A wide-band co-antenna array base station based on a composite wave-transparent structure

Abstract

The present application relates to a kind of wide frequency band co-aperture base station antenna array based on composite wave-transparent structure, belong to mobile communication technology base station array antenna field.It includes low-frequency antenna, high-frequency antenna and metal floor, wherein, low-frequency antenna is located above high-frequency antenna, the orthographic projection of low-frequency antenna and the orthographic projection of high-frequency antenna have partial or complete overlap on metal floor;Low-frequency antenna is composed of three layers of composite wave-transparent structure, when high-frequency electromagnetic wave irradiates to the composite wave-transparent structure of low-frequency antenna, composite wave-transparent structure is excited, and forms mixed wave-transparent structure;Mixed wave-transparent structure can introduce two or more resonance points, and then introduce wideband transmission window, suppress the shielding effect of high-frequency antenna caused by low-frequency antenna.The present application wide frequency band co-aperture base station array antenna can work in two wideband operating frequency bands, and the unit directional diagram of two frequency bands in array keeps stable, with the advantages of simple structure, easy design, convenient to realize array, low interference and the like.

Description

Technical Field

[0001] This invention belongs to the field of mobile communication technology base station array antennas, specifically relating to a wideband common aperture base station antenna array based on a composite wave-transparent structure. Background Technology

[0002] With the rapid development of mobile communication technology, the commercialization of 5G systems allows people to experience the convenience of high-speed internet anytime, anywhere. However, traditional frequency bands still play an indispensable role, providing stable communication over long distances and wide coverage. Traditional systems and communication systems with high-speed transmission capabilities can be used in a complementary manner. This requires current base station arrays to integrate more and more communication frequency bands. Currently, a more reasonable array arrangement is to use a common-aperture array, which places low-frequency antennas between high-frequency antenna elements or directly above the high-frequency antennas, enabling the coexistence of multiple frequency band antenna arrays without increasing array size or profile height.

[0003] Because low-frequency (LF) antennas are relatively large, partially obstructing them when placed between high-frequency (HF) antenna elements or completely obstructing them by placing them entirely above the HF antenna will significantly degrade the radiation pattern of the HF antenna. This is a problem that urgently needs to be solved in common-aperture base station arrays. Currently, the mainstream approach is to achieve electromagnetic transparency in the LF antenna at high frequencies while maintaining normal radiation at low frequencies. In this way, the electromagnetic waves radiated by the HF antenna will radiate outward through the electromagnetic transparency window on the LF antenna, reducing the harmful induced current excited on the LF antenna.

[0004] A relatively mature approach to achieving electromagnetic transparency windows is to introduce frequency selective surfaces. However, single-layer slotted or strip-type frequency selective surfaces are greatly limited by their operating bandwidth, making them incompatible with more frequency bands and devices. Furthermore, to integrate with broadband devices, multiple low-frequency arrays need to be designed, which increases manufacturing costs, array size, and design complexity.

[0005] Existing broadband co-aperture base station array antennas face significant challenges in manufacturing and fabrication to achieve high-frequency broadband transmission. This hinders expansion to three frequency bands and negatively impacts the matching and radiation performance of low-frequency antennas. Additional auxiliary structures are required to improve these performance characteristics. These limitations severely restrict the application scenarios of high-frequency broadband electromagnetically transparent low-frequency arrays.

[0006] Furthermore, while arrangement methods such as "top-to-bottom arrangement" and "coaxial nesting" can solve the problem of low-frequency antenna obstruction, they significantly increase the overall array size. Stacking high-frequency antennas above low-frequency antennas can also address the radiation pattern degradation issue, but this similarly increases the array's cross-sectional height. Summary of the Invention

[0007] The technical problem to be solved by this invention is: To overcome the shortcomings of existing technologies, this invention provides a wideband common-aperture base station antenna array based on a composite transparent structure. This array addresses the problems of high manufacturing costs, difficult manufacturing processes, and deteriorated matching and radiation performance of high-frequency broadband transparent antennas. It also eliminates the obstruction problem between internal antennas and enables normal radiation of the radiation pattern of the broadband high-frequency working units in the array.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A wideband common-aperture base station antenna array based on a composite wave-transparent structure is characterized in that it includes a low-frequency antenna, a high-frequency antenna and a metal ground plane, wherein the low-frequency antenna is located above the high-frequency antenna, and the orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna partially or completely overlap on the metal ground plane. The low-frequency antenna is composed of a three-layer composite wave-transparent structure. When high-frequency electromagnetic waves irradiate the composite wave-transparent structure of the low-frequency antenna, the composite wave-transparent structure is excited and forms a hybrid wave-transparent structure. The hybrid wave-transparent structure can introduce two or more resonant points, thereby introducing a broadband transmission window to suppress the blocking effect of the low-frequency antenna on the high-frequency antenna.

[0009] A further technical solution of the present invention: the low-frequency antenna includes a first electromagnetic surface, a second electromagnetic surface, and a third electromagnetic surface from top to bottom, the first electromagnetic surface, the second electromagnetic surface, and the third electromagnetic surface being separated by air layers of equal spacing; wherein, the second electromagnetic surface is the radiating structure of the low-frequency antenna.

[0010] A further technical solution of the present invention: the first electromagnetic surface includes a first dielectric substrate and a first metal square ring printed on the lower surface of the first dielectric substrate, wherein the first metal square ring is arranged in an array to form a first array.

[0011] A further technical solution of the present invention: The second electromagnetic surface includes a second dielectric substrate and a composite metal structure printed on the lower surface of the second dielectric substrate, wherein the composite metal structure is arranged in an array to form a second array, and two diagonally opposite second arrays respectively form a first square ring radiation group and a second square ring radiation group to achieve a ±45º polarized radiation function.

[0012] A further technical solution of the present invention: the composite metal structure includes a square metal frame and a Yale-Salem tortuous strip, wherein the Yale-Salem tortuous strip is located inside the square metal frame, and the two Yale-Salem tortuous strips are distributed in a cross-shaped manner.

[0013] A further technical solution of the present invention: A first bifurcated coupling metal strip and a second bifurcated coupling metal strip are printed in the middle of the upper surface of the second dielectric substrate. The first bifurcated coupling metal strip transfers the energy in the first coaxial line to the low-frequency first square ring radiation group through coupling. The second bifurcated coupling metal strip transfers the energy in the second coaxial line to the second square ring radiation group through coupling. One end of the first coaxial line is connected to the coupling metal strip of the first bifurcated coupling metal strip, and one end of the second coaxial line is connected to the second bifurcated coupling metal strip. The other ends of the first coaxial line and the other ends of the second coaxial line pass through the metal ground plane and are connected to the feed terminal.

[0014] A further technical solution of the present invention: the third electromagnetic surface includes a first dielectric substrate and a second metal square ring printed on the lower surface of the third dielectric substrate, wherein the second metal square ring is arranged in an array to form a third array.

[0015] A further technical solution of the present invention: the high-frequency antenna is single or multiple. When it is a single high-frequency antenna, it can be placed directly below the low-frequency antenna, and the orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna completely overlap on the metal floor. When it is an array composed of multiple high-frequency antennas, the low-frequency antenna and the high-frequency antenna are arranged alternately, and the orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna partially overlap on the metal floor.

[0016] A further technical solution of the present invention: the high-frequency antenna includes a fourth dielectric substrate and a fifth dielectric substrate, the fifth dielectric substrate being located above the fourth dielectric substrate; wherein, a rectangular radiating patch is printed on the lower surface of the fourth dielectric substrate, and a rectangular parasitic patch is printed on the lower surface of the fifth dielectric substrate.

[0017] A further technical solution of the present invention: The high-frequency antenna further includes a first feed group and a second feed group printed on the upper surface of a fourth dielectric substrate. Both feed structures feed the rectangular radiating patch through differential feeding to achieve a dual-polarized radiation effect. The first and fourth feed groups each include two identical bent feed structures. The first and second bent feed lines in the first feed group transfer energy from the third and fourth coaxial lines to the rectangular radiating patch through coupling. The amplitudes of the feed excitation in the third and fourth coaxial lines are the same, but the phases are opposite. The third and fourth bent feed lines in the second feed group transfer energy from the fifth and sixth coaxial lines to the rectangular radiating patch through coupling. The amplitudes of the feed excitation in the fifth and sixth coaxial lines are the same, but the phases are opposite.

[0018] The beneficial effects of this invention are as follows: This invention provides a wideband common-aperture base station antenna array based on a composite wave-transparent structure. It employs a low-frequency antenna with broadband high-frequency electromagnetic transparency characteristics, making it compatible with systems across more frequency bands. This reduces the design complexity and manufacturing costs associated with using multiple low-frequency antennas. While improving compatibility, it does not increase the array height or lateral dimensions, allowing for application in various scenarios. Compared with existing technologies, it has the following advantages: 1. This invention transforms the radiation structure of a low-frequency antenna into a composite broadband electromagnetically transparent surface, introducing two or more transmission resonant points within its operating frequency band to expand the transmission bandwidth. This reduces the blocking effect over a wide frequency range, enabling normal radiation from a broadband high-frequency antenna. Furthermore, the broadband transparent structure design is simple, easy to design, and convenient to optimize. Simultaneously, it achieves broadband compatibility with high-frequency antennas with almost no increase in the overall array profile height. It also avoids the introduction of high-dielectric-constant dielectric substrates and complex engineering structures to achieve broadband transmission, reducing array fabrication costs and complexity.

[0019] 2. This invention achieves high-frequency broadband transmission by directly improving the low-frequency array, without having to reduce the low-frequency antenna blocking effect by increasing the array spacing or stacking arrangement; it saves array size and does not increase array height; at the same time, it avoids the need to design an isolation surface between low-frequency and high-frequency antennas in the stacking arrangement to achieve low-frequency reflection and broadband high-frequency transmission, further reducing design complexity and array manufacturing cost.

[0020] 3. The improvements to the low-frequency antenna radiation structure and the introduction of multiple electromagnetic surfaces above and below the low-frequency radiation structure in this invention have almost no impact on the radiation performance and matching performance of the low-frequency antenna, avoiding the need to process corresponding matching networks and components, and also eliminating the need to make additional improvements to the antenna feeding structure.

[0021] 4. The improvements to the low-frequency antenna and the introduction of additional electromagnetic surfaces in this invention enable the expansion to dual-band broadband common-aperture base station array antennas. The multi-layer composite electromagnetic transmission surface expands the design freedom of traditional frequency-selective surfaces, allowing the introduction of multiple transmission poles in both transmission frequency bands, and enabling the expansion to dual-band broadband common-aperture base station arrays and even tri-band common-aperture broadband base station arrays.

[0022] In summary, this invention has the advantages of simple structure, wide operating bandwidth, stable radiation pattern, and convenient array deployment. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1This is a schematic diagram of the overall structure of the broadband common-aperture base station antenna array based on the composite wave-transparent structure of the present invention. Figure 2 This is a side view of the broadband common-aperture base station antenna array based on the composite wave-transparent structure of the present invention; Figure 3 This is a schematic diagram of the overall structure of the low-frequency antenna based on the composite wave-transmitting structure of the present invention, which is a high-frequency broadband wave-transmitting antenna. Figure 4 (a) is a diagram of the printed metal structure of the first dielectric substrate of the low-frequency antenna based on the composite wave-transparent structure of the present invention. Figure 4 (b) is a diagram of the printed metal structure of the second dielectric substrate of the low-frequency antenna based on the composite wave-transparent structure of the present invention; Figure 4 (c) is a diagram of the printed metal structure of the third dielectric substrate of the low-frequency antenna based on the composite wave-transparent structure of the present invention. Figure 5 This is a diagram of the low-frequency antenna feeding structure based on the high-frequency broadband wave-transparent structure of the present invention; Figure 6 (a) is an overall structural diagram of the high-frequency antenna in this invention; Figure 6 (b) is a diagram of the feeding structure of the high-frequency antenna in this invention; Figure 7 This is a port labeling diagram of the broadband common-aperture base station antenna of the present invention; Figure 8 (a) is a comparison of the radiation patterns of the proposed array, the conventional array, and the individual high-frequency unit when the ports Port3 and Port4 are differentially fed at 1.7 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180° to 180°. Figure 8 (b) is a comparison of the radiation patterns of the proposed array, the conventional array, and the individual high-frequency unit when the present invention is differentially fed at 1.9 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180°~180°. Figure 8 (c) is a comparison of the radiation patterns of the proposed array, the conventional array, and the individual high-frequency unit when the ports Port3 and Port4 are differentially fed at 2.1 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180°~180°. Figure 8(d) is a comparison of the radiation patterns of the proposed array, the conventional array, and the standalone high-frequency array when the ports Port3 and Port4 are differentially fed at 2.3 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180°~180°. Figure 8 (e) is a comparison of the radiation patterns of the proposed array, the conventional array, and the standalone high-frequency array when the ports Port3 and Port4 are differentially fed at 2.5 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180°~180°. Figure 8 (f) is a comparison of the radiation patterns of the proposed array, the conventional array, and the standalone high-frequency array when the ports Port3 and Port4 are differentially fed at 2.7 GHz, with azimuth angles φ = 0° and 90° and elevation angles θ = –180° to 180°. Figure 9 A schematic diagram of the overall structure of Embodiment 2 of the present invention; Figure 10 (a) is a schematic diagram of the blocking effect of a traditional common-aperture base station array antenna; Figure 10 (b) is a schematic diagram of the operation of the broadband common aperture base station array antenna based on the composite wave-transparent structure of the present invention; Figure 11 These are the S-parameters of the broadband composite electromagnetic transparent structure of this invention.

[0025] In the diagram: 1-Low-frequency antenna; 2-First electromagnetic surface; 3-Second electromagnetic surface; 4-Third electromagnetic surface; 5-High-frequency antenna; 6-Metal ground plane; 7-First support column; 8-First bifurcated coupling metal strip; 9-Second bifurcated coupling metal strip; 10-First coaxial line; 11-Second coaxial line; 12-Second support column; 21-First metal square ring; 22-First array; 23-First dielectric substrate; 31-Composite metal structure; 32-Square metal frame; 33-Yalesar curved metal strip; 34-Second dielectric substrate; 35-Second array; 36-First square ring radiating group; 37-Second square ring radiating group; 41-Second metal square ring; 42-First... Three arrays; 43-Third dielectric substrate; 51-Rectangular radiating patch; 52-Rectangular parasitic patch; 53-Fourth dielectric substrate; 54-Fifth dielectric substrate; 55-First rectangular slot; 56-First feed group; 57-Second feed group; 58-First feed coaxial line group; 59-Second feed coaxial line group; 521-First triangular chamfer; 522-Second rectangular slot; 561-First bent feed line; 562-Second bent feed line; 563-Second triangular chamfer; 571-Third bent feed line; 572-Fourth bent feed line; 581-Third coaxial line; 582-Fourth coaxial line; 591-Fifth coaxial line; 592-Sixth coaxial line. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] The present invention provides a wideband common aperture base station antenna array based on a composite transparent structure. Without affecting the radiation performance of the low-frequency antenna, the radiation structure is improved and a composite electromagnetic transparent resonant structure is formed by introducing multiple electromagnetic surfaces above and below it. Two or more resonant points can be introduced, which greatly broadens the electromagnetic transparency bandwidth at high frequencies.

[0030] By directly transforming the low-frequency antenna radiating structure into a composite surface with broadband electromagnetic transparency, a broadband reduction effect on the high-frequency antenna blocking effect is achieved with almost no increase in array profile height. This avoids the need to reduce the blocking effect of the low-frequency antenna on the high-frequency antenna by increasing the array size or by stacking the high-frequency array above the low-frequency antenna. Furthermore, the low-frequency antenna with high-frequency broadband electromagnetic transparency reduces the design complexity of introducing multiple low-frequency elements for compatibility with multi-frequency systems. The electromagnetic surfaces introduced above and below the low-frequency radiating structure have almost no impact on the radiation effect of the low-frequency antenna, avoiding application limitations caused by the degradation of the low-frequency antenna's own radiation performance. This array features simple structure, ease of design, stable radiation pattern, and broadband compatibility.

[0031] The present invention provides a wideband common aperture base station antenna array based on a composite wave-transparent structure, comprising a low-frequency antenna, a high-frequency antenna and a metal ground plane, wherein the low-frequency antenna is located above the high-frequency antenna, and the orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna partially or completely overlap on the metal ground plane. The low-frequency antenna is composed of a three-layer composite wave-transparent structure. When high-frequency electromagnetic waves irradiate the composite wave-transparent structure of the low-frequency antenna, the composite wave-transparent structure is excited and forms a hybrid wave-transparent structure. The hybrid wave-transparent structure can introduce two or more resonant points, thereby introducing a broadband transmission window to suppress the blocking effect of the low-frequency antenna on the high-frequency antenna.

[0032] The high-frequency antenna can be single or multiple. When it is a single high-frequency antenna, it can be placed directly below the low-frequency antenna in a stacked arrangement. The orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna completely overlap on the metal floor. When it is an array composed of multiple high-frequency antennas, the low-frequency antenna and the high-frequency antenna are arranged alternately. The orthographic projection of the low-frequency antenna and the orthographic projection of the high-frequency antenna partially overlap on the metal floor.

[0033] Example 1: like Figure 1 As shown, this embodiment of the invention provides a broadband common-aperture base station array antenna based on a composite wave-transparent structure, specifically a dual-frequency dual-polarization broadband common-aperture base station array antenna, including a metal ground plane 6 and a low-frequency antenna 1 disposed in the center of the upper surface of the metal ground plane 6. The low-frequency antenna 1 is composed of a three-layer composite wave-transparent structure, and a high-frequency antenna 5 is symmetrically arranged below the low-frequency antenna 1, forming a 4-layer structure. 4 arrays. For example... Figure 2 As shown, the low-frequency antenna 1 is located at the top of the entire array; the high-frequency antenna 5 is located at the bottom of the entire array.

[0034] The low-frequency antenna 1 operates in the range of 0.69-0.96 GHz, and the high-frequency antenna operates in the range of 1.7-2.7 GHz.

[0035] like Figure 3 As shown, the low-frequency antenna 1 includes a first electromagnetic surface 2, a second electromagnetic surface 3, and a third electromagnetic surface 4 from top to bottom. The first electromagnetic surface 2, the second electromagnetic surface 3, and the third electromagnetic surface 4 are separated by air layers of equal spacing. The second electromagnetic surface 3 acts as a radiating structure, and the feeding structure directly feeds the second electromagnetic surface 3. The first electromagnetic surface 2, the second electromagnetic surface 3, and the third electromagnetic surface 4 are all fixed to the metal floor 6 by the first support column 7.

[0036] Preferably, the dielectric substrates of the first electromagnetic surface 2, the second electromagnetic surface 3, and the third electromagnetic surface 4 have a dielectric constant of 3, an electrical loss of 0.0013, and a thickness of 1 mm.

[0037] like Figure 4 As shown in (a), the first electromagnetic surface 2 includes a first dielectric substrate 23 and a first metal square ring 21 printed on the lower surface of the first dielectric substrate 23. The first metal square ring 21 is located at the upper left corner of the dielectric substrate 23 at a distance of 3. The first array 22 is formed by arranging 3 in a way that constitutes a 2. The metal structure on the lower surface of the first dielectric substrate 23 is formed by arranging the metal in a 2-way manner.

[0038] like Figure 4 As shown in (b), the second electromagnetic surface 3 includes a second dielectric substrate 34 and a composite metal structure 31 printed on the lower surface of the second dielectric substrate 34. The composite metal structure 31 includes an outer square metal frame 32 and an inner Yale-Salon tortuous strip 33; the composite metal structure 31 is 3 The second array 35 is formed by arranging the elements in a 3-way manner. The second array 35 is arranged in a 2-way manner. The metal structure on the lower surface of the second dielectric substrate 34 is arranged in a manner of 2. Furthermore, the second array 35 is divided into a low-frequency first square ring radiation group 36 and a low-frequency second square ring radiation group 37 that are diagonally opposite each other, so as to achieve a radiation function with ±45º polarization.

[0039] like Figure 4 As shown in (c), the third electromagnetic surface 4 has the same structure as the first electromagnetic surface 2, including a third dielectric substrate 43 and a second metal square ring 41 printed on the lower surface of the third dielectric substrate 43. The second metal square ring 41 is located at the upper left corner of the dielectric substrate 43 at a 3-degree angle. The third array 42 is formed by arranging 3 in a way that constitutes the third array 42. The third array 42 is arranged in a way that constitutes the third array 42. The metal structure on the lower surface of the third dielectric substrate 43 is formed by arranging the metal in a manner described in section 2.

[0040] When the aforementioned three-layer composite wave-transmitting structure resonates, it forms a second-order broadband equivalent circuit, which generates two transmission poles, greatly expanding the wave-transmitting bandwidth.

[0041] like Figure 5 As shown, the second dielectric substrate 34 has intersecting first bifurcated coupling metal strips 8 and second bifurcated coupling metal strips 9 printed in the center of its front side. The first bifurcated coupling metal strip 8 transfers energy from the first coaxial line 10 to the low-frequency first square ring radiation group 36 through coupling; the second bifurcated coupling metal strip 9 transfers energy from the second coaxial line 11 to the low-frequency second square ring radiation group 37 through coupling; one end of the first coaxial line 10 is connected to the coupling metal strip of the first bifurcated coupling metal strip 8, and one end of the second coaxial line 11 is connected to the first bifurcated coupling metal strip 8. The two bifurcated metal strips 9 are connected; the other end of the first coaxial line 10 and the other end of the second coaxial line 11 pass through the metal floor 6 respectively; the first bifurcated metal strip 8 is not connected to the first square ring radiation group 36, and the second bifurcated metal strip 9 is not connected to the second radiation square ring group 37; the two bifurcated metal strips directly feed the first square ring radiation group 36 and the second square ring radiation group 37 on the lower surface of the second dielectric substrate 34; the metal structure printed on the lower surface of the first dielectric substrate 23 and the third dielectric substrate 43 has almost no effect on the radiation.

[0042] like Figure 7 As shown, in this embodiment of the invention, the high-frequency antenna 5 uses 2 The placement of 2 is around the low-frequency antenna 1.

[0043] like Figure 6 As shown in (a), the high-frequency antenna 5 includes a fourth dielectric substrate 53 and a fifth dielectric substrate 54, with the fifth dielectric substrate 54 located above the fourth dielectric substrate 51; both the fourth dielectric substrate 53 and the fifth dielectric substrate 54 are fixed above the floor 6 by the second support column 12.

[0044] The fourth dielectric substrate 53 has a rectangular radiating patch 51 printed on its lower surface. Each of the four vertices of the rectangular radiating patch 51 has a second triangular chamfer 563, and each side of the rectangular radiating patch 51 has a first rectangular slit 55 at its midpoint. The fifth dielectric substrate 54 has a rectangular parasitic patch 52 printed on its lower surface. Each of the four vertices of the rectangular parasitic patch has a first triangular chamfer 521, and each of its four sides has a second rectangular slit 522.

[0045] like Figure 6 As shown in (b), the high-frequency antenna 5 further includes a first feed group 56 and a second feed group 57 printed on the upper surface of the fourth dielectric substrate 54. Both feed groups feed the rectangular radiating patch 51 through differential feeding to achieve dual-polarized radiation effect. The first feed group 56 includes two identical first bent feed wires 561 and second bent feed wires 562. The second feed group 57 has the same structure as the first feed group 56, including two identical third bent feed wires 571 and fourth bent feed wires 572. The first feed group 56 is equipped with a first feed coaxial line group 58, and the second feed group 57 is equipped with a second feed coaxial line group 59. The first feed coaxial line group 58 includes a third coaxial line 581 and a fourth coaxial line 582, and the second feed coaxial line group 59 includes a fifth coaxial line 591 and a sixth coaxial line 592. The first bent feeder 561 and the second bent feeder 562 transfer energy from the third coaxial cable 581 and the fourth coaxial cable 582 to the rectangular radiating patch 51 through coupling. The third coaxial cable 584 and the fourth coaxial cable 582 have the same amplitude of power excitation but opposite phase. The third bent feeder 571 and the fourth bent feeder 572 transfer energy from the fifth coaxial cable 591 and the sixth coaxial cable 592 to the rectangular radiating patch 51 through coupling. The fifth coaxial cable 591 and the sixth coaxial cable 592 have the same amplitude of power excitation but opposite phase.

[0046] Preferably, the dielectric constant of the fourth dielectric substrate 53 and the fifth dielectric substrate 54 is 4.4, the electrical loss is 0.02, and the thickness is 0.8 mm.

[0047] Example 2: This embodiment provides a broadband common-aperture base station array antenna based on a composite wave-transparent structure, such as... Figure 9 As shown, this is a dual-frequency dual-polarization broadband common-aperture base station array antenna. In this embodiment, it includes one high-frequency antenna and a low-frequency antenna that is completely placed above the high-frequency antenna. The high-frequency antenna and the low-frequency antenna are stacked. The low-frequency antenna and the broadband high-frequency antenna based on the composite wave-transparent structure in the array are completely the same as in Embodiment 1. Their feeding structure passes through the middle of the high-frequency antenna and does not affect any radiation performance of the high-frequency antenna.

[0048] The dual-band common-aperture base station array antenna proposed in this invention does not carry any circuit components. The additional isolation surface consists only of a dielectric substrate and the metal etched on it, which can achieve stable operation of wide-band radiation pattern.

[0049] This invention avoids the use of high dielectric constant substrates, complex 3D resonant structures, expanded array spacing, and stacked arrangements. It achieves the design of a broadband common-aperture base station array antenna without increasing processing costs, difficulty, array size, or cross-section. The radiation pattern is stable in the high-frequency broadband range, and the matching between low-frequency and high-frequency antennas is good.

[0050] The effects of this invention can be further illustrated by the following simulations: I. Simulation Software: Commercial Ansoft HFSS 19.2 software.

[0051] II. Simulation Content: Simulation 1: like Figure 8 (a) As stated in the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 1.7 GHz... Figure 7 Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0052] Depend on Figure 8 (a) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is distorted in the axial direction, the gain is reduced, and the beamwidth is narrowed in the range of 0-30°; while when the low-frequency antenna is improved to generate a composite structure with broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as that of the only high-frequency unit, and no obvious distortion occurs.

[0053] Simulation 2: like Figure 8 (b) As stated, when the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 1.9 GHz... Figure 7Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0054] Depend on Figure 8 (b) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is distorted in the axial direction. Within ±30°, the gain and beamwidth are both degraded. However, when the low-frequency antenna is improved to produce a composite structure with broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as that of the unit with only high-frequency unit, and no obvious distortion occurs.

[0055] Simulation 3: like Figure 8 (c) As stated, when the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 2.1 GHz... Figure 7 Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0056] Depend on Figure 8 (c) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is significantly distorted in the axial direction, and the gain is significantly reduced by more than 3dBi; while when the low-frequency antenna is improved to generate a composite structure with broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as that of the unit with only high-frequency unit, and no significant distortion occurs.

[0057] Simulation 4: like Figure 8 (d) As stated, when the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 2.3 GHz... Figure 7Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0058] Depend on Figure 8 (d) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is severely suppressed in the axial direction, the radiation pattern is severely degraded, the gain is reduced, and the drop exceeds 5dBi; while when the low-frequency antenna is improved to generate a composite structure with broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as the radiation pattern when there is only a high-frequency unit, and no obvious distortion occurs.

[0059] Simulation 5: like Figure 8 As stated in (e), when the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 2.5 GHz... Figure 7 Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0060] Depend on Figure 8 (e) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is significantly distorted in the axial direction, and the radiation pattern is severely deteriorated within the range of ±30°. Although the axial gain is reduced less, the beamwidth is significantly reduced. However, when the low-frequency antenna is improved to generate a composite structure with broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as that of the unit with only high-frequency unit, and no significant distortion occurs.

[0061] Simulation 6: like Figure 8 (f) As stated in the description, when the azimuth angle φ = 0° and 90°, pitch angle θ When the angle is 0° to 360°, for the high-frequency antenna in this invention, at 2.7 GHz... Figure 7 Ports 3 and 4 are differentially fed under different conditions, including: 1. the radiation pattern of the high-frequency antenna array under the proposed broadband high-frequency electromagnetic transparent low-frequency antenna based on a composite wave-transparent structure; 2. the radiation pattern of the high-frequency element under a conventional low-frequency element, wherein the radiation structure of the low-frequency antenna is not modified in any way, consisting of a rectangular patch, and no additional electromagnetic surface is introduced; 3. the radiation pattern with only the high-frequency element. The dimensions of the conventional low-frequency antenna are the same as those of the low-frequency antenna in this invention.

[0062] Depend on Figure 8 (f) It can be seen that the radiation pattern of the high-frequency unit under the traditional low-frequency unit is significantly distorted in the axial direction, and the axial gain is reduced by more than 3 dBi; while when the low-frequency antenna is improved into a composite structure that generates broadband electromagnetic transparency at high frequency, the radiation pattern of the high-frequency unit is almost the same as that of the unit with only high-frequency unit, and no significant distortion occurs.

[0063] Figure 10 (a) is a schematic diagram of the blocking effect of traditional common aperture base station array antennas. If the overall array profile height is not increased and the antennas of each frequency band are placed on a common reflector floor, the low frequency antenna will generate secondary radiation under the excitation of the surrounding broadband high frequency antennas, resulting in a more serious blocking effect.

[0064] Figure 10 (b) is a schematic diagram of the operation of the broadband common aperture base station array antenna based on the composite transparent structure of the present invention. The multi-layer composite electromagnetic transparent structure is introduced into the design of the low frequency antenna to form a broadband transparent electromagnetic window for the high frequency antenna, reducing the blocking effect and thus realizing the normal radiation of the high frequency antenna.

[0065] Figure 11 The S-parameters of the broadband composite electromagnetic transparent structure of this invention are as follows: within the range of 1.7-2.7 GHz, the transmission coefficient is greater than -0.9 dB, which achieves good wave transmission effect and reduces the blocking effect of low-frequency antenna radiating patches.

[0066] The above descriptions are merely two embodiments of the present invention and do 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 construed 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 broadband common-aperture base station antenna array based on a composite wave-transparent structure, characterized in that, It includes a low-frequency antenna (1), a high-frequency antenna (5) and a metal ground plane (6), wherein the low-frequency antenna (1) is located above the high-frequency antenna, and the orthographic projection of the low-frequency antenna (1) and the orthographic projection of the high-frequency antenna (5) partially or completely overlap on the metal ground plane (6); The low-frequency antenna (1) is composed of a three-layer composite wave-transparent structure. When high-frequency electromagnetic waves irradiate the composite wave-transparent structure of the low-frequency antenna (1), the composite wave-transparent structure is excited and a hybrid wave-transparent structure is formed. The hybrid wave-transparent structure can introduce two or more resonant points, thereby introducing a broadband transmission window to suppress the blocking effect of the low-frequency antenna (1) on the high-frequency antenna (5). The low-frequency antenna (1) includes a first electromagnetic surface (2), a second electromagnetic surface (3), and a third electromagnetic surface (4) from top to bottom. The first electromagnetic surface (2), the second electromagnetic surface (3), and the third electromagnetic surface (4) are separated by air layers with equal spacing. The second electromagnetic surface (3) is the radiating structure of the low-frequency antenna (1). The first electromagnetic surface (2) includes a first dielectric substrate (23) and a first metal square ring (21) printed on the lower surface of the first dielectric substrate (23), wherein the first metal square ring (21) is arranged in an array to form a first array (22). The second electromagnetic surface (3) includes a second dielectric substrate (34) and a composite metal structure (31) printed on the lower surface of the second dielectric substrate (34). The composite metal structure (31) is arranged in an array to form a second array (35). Two diagonally opposite second arrays (35) respectively form a first square ring radiation group (36) and a second square ring radiation group (37) to achieve ±45º polarization radiation function. The composite metal structure (31) includes a square metal frame (32) and a Yale-Salem tortuous strip (33), wherein the Yale-Salem tortuous strip (33) is located inside the square metal frame (32), and the two Yale-Salem tortuous strips (33) are distributed in a cross-shaped manner. The upper surface of the second dielectric substrate (34) is printed with intersecting first bifurcated coupling metal strips (8) and second bifurcated coupling metal strips (9). The first bifurcated coupling metal strip (8) transfers the energy in the first coaxial line (10) to the low-frequency first square ring radiation group (36) through coupling. The second bifurcated coupling metal strip (9) transfers the energy in the second coaxial line (11) to the second square ring radiation group (37) through coupling. One end of the first coaxial line (10) is connected to the coupling metal strip of the first bifurcated coupling metal strip (8), and one end of the second coaxial line (11) is connected to the second bifurcated coupling metal strip (9). The other end of the first coaxial line (10) and the other end of the second coaxial line (11) pass through the metal ground plane (6) to connect to the feed terminal. The third electromagnetic surface (4) includes a first dielectric substrate (43) and a second metal square ring (41) printed on the lower surface of the third dielectric substrate (43), wherein the second metal square ring (41) forms a third array (42) in an array arrangement.

2. The broadband common-aperture base station antenna array based on a composite wave-transparent structure according to claim 1, characterized in that, The high-frequency antenna (5) can be single or multiple. When it is a single high-frequency antenna (5), it is placed directly below the low-frequency antenna (1), and the orthographic projection of the low-frequency antenna (1) and the orthographic projection of the high-frequency antenna (5) completely overlap on the metal floor (6). When it is an array composed of multiple high-frequency antennas (5), the low-frequency antenna (1) and the high-frequency antenna (5) are arranged alternately, and the orthographic projection of the low-frequency antenna (1) and the orthographic projection of the high-frequency antenna (5) partially overlap on the metal floor (6).

3. The broadband common-aperture base station antenna array based on a composite wave-transparent structure according to claim 2, characterized in that, The high-frequency antenna (5) includes a fourth dielectric substrate (53) and a fifth dielectric substrate (54), with the fifth dielectric substrate (54) located above the fourth dielectric substrate (53); wherein, a rectangular radiating patch (51) is printed on the lower surface of the fourth dielectric substrate (53), and a rectangular parasitic patch (52) is printed on the lower surface of the fifth dielectric substrate (54).

4. The broadband common-aperture base station antenna array based on a composite wave-transparent structure according to claim 3, characterized in that, The high-frequency antenna (5) also includes a first feed group (56) and a second feed group (57) printed on the upper surface of the fourth dielectric substrate (54). Both feed structures feed the rectangular radiating patch (51) through differential feeding to achieve dual-polarized radiation effect. The first feed group (56) and the fourth feed group (57) each contain two identical bent feed structures. The first bent feed wire (561) and the second bent feed wire (562) contained in the first feed group (56) are coupled to the third coaxial line (581) and the fourth coaxial line (581). The energy in the axis (582) is transferred to the rectangular radiating patch (51). The amplitude of the power excitation in the third coaxial line (581) and the fourth coaxial line (582) is the same, but the phase is opposite. The third bent feeder (571) and the fourth bent feeder (572) included in the second feeder group (57) transfer the energy in the fifth coaxial line (591) and the sixth coaxial line (592) to the rectangular radiating patch (51) through coupling. The amplitude of the power excitation in the fifth coaxial line (591) and the sixth coaxial line (592) is the same, but the phase is opposite.

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