Dual-frequency dual-polarization shared aperture base station antenna array based on mantle block structure

Abstract

The invention relates to a dual-frequency dual-polarization shared aperture base station antenna array loaded with a mantle lock, which can be used in a modern communication base station and aims to solve the problem that the performance of antennas is reduced due to the fact that cross-band pattern interference becomes serious when the antennas working in different frequency bands are close to each other. The array provided by the invention comprises a low-frequency antenna loaded with mantle load and a high-frequency antenna, and all the antennas share one metal plate reflector. The mantle clock structure is composed of a flexible medium sleeve and a rectangular metal patch periodic array. The mantle block is loaded on the low-frequency antenna to suppress total scattering of the low-frequency antenna, and the working frequency band of total scattering suppression can be adjusted by adjusting the diameter of the mantle block, the size of patch units in the rectangular metal patch array and the interval between the patch units, so that the influence of the low-frequency antenna on antennas of other frequency bands is reduced. The adopted mantle clock structure has the advantages of being simple in design, ultra-thin in thickness, easy to conform and the like, and is suitable for design of a dual-frequency aperture-sharing base station antenna in a modern communication system.

Description

Technical Field

[0001] The present invention belongs to the technical field of communication systems, and in particular relates to a dual-frequency dual-polarization shared aperture base station antenna array based on a mantle cloak structure. Background Art

[0002] In modern communication systems, 5G systems and 2 / 3 / 4G systems will coexist for a long time. A base station usually needs to support all frequency bands of these systems. Multi-band shared aperture base station antennas can integrate antennas working in different frequency bands into a compact space to meet the needs of high integration and miniaturization of modern communication systems. However, when antennas of different frequency bands are close to each other, the interference between the directional patterns of different frequency bands will become serious, resulting in a significant decrease in antenna performance. In response to this problem, many solutions have been proposed, such as: loading slots on the dipole radiation arm or using a choke structure for antenna design to suppress the induced current; setting a back cavity on the low-frequency antenna to provide an independent radiation environment for the high-frequency antenna; transferring the high-frequency antenna from the bottom of the low-frequency antenna to the top of the low-frequency antenna to solve the shielding problem of the low-frequency antenna on the high-frequency antenna, and at the same time, the structure of the low-frequency antenna can be used as the reflection surface of the high-frequency antenna; designing the frequency selective surface as the radiation unit of the low-frequency antenna to reduce the influence of the low-frequency antenna on the high-frequency antenna, etc., but these design methods inevitably require changing the structure of the antenna itself to reduce the influence between antennas of different frequency bands. Summary of the invention

[0003] The present invention discloses a dual-frequency dual-polarization shared aperture base station antenna array loaded with a mantle cloak structure, which can be used in modern communication base stations and aims to solve the problem that when antennas of different frequency bands are close to each other, the antenna performance is significantly reduced due to serious cross-band directional pattern interference.

[0004] A dual-frequency dual-polarization shared aperture base station antenna array with a mantle cloak structure is loaded on a low-frequency antenna. The structure can suppress the overall scattering of the low-frequency antenna in the high-frequency band and reduce the impact on the high-frequency antenna without affecting the normal radiation performance of the low-frequency antenna. The mantle cloak structure has the characteristics of simple design, flexible control, ultra-thin thickness and easy conformality, and does not need to change the structure of the antenna itself.

[0005] Preferably, the relative dielectric constant of the flexible dielectric layer of the mantle cloak structure is in the range of 1-5, the relative magnetic permeability is in the range of 1-5, and the electrical tangent loss tan σThe low-frequency antenna radiator is printed on the first substrate, the high-frequency antenna radiator is printed on the second substrate, and the balun feed structure substrate is the third substrate. The relative dielectric constant of the first substrate, the second substrate, and the third substrate used are all in the range of 2-5, the relative magnetic permeability is in the range of 1-5, and the electrical tangent loss tan σ All <0.1.

[0006] Preferably, the metal patch units of a layer of the metal patch array of the mantle cloak structure are spaced apart to present a periodic arrangement.

[0007] Preferably, the material of the metal patch unit of the mantle cloak structure is copper.

[0008] Preferably, the diameter of the outermost flexible medium of the mantle cloak structure is less than twice the width of the low-frequency antenna radiator.

[0009] Preferably, the dual-polarized low-frequency antenna loaded with the mantle cloak structure uses a balun feeding structure, so that the dual-polarized low-frequency antenna can achieve impedance matching in a wider frequency band.

[0010] Preferably, the low frequency antenna and the high frequency antenna in the array use cross dipole antennas to achieve dual polarization effect.

[0011] Preferably, in the dual-frequency dual-polarization shared aperture base station antenna array, the dual-polarization low-frequency antenna radiator loaded with a mantle cloak structure is located at the top of the array, the reflector is located at the bottom of the array, and the high-frequency antenna radiator is located between the low-frequency antenna radiator and the reflector.

[0012] Preferably, the metal patch array in the mantle cloak structure is located at the outermost layer and is printed on the outermost flexible dielectric layer. Several flexible dielectric layers are located inside the metal patch array. The mantle cloak structure is sleeve-shaped, and the mantle cloak structure is loaded on all four radiating arms of a low-frequency antenna.

[0013] Compared with the prior art, the present invention discloses a dual-frequency dual-polarization shared aperture base station antenna array loaded with a mantle cloak structure. In the present invention, the mantle cloak structure does not require changing the structure of the antenna itself; the operating frequency band of overall scattering suppression can be adjusted by reasonably adjusting the diameter of the mantle cloak structure and the size of the metal patch units in the rectangular metal patch array and the intervals between the metal patch units, thereby reducing the influence of the low-frequency antenna on the antennas working in other preset frequency bands, and has the advantages of simple and flexible design; the mantle cloak structure is ultra-thin and easy to conform. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0015] Figure 2 Schematic diagram of a low-frequency radiator loaded with a mantle cloak structure in the present invention.

[0016] Figure 3 This is a diagram of the balun feeding structure of the low frequency antenna in the present invention.

[0017] Figure 4 It is a schematic diagram of the high frequency antenna radiator of the present invention.

[0018] Figure 5 This is a diagram of the balun feeding structure of the high frequency antenna of the present invention.

[0019] Figure 6 This is a partial port allocation diagram of the antenna array in the present invention.

[0020] Figure 7 This is a reflection coefficient diagram of the low-frequency antenna in the present invention.

[0021] Figure 8 This is a reflection coefficient diagram of some high-frequency antennas in the present invention.

[0022] Fig. 9 It is the horizontal gain pattern of some frequency points of the high-frequency antenna in various cases when port 3 is excited in the present invention.

[0023] Fig.10 It is the horizontal gain pattern of the low frequency antenna at 0.825 GHz when port 1 is excited in the present invention.

[0024] Fig.11 This is the actual gain diagram of the low-frequency antenna in the present invention.

[0025] Fig.12 This is the actual gain diagram of the high frequency antenna of the present invention.

[0026] Explanation of the reference numerals: 1. low-frequency antenna; 11. first substrate; 12. periodic array of rectangular metal patches; 13. low-frequency radiation patch; 14. flexible dielectric layer; 15. low-frequency balun feeding structure; 2. high-frequency antenna; 21. high-frequency radiation patch; 22. second substrate; 23. high-frequency balun feeding structure; 3. metal plate reflector. DETAILED DESCRIPTION

[0027] like Figure 1As shown, this example discloses a dual-frequency dual-polarization shared aperture base station antenna array based on a mantle cloak structure, including a low-frequency antenna 1 and a 2×2 antenna array composed of high-frequency antenna units, and all antennas share a metal plate reflector 3. The side length of the metal plate reflector 3 is 160 mm, the width is 1 mm, and the material is copper. The low-frequency antenna 1 is located at the center of the metal plate reflector 3. The center distance between two adjacent high-frequency antennas in the high-frequency antenna array is 90 mm, distributed around the low-frequency antenna 1. Figure 2 As shown, a mantle cloak structure is loaded on the low-frequency antenna radiation patch 13 to suppress the overall scattering of the low-frequency antenna radiation patch 13 in the high-frequency band, thereby reducing the influence of the low-frequency antenna on the radiation performance of the high-frequency antenna. The length L2 of a single radiation arm of the low-frequency antenna radiation patch 13 is 58 mm, the width L1 is 10 mm, the interval L3 between two radiation arms on the same straight line is 6 mm, and the width L4 of the cut angle near the center of the four radiation arms is 4 mm. The mantle cloak structure consists of a cylindrical dielectric sleeve 14 and a rectangular metal periodic array 12 printed on the sleeve. The structure is supported by foam and sleeved on the low-frequency antenna radiation patch 13. The diameter L5 of the cylindrical dielectric sleeve 14 is 18 mm, and the length L6 is 50 mm. The length w1 of a single rectangular patch in the rectangular metal patch periodic array 12 is 9.7 mm, the width w2 is 5.7 mm, the horizontal spacing d1 of the rectangular metal patches is 0.3 mm, and the vertical spacing d2 is 0.3 mm. As shown Figure 3 The front and back sides of the substrate of the low-frequency antenna balun feeding structure 15 are respectively a microstrip feed line and a balun floor. A small hole is punched at the bottom of the substrate for welding of the coaxial line. At the same time, part of the substrate is cut off at the bottom to facilitate the substrate to stand on the metal plate reflector 3. The balun structure that feeds two orthogonal polarization dipoles is provided with a slot at the bottom and top of the dielectric plate, respectively, to facilitate the assembly of the two dielectric plates in a mutually perpendicular manner. The microstrip feed lines at the upper and lower slot edges are bent to both sides to prevent the two orthogonal microstrip feed lines from connecting and short-circuiting. The top of the balun substrate protrudes so that the balun substrate passes through the first substrate 11 and connects to the radiation patch 13. In addition, four square holes are punched on the first substrate 11 so that the top of the balun substrate passes through the first substrate 11. The low-frequency balun feeding structure 15 is located on the reflector 3, with a height LB16 of 30 mm, a total length LB13 of 40 mm, a width LB14 of 24 mm, and a line width LB6 and LB12 of 1.8 mm at the connection between the microstrip feeder and the coaxial line, and the remaining line widths LB5 and LB11 are 1.6 mm. The lengths of the microstrip feeder LB1-4 on one substrate are 10.5 mm, 2.9 mm, 11.6 mm, and 7 mm, respectively. The lengths of the microstrip feeder LB7-10 on the other substrate are 10.5 mm, 5.2 mm, 11.6 mm, and 8 mm, respectively. The width of the balun floor LB15 is 5.8 mm.

[0028] like Figure 4 As shown, a single radiating arm of the high-frequency antenna radiating patch 21 is a square ring, and a corner of the square ring is cut off, and this corner is connected to the balun feeding structure. The second substrate 22 is also punched with a square hole. The length H1 of a single circular radiating arm of the high-frequency antenna radiating patch 21 is 14 mm, the ring width H2 is 2 mm, the cut-off width H4 near the center of the four radiating arms is 2 mm, the gap H5 between adjacent radiating arms is 1 mm, and the length H3 of the second substrate 22 is 32 mm. Figure 5 The high frequency antenna balun feeding structure 23 shown is similar to the low frequency. The high frequency balun feeding structure 23 is located on the reflector 3, the height HB16 is 16 mm, the total length HB13 is 25 mm, the width HB14 is 16 mm, the line width HB6 and HB12 of the part where the microstrip feed line connects to the coaxial line is 2 mm, and the remaining line widths HB5 and HB11 are 1.7 mm. The lengths of the microstrip feed lines HB1-4 on one substrate are 10.5 mm, 10 mm, 9.4 mm and 4 mm respectively. The lengths of the microstrip feed lines HB7-10 on the other substrate are 10 mm, 10 mm, 9.4 mm and 4 mm respectively. The width HB15 of the balun floor is 4.8 mm.

[0029] The first substrate, the second substrate and the substrate of the balun feeding structure are all made of F4B material with a relative dielectric constant of 3 and a thickness of 0.8 mm. The cylindrical dielectric sleeve 14 is made of Taconic TSM-DS3 material with a relative dielectric constant of 3 and a thickness of 0.13 mm. The metal plate reflector 3 is made of copper plate with a thickness of 1 mm.

[0030] like Figure 6 As shown, ports 1 and 2 excite two mutually orthogonal low-frequency dipoles, and ports 3 and 4 excite two mutually orthogonal high-frequency dipoles. Figure 7 and Figure 8 As shown in the figure, in the working frequency band of 1.7 GHz-2.3 GHz for the low-frequency antenna in the array, S11 and S22 are both less than -10 dB, and the port isolation is less than -25 dB. In the working frequency band of 3.3 GHz-3.8 GHz for the high-frequency antenna, S33 and S44 are both less than -15 dB, and the port isolation is less than -25 dB, which meets the design requirements well. Fig. 9As shown in the figure, the horizontal normalized radiation patterns of the high-frequency antennas in the array at 3.3 GHz, 3.5 GHz, 3.6 GHz and 3.8 GHz in different cases are compared. It can be seen that when the low-frequency dipole antenna is not loaded with the mantle cloak structure, the high-frequency antenna patterns in the array are obviously interfered by the low-frequency antenna at each frequency point. After the mantle cloak structure is loaded, the high-frequency antenna patterns in the array have a good overlap with the patterns when the high-frequency antenna array is placed alone. Therefore, it can be seen that the mantlecloak structure reduces the influence of the low-frequency antenna on the high-frequency antenna, and the high-frequency antenna pattern is restored. Fig.10 As shown in the figure, the normalized radiation pattern of the low-frequency antenna loaded with the mantle cloak structure at 0.825 GHz, it can be seen that loading the mantle cloak structure does not affect the radiation characteristics of the low-frequency antenna. Fig.11 and Fig.12 As shown in the figure, the actual gain of the low-frequency antenna is greater than 7.5 dBi in the 1.7 GHz-2.3 GHz frequency band, and the actual gain of the high-frequency antenna is greater than 8.5 dBi in the 3.3 GHz-3.8 GHz frequency band. It can be seen from the above that this example can cover 1.7 GHz-2.3 GHz and 3.3 GHz-3.8 GHz, and the antennas working in their respective frequency bands have stable radiation performance.

[0031] The above is only a preferred embodiment of the present invention. The same mantle cloak structure can suppress the overall scattering of the low-frequency antenna in the desired frequency band by changing the diameter of the structure or the size and periodic arrangement of the rectangular patch units, thereby reducing the influence of the low-frequency antenna on the antenna working in the desired frequency band. At the same time, changing the size of the low-frequency antenna does not affect the design method of the mantle cloak structure. It should be pointed out that all equal changes and modifications made according to the scope of the patent application of the present invention should be covered by the scope of the present invention.

Claims

1. A dual-frequency dual-polarization shared aperture base station antenna array based on a mantle cloak structure, characterized in that: It includes a dual-polarized low-frequency antenna loaded with a mantle cloak structure and a dual-polarized high-frequency antenna, and all antennas share a metal plate reflector; the low-frequency antenna is a traditional cross-dipole antenna, and the mantle cloak structure includes several layers of flexible dielectric layers that are easy to conform to the shape and a layer of metal patch array, and the structure is sleeve-shaped.

2. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: There are gaps between the metal patch units of a layer of metal patch array in the mantle cloak structure, presenting a periodic arrangement.

3. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: The metal patch array in the mantle cloak structure is located on the outermost layer and is printed on the outermost flexible dielectric layer, and several flexible dielectric layers are located inside the metal patch array.

4. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: In the dual-band dual-polarization shared aperture base station antenna array, the low-frequency antenna radiator loaded with a mantle cloak structure is located at the top of the array, the metal plate reflector is located at the bottom of the array, the high-frequency antenna radiator is located between the low-frequency antenna radiator and the metal plate reflector, and the antennas are uniformly fed with a balun feeding structure.

5. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: The low-frequency antenna radiator is printed on the first substrate, the high-frequency antenna radiator is printed on the second substrate, and the balun feeding structure substrate is the third substrate.

6. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: The relative dielectric constant and relative magnetic permeability of the flexible dielectric layer of the mantle cloak structure are in the range of 1-5, and the electrical tangent loss tan σ The relative dielectric constants of the first substrate, the second substrate and the third substrate are all in the range of 2-5, the relative magnetic permeability is in the range of 1-5, and the electrical tangent loss tan σ All <0.

1.

7. A dual-frequency dual-polarization shared aperture base station antenna array based on a mantle cloak structure, characterized in that: The mantlecloak structure is loaded on the low-frequency antenna. This structure can suppress the overall scattering of the low-frequency antenna in the high-frequency band, reduce the impact of the low-frequency antenna on the antenna working in the high-frequency band, and will not affect the normal radiation performance of the low-frequency antenna. By reasonably adjusting the diameter of the mantle cloak structure, the size of the metal patch unit, and the spacing between the metal patch units, the operating frequency band of the overall scattering suppression can be adjusted without changing the internal low-frequency antenna radiator structure, thereby reducing the impact of the low-frequency antenna on antennas working in other preset frequency bands. The mantle cloak structure has the characteristics of simple design, flexible control, ultra-thin thickness and easy conformality, and does not need to change the structure of the low-frequency antenna itself. It is suitable for the design of dual-frequency shared aperture base station antennas in modern communication systems. The dual-frequency dual-polarization shared aperture base station antenna array based on the mantle cloak structure according to claim 1, characterized in that: The microstrip feed line and balun floor of the balun feed are printed on the front and back of the third substrate respectively. Grooves and holes are dug on the substrate to facilitate the assembly and welding of the coaxial line.

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