A multi-band common aperture base station antenna

Abstract

The application relates to a multi-frequency-band common-aperture base station antenna, which comprises low-frequency antennas, medium-frequency antennas and high double-frequency antennas which are coaxially arranged on the upper surface of a metal floor from top to bottom. The low-frequency antennas and the medium-frequency antennas are both composed of three-layer composite wave-transparent structures, the middle layer is used as a radiation structure of the antennas and is directly fed with electromagnetic waves from a feeder to radiate the electromagnetic waves outward, and the upper and lower layers are additional electromagnetic structures; the three-layer structure is a wave-transparent structure with frequency selection characteristics, and the introduction of the additional electromagnetic structures has little influence on the radiation effect and matching characteristics of the antennas; the medium-frequency antennas have wave-transparent characteristics to the high double-frequency antennas below; the low-frequency antennas have wave-transparent characteristics to the medium-frequency antennas and the high double-frequency antennas below; and the high double-frequency antennas are located at the bottom of the array. The multi-frequency-band common-aperture base station antenna realizes stable radiation in four working frequency bands, has the characteristics of multi-frequency band, wide bandwidth, small mutual interference and simple structure.

Description

Technical Field

[0001] This invention relates to the field of base station array antennas in mobile communication technology, and specifically to a multi-band common aperture base station antenna. Background Technology

[0002] The booming development of mobile communication technology, with the commercialization of 5G and the future planning of 6G, allows people to experience the convenience of high-speed internet anytime, anywhere, realizing the Internet of Things. However, this does not mean that traditional 3G and 4G communication will cease. On the contrary, traditional systems and communication systems with high-speed transmission capabilities can complement each other. In the long term, mobile communication will face the coexistence of 3G, 4G, 5G, and even 6G. This means that mobile communication networks will face multi-band communication operations, with base station density constantly increasing, leading to site space shortages and an unbearable burden on base station operation and maintenance. Integrating antennas of multiple frequency bands into a single array to achieve multi-network coverage, while allowing each frequency band antenna to work relatively independently, is a more ideal solution to alleviate rooftop resource shortages, improve resource utilization, and reduce costs. The development and application of dual-band or even multi-band base station arrays has become an inevitable trend in communication systems, giving rise to common-aperture antenna technology.

[0003] Taking the design of a dual-band co-aperture antenna as an example, for a dipole antenna, its antenna size and profile height are positively correlated with the operating wavelength. This means that the antenna operating at lower frequencies often has a larger aperture and a higher profile. Placing the low-frequency antenna among high-frequency antenna elements allows for the coexistence of multiple frequency bands without increasing the aperture size or profile height. However, the larger low-frequency antenna inevitably obstructs the high-frequency antenna in space, affecting its normal electromagnetic radiation and causing pattern distortion, thus impacting antenna performance. Overcoming the antenna pattern distortion caused by spatial obstruction is a key issue that needs to be addressed in the field of co-aperture antennas.

[0004] To address this issue, low-frequency antennas need to be designed to exhibit electromagnetic transparency to high-frequency antennas. This can be achieved by introducing a frequency-selective surface into the original low-frequency antenna radiation structure. Furthermore, the development of dual-band common-aperture antennas is insufficient to meet the demands of multi-band communication; therefore, the development and research of multi-band common-aperture antenna arrays are urgently needed. Extending to multi-band arrays requires low-frequency antennas to exhibit electromagnetic transparency across multiple frequency bands, placing higher demands on the design of the frequency-selective surface. Therefore, it is necessary to design low-frequency antennas with multi-band electromagnetic transparency and simultaneously develop multi-band common-aperture antenna arrays to support the coexistence of multi-band communication.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] This invention provides a multi-band common-aperture base station antenna based on a composite wave-transparent structure, which can realize a multi-band common-aperture antenna array, support the coexistence of multi-band communication, meet the needs of high-performance multi-band communication, and thus overcome the limitations of the prior art.

[0007] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0008] According to a first aspect of the present invention, a multi-band common-aperture base station antenna is provided, comprising:

[0009] From top to bottom, a low-frequency antenna, an intermediate-frequency antenna, and a high-frequency dual-band antenna are placed coaxially above a metal floor.

[0010] Both the low-frequency antenna and the intermediate-frequency antenna are composite wave-transparent structures composed of three layers of electromagnetic surfaces. When the electromagnetic waves from the high-frequency dual-band antenna irradiate the intermediate-frequency antenna and the low-frequency antenna, the composite wave-transparent structure is excited and exhibits electromagnetic transparency characteristics, enabling normal radiation of electromagnetic waves in the two high-frequency bands and suppressing the radiation pattern distortion problem caused by spatial obstruction. When the electromagnetic waves from the intermediate-frequency antenna irradiate the low-frequency antenna, the composite wave-transparent structure of the low-frequency antenna is excited and exhibits electromagnetic transparency characteristics, enabling normal radiation of intermediate-frequency electromagnetic waves.

[0011] In some exemplary embodiments, the low-frequency antenna includes a first low-frequency electromagnetic surface, a second low-frequency electromagnetic surface, and a third low-frequency electromagnetic surface placed from top to bottom, with adjacent surfaces separated by air layers of equal spacing; wherein the first low-frequency electromagnetic surface and the third low-frequency electromagnetic surface have the same structure.

[0012] In some exemplary embodiments, the low-frequency first electromagnetic surface includes a low-frequency first dielectric substrate and a low-frequency first folded square ring metal structure printed on its lower surface; the low-frequency first folded square ring metal structure is arranged in a 3×3 manner to form a low-frequency first square ring array, and the low-frequency first square ring array is arranged in a 2×2 manner to form a metal structure on the lower surface of the low-frequency first dielectric substrate; the low-frequency first square ring array is divided into a low-frequency first radiating square ring group and a low-frequency second radiating square ring group placed diagonally to achieve a ±45° polarized radiation function.

[0013] In some exemplary embodiments, the low-frequency first folded square ring metal structure includes coaxially nested low-frequency outer square ring strips, low-frequency middle square ring strips, and low-frequency inner square ring strips.

[0014] In some exemplary embodiments, the low-frequency second electromagnetic surface includes a low-frequency second dielectric substrate and a low-frequency first square ring metal structure printed on its lower surface, and intersecting low-frequency first Y-type feed lines and low-frequency second Y-type feed lines printed on its upper surface.

[0015] The low-frequency first Y-type feeder transfers the energy input from the low-frequency first coaxial line to the low-frequency first radiating square ring group through coupling; the low-frequency second Y-type feeder transfers the energy input from the second coaxial line to the low-frequency second radiating square ring group through coupling; one end of the low-frequency first coaxial line is connected to the low-frequency first Y-type feeder, and the other end is connected to the area below the metal floor; one end of the low-frequency second coaxial line is connected to the second Y-type feeder, and the other end is connected to the area below the metal floor.

[0016] In some exemplary embodiments, the intermediate frequency antenna includes an intermediate frequency first electromagnetic surface, an intermediate frequency second electromagnetic surface, and an intermediate frequency third electromagnetic surface placed from top to bottom; adjacent intermediate frequency antennas are separated by air layers of equal spacing; wherein the intermediate frequency first electromagnetic surface and the intermediate frequency third electromagnetic surface have the same structure.

[0017] In some exemplary embodiments, the intermediate frequency first electromagnetic surface includes an intermediate frequency first dielectric substrate and an intermediate frequency first folded square ring metal structure printed on its lower surface; the first folded square ring metal structure forms an intermediate frequency first square ring array in a 3×3 arrangement, and the intermediate frequency first square ring array forms a metal structure on the lower surface of the intermediate frequency first dielectric substrate in a 2×2 arrangement; the intermediate frequency first square ring array is divided into an intermediate frequency first radiating square ring group and an intermediate frequency second radiating square ring group placed diagonally to achieve a ±45° polarized radiation function.

[0018] In some exemplary embodiments, the first folded square ring metal structure includes a coaxially nested mid-frequency outer square ring strip and a mid-frequency inner square ring strip.

[0019] In some exemplary embodiments, the intermediate frequency second electromagnetic surface includes an intermediate frequency second dielectric substrate and an intermediate frequency first square ring metal structure printed on its lower surface, and an intersecting intermediate frequency first Y-type feed line and an intermediate frequency second Y-type feed line printed on its upper surface.

[0020] The intermediate frequency first Y-type feeder transfers the energy input from the intermediate frequency first coaxial line to the intermediate frequency first radiating square ring group through coupling; the intermediate frequency second Y-type feeder transfers the energy input from the intermediate frequency second coaxial line to the intermediate frequency second radiating square ring group through coupling; one end of the intermediate frequency first coaxial line is connected to the intermediate frequency first Y-type feeder, and the other end is connected to the area below the metal floor; one end of the intermediate frequency second coaxial line is connected to the intermediate frequency second Y-type feeder, and the other end is connected to the area below the metal floor.

[0021] In some exemplary embodiments, the high dual-frequency antenna includes a high dual-frequency first dielectric substrate and a parasitic patch printed on its upper surface, a high-frequency second dielectric substrate and a radiating patch printed on its lower surface; the high dual-frequency first dielectric substrate is located above the high dual-frequency second dielectric substrate.

[0022] The multi-band co-aperture base station antenna based on a composite electromagnetic transparent structure provided in the embodiments of the present invention improves the antenna's radiation structure and, together with an additional electromagnetic surface, forms a composite wave-transparent structure with multi-frequency broadband response. This suppresses antenna pattern distortion and inability to radiate normally caused by spatial obstruction, enabling low-interference cooperative operation of multi-band multi-antenna arrays under co-aperture conditions. This array features multi-frequency cooperation, stable radiation, simple structure, and ease of design.

[0023] Compared with existing technologies, it has the following advantages:

[0024] 1) The four-band common-aperture base station antenna proposed in this invention does not carry any circuit components, but consists only of a dielectric substrate and metal etched thereon, which can realize stable radiation of multiple antennas in their respective frequency bands. In addition, there is no need to introduce auxiliary structures to stabilize the radiation performance of low-frequency antennas.

[0025] 2) This invention combines the radiating patches of the low-frequency and intermediate-frequency antennas with additional electromagnetic surfaces to form a second-order filter structure, exhibiting broadband wave transmission characteristics. Simultaneously, the additional electromagnetic surface is designed to have multiple resonant frequency points, which, together with the antenna radiating patches, constitute a composite wave-transmitting structure with multi-frequency response, enabling multi-band operation.

[0026] 3) In this invention, the two additional electromagnetic structures introduced into the intermediate frequency antenna have dual-frequency resonant characteristics and are electromagnetically transparent to the high-frequency dual-frequency antenna; the two additional electromagnetic structures introduced into the low-frequency antenna have tri-frequency resonant characteristics and are electromagnetically transparent to both the high-frequency dual-frequency antenna and the intermediate frequency antenna. This avoids mutual obstruction between different antennas, and the array can achieve stable radiation in all four operating frequency bands.

[0027] 4) The introduction of additional electromagnetic structures did not affect the original radiation performance and matching performance of the low-frequency and intermediate-frequency antennas while maintaining the radiation pattern shape.

[0028] 5) This invention achieves multi-band transmission effect by directly improving the low-frequency array and the intermediate frequency array, without having to reduce the low-frequency antenna blocking effect by increasing the array spacing and stacking arrangement; the antennas in the array proposed in this invention are all placed on the same reflective floor, without increasing the cross-sectional height of the array; it avoids the use of high dielectric constant dielectric substrates and structures that require precision machining technology, thus reducing the manufacturing difficulty and cost.

[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0031] Figure 1 This schematic diagram illustrates the overall structure of a multi-band common-aperture base station antenna array based on a composite wave-transparent structure, according to an exemplary embodiment of the present invention.

[0032] Figure 2 The diagram schematically shows a side view of a multi-band common-aperture base station antenna array based on a composite wave-transparent structure, according to an exemplary embodiment of the present invention.

[0033] Figure 3 This schematic diagram illustrates the overall structure of a low-frequency antenna for a multi-band common-aperture base station antenna array based on a composite wave-transparent structure, according to an exemplary embodiment of the present invention.

[0034] Figure 4 The following schematic diagrams illustrate the structure of a low-frequency antenna according to an exemplary embodiment of the present invention: (a) a printed metal structure diagram of a first dielectric substrate; (b) a printed metal structure diagram of a second dielectric substrate; and (c) a printed metal structure diagram of a third dielectric substrate.

[0035] Figure 5 This schematic diagram illustrates the overall structure of an intermediate frequency antenna according to an exemplary embodiment of the present invention.

[0036] Figure 6 The following schematic diagrams illustrate intermediate frequency antenna structures according to exemplary embodiments of the present invention: (a) a printed metal structure diagram of a first dielectric substrate; (b) a printed metal structure diagram of a second dielectric substrate; and (c) a printed metal structure diagram of a third dielectric substrate.

[0037] Figure 7 The diagrams schematically illustrate a high-frequency antenna structure according to an exemplary embodiment of the present invention; (a) an overall structural diagram; and (b) a diagram of the second dielectric substrate and printed metal structure.

[0038] Figure 8 This schematic diagram illustrates the port labeling of a multi-band common-aperture base station antenna array based on a composite wave-transparent structure, according to an exemplary embodiment of the present invention.

[0039] Figure 9The following are schematic diagrams of electromagnetic wave radiation: (a) Schematic diagram of electromagnetic wave radiation of a conventional multi-band common-aperture base station antenna array; (b) Schematic diagram of electromagnetic wave radiation of the multi-band common-aperture base station antenna array of the present invention.

[0040] Figure 10 shows a comparison of simulation results: (a) At 4.8 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°, when ports 5 and 8 are differentially fed, the radiation patterns of a single high-frequency dual-band antenna, the array of this invention, and a conventional array are compared; (b) At 5 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°, when ports 5 and 8 are differentially fed, the radiation patterns of a single high-frequency dual-band antenna, the array of this invention, and a conventional array are compared; (c) At 3.4 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°, when ports 5 and 8 are differentially fed, the radiation patterns of a single high-frequency dual-band antenna, the array of this invention, and a conventional array are compared. (d) Comparison of radiation patterns in arrays and conventional arrays; (e) Comparison of radiation patterns in arrays with a single high-frequency dual-band antenna, array of the present invention, and conventional arrays when differentially fed at ports 5 and 8 at 3.6 GHz with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°; (f) Comparison of radiation patterns in arrays with a single intermediate frequency antenna, array of the present invention, and conventional arrays when fed at port 3 at 1.8 GHz with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°; (c) Comparison of radiation patterns in arrays with a single intermediate frequency antenna, array of the present invention, and conventional arrays when fed at port 3 at 2 GHz with azimuth angles φ = 0° and 90° and elevation angles θ = –90° to 90°.

[0041] Figure 11 Frequency response of composite wave-transmitting structure: (a) Frequency response of composite wave-transmitting structure with three-band wave-transmitting function applied to low-frequency antenna; (b) Frequency response of composite wave-transmitting structure with two-band wave-transmitting function applied to medium-frequency antenna.

[0042] In the diagram: 1-Low-frequency antenna; 2-Low-frequency first electromagnetic surface; 3-Low-frequency second electromagnetic surface; 4-Low-frequency third electromagnetic surface; 5-Intermediate-frequency antenna; 6-Intermediate-frequency first electromagnetic surface; 7-Intermediate-frequency second electromagnetic surface; 8-Intermediate-frequency third electromagnetic surface; 9-High-frequency dual-band antenna; 10-Metal ground plane; 11-Low-frequency first Y-type feeder; 12-Low-frequency second Y-type feeder; 13-Low-frequency first coaxial cable; 14-Low-frequency second coaxial cable; 15-Intermediate-frequency first Y-type feeder; 16-Intermediate-frequency second Y-type feeder; 17-Intermediate-frequency first coaxial cable; 18-Intermediate-frequency second coaxial cable; 21-Low-frequency first dielectric substrate; 22-Low-frequency first folded square ring. Metal structure; 23-Low-frequency first square ring array; 24-Low-frequency outer square ring strip; 25-Low-frequency middle square ring strip; 26-Low-frequency inner square ring strip; 27-Low-frequency first radiating square ring group; 28-Low-frequency second radiating square ring group; 31-Low-frequency second dielectric substrate; 32-Low-frequency first square ring metal structure; 33-Low-frequency second square ring array; 41-Low-frequency third dielectric substrate; 42-Low-frequency second folded square ring metal structure; 43-Low-frequency third ring array; 44-Low-frequency third radiating square ring group; 45-Low-frequency fourth radiating square ring group; 61-Intermediate frequency antenna first dielectric substrate; 62-Intermediate frequency first folded square ring metal structure; 63 - IF first square ring array; 64 - IF outer square ring strip; 65 - IF inner square ring strip; 66 - IF first radiating square ring group; 67 - IF second radiating square ring group; 71 - IF second dielectric substrate; 72 - IF first square ring metal structure; 73 - IF second square ring array; 81 - IF third dielectric substrate; 82 - IF second folded square ring metal structure; 83 - IF third ring array; 84 - IF third radiating square ring group; 85 - IF fourth radiating square ring group; 91 - High dual-frequency first dielectric substrate; 92 - Parasitic patch; 921 - Parasitic patch chamfer; 922 - Parasitic patch central circular gap; 93 - High Dual-frequency second dielectric substrate; 94-Radiating patch; 941-Radiating patch chamfer; 942-Radiating patch edge rectangular gap; 95-High dual-frequency first L-shaped feeder group; 951-High dual-frequency first L-shaped bent feeder; 952-High dual-frequency second L-shaped bent feeder; 96-High dual-frequency second L-shaped feeder group; 961-High dual-frequency third L-shaped bent feeder; 962-High dual-frequency fourth L-shaped bent feeder; 97-High dual-frequency first coaxial feeder group; 971-High dual-frequency first coaxial line; 972-High dual-frequency second coaxial line; 98-High dual-frequency second coaxial feeder group; 981-High dual-frequency third coaxial line; 982-High dual-frequency fourth coaxial line. Detailed Implementation

[0043] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0044] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0045] A multi-band common-aperture base station antenna array includes multiple antennas operating in different frequency bands stacked together. An intermediate frequency (IF) antenna is positioned above a high-frequency dual-band antenna, and a low-frequency (LFM) antenna is positioned above the IF antenna. The orthographic projection of the IF antenna and the high-frequency dual-band antenna partially or completely overlaps on a reflector. The orthographic projection of the LFM antenna partially or completely overlaps on the reflector with the orthographic projections of both the IF antenna and the high-frequency dual-band antenna. When electromagnetic waves from the high-frequency dual-band antenna irradiate the IF antenna and the LFM antenna, the composite wave-transparent structure is excited, exhibiting electromagnetic transparency, thus enabling normal radiation of electromagnetic waves in both high-frequency bands and suppressing pattern distortion caused by spatial obstruction. When electromagnetic waves from the IF antenna irradiate the LFM antenna, the composite wave-transparent structure of the LFM antenna is excited, exhibiting electromagnetic transparency, thus enabling normal radiation of the IF electromagnetic waves.

[0046] like Figure 1 As shown, this embodiment of the invention provides a multi-band common-aperture base station antenna, specifically a four-band dual-polarized common-aperture base station antenna, including a low-frequency antenna 1, an intermediate-frequency antenna 5, and a high-frequency dual-band antenna 9, coaxially placed on the upper surface of a metal floor 10. The low-frequency antenna 1 is a composite wave-transparent structure composed of three electromagnetic surfaces: a first low-frequency electromagnetic surface 2, a second low-frequency electromagnetic surface 3, and a third low-frequency electromagnetic surface 4. The second low-frequency electromagnetic surface 3 acts as the antenna's radiating structure and is connected to a feeding structure for power supply. The intermediate-frequency antenna 5 is also a composite wave-transparent structure composed of three electromagnetic surfaces: a first intermediate-frequency electromagnetic surface 6, a second intermediate-frequency electromagnetic surface 7, and a third intermediate-frequency electromagnetic surface 8. The second intermediate-frequency electromagnetic surface 7 acts as the antenna's radiating structure and is connected to a feeding structure for power supply. The low-frequency antenna 1 is located at the top of the array; the intermediate-frequency antenna 5 is located below the low-frequency antenna 1; and the high-frequency dual-band antenna 9 is located below the intermediate-frequency antenna 5, i.e., at the bottom of the entire array.

[0047] Specifically, the low-frequency antenna 1 operates at 0.78-1.08 GHz, the intermediate-frequency antenna 5 operates at 1.7-2.1 GHz, and the high-frequency dual-band antenna 9 operates at 3.3-3.5 GHz and 4.7-4.9 GHz.

[0048] like Figure 3 As shown, the low-frequency antenna 1 is located at the top of the array and includes a first low-frequency electromagnetic surface 2, a second low-frequency electromagnetic surface 3, and a third low-frequency electromagnetic surface 4. The first low-frequency electromagnetic surface 2 includes a first low-frequency dielectric substrate 21 with a low-frequency first folded square ring metal structure 22 printed on its lower surface. The second low-frequency electromagnetic surface 3 includes a second low-frequency dielectric substrate 31 with a low-frequency first square ring metal structure 32 printed on its lower surface. The third low-frequency electromagnetic surface 4 includes a third low-frequency dielectric substrate 41 and a second low-frequency folded square ring metal structure 42 printed on its lower surface. The third low-frequency electromagnetic surface 4 has the same structure as the first low-frequency electromagnetic surface 2. The first dielectric substrate 21, the second dielectric substrate 31, and the third dielectric substrate 41 are separated by equally spaced air layers.

[0049] like Figure 4 As shown, the metal pattern printed on the lower surface of the first dielectric substrate 21 of the low-frequency antenna is a low-frequency first folded square ring metal structure 22. The low-frequency first folded square ring metal structure 22 includes a low-frequency outer square ring strip 24, a low-frequency middle square ring strip 25 and a low-frequency inner square ring strip 26, which are coaxially nested. The low-frequency first folded square ring metal structure 22 is arranged in a 3×3 manner to form a low-frequency first square ring array 23. Furthermore, the low-frequency first square ring array 23 is arranged in a 2×2 manner to form the metal structure on the lower surface of the first dielectric substrate 21.

[0050] Furthermore, the first square ring array 23 is divided into a low-frequency first radiation square ring group 27 and a low-frequency second radiation square ring group 28 placed diagonally opposite each other to achieve a radiation function with ±45° polarization.

[0051] like Figure 4 As shown, the metal pattern printed on the lower surface of the low-frequency second dielectric substrate 31 is a low-frequency first square ring metal structure 32, and the low-frequency first square ring metal structure 32 is arranged in a 3×3 manner to form a second square ring array 33; further, the second square ring array 33 is arranged in a 2×2 manner to form the metal structure on the lower surface of the low-frequency second dielectric substrate 31.

[0052] A low-frequency first Y-shaped feed line 11 and a low-frequency second Y-shaped feed line 12, which intersect each other, are printed on the middle position of the upper surface of the low-frequency second dielectric substrate 31. The low-frequency first Y-shaped feed line 11 transfers the energy input from the low-frequency first coaxial line 13 to the low-frequency first radiating square ring group 27 through coupling. The low-frequency second Y-shaped feed line 12 transfers the energy input from the low-frequency second coaxial line 14 to the low-frequency second radiating square ring group 28 through coupling. One end of the low-frequency first coaxial line 13 passes through the low-frequency second dielectric substrate 31 and connects to the low-frequency first Y-shaped feed line 11, and the other end passes through the low-frequency third dielectric substrate 4 in sequence. 1. The intermediate frequency first dielectric substrate 61, intermediate frequency second dielectric substrate 71, intermediate frequency third dielectric substrate 81, and high-frequency dual-mode first dielectric substrate 91 and high-frequency dual-mode second dielectric substrate 93 are connected to the area below the metal ground plane 10. One end of the low-frequency second coaxial cable 14 passes through the low-frequency second dielectric substrate 31 and connects to the low-frequency second Y-shaped feed line 12, while the other end passes sequentially through the low-frequency third dielectric substrate 41, intermediate frequency first dielectric substrate 61, intermediate frequency second dielectric substrate 71, intermediate frequency third dielectric substrate 81, and high-frequency dual-mode first dielectric substrate 91 and high-frequency dual-mode second dielectric substrate 93, connecting to the area below the metal ground plane 10. The metal structure printed on the lower surface of the low-frequency first dielectric substrate 21 and the low-frequency third dielectric substrate 41 has almost no effect on radiation.

[0053] like Figure 4 As shown, the low-frequency third dielectric substrate 41 and the low-frequency second folded square ring metal structure 42 on its lower surface are completely identical to the low-frequency first dielectric substrate 21 and the low-frequency first folded square ring metal structure 2 on its lower surface.

[0054] Specifically, the low-frequency first dielectric substrate 21, the low-frequency second dielectric substrate 31, and the low-frequency third dielectric substrate 41 are all made of 0.8mm thick F4BM300 material with a dielectric constant of 3.0 and a loss tangent of 0.0018. Adjacent dielectric substrates are separated by an air layer of 4.2mm. When the composite wave-transmitting structure of the low-frequency antenna resonates, it generates three wave-transmitting frequency bands covering the operating frequency bands of the intermediate frequency antenna and the high-frequency dual-band antenna, and simultaneously forms a second-order broadband resonance, thus expanding the wave-transmitting bandwidth.

[0055] like Figure 5As shown, the intermediate frequency (IF) antenna 5 is located below the low-frequency antenna 1 and includes a first electromagnetic surface 6, a second electromagnetic surface 7, and a third electromagnetic surface 8. The first electromagnetic surface 6 includes a first folded square ring metal structure 62 printed on the lower surface of a first dielectric substrate 61. The second electromagnetic surface 7 includes a second dielectric substrate 71 and the first square ring metal structure 72 printed on its lower surface. The third electromagnetic surface 8 includes a third dielectric substrate 81 and the second folded square ring metal structure 82 printed on its lower surface. The third electromagnetic surface 8 has the same structure as the first electromagnetic surface 6. The first dielectric substrate 61, the second dielectric substrate 71, and the third dielectric substrate 81 are separated by equally spaced air layers.

[0056] like Figure 6 As shown, the metal pattern printed on the lower surface of the first dielectric substrate 61 of the intermediate frequency antenna is an intermediate frequency first folded square ring metal structure 62. The intermediate frequency first folded square ring metal structure 62 includes a coaxially nested intermediate frequency outer square ring strip 64 and an intermediate frequency inner square ring strip 65. The intermediate frequency first folded square ring metal structure 62 is arranged in a 2×2 manner to form an intermediate frequency first square ring array 63. Furthermore, the intermediate frequency first square ring array 63 is arranged in a 2×2 manner to form the metal structure on the lower surface of the intermediate frequency first dielectric substrate 61.

[0057] Furthermore, the intermediate frequency first square ring array 63 is divided into an intermediate frequency first radiation square ring group 66 and an intermediate frequency second radiation square ring group 67 that are diagonally opposite each other to achieve a radiation function with ±45° polarization.

[0058] like Figure 6 As shown, the metal pattern printed on the lower surface of the intermediate frequency second dielectric substrate 71 is an intermediate frequency first square ring metal structure 72. The intermediate frequency first square ring metal structure 72 is arranged in a 2×2 manner to form an intermediate frequency second square ring array 73. Furthermore, the intermediate frequency second square ring array 73 is arranged in a 2×2 manner to form the metal structure on the lower surface of the intermediate frequency second dielectric substrate 71.

[0059] Intersecting intermediate frequency first Y-type feed lines 15 and second intermediate frequency Y-type feed lines 16 are printed at the middle position of the upper surface of the intermediate frequency second dielectric substrate 71. The intermediate frequency first Y-type feed line 15 transmits the energy input from the intermediate frequency first coaxial line 17 to the intermediate frequency first radiating square ring group 66 through coupling. The intermediate frequency second Y-type feed line 16 transmits the energy input from the intermediate frequency second coaxial line 18 to the low frequency second radiating square ring group 67 through coupling. One end of the intermediate frequency first coaxial line 17 passes through the intermediate frequency second dielectric substrate 61 and connects to the intermediate frequency first Y-type feed line 15, and the other end passes through the intermediate frequency third dielectric substrate 81, the high dual-frequency first dielectric substrate 91, and the high dual-frequency second dielectric substrate 93 and connects to the area below the metal ground plane 10. One end of the intermediate frequency second coaxial line 18 passes through the intermediate frequency second dielectric substrate 71 and connects to the intermediate frequency second Y-type feed line 16, and the other end passes through the intermediate frequency third dielectric substrate 81, the high dual-frequency first dielectric substrate 91, and the high dual-frequency second dielectric substrate 93 and connects to the area below the metal ground plane 10. The metal structures printed on the lower surfaces of the first dielectric substrate 61 and the third dielectric substrate 81 have almost no effect on radiation.

[0060] like Figure 6 As shown, the intermediate frequency third dielectric substrate 81 and the intermediate frequency second folded square ring metal structure 82 on its lower surface are completely identical in composition to the intermediate frequency first dielectric substrate 61 and the intermediate frequency first folded square ring metal structure 62 on its lower surface.

[0061] Specifically, the first intermediate frequency dielectric substrate 61, the second intermediate frequency dielectric substrate 71, and the third intermediate frequency dielectric substrate 81 are all made of 0.5mm thick F4BM220 substrate with a dielectric constant of 2.2 and a loss tangent of 0.001. Adjacent dielectric substrates are separated by a 2.9mm air gap. When the composite wave-transmitting structure of the intermediate frequency antenna resonates, it generates two wave-transmitting frequency bands covering the operating frequency band of the high-frequency dual-band antenna, simultaneously forming a second-order broadband resonance and expanding the wave-transmitting bandwidth. The metal structure printed on the lower surface of the first intermediate frequency dielectric substrate 61 and the third intermediate frequency dielectric substrate 81 has almost no effect on the antenna radiation.

[0062] like Figure 7 As shown, the high-frequency dual-band antenna 9 is located below the intermediate-frequency antenna 5, and includes a high-frequency first dielectric substrate 91 and a parasitic patch 921 printed on its upper surface, a high-frequency second dielectric substrate 93 and a radiating patch 941 printed on its lower surface; the high-frequency first dielectric substrate 91 is located above the high-frequency second dielectric substrate 93.

[0063] Specifically, both dielectric substrates of the high-frequency antenna 9 are FR4 plates with a thickness of 0.8 mm, a dielectric constant of 4.4, and a loss tangent of 0.02. The two dielectric substrates are separated by an air layer with a spacing of 6.7 mm.

[0064] The upper surface of the high-dual-frequency second dielectric substrate 93 is printed with orthogonally placed first L-shaped feed line group 95 and second L-shaped feed line group 96. The two feed lines excite the high-dual-frequency antenna through differential feeding to achieve dual-polarized radiation. The first L-shaped feed line group 95 includes two identical high-dual-frequency first L-shaped bent feed structure 951 and high-dual-frequency second L-shaped bent feed line 952. The high-dual-frequency first L-shaped bent feed line 951 and high-dual-frequency second L-shaped bent feed line 952 transfer the energy in the high-dual-frequency first coaxial line 971 and high-dual-frequency second coaxial line 972 to the radiating patch 94 through coupling. The input signals in the high-dual-frequency first coaxial line 971 and high-dual-frequency second coaxial line 972 have the same amplitude but opposite phase. The high-dual-frequency second L-shaped feeder group 96 is constructed in exactly the same way as the high-dual-frequency first L-shaped feeder group 95, including a high-dual-frequency third L-shaped bent feeder 961 and a high-dual-frequency fourth L-shaped bent feeder 962. The high-dual-frequency third L-shaped bent feeder 961 and the high-dual-frequency fourth L-shaped bent feeder 962 transfer the energy in the high-dual-frequency third coaxial line 981 and the high-dual-frequency fourth coaxial line 982 to the radiating patch 94 through coupling. The input signals in the high-dual-frequency third coaxial line 981 and the high-dual-frequency fourth coaxial line 982 have the same amplitude but opposite phase.

[0065] The four-band common-aperture base station antenna array proposed in this invention does not carry any additional circuit components. All electromagnetic structures consist only of a dielectric substrate and the metal etched onto its surface, resulting in a simple structure and a wide degree of design freedom. The introduction of additional electromagnetic structures does not affect the antenna's original radiation and matching performance while maintaining the radiation pattern conformal. Ultimately, the array achieves stable radiation and matching in all four operating frequency bands.

[0066] Figure 9 (a) is a schematic diagram of electromagnetic wave radiation in a traditional common-aperture base station array antenna. Antennas of various frequency bands are placed on a shared reflector floor. The low-frequency antenna with the higher profile is located at the top of the array, followed by the intermediate-frequency antenna, and the high-frequency dual-band antenna is located at the bottom. Due to spatial obstruction, the low-frequency and intermediate-frequency antennas will generate secondary radiation under the excitation of the high-frequency dual-band antenna, affecting the normal radiation of the high-frequency dual-band antenna and causing radiation pattern distortion. Similarly, the low-frequency antenna will also generate secondary radiation under the excitation of the intermediate-frequency antenna, affecting the radiation performance of the intermediate-frequency antenna. The different antennas in this array interfere with each other, making coordinated operation difficult.

[0067] Figure 9(b) is a schematic diagram of the electromagnetic wave radiation of the multi-band common-aperture base station antenna array of the present invention. A multi-layer composite electromagnetic transparency structure is introduced into the low-frequency antenna and the intermediate-frequency antenna to achieve multi-band electromagnetic transparency design. Specifically, the composite wave-transparent structure formed by the intermediate-frequency antenna has wave-transparent windows in two high-frequency bands, suppressing obstruction of the high-frequency dual-band antenna and achieving pattern conformal preservation for the high-frequency dual-band antenna. The composite wave-transparent structure formed by the low-frequency antenna not only has wave-transparent windows in two high-frequency bands but also achieves wave-transparent performance in the intermediate-frequency band, simultaneously achieving pattern conformal preservation for both the high-frequency dual-band antenna and the intermediate-frequency antenna.

[0068] The effects of this invention can be further illustrated by the following simulations:

[0069] I. Simulation Software:

[0070] Commercial Ansoft HFSS19.2 software.

[0071] II. Simulation Content:

[0072] Simulation 1:

[0073] Figure 10(a) shows the high dual-band antenna of this invention when the azimuth angle φ = 0° and 90° and the elevation angle θ = -90° to 90°. Figure 8 The high-frequency dual-band antenna, with ports 5 and 8 differentially fed, exhibits a normalized radiation pattern at 4.8 GHz. This includes: 1. A radiation pattern of only the high-frequency dual-band antenna; 2. Radiation patterns of the high-frequency dual-band antenna under the proposed composite transparent structure three-band electromagnetically transparent low-frequency antenna and dual-band electromagnetically transparent intermediate-frequency antenna; 3. Radiation patterns of the high-frequency dual-band antenna under conventional low-frequency and intermediate-frequency antennas, wherein the radiation structure of the conventional low-frequency and intermediate-frequency antennas is a rectangular patch with the same dimensions as the antenna in this invention.

[0074] As shown in Figure 10(a), the radiation pattern of the high-frequency dual-band antenna in the conventional array exhibits significant distortion within a range of ±60° in the axial direction, resulting in deterioration of both gain and beamwidth. However, in the array of this invention, the radiation pattern of the high-frequency dual-band antenna shows no significant distortion and is almost identical to the radiation pattern when only the high-frequency dual-band antenna is present. This indicates that the low-frequency and intermediate-frequency antennas in this invention achieve "electromagnetic transparency" to the high-frequency dual-band antenna.

[0075] Simulation 2:

[0076] Figure 10(b) shows the high dual-band antenna of this invention when the azimuth angle φ = 0° and 90° and the elevation angle θ = -90° to 90°. Figure 8The high-frequency dual-band antenna, with ports 5 and 8 differentially fed, exhibits a normalized radiation pattern at 5.0 GHz. This includes: 1. A radiation pattern of only the high-frequency dual-band antenna; 2. Radiation patterns of the high-frequency dual-band antenna under the proposed composite transparent structure of a three-band electromagnetically transparent low-frequency antenna and a dual-band electromagnetically transparent intermediate-frequency antenna; 3. Radiation patterns of the high-frequency dual-band antenna under conventional low-frequency and intermediate-frequency antennas, wherein the radiation structure of the conventional low-frequency and intermediate-frequency antennas is a rectangular patch with the same dimensions as the antenna in this invention.

[0077] As shown in Figure 10(b), the radiation pattern of the high-frequency dual-band antenna in the conventional array exhibits significant distortion within a range of ±60° in the axial direction, resulting in deterioration of both gain and beamwidth. However, the radiation pattern of the high-frequency dual-band antenna in the array of this invention does not show significant distortion and is almost identical to the radiation pattern when only the high-frequency dual-band antenna is used. This indicates that the low-frequency and intermediate-frequency antennas in this invention achieve "electromagnetic transparency" to the high-frequency dual-band antenna.

[0078] Simulation 3:

[0079] Figure 10(c) shows the high dual-band antenna of this invention when the azimuth angle φ = 0° and 90° and the elevation angle θ = -90° to 90°. Figure 8 The high-frequency dual-band antenna, with ports 5 and 8 differentially fed, exhibits a normalized radiation pattern at 3.4 GHz. This includes: 1. A radiation pattern of only the high-frequency dual-band antenna; 2. Radiation patterns of the high-frequency dual-band antenna under the proposed composite wave-transparent structure with tri-band electromagnetic transparency (LTV) and dual-band electromagnetic transparency (IF) antennas; 3. Radiation patterns of the high-frequency dual-band antenna under conventional LTV and IF antennas, where the conventional LTV and IF antennas have a rectangular patch with the same dimensions as the antenna in this invention.

[0080] As shown in Figure 10(c), the radiation pattern of the high dual-frequency antenna in the conventional array exhibits significant distortion within a range of ±60° in the axial direction, with a maximum gain drop of 18dB. However, in the array of the present invention, the radiation pattern of the high dual-frequency antenna does not show significant distortion and is almost identical to the radiation pattern when only the high dual-frequency antenna is used, thus achieving stable radiation.

[0081] Simulation 4:

[0082] Figure 10(d) shows the high dual-band antenna of this invention when the azimuth angle φ = 0° and 90° and the elevation angle θ = -90° to 90°. Figure 8The high-frequency dual-band antenna, with ports 5 and 8 differentially fed, exhibits a normalized radiation pattern at 3.6 GHz. This includes: 1. A radiation pattern of only the high-frequency dual-band antenna; 2. Radiation patterns of the high-frequency dual-band antenna under the proposed composite wave-transparent structure of a three-band electromagnetically transparent low-frequency antenna and a two-band electromagnetically transparent intermediate-frequency antenna; 3. Radiation patterns of the high-frequency dual-band antenna under conventional low-frequency and intermediate-frequency antennas, wherein the radiation structure of the conventional low-frequency and intermediate-frequency antennas is a rectangular patch with the same dimensions as the antenna in this invention.

[0083] As shown in Figure 10(d), the radiation pattern of the high dual-frequency antenna in the conventional array is severely distorted within a range of ±60° in the axial direction, and even the split lobe phenomenon occurs, resulting in a significant decrease in gain. However, the radiation pattern of the high dual-frequency antenna in the array of the present invention does not show obvious distortion and is almost consistent with the radiation pattern when there is only a high dual-frequency antenna, thus achieving stable radiation.

[0084] Simulation 5:

[0085] Figure 10(e) shows the azimuth angles φ = 0° and 90°, and the elevation angles θ = -90° to 90° for the intermediate frequency antenna in this invention. Figure 8 The intermediate frequency (IF) antenna is excited at port 3, and its normalized radiation pattern is obtained at 1.8 GHz. This includes: 1. A radiation pattern with only the IF antenna; 2. A radiation pattern of the IF antenna under the proposed three-band electromagnetically transparent low-frequency antenna based on a composite wave-transparent structure; 3. A radiation pattern of the IF antenna under a conventional low-frequency antenna, wherein the radiation structure of the conventional low-frequency antenna is a rectangular patch with the same dimensions as the antenna in this invention.

[0086] As shown in Figure 10(e), the radiation pattern of the intermediate frequency (IF) antenna in a conventional array exhibits significant distortion, resulting in a narrower beamwidth. However, in the array of this invention, the IF antenna's radiation pattern shows no significant distortion and is almost identical to the radiation pattern when only an IF antenna is used. This demonstrates that the low-frequency antenna in this invention achieves "electromagnetic transparency" to the dual-frequency antenna.

[0087] Simulation 6:

[0088] Figure 10(f) shows the azimuth angles φ = 0° and 90°, and the elevation angles θ = -90° to 90° for the intermediate frequency antenna in this invention. Figure 8 The intermediate frequency (IF) antenna is excited at port 3 to achieve a normalized radiation pattern at 2.0 GHz. This includes: 1. a radiation pattern with only the IF antenna; 2. a radiation pattern of the IF antenna under the proposed three-band electromagnetically transparent low-frequency antenna with a composite wave-transparent structure; and 3. a radiation pattern of the IF antenna under a conventional low-frequency antenna, wherein the radiation structure of the conventional low-frequency antenna is a rectangular patch with the same dimensions as the antenna in this invention.

[0089] As shown in Figure 10(f), the radiation pattern of the intermediate frequency (IF) antenna in a conventional array exhibits significant distortion, resulting in a narrower beamwidth. However, in the array of this invention, the IF antenna's radiation pattern shows no significant distortion and is almost identical to the radiation pattern when only an IF antenna is used. This demonstrates that the low-frequency antenna in this invention achieves "electromagnetic transparency" to the dual-frequency antenna.

[0090] Figure 11 (a) is the frequency response of the composite wave-transmitting structure with three-band wave-transmitting function applied in the low-frequency antenna of the present invention. Its transmission coefficient is greater than -1dB in the three frequency bands of 1.7-2.1GHz, 3.3-3.5GHz and 4.7-4.9GHz, achieving good wave-transmitting effect.

[0091] Figure 11 (b) is the frequency response of the composite wave-transmitting structure with dual-band wave-transmitting function applied in the intermediate frequency antenna of the present invention. Its transmission coefficient is greater than -1dB in the two frequency bands of 3.3-3.5GHz and 4.7-4.9GHz, achieving good wave-transmitting effect.

[0092] The above description is merely one embodiment of the present invention and does not constitute any limitation on the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be considered as excluding other embodiments. Specific features, structures, materials, or characteristics described in the present invention can be combined or modified in any suitable manner in one or more embodiments. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention. However, these modifications and changes based on the inventive concept are still within the scope of the claims and protection of the present invention.

Claims

1. A multi-band common-aperture base station antenna, characterized in that, include: The low-frequency antenna (1), the intermediate-frequency antenna (5), and the high-frequency dual-frequency antenna (9) are placed coaxially above the metal floor (10) from top to bottom. Both the low-frequency antenna (1) and the intermediate-frequency antenna (5) are composite wave-transparent structures composed of three layers of electromagnetic surfaces. When the electromagnetic waves of the high-frequency dual-frequency antenna (9) irradiate the intermediate-frequency antenna (5) and the low-frequency antenna (1), the composite wave-transparent structure is excited and exhibits electromagnetic transparency characteristics, realizing normal radiation of electromagnetic waves in the two high-frequency bands and suppressing the radiation pattern distortion problem caused by spatial obstruction. When the electromagnetic waves of the intermediate-frequency antenna (5) irradiate the low-frequency antenna (1), the composite wave-transparent structure of the low-frequency antenna (1) is excited and exhibits electromagnetic transparency characteristics, realizing normal radiation of intermediate-frequency electromagnetic waves. The low-frequency antenna (1) includes a low-frequency first electromagnetic surface (2), a low-frequency second electromagnetic surface (3) and a low-frequency third electromagnetic surface (4) placed from top to bottom, with adjacent surfaces separated by air layers of equal spacing; wherein the low-frequency first electromagnetic surface (2) and the low-frequency third electromagnetic surface (4) have the same structure. The low-frequency first electromagnetic surface (2) includes a low-frequency first dielectric substrate (21) and a low-frequency first folded square ring metal structure (22) printed on its lower surface; the low-frequency first folded square ring metal structure (22) is... The arrangement of the elements constitutes a low-frequency first square ring array (23), wherein the low-frequency first square ring array (23) is based on... The arrangement of the elements constitutes the metal structure on the lower surface of the low-frequency first dielectric substrate (21); the low-frequency first square ring array (23) is divided into a low-frequency first radiation square ring group (27) and a low-frequency second radiation square ring group (28) placed diagonally to achieve the radiation function of ±45º polarization. The low-frequency first folded square ring metal structure (22) includes a low-frequency outer square ring strip (24), a low-frequency middle square ring strip (25), and a low-frequency inner square ring strip (26) nested in an axle. The low-frequency second electromagnetic surface (3) includes a low-frequency second dielectric substrate (31) and a low-frequency first square ring metal structure (32) printed on its lower surface, and intersecting low-frequency first Y-type feed lines (11) and low-frequency second Y-type feed lines (12) printed on its upper surface. The low-frequency first Y-type feed line (11) transmits the energy input from the low-frequency first coaxial line (13) to the low-frequency first radiating square ring group (27) through coupling; the low-frequency second Y-type feed line (12) transmits the energy input from the low-frequency second coaxial line (14) to the low-frequency second radiating square ring group (28) through coupling; one end of the low-frequency first coaxial line (13) is connected to the low-frequency first Y-type feed line (11), and the other end is connected to the metal floor (10); one end of the low-frequency second coaxial line (14) is connected to the second Y-type feed line (12), and the other end is connected to the metal floor (10).

2. The multi-band common-aperture base station antenna according to claim 1, characterized in that, The intermediate frequency antenna (5) includes an intermediate frequency first electromagnetic surface (6), an intermediate frequency second electromagnetic surface (7), and an intermediate frequency third electromagnetic surface (8) placed from top to bottom; adjacent surfaces are separated by air layers of equal spacing; wherein the intermediate frequency first electromagnetic surface (6) and the intermediate frequency third electromagnetic surface (8) have the same structure.

3. The multi-band common-aperture base station antenna according to claim 2, characterized in that, The intermediate frequency first electromagnetic surface (6) includes an intermediate frequency first dielectric substrate (61) and an intermediate frequency first folded square ring metal structure (62) printed on its lower surface; the intermediate frequency first folded square ring metal structure (62) is... The arrangement of the elements constitutes a first square ring array (63) of intermediate frequency, wherein the first square ring array (63) of intermediate frequency is based on... The arrangement of the elements constitutes the metal structure on the lower surface of the intermediate frequency first dielectric substrate (61); the intermediate frequency first square ring array (63) is divided into an intermediate frequency first radiation square ring group (66) and an intermediate frequency second radiation square ring group (67) placed diagonally to achieve the radiation function of ±45º polarization.

4. The multi-band common-aperture base station antenna according to claim 3, characterized in that, The intermediate frequency first folded square ring metal structure (62) includes a coaxially nested intermediate frequency outer square ring strip (64) and an intermediate frequency inner square ring strip (65).

5. The multi-band common-aperture base station antenna according to claim 4, characterized in that, The intermediate frequency second electromagnetic surface (7) includes an intermediate frequency second dielectric substrate (71) and an intermediate frequency first square ring metal structure (73) printed on its lower surface, and an intersecting intermediate frequency first Y-type feed line (15) and intermediate frequency second Y-type feed line (16) printed on its upper surface. The intermediate frequency first Y-type feed line (15) transmits the energy input from the intermediate frequency first coaxial line (17) to the intermediate frequency first radiating square ring group (66) through coupling; the intermediate frequency second Y-type feed line (16) transmits the energy input from the intermediate frequency second coaxial line (18) to the intermediate frequency second radiating square ring group (67) through coupling; one end of the intermediate frequency first coaxial line (17) is connected to the intermediate frequency first Y-type feed line (15), and the other end is connected to the metal floor (10); one end of the intermediate frequency second coaxial line (18) is connected to the intermediate frequency second Y-type feed line (16), and the other end is connected to the metal floor (10).

6. The multi-band common-aperture base station antenna according to claim 1, characterized in that, The high dual-frequency antenna (9) includes a high dual-frequency first dielectric substrate (91) and a parasitic patch (92) printed on its upper surface, a high frequency second dielectric substrate (93) and a radiating patch (94) printed on its lower surface; the high dual-frequency first dielectric substrate (91) is located above the high dual-frequency second dielectric substrate (93).

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