracking.

[0003] From the perspective of antenna elements, a differential antenna has two ports fed with equal amplitude and opposite phases, which overcomes the problem of the asymmetric structure of a single-ended antenna and reduces the cross-polarization level of the radiation pattern, thereby effectively improving the system stability and becoming an optimal solution to replace single-ended antennas. However, whether it is a single-ended antenna or a differential antenna, when each element is closely arranged to form an array, the coupling problem becomes particularly prominent. Moreover, compared with single-ended antennas, the dual-port structure of differential antennas results in a more complex coupling path, making it impossible to directly apply single-ended antenna decoupling methods such as electromagnetic bandgap structures, neutralization lines, and decoupling surfaces to differential antennas.

[0004] Therefore, the current decoupling methods for differential antennas are as follows: 1. Single-ended conversion method: The differential antenna is fed through a one-to-two power divider. After converting it into a single-ended antenna first, a single-ended decoupling method is then used to suppress coupling. However, this method destroys the symmetry of the differential antenna, resulting in the loss of the advantages of high linearity and strong anti-interference of the differential antenna; 2. Multi-port network method: Directly design a multi-port decoupling network for the differential antenna and obtain the corresponding parameters through matrix derivation. However, this method involves a large amount of mathematical calculations, complex operations, more reliance on simulation parameter tuning, and a narrow decoupling bandwidth, making it difficult to be applied in practice.

[0005] From the perspective of antenna arrays, the multi-frequency common-aperture antenna array technology can effectively improve the space utilization rate, achieve multi-band communication, and reduce the volume of equipment, thus being widely used. However, the multi-frequency common-aperture antenna array not only needs to consider the coupling of elements within a single frequency band but also needs to consider inter-band coupling simultaneously. Therefore, developing an effective decoupling technology for multi-frequency common-aperture antenna arrays is crucial for improving the performance of antenna arrays and meeting the requirements of future wireless communication systems.

[0006] At present, the decoupling research on multi-frequency co-aperture arrays mostly focuses on arrays composed of single-ended antennas. For example: 1. Traditional decoupling methods such as using matching networks, defected ground structures, frequency selective surfaces, etc. essentially aim to suppress the coupling current at the center frequency and make it approach 0. This results in unbalanced coupling currents still existing at other frequency points within the working bandwidth, causing the problems of narrow decoupling bandwidth and low efficiency in actual engineering applications. 2. Wideband decoupling methods such as loading multiple parasitic structures and adding decoupling reflectors are usually only effective for a single frequency band or a limited number of frequency bands. It is difficult to use only one structure to simultaneously meet the requirements of multi-band and wideband decoupling, and it is impossible to suppress both in-band and inter-band couplings at the same time. 3. Changing the antenna structure of a certain frequency band to decouple other frequency band antenna arrays, but this method is often used for the decoupling of base station antenna co-aperture arrays and requires considering the scattering problem between frequency bands simultaneously, with high design complexity and system cost. 4. By designing antenna elements to operate in different modes to achieve decoupling of different frequency bands, this method usually increases the design complexity of antenna elements and may reduce antenna efficiency.

[0007] In summary, there is no effective decoupling method for multi-frequency co-aperture differential antenna arrays yet. Moreover, the above-mentioned decoupling methods only target co-aperture single-ended antennas with specific frequency ratios. Decoupling of arrays with different frequency ratios requires special design, and the decoupling network cannot be finely adjusted with the change of frequency ratio, resulting in low decoupling effect and decoupling flexibility, as well as a large workload. Summary of the Invention

[0008] The objective of the present invention is to provide a triple-band co-aperture differential antenna with an adjustable decoupling network and a decoupling method to solve the above technical problems.

[0009] To achieve the above objective, the present invention provides a triple-band co-aperture differential antenna with an adjustable decoupling network, which includes a triple-band differential antenna array, a co-aperture decoupling network layer, a first dielectric layer, an adhesive layer, a ground layer, a second dielectric layer, and a differential power divider layer arranged in sequence from top to bottom. The triple-band differential antenna array and the co-aperture decoupling network layer include coplanarly integrated triple-band differential antenna elements and an adjustable decoupling network, and the adjustable decoupling network is used to suppress the in-band and inter-band couplings of the triple-band differential antenna.

[0010] Preferably, the triple-band differential antenna elements include a high-frequency antenna group, a medium-frequency antenna group, and a low-frequency antenna group located at the same height. The high-frequency antenna group includes two high-frequency differential antennas symmetrically distributed around the center of the triple-band differential antenna array and the co-aperture decoupling network layer. The medium-frequency antenna group includes two medium-frequency differential antennas symmetrically distributed above and below the high-frequency antenna group. The low-frequency antenna group includes two low-frequency differential antennas symmetrically distributed on the left and right sides of the high-frequency antenna group. The adjustable decoupling network includes an H-shaped strip horizontally arranged between two high-frequency differential antennas, a bracket-shaped strip vertically arranged on the left and right sides of two intermediate-frequency differential antennas, and a T-shaped strip arranged between the intermediate-frequency differential antenna and the low-frequency differential antenna, and the T-shaped strip is perpendicularly and cross-connected to the bracket-shaped strip.

[0011] Preferably, the H-shaped strip and the bracket-shaped strip form a high-frequency decoupling network, which is used to make the coupling currents equal at the two differential ports of the non-excited high-frequency differential antenna when one of the high-frequency differential antennas is excited, so that they can cancel each other out after passing through the differential power divider, and at the same time, the bracket-shaped strip is used to suppress the inter-band coupling between the high-frequency differential antenna and the intermediate-frequency differential antenna; The bracket-shaped strip and the T-shaped strip form an intermediate-frequency decoupling network, which is used to improve the isolation between the two intermediate-frequency differential antennas by adjusting the parameters of the T-shaped strip when one of the intermediate-frequency differential antennas is excited, realizing decoupling between the two intermediate-frequency differential antennas, and at the same time, the bracket-shaped strip and the T-shaped strip form a cascade network to perform inter-band decoupling between the intermediate-frequency differential antenna and the high-frequency differential antenna; The H-shaped strip, the bracket-shaped strip and the T-shaped strip form a common-aperture decoupling network, which is used to suppress the in-band coupling of the two low-frequency differential antennas as a whole when one of the low-frequency differential antennas is excited, where the high-frequency antenna group, the intermediate-frequency antenna group and the common-aperture decoupling network are regarded as a whole.

[0012] Preferably, when loading the high-frequency decoupling network, the residual currents at the two ports of the non-excited high-frequency differential antenna are set to and , and the residual currents at the two ports of the intermediate-frequency differential antenna are set to and , and after passing through the differential power divider, there is , and .

[0013] Preferably, in the intermediate-frequency decoupling network, the original admittance matrix between the two intermediate-frequency differential antennas is , the admittance matrix of the intermediate-frequency decoupling network is , the impedance and electrical length of the bracket-shaped strip are and , the impedance and electrical length of the T-shaped strip are and , and , and are all fixed values. By adjusting to make , the in-band coupling suppression between the two intermediate-frequency differential antennas is realized.

[0014] Preferably, the materials of the first dielectric layer and the second dielectric layer are both Rogers 5880.

[0015] Decoupling method for a triple - band common - aperture differential antenna with an adjustable decoupling network, including in - band decoupling method and inter - band decoupling method. The in - band decoupling method includes decoupling between two high - frequency differential antennas, decoupling between two intermediate - frequency differential antennas, and decoupling between two low - frequency differential antennas. The inter - band decoupling method includes decoupling between the high - frequency differential antenna, the intermediate - frequency differential antenna, and the low - frequency differential antenna.

[0016] Preferably, the decoupling between two high - frequency differential antennas is achieved by an H - shaped strip and a bracket - shaped strip based on the principle of symmetric residual current cancellation. The decoupling between two intermediate - frequency differential antennas is achieved by adjusting the parameters of a T - shaped strip. The decoupling between two low - frequency differential antennas is indirectly achieved by inserting high - frequency antenna groups, intermediate - frequency antenna groups, and a common - aperture decoupling network. The decoupling between the high - frequency differential antenna and the intermediate - frequency differential antenna is achieved by a cascaded network composed of a bracket - shaped strip and a T - shaped strip.

[0017] Therefore, the present invention adopts the above - mentioned triple - band common - aperture differential antenna with an adjustable decoupling network and the decoupling method, and has the following beneficial effects: 1. Adopting a highly symmetric H - shaped, bracket - shaped, and T - shaped strip structure to ensure the inherent high linearity, strong anti - interference ability, and low cross - polarization characteristics of the differential antenna, avoiding the defect of destroying symmetry in traditional single - ended - to - differential decoupling methods and maintaining system stability. 2. Based on the symmetric residual current cancellation strategy, allowing equal coupling currents at the ports, breaking through the limitation of the traditional method that only suppresses the coupling at the center frequency, so that the isolation in the high - frequency band is increased to more than 20 dB, the bandwidth covers 25 - 31 GHz, and the in - band isolation in the intermediate - frequency band is better than 25 dB. 3. The triple - band antenna and the decoupling network are integrated at the same height, reducing the volume by about 40% compared with the traditional layered structure, avoiding the scattering problem caused by the height difference of different frequency bands, and improving the system integration. 4. The multi - band collaborative decoupling network can simultaneously handle in - band (high - frequency, intermediate - frequency, low - frequency) and inter - band (high - intermediate - frequency, high - low - frequency) coupling. The high - intermediate - frequency isolation is increased to 32 dB, and the high - low - frequency isolation is 20 dB, breaking through the limitation that the traditional method needs to be designed for a single frequency band or a specific frequency ratio.

[0018] In summary, by finely adjusting the length of the strip structure of the common - aperture decoupling network, the present invention can be applied to common - aperture differential antenna arrays with different frequency ratios, realizing simultaneous decoupling of different frequency bands through the same structure, without the need to specifically design decoupling for each multi - frequency array separately, improving the overall design flexibility and system integration. It can be applied to antenna arrays in fields such as 6G, satellite communication, and radar, providing the possibility for the realization of future communication - sensing integration technology.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0020] Figure 1 The three - band differential antenna array and the common - aperture decoupling network layer of the three - band common - aperture differential antenna with an adjustable decoupling network according to the present invention; Figure 2 The inter - layer layout diagram of the three - band common - aperture differential antenna with an adjustable decoupling network according to the present invention; Figure 3 The decoupling principle diagram of the high - frequency decoupling network of the three - band common - aperture differential antenna with an adjustable decoupling network according to the present invention; Figure 4 The decoupling principle diagram of the intermediate - frequency decoupling network of the three - band common - aperture differential antenna with an adjustable decoupling network according to the present invention; Figure 5 The comparison diagram of the working frequency bands before and after decoupling in the simulation experiment of the present invention Figure 6 The comparison diagram of the isolation degrees of the three - band common - aperture differential antenna before and after decoupling in the simulation experiment of the present invention, where (a) is the comparison diagram of the isolation degrees of the three - band common - aperture differential antenna before and after decoupling at high frequency, (b) is the comparison diagram of the isolation degrees of the three - band common - aperture differential antenna before and after decoupling at intermediate frequency, and (c) is the comparison diagram of the isolation degrees of the three - band common - aperture differential antenna before and after decoupling at low frequency; Figure 7 The comparison diagram of the radiation patterns of the three - band common - aperture differential antenna before and after decoupling in the simulation experiment of the present invention, where (a) is the comparison diagram of the radiation patterns of the three - band common - aperture differential antenna before and after decoupling at 10 GHz (low frequency), (b) is the comparison diagram of the radiation patterns of the three - band common - aperture differential antenna before and after decoupling at 18.5 GHz (intermediate frequency), and (c) is the comparison diagram of the radiation patterns of the three - band common - aperture differential antenna before and after decoupling at 28 GHz (high frequency). Detailed Embodiments

[0021] In order to make the objectives, technical solutions, and advantages of the embodiments disclosed in the present invention clearer, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not used to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of this application. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or server that includes a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0023] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] As Figure 1 and Figure 2 shown, a triple-band common-aperture differential antenna with an adjustable decoupling network includes a triple-band differential antenna array and a common-aperture decoupling network layer, a first dielectric layer, an adhesive layer, a ground layer, a second dielectric layer, and a differential power divider layer arranged in sequence from top to bottom. The triple-band differential antenna array and the common-aperture decoupling network layer include coplanar integrated triple-band differential antenna units and an adjustable decoupling network, and the adjustable decoupling network is used to suppress in-band coupling and inter-band coupling of the triple-band differential antenna.

[0025] Among them, the triple-band differential antenna units include a high-frequency antenna group, an intermediate-frequency antenna group, and a low-frequency antenna group located at the same height (designing all radiation patches at the same height, compared with the traditional common-aperture base station antenna array with height differences between each unit, its system posture is low, which is convenient for integration and avoids the inter-band scattering problem caused by the height difference of antennas in different frequency bands). The high-frequency antenna group includes two high-frequency differential antennas symmetrically distributed around the center of the triple-band differential antenna array and the common-aperture decoupling network layer. The intermediate-frequency antenna group includes two intermediate-frequency differential antennas symmetrically distributed on the upper and lower sides of the high-frequency antenna group. The low-frequency antenna group includes two low-frequency differential antennas symmetrically distributed on the left and right sides of the high-frequency antenna group. The adjustable decoupling network includes an H-shaped strip horizontally arranged between two high-frequency differential antennas, bracket-shaped strips vertically arranged on the left and right sides of two intermediate-frequency differential antennas, and a T-shaped strip arranged between the intermediate-frequency differential antenna and the low-frequency differential antenna, and the T-shaped strip is perpendicularly cross-connected with the bracket-shaped strip.

[0026] As Figure 3 shown, the H-shaped strip and the bracket-shaped strip form a high-frequency decoupling network, which is used to make the coupling currents equal at the two differential ports of the non-excited high-frequency differential antenna when one of the high-frequency differential antennas is excited, so that they can cancel each other out after passing through the differential power divider, and at the same time, the bracket-shaped strip is used to suppress the inter-band coupling between the high-frequency differential antenna and the intermediate-frequency differential antenna; When the high-frequency decoupling network is loaded, the residual currents of the two ports of the non-excited high-frequency differential antenna are set to be and , and the residual currents of the two ports of the intermediate-frequency differential antenna are set to be and , after passing through the differential power divider, there is , and .

[0027] As Figure 4 shown, the bracket-shaped strip and the T-shaped strip form an intermediate-frequency decoupling network, which is used to improve the isolation between two intermediate-frequency differential antennas by adjusting the parameters of the T-shaped strip when one of the intermediate-frequency differential antennas is excited, realizing the decoupling between the two intermediate-frequency differential antennas. At the same time, a cascade network is formed by the bracket-shaped strip and the T-shaped strip to perform inter-band decoupling between the intermediate-frequency differential antenna and the high-frequency differential antenna; In the intermediate-frequency decoupling network, the original admittance matrix between two intermediate-frequency differential antennas is , and the admittance matrix of the intermediate-frequency decoupling network is , the impedance and electrical length of the bracket-shaped strip are and , the impedance and electrical length of the T-shaped strip are and , and , and are all fixed values. Adjust so that when, the in-band coupling suppression between two intermediate-frequency differential antennas is realized.

[0028] For a transmission line with a specific impedance and electrical length , its admittance matrix is : ; In the formula, is an imaginary unit; therefore, when the impedance is fixed, adjusting the electrical length can adjust the admittance matrix to , verifying the possibility of adjusting the admittance matrix by adjusting the electrical length .

[0029] The H-shaped strip, the bracket-shaped strip and the T-shaped strip form a common-aperture decoupling network, which is used to suppress the in-band coupling of two low-frequency differential antennas as a whole when one of the low-frequency differential antennas is excited (the high-frequency antenna group, the intermediate-frequency antenna group and the common-aperture decoupling network do not greatly suppress the coupling between the two low-frequency differential antennas as a whole, but due to the large distance between the two low-frequency differential antennas, the common-aperture decoupling network does not deteriorate the isolation level between the two low-frequency differential antennas. And the sizes of the high-frequency differential antenna and the intermediate-frequency differential antenna are smaller than those of the low-frequency differential antenna, thus suppressing the inter-band coupling current existing on the high- and intermediate-frequency differential antennas).

[0030] The materials of the first dielectric layer and the second dielectric layer are both Rogers 5880.

[0031] A decoupling method for a triple-band common-aperture differential antenna with an adjustable decoupling network, including in-band decoupling methods and inter-band decoupling methods. The in-band decoupling methods include decoupling between two high-frequency differential antennas, decoupling between two intermediate-frequency differential antennas, and decoupling between two low-frequency differential antennas; the inter-band decoupling methods include decoupling between the high-frequency differential antenna, the intermediate-frequency differential antenna, and the low-frequency differential antenna.

[0032] Decoupling between two high-frequency differential antennas is achieved by an H-shaped strip and a bracket-shaped strip based on the principle of symmetric residual current cancellation; decoupling between two intermediate-frequency differential antennas is achieved by adjusting the parameters of a T-shaped strip; decoupling between two low-frequency differential antennas is indirectly achieved by inserting a high-frequency antenna group, an intermediate-frequency antenna group, and a common-aperture decoupling network; decoupling between the high-frequency differential antenna and the intermediate-frequency differential antenna is achieved by a bracket-shaped strip, or by forming a cascade network with a bracket-shaped strip and a T-shaped strip.

[0033] Simulation experiment In this simulation experiment, an electromagnetic simulation software is used to construct a three-dimensional model of the triple-band common-aperture differential antenna with an adjustable decoupling network described in the present invention, and the size parameters of the adjustable decoupling network are set, and the result before decoupling is added for comparison, and the results are as Figures 5 - 7 shown. It should be noted that in Figure 5 , , , respectively represent the reflection coefficients of the high, intermediate, and low-frequency differential antenna elements; in Figure 6 , , , , , , respectively represent high-frequency in-band coupling, high-intermediate-frequency inter-band coupling, high-low-frequency inter-band coupling, intermediate-frequency in-band coupling, intermediate-low-frequency inter-band coupling, and low-frequency in-band coupling.

[0034] It can be seen from Figure 5 that after decoupling, the center frequencies of the high, intermediate, and low frequencies are 10 GHz (low frequency), 18.5 GHz (intermediate frequency), and 28 GHz (high frequency) respectively, and the frequency ratio is 1:1.85:2.8. Moreover, the high-frequency band (25 - 31 GHz) covers a 2-GHz working bandwidth, the low-frequency band (9 - 11 GHz) covers a 0.5-GHz working bandwidth, and the intermediate-frequency band (17 - 20 GHz) covers a 1-GHz working bandwidth, verifying the coverage ability of the adjustable decoupling network described in the present invention for the working frequency bands of the triple-band common-aperture antenna.

[0035] It can be seen from Figure 6As can be seen from (a) of [reference], the isolation between high-frequency antennas before decoupling is about 10 dB, and it is increased to more than 20 dB after decoupling (reaching 54 dB at 28 GHz for example). At the same time, the isolation between the high and intermediate frequency bands is increased from 30 dB to 42 dB, and the isolation between the high and low frequency bands is increased from 17 dB to 21 dB. It can be seen that the adjustable decoupling network described in the present invention can effectively suppress the coupling within the high-frequency band and between different frequency bands, meeting the requirements of multi-frequency communication.

[0036] From Figure 6 As can be seen from (b) of [reference], the isolation between intermediate-frequency antennas before decoupling is about 12 dB, and it is increased to more than 27 dB after decoupling (reaching 29 dB at 18.5 GHz for example). The isolation between the intermediate and high frequency bands remains above 32 dB, and the isolation between the intermediate and low frequency bands is increased to 25 dB. It is verified that through the synergistic effect of the T-shaped strip and the bracket-shaped strip described in the present invention, efficient isolation within the intermediate frequency band and between different frequency bands is achieved.

[0037] From Figure 6 As can be seen from (c) of [reference], the isolation between low-frequency antennas before decoupling is about 20 dB, and it is increased to more than 25 dB after decoupling (reaching 26 dB at 10 GHz for example). The isolation between the low and high frequency bands remains above 25 dB, and the isolation between the low and intermediate frequency bands is increased to 24 dB. It is verified the coupling suppression effect of the common-aperture decoupling network described in the present invention at low frequencies.

[0038] From Figure 7 As can be seen, the gain in the high-frequency band is increased by 0.5 - 1.2 dB after decoupling (the gain at 28 GHz is increased from 5.6 dB to 6.8 dB for example), and the gain in the middle and low frequency bands is stable. The main polarization pattern maintains good consistency. It is verified that the adjustable decoupling network described in the present invention does not sacrifice the antenna radiation performance while suppressing the coupling, and even improves the gain due to reducing the energy coupling loss.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A triple-band common-aperture differential antenna with an adjustable decoupling network, comprising a triple-band differential antenna array, a common-aperture decoupling network layer, a first dielectric layer, an adhesive layer, a ground layer, a second dielectric layer, and a differential power divider layer, which are arranged in sequence from top to bottom, and is characterized in that: The triple-band differential antenna array and the common-aperture decoupling network layer include a coplanar integrated triple-band differential antenna unit and an adjustable decoupling network, and the adjustable decoupling network is used to suppress the in-band coupling and inter-band coupling of the triple-band differential antenna.

2. The triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 1, characterized in that: The triple-band differential antenna array includes a high-frequency antenna group, a medium-frequency antenna group, and a low-frequency antenna group at the same height. The high-frequency antenna group includes two high-frequency differential antennas symmetrically distributed around the center of the triple-band differential antenna array and the common-aperture decoupling network layer. The medium-frequency antenna group includes two medium-frequency differential antennas symmetrically distributed on the upper and lower sides of the high-frequency antenna group. The low-frequency antenna group includes two low-frequency differential antennas symmetrically distributed on the left and right sides of the high-frequency antenna group. The adjustable decoupling network includes an H-shaped strip horizontally disposed between the two high-frequency differential antennas, bracket-shaped strips vertically arranged on the left and right sides of the two medium-frequency differential antennas, and a T-shaped strip disposed between the medium-frequency differential antenna and the low-frequency differential antenna, and the T-shaped strip is perpendicularly cross-connected to the bracket-shaped strip.

3. The triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 2, characterized in that: The H-shaped strip and the bracket-shaped strip form a high-frequency decoupling network, which is used to make the coupling currents equal at the two differential ports of the non-excited high-frequency differential antenna when one of the high-frequency differential antennas is excited, so that they can cancel each other out after passing through the differential power divider. At the same time, the bracket-shaped strip is used to suppress the inter-band coupling between the high-frequency differential antenna and the medium-frequency differential antenna. The bracket-shaped strip and the T-shaped strip form a medium-frequency decoupling network, which is used to improve the isolation between the two medium-frequency differential antennas by adjusting the parameters of the T-shaped strip when one of the medium-frequency differential antennas is excited. At the same time, the bracket-shaped strip and the T-shaped strip form a cascaded network for inter-band decoupling between the medium-frequency differential antenna and the high-frequency differential antenna. The H-shaped strip, the bracket-shaped strip, and the T-shaped strip form a common-aperture decoupling network, which is used to suppress the in-band coupling between the two low-frequency differential antennas when one of the low-frequency differential antennas is excited, with the high-frequency antenna group, the medium-frequency antenna group, and the common-aperture decoupling network acting as a whole.

4. The triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 3, characterized in that: When loading the high-frequency decoupling network, the residual currents of the two ports of the non-excited high-frequency differential antenna are set to be and , respectively, and the residual currents of the two ports of the intermediate-frequency differential antenna are set to be and , respectively. After passing through the differential power divider, there is , and .

5. The triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 3, characterized in that: In the intermediate-frequency decoupling network, the original admittance matrix between two intermediate-frequency differential antennas is , the admittance matrix of the intermediate-frequency decoupling network is , the impedance and electrical length of the bracket-shaped strip are and , the impedance and electrical length of the T-shaped strip are and , and , and are all fixed values. Adjust so that to achieve in-band coupling suppression between two intermediate-frequency differential antennas.

6. The triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 3, characterized in that: The materials of the first dielectric layer and the second dielectric layer are both Rogers 5880.

7. A decoupling method for the triple-band common-aperture differential antenna with an adjustable decoupling network according to any one of claims 3-6, characterized in that: It includes an in-band decoupling method and an inter-band decoupling method. The in-band decoupling method includes decoupling between the two high-frequency differential antennas, decoupling between the two medium-frequency differential antennas, and decoupling between the two low-frequency differential antennas. The inter-band decoupling method includes decoupling between the high-frequency differential antenna, the medium-frequency differential antenna, and the low-frequency differential antenna.

8. The decoupling method for the triple-band common-aperture differential antenna with an adjustable decoupling network according to claim 7, characterized in that: The decoupling between the two high-frequency differential antennas is achieved by the H-shaped strip and the bracket-shaped strip based on the principle of symmetric residual current cancellation. The decoupling between the two medium-frequency differential antennas is achieved by adjusting the parameters of the T-shaped strip. The decoupling between the two low-frequency differential antennas is indirectly achieved by inserting the high-frequency antenna group, the medium-frequency antenna group, and the common-aperture decoupling network. The decoupling between the high-frequency differential antenna and the medium-frequency differential antenna is achieved by the bracket-shaped strip and the T-shaped strip forming a cascaded network.

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