High-isolation broadband base station common-caliber antenna array

Abstract

A high-isolation broadband base station common-caliber antenna array comprises a metal floor, a high-frequency antenna array, a frequency selection surface layer and a low-frequency antenna which are sequentially arranged from bottom to top. The metal floor plays a supporting role, the high-frequency antenna array is responsible for high-frequency-band radiation of the antenna array, the frequency selection surface layer enables the low-frequency antenna and the high-frequency antenna array to be in electromagnetic isolation, and the low-frequency antenna is responsible for low-frequency-band radiation of the antenna array; a suppression structure is loaded on the low-frequency antenna, the frequency selection surface layer is composed of M1 * N1 identical frequency selection units, the frequency selection units broaden the wave transmission bandwidth in a mode that double PLC resonance structures are connected in series, equivalent capacitors are connected to the two sides of the double PLC resonance structures in series, and the reflection frequency band of the frequency selection surface layer is regulated and controlled to cover the working frequency band of the low-frequency antenna. The high-frequency antenna array is composed of M2 * N2 identical high-frequency antenna units; according to the invention, the broadband electromagnetic transparent design of the low-frequency antenna is realized; electromagnetic isolation between the low-frequency antenna and the high-frequency antenna is improved by introducing the frequency selective surface, and array modularization is achieved.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to a common aperture antenna array for a high-isolation broadband base station. Background Technology

[0002] A common-aperture antenna refers to an antenna that combines antennas operating in different frequency bands. This is achieved through methods such as a reasonable layout or special design of different antenna elements, allowing them to share the same radiating aperture. Compared to installing antennas for each frequency band independently, this method can greatly save space resources, making the antenna array extremely compact.

[0003] In existing interlaced common aperture antenna arrays, the transmission frequency band of low-frequency antennas to high-frequency antennas is relatively narrow, which cannot meet the requirements of communication systems for operating frequency. In order to achieve electromagnetic transparency, filter structures are often etched on the low-frequency antenna arms to improve the transmission effect of low-frequency antennas, but this will deteriorate the matching of the low-frequency antenna itself and seriously affect its radiation performance.

[0004] Patent application CN114725698A discloses a broadband transparent low-frequency antenna. This low-frequency antenna achieves electromagnetic transparency in the 3.4-5 GHz range (47% bandwidth) by loading dielectric blocks on both sides of the low-frequency radiator. However, this method increases the manufacturing cost of the antenna and worsens the impedance matching of the low-frequency antenna.

[0005] Patent application CN119447830A discloses a frequency selective surface element with large-angle stability. This frequency selective surface exhibits reflection characteristics in the low-frequency band and transmission characteristics in the high-frequency band through slot line resonance. However, this method increases the parabolic height of the antenna system, and the transmission bandwidth cannot meet the requirements of modern multi-communication systems coexisting. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention addresses the issues of widening the operating bandwidth of a common-aperture antenna array and decoupling between high- and low-frequency antennas. It provides a high-isolation broadband common-aperture antenna array for base stations. By loading a suppression structure onto the low-frequency antenna, broadband electromagnetic transparency of the low-frequency antenna is achieved without affecting its matching. Furthermore, utilizing a dual-PLC resonant structure, a frequency-selective surface is proposed. Compared to a single-PLC structure, the dual-PLC resonant structure, connected in series, widens the transmission bandwidth without changing its resonant frequency. This frequency-selective surface exhibits reflective characteristics in the low-frequency band and can serve as a reflective ground plane for the low-frequency antenna, improving the inter-frequency isolation between the low-frequency antenna and the high- and low-frequency antennas.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-isolation broadband base station common-aperture antenna array includes, from bottom to top, a metal ground plane 4, a high-frequency antenna array 3, a frequency selective surface layer 2, and a low-frequency antenna 1. The metal ground plane 4 is located at the bottom of the antenna array and serves as a support. The high-frequency antenna array 3 is located above the metal ground plane 4 to achieve high-frequency radiation. The frequency selective surface layer 2 is located above the high-frequency antenna array 3 and is used to electromagnetically isolate the low-frequency antenna 1 from the high-frequency antenna array 3. The low-frequency antenna 1 is located at the top of the antenna array to achieve low-frequency radiation. The low-frequency antenna 1 is equipped with a suppression structure. The frequency selective surface layer 2 is composed of M1 × N1 identical frequency selective units 5. The frequency selective units 5 broaden the transmission bandwidth through a series connection of dual PLC resonant structures, and equivalent capacitors are connected in series on both sides of the dual PLC resonant structures to control the reflection frequency band of the frequency selective surface layer 2 to cover the operating frequency band of the low-frequency antenna 1. The high-frequency antenna array 3 is composed of M2 × N2 identical high-frequency antenna elements 6.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The low-frequency antenna 1 proposed in this invention designs the low-frequency antenna arm 113 as a structure with multiple suppression units arranged end to end. While not affecting the matching of the low-frequency antenna, it changes the propagation path of the scattered current on the low-frequency antenna arm 113, so that the radiated electric field in the far field region of the scattered current cancels out, thereby realizing the broadband electromagnetic transparency characteristics of the low-frequency antenna. The suppression unit maintains the original radiation current characteristics of the low-frequency antenna 1 while suppressing scattering, thereby achieving good port matching of the low-frequency antenna 1.

[0009] 2. The dual PLC resonant structure on the back of the horizontal dielectric substrate of the frequency selection unit proposed in this invention achieves high-frequency transmission characteristics. The single PLC structure can be equivalent to a capacitor-inductor parallel circuit. When the capacitor and inductor resonate in parallel, it can be equivalent to an open circuit. The dual PLC structure is connected in series, which further expands the filtering bandwidth without changing its resonant frequency.

[0010] 3. The first frequency selection unit 5a proposed in this invention provides a parallel plate capacitance component through the overlapping portion of the top metal sheet 53 and the first dual PLC resonant structure 52a, thereby achieving miniaturization of the frequency selection surface. The reflection band of this frequency selection unit can be adjusted by regulating the size of the overlapping portion. The second frequency selection unit 5b and the third frequency selection unit 5c can respectively adjust the reflection band by changing the sizes of the first interdigitated capacitor 56 and the parallel plate capacitor 57.

[0011] 4. The PLC resonant structure of the present invention has high integration. By changing the size of the distributed inductor structure 5211a and the distributed capacitor structure 5212a or the toggle inductor 5211b and the second cross-toe capacitor 5212b, the reflection and transmission bandwidth of the frequency selection unit 5 can be adjusted.

[0012] 5. The frequency-selective surface layer 2 proposed in this invention has low-frequency reflection and high-frequency transmission characteristics. While not affecting the radiation of the high-frequency antenna array 3, it serves as a reflective ground plane for the low-frequency antenna 1. This improves the port isolation between the low- and high-frequency antennas and also enables modularity of the base station system.

[0013] 6. The low-frequency antenna 1 and the frequency selective surface layer 2 of this invention are designed as a high-frequency electromagnetically transparent structure. When the electromagnetic waves from the high-frequency antenna array 3 below irradiate the low-frequency antenna 1 and the frequency selective surface layer 2, electromagnetic transmission characteristics are achieved, allowing the high-frequency electromagnetic waves to radiate normally. The frequency selective surface layer 2 exhibits electromagnetic reflection properties in the low-frequency band, which can reflect the electromagnetic waves irradiated below by the low-frequency antenna 1, thereby achieving electromagnetic isolation between the low-frequency antenna 1 and the high-frequency antenna array 3.

[0014] In summary, this invention proposes a high-isolation broadband base station common-aperture antenna array. By introducing a suppression unit 112 into the low-frequency antenna 1, the propagation path of the scattered current is altered, causing adjacent currents to have opposite phases and cancel each other out in the far field, thus achieving broadband electromagnetic transparency and low scattering characteristics for the low-frequency antenna 1. Simultaneously, the frequency-selective surface layer 2 employs a dual-PLC resonant structure and a capacitive structure in series design, achieving low-frequency reflection and high-frequency transmission, with the reflection and transmission bandwidth adjustable through structural parameters. Without affecting the normal radiation of the high-frequency antenna array 3, this frequency-selective surface layer 2 serves as the reflector ground plane for the low-frequency antenna 1, improving the isolation between the low- and high-frequency antennas and the system integration. Attached Figure Description

[0015] Figure 1 This is an exploded view of the common-aperture antenna array for the high-isolation broadband base station of the present invention.

[0016] Figure 2(a) is a schematic diagram of the overall structure of the low-frequency antenna 1 of the present invention.

[0017] Figure 2(b) is a schematic diagram of the structure of the first type of suppression unit 112a of the low-frequency antenna 1 of the present invention.

[0018] Figure 2(c) is a schematic diagram of the structure and included angle of the low-frequency antenna arm 113 of the low-frequency antenna 1 of the present invention.

[0019] Figure 3 This is the port matching diagram of the low-frequency antenna of the present invention.

[0020] Figure 4(a) is a schematic diagram of the overall structure of the first frequency selection unit 5a of the present invention.

[0021] Figure 4(b) is a schematic diagram of the structure and dimensions of the first dual PLC resonant structure 52a of the first frequency selection unit 5a of the present invention.

[0022] Figure 4(c) is a schematic diagram of the structure and dimensions of the top metal sheet 53 of the first frequency selection unit 5a of the present invention.

[0023] Figure 5 This is a simulation diagram of the S-parameters of the first frequency selection unit 5a of the present invention.

[0024] Figure 6(a) is an overall schematic diagram of the high-frequency antenna unit 6 of the present invention.

[0025] Figure 6(b) is a schematic diagram of the structure of the first high-frequency antenna arm 6121 of the high-frequency antenna unit 6 of the present invention.

[0026] Figure 6(c) is a schematic diagram of the structure of the first vertical substrate 621 of the high-frequency antenna unit 6 of the present invention.

[0027] Figure 6(d) is a schematic diagram of the structure of the second vertical substrate 624 of the high-frequency antenna unit 6 of the present invention; Figure 7 This is a matching simulation diagram of the high-frequency antenna element 6 of the present invention.

[0028] Figure 8(a) is an array diagram of the high-frequency antenna array 3 and the metal ground plane 4 of the present invention.

[0029] Figure 8(b) is an array diagram of the frequency selective surface layer 2, high-frequency antenna array 3 and metal ground plane 4 of the present invention.

[0030] Figure 9(a) is the radiation pattern at 1.6 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0031] Figure 9(b) is the radiation pattern of 2.4 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0032] Figure 9(c) is the radiation pattern at 3.2 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0033] Figure 10(a) is the radiation pattern at 1.6 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0034] Figure 10(b) is the radiation pattern of 2.4 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0035] Figure 10(c) is the radiation pattern at 3.2 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0036] Figure 11(a) is the radiation pattern at 1.6 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0037] Figure 11(b) is the radiation pattern of 2.4 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0038] Figure 11(c) is the radiation pattern at 3.2 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 2 of the present invention.

[0039] Figure 12(a) is the radiation pattern at 1.6 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0040] Figure 12(b) is the radiation pattern of 2.4 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0041] Figure 12(c) is the radiation pattern at 3.2 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 2 of the present invention.

[0042] Figure 13(a) is a schematic diagram of the low-frequency antenna 1 of the present invention connected to the metal ground plate 4.

[0043] Figure 13(b) is a schematic diagram of the low-frequency antenna 1 and the frequency selective surface layer 2 of the present invention connected together.

[0044] Figure 14 This is a matching simulation diagram of the low-frequency antenna 1 in Embodiment 3 of the present invention.

[0045] Figure 15(a) is the radiation pattern of the low-frequency antenna 1 in Embodiment 3 of the present invention when the azimuth angle φ = 0°.

[0046] Figure 15(b) is the radiation pattern of the low-frequency antenna 1 in Embodiment 3 of the present invention when the azimuth angle φ = 90°.

[0047] Figure 16(a) is the radiation pattern at 1.6 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0048] Figure 16(b) is the radiation pattern at 2.4 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0049] Figure 16(c) is the radiation pattern at 3.2 GHz when the feed port is Port 1 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0050] Figure 17(a) is the radiation pattern at 1.6 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 1 of the present invention.

[0051] Figure 17(b) is the radiation pattern of 2.4 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 1 of the present invention.

[0052] Figure 17(c) is the radiation pattern at 3.2 GHz when the feed port is Port 1 and the azimuth angle φ = 90° in Embodiment 1 of the present invention.

[0053] Figure 18(a) is the radiation pattern at 1.6 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0054] Figure 18(b) is the radiation pattern at 2.4 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0055] Figure 18(c) is the radiation pattern at 3.2 GHz when the feed port is Port 2 and the azimuth angle φ = 0° in Embodiment 1 of the present invention.

[0056] Figure 19(a) is the radiation pattern at 1.6 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 3 of the present invention.

[0057] Figure 19(b) is the radiation pattern of 2.4 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 3 of the present invention.

[0058] Figure 19(c) is the radiation pattern at 3.2 GHz when the feed port is Port 2 and the azimuth angle φ = 90° in Embodiment 3 of the present invention.

[0059] Figure 20 This is an array diagram consisting of the low-frequency antenna 1, the high-frequency antenna array 3, and the metal ground plane 4 of the present invention.

[0060] Figure 21 These are simulation diagrams of low-frequency port isolation in Embodiments 1 and 4 of the present invention.

[0061] Figure 22(a) shows the alternative structure of the second suppression unit 112b of the present invention using a wavy microstrip line.

[0062] Figure 22(b) shows the alternative structure of the third suppression unit 112c of the present invention, which uses a sawtooth microstrip line.

[0063] Figure 23 This is a schematic diagram of an alternative structure to the first PLC resonant structure 521a of the present invention.

[0064] Figure 24(a) shows the alternative structure of the second frequency selection unit 5b of the present invention, which uses a cross-toe capacitor 56.

[0065] Figure 24(b) shows the alternative structure of the third frequency selection unit 5c of the present invention, which uses a parallel plate capacitor 57.

[0066] Reference numerals: Low-frequency antenna 1; Low-frequency radiating structure 11; Low-frequency radiating substrate 111; Suppression unit 112; First suppression unit 112a; Second suppression unit 112b; Third suppression unit 112c; First center line 1121a; Second center line 1121b; Third center line 1121c; First left bend line 1122a; Second left bend line 1122b; Third left bend line 1122c; First right bend line 1123a; Second right bend line 1123b; Third right bend line 1123c; Low-frequency antenna arm 113; First connecting line 1131; Left first suppression unit 1132; Left second suppression unit 1133; Left Third suppression unit 1134; left fourth suppression unit 1135; right first suppression unit 1136; right second suppression unit 1137; right third suppression unit 1138; right fourth suppression unit 1139; and second connecting line 11310; low-frequency feeding structure 12; first coaxial line 121; second coaxial line 122; first Y-shaped stub 123; second Y-shaped stub 124; frequency selective surface layer 2; high-frequency antenna array 3; metal ground plane 4; frequency selective unit 5; first type frequency selective unit 5a; second type frequency selective unit 5b; third type frequency selective unit 5c; first horizontal dielectric substrate 51a; second horizontal dielectric substrate 51b; first dual PLC resonant structure 52 a; Second dual PLC resonant structure 52b; First PLC resonant structure 521a; Distributed inductor structure 5211a; Horizontally distributed zigzag inductor 5211b; Distributed capacitor structure 5212a; Second cross-toe capacitor 5212b; Top metal plate 53; Inner first arrow-shaped metal plate 531; Inner second arrow-shaped metal plate 532; Inner third arrow-shaped metal plate 533; Inner fourth arrow-shaped metal plate 534; Outer first arrow-shaped metal plate 535; Outer second arrow-shaped metal plate 536; Outer third arrow-shaped metal plate 537; Outer fourth arrow-shaped metal plate 538; Rectangular metal patch 54; Isosceles right-angled triangular patch 55; First cross-toe capacitor 56; Parallel plate capacitor; 57; High-frequency antenna element; 6; High-frequency radiating structure; 61; High-frequency radiating substrate; 611; High-frequency antenna arm; 612; First high-frequency antenna arm; 6121; Second high-frequency antenna arm; 6122; Third high-frequency antenna arm; 6123; Fourth high-frequency antenna arm; 6124; High-frequency feeding structure; 62; First square metal; 61211; Second 1 / 4 metal square ring; 61212; Third 1 / 4 metal square ring; 61213; High-frequency feeding structure; 62; High-frequency radiating substrate; 611; First vertical substrate; 621; First microstrip line; 622; First metal backplate; 623; Second vertical substrate; 624; Second microstrip line; 625; Second metal backplate; 626. Detailed Implementation

[0067] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0068] like Figure 1 As shown, a high-isolation broadband base station common-aperture antenna array includes, from bottom to top, a metal ground plane 4, a high-frequency antenna array 3, a frequency selective surface layer 2, and a low-frequency antenna 1. The metal ground plane 4 is located at the bottom of the antenna array and serves as a support. The high-frequency antenna array 3 is located above the metal ground plane 4 to achieve high-frequency radiation. The frequency selective surface layer 2 is located above the high-frequency antenna array 3 and is used to electromagnetically isolate the low-frequency antenna 1 from the high-frequency antenna array 3. The low-frequency antenna 1 is located at the top of the antenna array to achieve low-frequency radiation. The low-frequency antenna 1 is loaded with a suppression structure. The frequency selective surface layer 2 is composed of M1 × N1 identical frequency selective units 5. The frequency selective units 5 are widened by connecting a dual PLC resonant structure in series, and an equivalent capacitor is connected in series on both sides of the dual PLC resonant structure to control the reflection frequency band of the frequency selective surface layer 2 to cover the operating frequency band of the low-frequency antenna 1. The high-frequency antenna array 3 is composed of M2 × N2 identical high-frequency antenna elements 6.

[0069] As shown in Figure 2(a), the low-frequency antenna 1 includes a low-frequency radiating structure 11, and a low-frequency feeding structure 12 is vertically connected to the bottom of the low-frequency radiating structure 11. The low-frequency radiation structure 11 includes a low-frequency radiation substrate 111 and four low-frequency antenna arms 113 printed on the back side of the low-frequency radiation substrate 111; the suppression structure includes four suppression units 112 printed on the front side of the low-frequency radiation substrate 111, and suppression units loaded on the four low-frequency antenna arms 113 on the back side of the low-frequency radiation substrate 111; the four suppression units 112 and the four low-frequency antenna arms 113 are all centrally symmetrically arranged on the low-frequency radiation substrate 111, and the four suppression units 112 are distributed sequentially at the middle of adjacent low-frequency antenna arms 113; The low-frequency radiation substrate 111 is a cross-shaped dielectric plate with a thickness of 0.8 mm, including an integrally formed central structure and four end structures. The suppression unit 112 includes three structures: a first suppression unit 112a, a first suppression unit 112b, and a first suppression unit 112c; wherein: As shown in Figure 2(b), each of the four first type of suppression units 112a is composed of a first center line 1121a and two first left bend lines 1122a and first right bend lines 1123a that are symmetrical about the first center line 1121a. The first left bend lines 1122a and first right bend lines 1123a are rectangular bend lines and are connected to the top of the first center line 1121a. The four first type of suppression units 112a are centrally symmetrical about the low-frequency radiation substrate 111. As shown in Figure 22(a), each of the four second type of suppression units 112b is composed of a second center line 1121b and two second left bend lines 1122b and a second right bend line 1123b that are symmetrical about the second center line 1121b. The second left bend lines 1122b and the second right bend lines 1123b are wavy microstrip lines and are connected to the top of the second center line 1121b. The four second type of suppression units 112b are centrally symmetrical about the low-frequency radiation substrate 111. As shown in Figure 22(b), each of the four third-type suppression units 112c is composed of a third center line 1121c and two third left-hand bend lines 1122c and a third right-hand bend line 1123c that are symmetrical about the third center line 1121c. The third left-hand bend line 1122c and the third right-hand bend line 1123c are sawtooth microstrip lines and are connected to the top of the third center line 1121c. The four third-type suppression units 112c are centrally symmetrical about the low-frequency radiation substrate 111.

[0070] As shown in Figure 2(c), all four low-frequency antenna arms 113 are rhomboid in shape and are each composed of a first connecting line 1131, a left first suppression unit 1132, a left second suppression unit 1133, a left third suppression unit 1134, a left fourth suppression unit 1135, a right first suppression unit 1136, a right second suppression unit 1137, a right third suppression unit 1138, a right fourth suppression unit 1139, and a second connecting line 11310. The first connecting line 1131 connects the tails of the left first suppression unit 1132 and the right first suppression unit 1136 at both ends, the head of the left first suppression unit 1132 connects to the tail of the left second suppression unit 1133, and the head of the left second suppression unit 1133 connects to the tail of the left third suppression unit 1136. The four tails are connected at an angle. The head of the left third suppression unit 1134 is connected to the tail of the left fourth suppression unit 1135, and the head of the left fourth suppression unit 1135 is connected to one end of the second connecting line 11310. The head of the right first suppression unit 1136 is connected to the tail of the right second suppression unit 1137, the head of the right second suppression unit 1137 is connected to the tail of the right third suppression unit 1138 at an angle, the head of the right third suppression unit 1138 is connected to the tail of the right fourth suppression unit 1139, and the head of the right fourth suppression unit 1139 is connected to the other end of the second connecting line 11310. The four low-frequency antenna arms 113 are distributed on the four end structures of the low-frequency radiation substrate 111 and are centrally symmetrical about the low-frequency radiation substrate 111. The angle between the head of the left second suppression unit 1133 and the tail of the left third suppression unit 1134 θ 1. And the angle between the head of the right second suppression unit 1137 and the tail of the right third suppression unit 1138. θ1. Both are set at an angle greater than 90 degrees; the angle between the tail of the left first suppression unit 1132 and the tail of the right first suppression unit 1136 θ 2. And the angle between the head of the left fourth suppression unit 1135 and the head of the right fourth suppression unit 1139. θ Both are set at an angle of less than 90 degrees.

[0071] The structures and dimensions of the left first suppression unit 1132, left second suppression unit 1133, left third suppression unit 1134, left fourth suppression unit 1135, right first suppression unit 1136, right second suppression unit 1137, right third suppression unit 1138, and right fourth suppression unit 1139 of the low-frequency antenna arm 113 are the same as those of the suppression unit 112.

[0072] The first connecting line 1131 is a V-shaped metal, and the second connecting line 11310 and the remaining connecting lines are all rectangular.

[0073] The low-frequency feeding structure 12 includes a first coaxial line 121, a second coaxial line 122, a first Y-shaped stub 123, and a second Y-shaped stub 124. The first Y-shaped stub 123 and the second Y-shaped stub 124 are printed on the front side of the low-frequency radiation substrate 111 and are orthogonally arranged between the suppression units 112. The first coaxial line 121 and the second coaxial line 122 stand parallel to each other on the metal floor 4. The lower ends of the first coaxial line 121 and the second coaxial line 122 are connected to the metal floor 4. The upper end of the first coaxial line 121 passes through the substrate and connects to the tail end of the first Y-shaped stub 123. The upper end of the second coaxial line 122 passes through the substrate and connects to the tail end of the second Y-shaped stub 124.

[0074] The frequency selection unit 5 includes three structures: a first frequency selection unit 5a, a second frequency selection unit 5b, and a third frequency selection unit 5c; wherein: As shown in Figure 4(a), the first type of frequency selection unit 5a includes a first horizontal dielectric substrate 51a, four first dual PLC resonant structures 52a are loaded on the back side of the first horizontal dielectric substrate 51a, and a top metal sheet 53 is printed on the front side of the first horizontal dielectric substrate 51a. As shown in Figure 4(b), the first dual PLC resonant structure 52a is distributed at the four corners of the back side of the first horizontal dielectric substrate 51a and is centrally symmetrical about the first horizontal dielectric substrate 51a; the first dual PLC resonant structure 52a is formed by two identical first PLC resonant structures 521a connected in series; the first PLC resonant structure 521a is formed by a distributed inductor structure 5211a composed of zigzag thin lines and a distributed capacitor structure 5212a composed of two parallel metal strips connected in parallel. As shown in Figure 4(c), the top metal sheet 53 includes an inner arrow-shaped metal sheet located at the center of the diagonal of the front side of the first horizontal dielectric substrate 51a and outer arrow-shaped metal sheets distributed at the four corners of the front side of the first horizontal dielectric substrate 51a, wherein: The inner arrow-shaped metal sheet includes an inner first arrow-shaped metal sheet 531, an inner second arrow-shaped metal sheet 532, an inner third arrow-shaped metal sheet 533, and an inner fourth arrow-shaped metal sheet 534 located at the center of the diagonal of the front side of the first horizontal dielectric substrate 51a. The inner arrow-shaped metal sheets have the same structure and size, and the arrows all point towards the center. The edges of the arrows are attached together to form a cross-shaped structure. The outer arrow-shaped metal sheet includes an outer first arrow-shaped metal sheet 535, an outer second arrow-shaped metal sheet 536, an outer third arrow-shaped metal sheet 537, and an outer fourth arrow-shaped metal sheet 538 distributed at the four corners of the front side of the first horizontal dielectric substrate 51a. The outer arrow-shaped metal sheets have the same structure and size, and the arrows all point outwards. The edges of the arrows are flush with the edges of the four corners of the first horizontal dielectric substrate 51a. The four first dual PLC resonant structures 52a are located between the inner and outer arrow-shaped metal sheets, respectively, and coincide with the tail end of the arrow-shaped metal sheets.

[0075] As shown in Figure 24(a), the second type of frequency selection unit 5b includes a second horizontal dielectric substrate 51b. A rectangular metal patch 54 is printed at the center of the second horizontal dielectric substrate 51b. Isosceles right-angled triangular metal patches 55 with the same structure and size are printed at the four corners of the second horizontal dielectric substrate 51b. The right-angled edges of the isosceles right-angled triangular metal patches 55 are flush with the edges of the four corners of the second horizontal dielectric substrate 51b. A second dual PLC resonant structure 52b is loaded between the rectangular metal patch 54 and the isosceles right-angled triangular patches 55. Both ends of the second dual PLC resonant structure 52b are connected to the rectangular metal patch 54 and the isosceles right-angled triangular patches 55 respectively through a first interdigitated capacitor 56. The second dual PLC resonant structure 52b, the rectangular metal patch 54, the four isosceles right-angled triangular metal patches 55 with the same structure and size, and the first interdigitated capacitor 56 are all located on the same side of the second horizontal dielectric substrate 51b. The second dual PLC resonant structure 52b has the same structure and size as the first dual PLC resonant structure 52a, and is centrally symmetrical about the second horizontal dielectric substrate 51b. The first interdigitated capacitor 56 consists of two sets of interlaced finger-shaped metal strips, with gaps between the two sets of finger-shaped metal strips that are not connected.

[0076] As shown in Figure 24(b), the first cross-toe capacitor 56 in the second type of frequency selection unit 5b is replaced with a parallel plate capacitor 57, while the rest of the structure remains unchanged, to form the third type of frequency selection unit 5c. The parallel plate capacitor 57 is composed of two adjacent rectangular metal patches with a narrow gap between their opposite edges. The two rectangular metal patches on the inner side are connected to the two ends of the second dual PLC resonant structure 52b, and the two rectangular metal patches on the outer side are connected to the rectangular metal patch 54 and the isosceles right-angled triangular patch 55, respectively.

[0077] like Figure 23 As shown, in the first PLC resonant structure 521a, the distributed inductor structure 5211a can be replaced by a horizontally distributed zigzag inductor 5211b; the distributed capacitor structure 5212a can be replaced by a cross-toe capacitor 5212b, and the horizontally distributed zigzag inductor 5211b is connected in parallel with the second cross-toe capacitor 5212b.

[0078] As shown in Figure 6(a), the high-frequency antenna unit 6 includes a high-frequency radiating structure 61, and a high-frequency feeding structure 62 is vertically connected to the bottom of the high-frequency radiating structure 61. The high-frequency radiating structure 61 includes a high-frequency radiating substrate 611 and high-frequency antenna arms 612 printed on the front side of the high-frequency radiating substrate 611. The high-frequency radiating arms 612 include a first high-frequency antenna arm 6121, a second high-frequency antenna arm 6122, a third high-frequency antenna arm 6123, and a fourth high-frequency antenna arm 6124, which are distributed sequentially at the four corners of the front side of the high-frequency radiating substrate 611. As shown in Figure 6(b), the first high-frequency antenna arm 6121 includes a first square metal 61211 arranged sequentially from the inside to the outside. The openings of the second 1 / 4 metal square ring 61212 and the third 1 / 4 metal square ring 61213, the first square metal 61211 and the second 1 / 4 metal square ring 61212 all face the first square metal 61211, and both ends are connected to the first square metal 61211; the first high-frequency antenna arm 6121, the second high-frequency antenna arm 6122, the third high-frequency antenna arm 6123 and the fourth high-frequency antenna arm 6124 have the same structure and size, and are symmetrical about the center of the high-frequency radiation substrate 611.

[0079] The high-frequency feeding structure 62 includes a first vertical substrate 621 and a second vertical substrate 624 perpendicular to the high-frequency radiation substrate 611. Both the first vertical substrate 621 and the second vertical substrate 624 are rectangular structures. As shown in Figure 6(c), the upper rectangular groove 6211 is provided at the upper end of the middle position of the first vertical substrate 621. The first metal back plate 623 is printed on both sides of the back of the first vertical substrate 621, and the first microstrip line 622 is printed on the front of the first vertical substrate 621. As shown in Figure 6(d), a lower rectangular groove 6241 is provided at the lower end of the middle position of the second vertical substrate 624, a second metal back plate 626 is printed on both sides of the back of the second vertical substrate 624, and a second microstrip line 625 is printed on the front of the second vertical substrate 624. The first vertical substrate 621 and the second vertical substrate 624 are placed orthogonally through the upper rectangular groove 6211 and the lower rectangular groove 6241 to form a cross structure. The upper ends of the first vertical substrate 621 and the second vertical substrate 624 are inserted into the high-frequency radiation substrate 611 to provide support. At the same time, the first metal back plate 623 is electrically connected to the first high-frequency antenna arm 6121 and the third high-frequency antenna arm 6123; the second metal back plate 626 is electrically connected to the second high-frequency antenna arm 6122 and the fourth high-frequency antenna arm 6124.

[0080] Furthermore, the length of the first left bend 1122a or the first right bend 1123a of each first type of suppression unit 112a cl1 ,width cw1 ,spacing cd1 The first type of suppression unit 112a at the center frequency of the transmission frequency band f h The decision is made. The working principle of the second suppression unit 112b and the third suppression unit 112c is the same as that of the first suppression unit 112a.

[0081] As shown in Figure 4(b), the length of the distributed inductor structure 5211a of each first PLC resonant structure 521a is... lcgl1 The center operating frequency of the antenna f l With the center frequency of the pass-through radio frequency band f h The length of the distributed capacitor structure 5212a of each first PLC resonant structure 521a is jointly determined; lcrl1 The center operating frequency of the antenna f l With the center frequency of the pass-through radio frequency band f h The overlap length between each first dual PLC resonant structure 52a and the top metal plate 53 is jointly determined; as shown in Figure 4(c), bml2 The center frequency of the reflection frequency of this frequency-selective surface f l The second dual PLC resonant structure 52b operates on the same principle as the first dual PLC resonant structure 52a. The gap size between the first interdigitated capacitor 56 and the parallel plate capacitor 57 is determined by the center operating frequency of the antenna. f l Decide.

[0082] Furthermore, the low-frequency antenna 1 is connected to the frequency-selective surface layer 2, which is located above the high-frequency antenna array 3, with a distance between them. f It is 20mm.

[0083] Example 1 Reference Figure 1Embodiment 1 of the present invention includes a low-frequency antenna 1, a frequency selective surface layer 2, a high-frequency antenna array 3, and a metal ground plane 4; wherein, the frequency selective surface layer 2 is located 20mm above the high-frequency antenna array 3, and the lower end of the low-frequency antenna 1 is connected to the frequency selective surface layer 2. The operating frequency band of the antenna array is 690-960MHz and 1.6-3.2GHz.

[0084] Example 2 Embodiment 2 of the present invention includes two types of antenna arrays as shown in Figure 8(a) and Figure 8(b). The array shown in Figure 8(a) is an array composed of a high-frequency antenna array 3 and a metal ground plane 4; the array shown in Figure 8(b) is an array composed of a frequency selective surface layer 2, a high-frequency antenna array 3, and a metal ground plane 4. Its dimensions are the same as those in Embodiment 1.

[0085] Example 3 Embodiment 3 of the present invention includes two types of low-frequency antennas 1 as shown in Figure 13(a) and Figure 13(b). In Figure 13(a), the lower end of the low-frequency antenna 1 is connected to the metal ground plane 4; in Figure 13(b), the lower end of the low-frequency antenna 1 is connected to the frequency selective surface layer 2. The size of the metal ground plane 4 is the same as that of the frequency selective surface layer 2.

[0086] Example 4 Embodiment 4 of the present invention includes an array consisting of a low-frequency antenna 1, a high-frequency antenna array 3, and a metal ground plane 4, the structure of which is as follows: Figure 20 As shown; the lower end of the low-frequency antenna 1 is connected to the metal ground plate 4, and its size is the same as that in Embodiment 1.

[0087] Example 5 Embodiment 5 of the present invention is an electromagnetic simulation of the first frequency unit 5a when electromagnetic waves are incident perpendicularly.

[0088] Simulation 1: A simulation was performed on the low-frequency antenna 1 in Embodiment 1 of the present invention. The simulation results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the operating frequency band of the low-frequency antenna dual-port is 690~960MHz.

[0089] Simulation 2, when the incident angle θ When the angle is 0°, a simulation was performed on the first frequency selection unit 5a of Embodiment 5 of the present invention, and the simulation results are as follows: Figure 5 As shown, when incident at 0°, the frequency-selective surface can cover the transmission frequency band of TE and TM waves from 1.6 to 3.2 GHz, and the reflection frequency band from 0.69 to 0.96 GHz.

[0090] Simulation 3: The high-frequency antenna element in Embodiment 1 of this invention was simulated, and the simulation results are as follows. Figure 7 As shown. From Figure 7It can be seen that the operating frequency band of the dual-port high-frequency antenna is 1.6~3.2GHz.

[0091] Simulation 4, when the power supply port is Port 1, azimuth angle φ When the angle is 0°, simulation of Example 2 is performed, and the simulation results are as follows: Figures 9(a)-9(c) As shown, the solid line is the array radiation pattern in Figure 8(b), and the dashed line is the array radiation pattern in Figure 8(a). Figures 9(a)-9(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.4 dB, the beamwidth difference is within 5°, and the beamwidth at all frequency points is maintained above 60°. This shows that the designed frequency selection surface layer 2 exhibits good transmission characteristics for the high-frequency antenna array 3.

[0092] Simulation 5, when the feed port is Port 1, azimuth angle φ When the angle is 90°, simulation of Example 2 is performed, and the simulation results are as follows: Figures 10(a)-10(c) As shown, the solid line is the array radiation pattern in Figure 8(b), and the dashed line is the array radiation pattern in Figure 8(a). Figures 10(a)-10(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.4 dB and the beamwidth difference is within 8°. This shows that the designed frequency selection surface layer 2 exhibits good transmission characteristics for the high-frequency antenna array 3.

[0093] Simulation 6, when the feed port is Port 2, azimuth angle φ When the angle is 0°, simulation of Example 2 is performed, and the simulation results are as follows: Figures 11(a)-11(c) As shown, the solid line is the array radiation pattern in Figure 8(b), and the dashed line is the array radiation pattern in Figure 8(a). Figures 11(a)-11(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.2 dB, the beamwidth difference is within 8°, and the beamwidth at all frequency points is maintained above 60°. This shows that the designed frequency selection surface layer 2 exhibits good transmission characteristics for the high-frequency antenna array 3.

[0094] Simulation 7, when the power supply port is Port 1, azimuth angle φ When the angle is 90°, simulation of Example 2 is performed, and the simulation results are as follows: Figures 12(a)-12(c) As shown, the solid line is the array radiation pattern in Figure 8(b), and the dashed line is the array radiation pattern in Figure 8(a). Figures 12(a)-12(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.4 dB and the beamwidth difference is within 8°. This shows that the designed frequency selection surface layer 2 exhibits good transmission characteristics for the high-frequency antenna array 3.

[0095] Simulation 8 simulated the two low-frequency antenna elements in Embodiment 3 of the present invention. The simulation results are as follows: Figure 14 As shown in Figures 15(a) and 15(b). From Figure 14 It can be seen from Figures 15(a) and 15(b) that the low-frequency antenna 1, which uses the frequency-selective surface layer 2 as a reflector, can achieve good radiation, with the gain maintained above 7dBi and the beamwidth above 70° within the frequency band.

[0096] Simulation 9, when the power supply port is Port 1, azimuth angle φ At 0°, the antenna array in Embodiment 1 of the present invention was simulated, and the simulation results are as follows: Figures 16(a)-16(c) As shown, the solid line is the array radiation pattern in Example 1, and the dashed line is the array radiation pattern in Figure 8(b). Figures 16(a)-16(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.6 dB and the beamwidth difference is within 8°, indicating that the designed low-frequency antenna 1 exhibits good transmission characteristics to the high-frequency antenna array 3.

[0097] Simulation 10, when the feed port is Port 1, azimuth angle φ At a radius of 90°, the antenna array in Embodiment 1 of this invention was simulated, and the simulation results are as follows: Figures 17(a)-17(c) As shown, the solid line is the array radiation pattern in Example 1, and the dashed line is the array radiation pattern in Figure 8(b). Figures 17(a)-17(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.6 dB and the beamwidth difference is within 5°, indicating that the designed low-frequency antenna 1 exhibits good transmission characteristics to the high-frequency antenna array 3.

[0098] Simulation 11, when the power supply port is Port 2, azimuth angle φ At 0°, the antenna array in Embodiment 1 of the present invention was simulated, and the simulation results are as follows: Figures 18(a)-18(c)As shown, the solid line is the array radiation pattern in Example 1, and the dashed line is the array radiation pattern in Figure 8(b). Figures 18(a)-18(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.3 dB and the beamwidth difference is within 8°, indicating that the designed low-frequency antenna 1 exhibits good transmission characteristics to the high-frequency antenna array 3.

[0099] Simulation 12, when the power supply port is Port 2, azimuth angle φ At 90°, the antenna array in Embodiment 1 of the present invention was simulated, and the simulation results are as follows: Figures 19(a)-19(c) As shown, the solid line is the array radiation pattern in Example 1, and the dashed line is the array radiation pattern in Figure 8(b). Figures 19(a)-19(c) The radiation patterns of the two arrays at 1.6 GHz, 2.4 GHz and 3.2 GHz are given respectively. It can be seen that the two arrays achieve almost the same radiation performance. The gain difference of the two arrays at 0° is within 0.3 dB and the beamwidth difference is within 7°, indicating that the designed low-frequency antenna 1 exhibits good transmission characteristics to the high-frequency antenna array 3.

[0100] Simulation 13 simulated the antenna array in Embodiment 1 and the antenna array in Embodiment 4 of the present invention. The simulation results are as follows: Figure 21 As shown, the solid line represents the array radiation pattern in Example 1, and the dashed line represents the array radiation pattern in Example 4. From Figure 21 As can be seen from the data, in Example 1, the isolation between low-frequency ports is below -30dB, and can reach as low as -50dB; in Example 4, the isolation between low-frequency ports is above -25dB, and the frequency-selective surface layer 2 plays a good role in isolating the low-frequency antenna 1 and the high-frequency antenna array 3.

[0101] The application prospects of this invention are: With the advent of the 5G era in mobile communication, massive MIMO antennas have been applied. Simultaneously, 5G systems coexist with 2G, 3G, and 4G systems. The broadband common-aperture antenna array proposed in this invention can cover the operating frequency bands of 2G, 3G, 4G, and 5G, greatly improving the utilization rate of array space and showing promising application prospects in future base station antenna communication and other fields.

Claims

1. A common-aperture antenna array for a high-isolation broadband base station, characterized in that, The antenna array consists of a metal floor (4), a high-frequency antenna array (3), a frequency selective surface layer (2), and a low-frequency antenna (1), arranged from bottom to top. The metal floor (4) is located at the bottom of the antenna array and serves as a support. The high-frequency antenna array (3) is located above the metal floor (4) and enables high-frequency radiation of the antenna array. The frequency selective surface layer (2) is located above the high-frequency antenna array (3) and is used to electromagnetically isolate the low-frequency antenna (1) from the high-frequency antenna array (3). The low-frequency antenna (1) is located at the top of the antenna array and enables low-frequency radiation of the antenna array. The low-frequency antenna (1) is loaded with a suppression structure. The frequency selective surface layer (2) is composed of M1 × N1 identical frequency selective units (5). The frequency selective units (5) are connected in series through a dual PLC resonant structure to broaden the transmission bandwidth. An equivalent capacitor is connected in series on both sides of the dual PLC resonant structure to control the frequency selective surface layer (2) to cover the working frequency band of the low-frequency antenna (1). The high-frequency antenna array (3) is composed of M2 × N2 identical high-frequency antenna units (6).

2. The high-isolation broadband base station common-aperture antenna array according to claim 1, characterized in that, The low-frequency antenna (1) includes a low-frequency radiating structure (11), and a low-frequency feeding structure (12) is vertically connected to the bottom of the low-frequency radiating structure (11). The low-frequency radiation structure (11) includes a low-frequency radiation substrate (111) and four low-frequency antenna arms (113) printed on the back side of the low-frequency radiation substrate (111); the suppression structure includes four suppression units (112) printed on the front side of the low-frequency radiation substrate (111) and suppression units loaded on the four low-frequency antenna arms (113) on the back side of the low-frequency radiation substrate (111). The four suppression units (112) and the four low-frequency antenna arms (113) are all located on the low-frequency radiation substrate (111) and arranged in a centrally symmetrical manner. The four suppression units (112) are distributed in the middle of adjacent low-frequency antenna arms (113). The low-frequency feeding structure (12) includes a first coaxial line (121), a second coaxial line (122), a first Y-shaped stub (123), and a second Y-shaped stub (124). The first Y-shaped stub (123) and the second Y-shaped stub (124) are printed on the front side of the low-frequency radiation substrate (111) and orthogonally arranged between the suppression units (112). The first coaxial line (121) and the second coaxial line (122) stand parallel to each other on the metal floor (4). The lower ends of the first coaxial line (121) and the second coaxial line (122) are connected to the metal floor (4). The upper end of the first coaxial line (121) passes through the substrate and connects to the tail end of the first Y-shaped stub (123). The upper end of the second coaxial line (122) passes through the substrate and connects to the tail end of the second Y-shaped stub (124).

3. The high-isolation broadband base station common-aperture antenna array according to claim 1, characterized in that, The frequency selection unit (5) includes a first type of frequency selection unit (5a), which includes a first horizontal dielectric substrate (51a). Four first dual PLC resonant structures (52a) are loaded on the back side of the first horizontal dielectric substrate (51a), and a top metal sheet (53) is printed on the front side of the first horizontal dielectric substrate (51a). The first dual PLC resonant structure (52a) is distributed at the four corners of the back side of the first horizontal dielectric substrate (51a) and is centrally symmetrical about the first horizontal dielectric substrate (51a); the first dual PLC resonant structure (52a) is formed by two identical first PLC resonant structures (521a) connected in series; the first PLC resonant structure (521a) is formed by a distributed inductor structure (5211a) composed of zigzag thin lines and a distributed capacitor structure (5212a) composed of two parallel metal strips connected in parallel; The top metal sheet (53) includes an inner arrow-shaped metal sheet located at the center of the diagonal of the front side of the first horizontal dielectric substrate (51a) and outer arrow-shaped metal sheets distributed at the four corners of the front side of the first horizontal dielectric substrate (51a), wherein: The inner arrow-shaped metal sheet includes an inner first arrow-shaped metal sheet (531), an inner second arrow-shaped metal sheet (532), an inner third arrow-shaped metal sheet (533), and an inner fourth arrow-shaped metal sheet (534) located at the center of the diagonal of the front side of the first horizontal dielectric substrate (51a). The inner arrow-shaped metal sheets have the same structure and size, and the arrows all point towards the center. The edges of the arrows are attached together to form a cross-shaped structure. The outer arrow-shaped metal sheet includes an outer first arrow-shaped metal sheet (535), an outer second arrow-shaped metal sheet (536), an outer third arrow-shaped metal sheet (537), and an outer fourth arrow-shaped metal sheet (538) distributed at the four corners of the front side of the first horizontal dielectric substrate (51a). The outer arrow-shaped metal sheets have the same structure and size, and the arrows all point outwards. The edges of the arrows are flush with the edges of the four corners of the first horizontal dielectric substrate (51a). The four first dual PLC resonant structures (52a) are located between the inner arrow-shaped metal sheet and the outer arrow-shaped metal sheet, respectively, and coincide with the tail end of the arrow-shaped metal sheet.

4. The high-isolation broadband base station common-aperture antenna array according to claim 1, characterized in that, The high-frequency antenna unit (6) includes a high-frequency radiating structure (61), and a high-frequency feeding structure (62) is vertically connected to the bottom of the high-frequency radiating structure (61). The high-frequency radiation structure (61) includes a high-frequency radiation substrate (611) and high-frequency antenna arms (612) printed on the front side of the high-frequency radiation substrate (611). The high-frequency radiation arms (612) include a first high-frequency antenna arm (6121), a second high-frequency antenna arm (6122), a third high-frequency antenna arm (6123), and a fourth high-frequency antenna arm (6124), which are distributed sequentially at the four corners of the front side of the high-frequency radiation substrate (611). The first high-frequency antenna arm (6121) includes a first square metal (61211), a second square metal (612211), a third square metal (612211), a third square metal (612311), a fourth square metal (612411), and a fourth square metal (612411) arranged sequentially from the inside to the outside. The openings of the 1 / 4 metal square ring (61212) and the third 1 / 4 metal square ring (61213), the first square metal (61211) and the second 1 / 4 metal square ring (61212) all face the first square metal (61211), and both ends are connected to the first square metal (61211); the structure and size of the first high-frequency antenna arm (6121), the second high-frequency antenna arm (6122), the third high-frequency antenna arm (6123) and the fourth high-frequency antenna arm (6124) are the same, and they are symmetrical about the center of the high-frequency radiating substrate (611); The high-frequency feeding structure (62) includes a first vertical substrate (621) and a second vertical substrate (624) perpendicular to the high-frequency radiation substrate (611). Both the first vertical substrate (621) and the second vertical substrate (624) are rectangular structures. The first vertical substrate (621) has an upper rectangular groove (6211) at the upper end of the middle position. The first vertical substrate (621) has a first metal back plate (623) printed on both sides of the back side. The first vertical substrate (621) has a first microstrip line (622) printed on the front side. The second vertical substrate (624) has a lower rectangular groove (6241) at the lower end of the middle position. The second metal back plate (626) is printed on both sides of the back of the second vertical substrate (624). The second microstrip line (625) is printed on the front of the second vertical substrate (624). The first vertical substrate (621) and the second vertical substrate (624) are placed orthogonally through the upper rectangular groove (6211) and the lower rectangular groove (6241) to form a cross structure. The upper ends of the first vertical substrate (621) and the upper ends of the second vertical substrate (624) are inserted into the high-frequency radiation substrate (611) to provide support. At the same time, the first metal back plate (623) is electrically connected to the first high-frequency antenna arm (6121) and the third high-frequency antenna arm (6123); the second metal back plate (626) is electrically connected to the second high-frequency antenna arm (6122) and the fourth high-frequency antenna arm (6124).

5. A high-isolation broadband base station common-aperture antenna array according to claim 2, characterized in that, The low-frequency radiation substrate (111) is a cross-shaped dielectric plate, including an integrally formed central structure and four end structures; The suppression unit (112) includes a first type of suppression unit (112a). Each of the four first type of suppression units (112a) is composed of a first center line (1121a) and two first left zigzag lines (1122a) and a first right zigzag line (1123a) that are symmetrical about the first center line (1121a). The first left zigzag line (1122a) and the first right zigzag line (1123a) are rectangular zigzag lines and are connected to the top of the first center line (1121a). The four first type of suppression units (112a) are centrally symmetrical about the low-frequency radiation substrate (111). All four low-frequency antenna arms (113) are rhomboid in shape and are each composed of a first connecting line (1131), a left first suppression unit (1132), a left second suppression unit (1133), a left third suppression unit (1134), a left fourth suppression unit (1135), a right first suppression unit (1136), a right second suppression unit (1137), a right third suppression unit (1138), a right fourth suppression unit (1139), and a second connecting line (11310). The first connecting line (1131) connects at both ends to the tail of the left first suppression unit (1132) and the tail of the right first suppression unit (1136), respectively. The head of the left first suppression unit (1132) connects to the tail of the left second suppression unit (1133), and the head of the left second suppression unit (1133) connects to the left third suppression unit (1134). The tails are connected at an angle. The head of the left third suppression unit (1134) is connected to the tail of the left fourth suppression unit (1135), and the head of the left fourth suppression unit (1135) is connected to one end of the second connecting line (11310). The head of the right first suppression unit (1136) is connected to the tail of the right second suppression unit (1137), the head of the right second suppression unit (1137) is connected to the tail of the right third suppression unit (1138) at an angle, the head of the right third suppression unit (1138) is connected to the tail of the right fourth suppression unit (1139), and the head of the right fourth suppression unit (1139) is connected to the other end of the second connecting line (11310). The four low-frequency antenna arms (113) are distributed on the four end structures of the low-frequency radiation substrate (111) and are centrally symmetrical about the low-frequency radiation substrate (111).

6. The high-isolation broadband base station common-aperture antenna array according to claim 5, characterized in that, The left first suppression unit (1132), left second suppression unit (1133), left third suppression unit (1134), left fourth suppression unit (1135), right first suppression unit (1135), right second suppression unit (1137), right third suppression unit (1138), and right fourth suppression unit (1139) of the low-frequency antenna arm (113) have the same structure and size as the suppression unit (112).

7. A high-isolation broadband base station common-aperture antenna array according to claim 5, characterized in that, The angle between the head of the left second suppression unit (1133) and the tail of the left third suppression unit (1134) θ 1. and the angle between the head of the right second suppression unit (1137) and the tail of the right third suppression unit (1138). θ 1. All are set at an angle greater than 90 degrees; the angle between the tail of the left first suppression unit (1132) and the tail of the right first suppression unit (1136) θ 2. And the angle between the head of the left fourth suppression unit (1135) and the head of the right fourth suppression unit (1139). θ Both are set at an angle of less than 90 degrees.

8. The high-isolation broadband base station common-aperture antenna array according to claim 3, characterized in that, The first frequency selection unit (5a) can be replaced by a second frequency selection unit (5b) or a third frequency selection unit (5c) structure; wherein: The second type of frequency selection unit (5b) includes a second horizontal dielectric substrate (51b). A rectangular metal patch (54) is printed at the center of the second horizontal dielectric substrate (51b). Isosceles right-angled triangular metal patches (55) with the same structure and size are printed at the four corners of the second horizontal dielectric substrate (51b). The right-angled edges of the isosceles right-angled triangular metal patches (55) are flush with the edges of the four corners of the second horizontal dielectric substrate (51b). A second dual PLC resonant structure (52b) is loaded between the rectangular metal patch (54) and the isosceles right-angled triangular metal patches (55). Both ends of the second dual PLC resonant structure (52b) are connected to the rectangular metal patch (54) and the isosceles right-angled triangular metal patches (55) respectively through a first interdigitated capacitor (56). The second dual PLC resonant structure (52b), the rectangular metal patch (54), the four isosceles right-angled triangular metal patches (55) with the same structure and size, and the first interdigitated capacitor (56) are all located on the same side of the second horizontal dielectric substrate (51b). The second dual PLC resonant structure (52b) has the same structure and size as the first dual PLC resonant structure (52a), and is centrally symmetrical about the second horizontal dielectric substrate (51b). The first interdigitated capacitor (56) consists of two sets of interlaced finger-shaped metal strips, with a gap between the two sets of finger-shaped metal strips that are not connected. The first cross-toe capacitor (56) in the second type of frequency selection unit (5b) is replaced with a parallel plate capacitor (57), while the rest of the structure remains unchanged, to form the third type of frequency selection unit (5c). The parallel plate capacitor (57) is composed of two rectangular metal patches arranged adjacent to each other, with a narrow gap between their opposite edges. The two rectangular metal patches on the inner side are connected to the two ends of the second dual PLC resonant structure (52b), and the two rectangular metal patches on the outer side are connected to the rectangular metal patch (54) and the isosceles right triangle patch (55) respectively.

9. A high-isolation broadband base station common-aperture antenna array according to claim 3, characterized in that, In the first PLC resonant structure (521a), the distributed inductor structure (5211a) can be replaced with a horizontally distributed zigzag inductor (5211b); the distributed capacitor structure (5212a) can be replaced with a cross-toe capacitor (5212b), and the horizontally distributed zigzag inductor (5211b) is connected in parallel with the second cross-toe capacitor (5212b).

10. A high-isolation broadband base station common-aperture antenna array according to claim 5, characterized in that, The first type of suppression unit (112a) can be replaced by a second type of suppression unit (112b) or a third type of suppression unit (112c); wherein: Each of the four second type of suppression units (112b) is composed of a second center line (1121b) and two second left zigzag lines (1122b) and a second right zigzag line (1123b) symmetrical about the second center line (1121b). The second left zigzag line (1122b) and the second right zigzag line (1123b) are wavy microstrip lines and are connected to the top of the second center line (1121b). The four second type of suppression units (112b) are centrally symmetrical about the low-frequency radiation substrate (111). Each of the four third-type suppression units (112c) is composed of a third center line (1121c) and two third left zigzag lines (1122c) and a third right zigzag line (1123c) that are symmetrical about the third center line (1121c). The third left zigzag line (1122c) and the third right zigzag line (1123c) are sawtooth microstrip lines and are connected to the top of the third center line (1121c). The four third-type suppression units (112c) are centrally symmetrical about the low-frequency radiation substrate (111).

Images