A triple-radiation null-point coplanar waveguide dual-polarization notched cross-dipole antenna

Abstract

The present invention relates to a three-radiation zero-point coplanar waveguide dual-polarization notch cross-dipole antenna, comprising a dielectric substrate, a metal reflector and two coaxial cables, wherein the cross-dipole antenna is printed on the upper and lower layers of the substrate and fed by the two coaxial cables, and the metal reflector is located below the dielectric substrate. The present invention firstly designs a broadband dual-polarization cross-dipole antenna covering 1.7-3.6GHz using a coplanar waveguide feeding structure, and then designs a coplanar waveguide DMS-DGS hybrid third-order band-stop filter, and prints a miniaturized and highly selective coplanar waveguide filter and antenna on the same dielectric substrate, thereby achieving a stop band covering 2.9-3.1GHz. Under the condition of VSWR<2, compared with the original broadband antenna covering the 1.7‑3.6 GHz frequency band, the proposed notch antenna operates in two operating frequency bands, 1.7‑2.7 GHz and 3.4‑3.6 GHz, and introduces a notch frequency band covering 2.9‑3.1 GHz. The notch antenna can be used for 2G / 3G / 4G / 5G base station applications that require notch function.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a coplanar waveguide dual-polarization notch cross-dipole antenna suitable for 2G / 3G / 4G / 5G base station applications. Background Art

[0002] For applications in 2G / 3G / 4G communication systems, broadband dual-polarized antennas with an operating frequency band of 1.71-2.69GHz have been widely used in wireless base station communications. With the maturity of 5G technology, the 3.4-3.6GHz frequency band is applied to large-scale MIMO technology, which not only ensures signal coverage but also channel capacity, and becomes the first frequency band for operators to deploy 5G networks. For operators, building a 3.4-3.6GHz 5G network by reusing 2G / 3G / 4G sites is more cost-effective than building micro sites on a large scale, and covers a wider range of users. Therefore, for 2G / 3G / 4G / 5G base station applications, it is necessary to study and design broadband dual-polarized antennas covering the 2G / 3G / 4G / 5G frequency band (1.7-3.6GHz).

[0003] According to the International Telecommunication Union, the 2.9-3.1GHz frequency band between 2G / 3G / 4G (1.71-2.69GHz) and 5G (3.4-3.6GHz) is used for radio navigation and positioning. Therefore, for 2G / 3G / 4G / 5G base stations, it is commercially valuable to study and design dual-polarized antennas with a notch band of 2.9-3.1GHz. In order to suppress interference signals from these narrowbands, introducing notch characteristics in broadband antennas is an effective method without affecting other technical parameters.

[0004] Several broadband dual-polarized antennas, such as patch antennas, magnetoelectric dipole antennas, and cross-dipole antennas, can be used in base station applications. Cross-dipole antennas have been widely used in wireless communication systems due to their wide bandwidth, dual-polarization characteristics, stable radiation direction, small size, and easy manufacturing. Reference [1] (Huang Hai, Liu Yi, Gong S. A broadband dual-polarized base station antenna with anti-interference capability [J]. IEEE Antennas and Wireless Propagation Letters, 2016: 1-1) achieves a stopband of 2.27-2.53 GHz by setting a C-shaped stub next to the feed line. References [2] (Chen Yili, Chu Qiuxin. A novel base station filter antenna [C]. IEEE-APS Wireless Communication Antennas and Propagation Special Conference (APWC). IEEE, 2019: 063-065)-[3] (Li YN, Chu Q X. A broadband dual-polarized base station antenna with second-order notch characteristics [C]. IEEE MTT-S International Wireless Symposium (IWS). IEEE, 2019) achieve the second-order notch characteristics by placing a U-shaped stub next to the feed line and etching an open resonant ring on the main radiator. Reference [4] (Fu S, Cao Z, Quan X, et al. A broadband dual-polarized notch antenna for 2 / 3 / 4 / 5G base stations [J]. IEEE Antennas and Wireless Propagation Letters, 2020, 19(1): 69-73) is different from reference [3] in that reference [4] adds two additional open resonant rings on the main radiator, so that both the first-order notch characteristics and the second-order notch characteristics can be achieved. Reference [5] (Zhang Yi, Zhang Yi, Li De, et al. Dual-polarization band-notched antenna without additional circuit for 2.4 / 5GHz WLAN applications [J]. IEEE Access, 2019, PP(99):1-1) proposed introducing a cross dumbbell-shaped parasitic unit on the radiator to generate a 2.9-3.1GHz notch. However, references [1]-[5] all achieve the notch characteristic by adding additional feeding structures or parasitic units under the cross dipole antenna, which increases the difficulty of antenna installation and the processing cost of the antenna.

[0005] In the literature [6] (Feng Yi, Lei Li, Zeng Qing, et al. A thin metamaterial loaded antenna array with anti-interference and polarization reconfigurable characteristics [J]. IEEE Access, 2018, PP: 1-1), the notch function is realized by introducing a C-shaped open resonant ring in a broadband dipole antenna without adding additional filtering circuits. Compared with the broadband dipole antenna used as a reference, the minimum gain of the notch band is suppressed from 8dBi to -6dBi. Although the antenna is easy to install and can achieve good suppression, the notch band with VSWR>2 is too wide and is not suitable for 2G / 3G / 4G / 5G base station applications. Summary of the invention

[0006] In view of the difficulties such as poor notch effect and processing difficulty in the background technology, the present invention studies a three-radiation zero-point coplanar waveguide dual-polarization notch cross dipole antenna suitable for 2G / 3G / 4G / 5G base station applications. Under the condition of VSWR<2, the proposed notch antenna operates in two working frequency bands of 1.7-2.7GHz and 3.4-3.6GHz, and introduces a notch frequency band of 2.9-3.1GHz. The proposed notch antenna has three radiation zero points, which solves the difficulty of poor notch effect. At the same time, the antenna processing only requires a dielectric substrate, and the processing is simple.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A three-radiation zero-point coplanar waveguide dual-polarization notched cross-dipole antenna, comprising a dielectric substrate, a metal reflector and two coaxial cables, wherein the cross-dipole antenna is printed on the upper and lower layers of the substrate and fed by the two coaxial cables, and the metal reflector is located below the dielectric substrate; the cross-dipole antenna comprises an upper metal layer and a lower metal layer, each layer having two pairs of annular dipole antennas, the inside of the annular dipole arm is a rectangular metal layer, and the antenna arm edge between the cross dipoles is designed to be in the shape of an exponential function; the upper metal layer has a plurality of pairs of annular dipole antennas, and the inner part ... Two sections of coplanar waveguide transmission lines are provided, an M-shaped DMS coplanar waveguide filter is embedded in the coplanar waveguide transmission lines, and two hexagonal open-circuit branches are provided along the coplanar waveguide transmission lines; in the lower metal layer, a double-turn hexagonal DGS resonator is provided just below each hexagonal open-circuit branch of the upper metal layer, a hexagonal open-circuit branch and a DGS resonator form a DGS band-stop filter unit, and a DMS filter and two DGS filter units form a DMS-DGS hybrid third-order band-stop filter.

[0009] Preferably, the dielectric substrate is Rogers-4350, whose dielectric constant is ε r =3.66, the length of the substrate is L s =55mm, thickness is H s =1mm, the thickness of the metal layer of the substrate is H m =0.035mm.

[0010] Preferably, the metal reflector is square and is placed 35 mm below the dielectric substrate to achieve a directional radiation pattern of about 65°.

[0011] Preferably, the upper and lower metal layers are interconnected by 21 short-circuit metallized vias, 20 of which are used to connect the upper and lower dipole antennas, and one short-circuit metallized via is used to connect the coplanar waveguide transmission line.

[0012] Preferably, in order to avoid overlapping, one of the coplanar waveguide transmission lines is modified so that a portion of the line is printed on the bottom layer of the substrate, and then the upper and bottom parts of the coplanar waveguide transmission line are connected through short-circuit metallized vias.

[0013] Furthermore, the exponential function is expressed as Y(x)=Ce kx +B, where k is the constant coefficient of the exponential function and B is the parameter of the exponential function.

[0014] Furthermore, the outer conductor of the coaxial cable is connected to one arm of the dipole at the bottom of the substrate, the inner conductor of the coaxial cable passes through the substrate and is connected to one end of the coplanar waveguide transmission line, and the other end of the coplanar waveguide transmission line is connected to the other arm of the dipole.

[0015] Preferably, the length of the DMS is 12.09 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention firstly designs a broadband dual-polarized cross-dipole antenna covering 1.7-3.6GHz using a coplanar waveguide feeding structure. Then, a coplanar waveguide DMS-DGS hybrid third-order band-stop filter is designed, and the miniaturized and highly selective coplanar waveguide filter and the antenna are printed on the same dielectric substrate, thereby achieving a stopband covering 2.9-3.1GHz. Under the condition of VSWR<2, compared with the original broadband antenna covering the 1.7-3.6GHz frequency band, the proposed notch antenna operates in two operating frequency bands of 1.7-2.7GHz and 3.4-3.6GHz, and introduces a notch frequency band covering 2.9-3.1GHz. The proposed notch antenna has an average gain of about 8.3dBi in the low frequency band and an average gain of about 6.9dBi in the high frequency band. In the stopband of 2.87-3.17GHz, the antenna gain is lower than 0dBi, and the minimum gain is -14.5dBi. Therefore, when VSWR<2, the dual-polarization notch antenna proposed in the present invention has operating frequency bands of 1.7-2.7 GHz and 3.4-3.6 GHz, and the notch frequency band with a gain lower than 0 dBi is 2.87-3.17 GHz. The notch antenna can be used in 2G / 3G / 4G / 5G base station applications that require notch function. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1-1 It is the overall structure diagram of the trap antenna of the present invention.

[0019] Figure 1-2 This is the overall test diagram of the trap antenna of the present invention.

[0020] Figure 2-1 It is a top view of the upper metal layer of the present invention.

[0021] Figure 2-2 It is a top view of the lower metal layer of the present invention.

[0022] Figure 3 Figures 1 and 2 are two broadband antenna diagrams, where (a) is a reference broadband antenna and (b) is a coplanar waveguide-fed broadband antenna proposed in the present invention.

[0023] Figure 4 Figure 2 is a graph showing the relationship between the single-turn DGS and double-turn DGS resonators and their resonant frequencies and W3.

[0024] Figure 5 It is a coplanar waveguide DGS filter unit.

[0025] Figure 6 Electromagnetic and circuit simulation results of the coplanar waveguide filter unit.

[0026] Figure 7 There are three types of DMS resonators.

[0027] Figure 8 The relationship between the resonant frequency and F2 of the three DMS resonators.

[0028] Fig. 9 Electromagnetic and circuit simulation results of coplanar waveguide DMS filter.

[0029] Fig.10 This is a coplanar waveguide hybrid third-order band-stop filter proposed by the present invention.

[0030] Fig.11 The equivalent circuit of the coplanar waveguide hybrid third-order band-stop filter proposed by the present invention.

[0031] Fig.12 These are the electromagnetic and circuit simulation results of the coplanar waveguide DMS filter proposed in this invention.

[0032] Fig.13 |S11| simulation results of DGS notch unit, DMS notch unit and hybrid filter.

[0033] Fig.14 It is a coplanar waveguide broadband antenna and a notch antenna.

[0034] Fig.15 These are the simulation results for two types of antennas: coplanar waveguide broadband antenna and notch antenna. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0036] like Figure 1-1 and Figure 1-2 As shown, the overall structure of the present invention includes a dielectric substrate, a metal reflector and two coaxial cables. The cross dipole antenna is printed on the upper and lower layers of the substrate and fed by two coaxial cables. The dielectric substrate uses Rogers-4350, whose dielectric constant is ε r =3.66, the length of the substrate is L s =55mm, thickness is H s =1mm, the thickness of the metal layer of the substrate is H m =0.035mm. Due to the thickness of the metal layer H m It will affect the performance of the proposed coplanar waveguide filter, so H needs to be considered when simulating and designing the filter. m A square metal reflector is placed 35 mm below the dielectric substrate to achieve a directional radiation pattern of about 65°.

[0037] like Figure 2-1 and Figure 2-2 As shown, the parameter values ​​of the top view of the upper metal layer and the top view of the lower metal layer are given respectively. The upper and lower metal layers are interconnected by 21 short-circuit metallized vias, of which 20 short-circuit metallized vias are used to connect the upper and lower dipole antennas, and 1 short-circuit metallized via is used to connect the coplanar waveguide transmission line. Each layer has two pairs of annular dipole antennas, and the interior of the annular dipole arms is a rectangular metal layer. At the same time, the designed antenna adopts an exponential antenna arm to achieve wideband characteristics. The edges of the antenna arms between the crossed dipoles are designed to be in the shape of an exponential function. The expression of the exponential function is Y(x)=Ce kx +B, where k is a constant coefficient of the exponential function. The outer conductor of the coaxial cable is connected to one arm of the dipole at the bottom of the substrate, and the inner conductor of the coaxial cable passes through the substrate and is connected to one end of the coplanar waveguide transmission line. The other end of the coplanar waveguide transmission line is connected to the other arm of the dipole. In order to avoid overlap, one of the coplanar waveguide transmission lines is modified so that part of this line is printed on the bottom layer of the substrate, and then the upper and bottom parts of the coplanar waveguide transmission line are connected through short-circuit metallized vias.

[0038] like Figure 2-1 As shown, in the upper metal layer, an M-shaped DMS coplanar waveguide filter is embedded in the coplanar waveguide microstrip line. The length of DMS is F2 = 12.09 mm, and the slot width and metal line width are both set to W n Along each section of the coplanar waveguide transmission line, there is a hexagonal open branch. Figure 2-2As shown, in the lower metal layer, there is a double-turn hexagonal DGS resonator directly below each hexagonal open branch. A hexagonal open branch and a defective ground structure DGS resonator can form a DGS band-stop filter unit. A DMS filter and two DGS filter units form a DMS-DGS hybrid third-order band-stop filter.

[0039] Experimental data:

[0040] 1. Coplanar waveguide broadband antenna

[0041] The present invention takes the broadband cross-dipole antenna based on the improved direct feeding structure proposed in the literature [7] (Zhang Yi, Zhang Yi, Li De, et al. Ultra-wideband dual-polarization antenna with three resonant modes for 2G / 3G / 4G / 5G communication systems [J]. IEEE Access, 2019: 1-1) as the reference antenna. Figure 3 (a). Figure 3 In (b), the feeding structure of the antenna proposed in the present invention is changed from a ring structure to a coplanar waveguide structure with full metal printing on the inner arm. Figure 4 The simulation results of the two antennas are shown. The proposed broadband antenna with coplanar waveguide feeding structure can also achieve wide bandwidth (1.7-3.6GHz) and high isolation (>30dB). The proposed antenna can integrate the filter into the coplanar waveguide feeding transmission line. Therefore, the proposed broadband antenna is the basis for integrating the filter inside the antenna to achieve filtering characteristics.

[0042] 2. Coplanar waveguide third-order hybrid filter

[0043] In order to integrate the band-stop filter into the proposed coplanar waveguide-fed broadband antenna, the band-stop filter needs to be miniaturized. In order to achieve notch characteristics in the 2.9-3.1 GHz frequency band, the band-stop filter needs to have a high rectangular coefficient. Therefore, the present invention designs a miniaturized coplanar waveguide hybrid filter with three transmission zeros.

[0044] (1) Coplanar waveguide DGS band-stop filter

[0045] The experiment uses a DGS band-stop filter. The working principle of the DGS band-stop filter unit is that it consists of a double-turn defective ground structure DGS (Defected Ground Structure) resonator and an open-circuit branch used as a compensation capacitor. Figure 4The relationship between the resonant frequency and W3 of the single-turn DGS and double-turn DGS resonators is given. It can be seen that to achieve the same resonant frequency, the double-turn DGS resonator can adopt a smaller size to achieve miniaturization. The size of W3 determines the resonant frequency of the DGS resonator. Choosing the appropriate size of W3 can achieve the desired notch frequency.

[0046] In order to improve the suppression characteristics of the notch filter, such as Figure 5 As shown in the figure, a hexagonal coplanar waveguide capacitive open-circuit branch with a side length of W2 = 1.62 mm is added to the transmission line above the defective ground structure. The proposed coplanar waveguide filter unit is simulated using HFSS software, with a resonant frequency of f0 = 2.96 GHz and a cutoff frequency of f c =2.889GHz, |S11|=-0.6, dB=0.93, characteristic impedance Z0 is set to 50Ω. According to formula (1-3), we can calculate C=11.07nF, L=0.2611nH, R=1392Ω, (C: capacitance, L: inductance, R: resistance),

[0047]

[0048]

[0049]

[0050] The electromagnetic simulation and circuit simulation results are as follows Figure 6 As shown, the DGS filter unit has good suppression performance, but the rectangular coefficient is not high enough and the selectivity is poor.

[0051] (2) Coplanar waveguide DMS band-stop filter

[0052] The experiment uses a DMS band-stop filter, which achieves a 3.4-3.6 GHz stopband by etching a DMS resonator in a coplanar waveguide transmission line. The total length of the DMS resonator is close to half the wavelength of the resonant frequency. Figure 7 (a), (b) and (c) are DMS resonators with U-shaped, N-shaped and M-shaped slots, respectively. The DMS resonators with U-shaped, N-shaped and M-shaped slots are bent once, twice and three times, respectively. The resonant frequencies of these three resonators change with F2. Figure 8 As shown. It can be seen that at the same size, the M-shaped DMS resonator can achieve a lower resonant frequency. When it is required to resonate near the 3.1 GHz frequency point, only the M-shaped DMS resonator can be embedded in the broadband antenna proposed in the present invention. Therefore, the miniaturization design of using the M-shaped DMS resonator as a notch filter is experimentally compared.

[0053] References [8] (Sam WY, Zakaria Z, Mutalib MA, et al. Compact DMS three-band band-stop filter with U-slot for communication systems [C]. International Conference on Electronic Design (ICED). IEEE, 2014) and [9] (Zakaria Z, Mutalib MA, Ismail A, et al. Compact structure of integrated defect microstrip structure (DMS) bandpass filter for broadband applications [C]. European Antennas and Propagation Conference. IEEE, 2014) give the equivalent circuit of parallel RLC lumped elements of DMS resonator. The traditional band-stop circuit parameters can be expressed by formulas (1)-(3), where f c The cut-off frequency of the band-stop filter, f0 is the resonant frequency, and Z0 is the characteristic impedance. The coplanar waveguide M-shaped DMS filter with F2 = 12.34 mm was simulated using HFSS software. The electromagnetic simulation results show that the resonant frequency f0 = 3.043 GHz, the cut-off frequency f c =2.975GHz, |S11| = -0.62dB = 0.93, characteristic impedance Z0 is set to 50Ω. According to formulas (1)-(3), C = 11.57nF, L = 0.2364nH and R = 1355Ω can be calculated. Fig. 9 The electromagnetic and circuit simulation results of the coplanar waveguide DMS filter are shown in the figure. The two simulation results are consistent, which verifies the correctness of the equivalent circuit. The DMS filter unit has good suppression performance, but the rectangular coefficient is not high enough and the selectivity is poor.

[0054] (3) Coplanar waveguide hybrid third-order band-stop filter

[0055] From the above analysis, it can be seen that the DGS unit or DMS filter has only one transmission zero point, the rectangular coefficient is not high enough, and the selectivity is poor. In order to ensure that the notch function with high rectangular coefficient is realized within the length range of the coplanar waveguide transmission line (F2=12.09mm) of the broadband antenna, the present invention proposes a coplanar waveguide DMS-DGS hybrid third-order notch filter, such as Fig.10 The corresponding equivalent circuit can be understood as a DMS filter and a DGS second-order filter connected in series through a coplanar waveguide transmission line, as shown in Fig.11 The electromagnetic simulation and circuit simulation results are shown in Fig.12 As shown in Figure 2, the two simulation results are consistent. From the electromagnetic and circuit simulation results, it can be seen that the proposed filter can achieve notch characteristics in the 2.7-3.3 GHz frequency range, has three transmission zeros, and thus has high selectivity.

[0056] Fig.13The simulation results of the DGS notch unit, the DMS notch unit and the proposed third-order hybrid filter are given to facilitate better comparative analysis. It can be seen that the DGS filter or the DMS filter has only one transmission zero point, the rectangular coefficient is not high enough, and the selectivity is poor. With the same length as the DMS unit (F2 = 12.09mm), the proposed hybrid filter realizes three transmission zero points, a wider stopband frequency band, a larger rectangular coefficient, and a higher notch selectivity. In summary, the proposed coplanar waveguide hybrid third-order band-stop filter meets the requirements of wide stopband, high selectivity and miniaturization.

[0057] 3. Notch antenna based on coplanar waveguide

[0058] Fig.14 (a) and (b) are the structural diagrams of the reference coplanar waveguide broadband antenna and the proposed coplanar waveguide notch antenna, respectively. Compared with the broadband antenna, the notch antenna introduces a hybrid third-order band-stop filter while keeping other designs unchanged. The VSWR of these two antennas is shown in Figure 2. Fig.15 As shown in (a), the results show that when VSWR < 2, the broadband antenna works in the 1.7-3.6 GHz frequency band, while the band-stop antenna proposed in the present invention works in two working frequency bands, 1.7-2.7 GHz and 3.4-3.6 GHz, and introduces a notch frequency band of 2.9-3.1 GHz. In the notch frequency band of 2.87-3.17 GHz, the VSWR of the antenna is greater than 10. Fig.15 (b) gives a comparison of the radiation gain of the two antennas in the main radiation direction. The average gain of the notch antenna proposed in the present invention is about 8.3dBi in the low frequency band and about 6.9dBi in the high frequency band. In the stop band, the antenna gain is lower than 0dBi, and the minimum gain is -14.5dBi. The results show that the proposed antenna can achieve two operating frequency bands of 1.7-2.7GHz and 3.4-3.6GHz when VSWR<2, and the notch band with gain lower than 0dBi is 2.87-3.17GHz.

[0059] In summary, the present invention firstly designs a broadband dual-polarized cross-dipole antenna covering 1.7-3.6GHz using a coplanar waveguide feeding structure. Then, a coplanar waveguide DMS-DGS hybrid third-order band-stop filter is designed, and the miniaturized and highly selective coplanar waveguide filter and the antenna are printed on the same dielectric substrate, thereby achieving a stopband of 2.9-3.1GHz. Under the condition of VSWR<2, compared with the original broadband antenna covering the 1.7-3.6GHz frequency band, the proposed notch antenna operates in two operating frequency bands of 1.7-2.7GHz and 3.4-3.6GHz, and at the same time introduces a notch frequency band of 2.9-3.1GHz. The proposed notch antenna has an average gain of about 8.3dBi in the low frequency band and an average gain of about 6.85dBi in the high frequency band. In the stopband, the antenna gain is lower than 0dBi, and the minimum gain is -14.5dBi. Therefore, when VSWR<2, the dual-polarization notch antenna proposed in the present invention has operating frequency bands of 1.7-2.7 GHz and 3.4-3.6 GHz, and a notch frequency band of 2.9-3.1 GHz, and can be used for 2G / 3G / 4G / 5G base station applications that require notch function.

[0060] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A three-radiation null-point coplanar waveguide dual-polarization notched cross-dipole antenna, characterized in that: The invention comprises a dielectric substrate, a metal reflector and two coaxial cables, wherein the cross dipole antenna is printed on the upper and lower layers of the substrate and fed by the two coaxial cables, and the metal reflector is located below the dielectric substrate; the cross dipole antenna comprises an upper metal layer and a lower metal layer, and the upper and lower metal layers are connected to each other by 21 short-circuit metallized vias, wherein 20 short-circuit metallized vias are used to connect the upper and lower dipole antennas, and 1 short-circuit metallized via is used to connect the coplanar waveguide transmission line; each layer has two pairs of annular dipole antennas, the inside of the annular dipole arms is a rectangular metal layer, and the antenna arm edges between the cross dipoles are designed to be in the shape of an exponential function; the outer conductor of the coaxial cable is connected to one arm of the dipole at the bottom of the substrate, and the inner conductor of the coaxial cable passes through a connection between the substrate and the coplanar waveguide transmission line. The upper metal layer is provided with two sections of coplanar waveguide transmission lines, a part of which is printed on the bottom layer of the substrate, and then the upper and bottom parts of the coplanar waveguide transmission lines are connected through short-circuit metallized vias; an M-shaped DMS coplanar waveguide filter is embedded in the coplanar waveguide transmission line, and two hexagonal open-circuit branches are provided along the coplanar waveguide transmission line; in the lower metal layer, a double-turn hexagonal DGS resonator is provided directly below each hexagonal open-circuit branch of the upper metal layer, a hexagonal open-circuit branch and a DGS resonator form a DGS band-stop filter unit, and a DMS filter and two DGS filter units form a DMS-DGS hybrid third-order band-stop filter.

2. A three-radiation null-point coplanar waveguide dual-polarization notched cross-dipole antenna as claimed in claim 1, characterized in that: The dielectric substrate is Rogers-4350, and its dielectric constant is ε r =3.66, the length of the substrate is L s =55mm, thickness is H s =1mm, the thickness of the metal layer of the substrate is H m =0.035mm.

3. A three-radiation null-point coplanar waveguide dual-polarization notched cross-dipole antenna as claimed in claim 1, characterized in that: The metal reflector is square and is placed 35 mm below the dielectric substrate to achieve a directional radiation pattern of about 65°.

4. A three-radiation null-point coplanar waveguide dual-polarization notched cross-dipole antenna as claimed in claim 1, characterized in that: The expression of the exponential function is Y(x)=Ce kx +B, where k is the constant coefficient of the exponential function and B is the parameter of the exponential function.

5. A three-radiation null-point coplanar waveguide dual-polarization notch cross-dipole antenna according to any one of claims 1 to 4, characterized in that: The length of the DMS is 12.09 mm.

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