Broadband electromagnetic transparent base station antenna based on irregular fragmentation design

Abstract

The invention belongs to the technical field of antenna engineering, and relates to a broadband electromagnetic transparent base station antenna and array based on irregular fragmentation design, which comprises a low-frequency antenna with multiple electromagnetic transparent effects, a high-frequency antenna and a reflection floor. The low-frequency antenna structure with the multiple electromagnetic transparent effects comprises a plurality of groups of fragmented metal patches with different sizes and slender metal strip lines connected with the four-corner patches. According to the low-frequency antenna with the multiple electromagnetic transparent effects, the structure of the low-frequency antenna is regulated and controlled through irregular fragmentation design, the multiple electromagnetic transparent effects are achieved, the electromagnetic transparent characteristic of the low-frequency antenna in a broadband range is achieved, the shielding and scattering effects of the low-frequency antenna are remarkably reduced, and the antenna performance is improved. The problem of cross-band scattering coupling in a multi-frequency common-caliber base station antenna array is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of antenna engineering technology, and in particular to a broadband electromagnetically transparent base station antenna and array based on irregular fragmentation design. Background Art

[0002] With the advent of the 5G era and the explosive growth of communication data, more wireless communication frequency bands are being applied to modern communication systems. Multi-band co-aperture base station antenna arrays have become the mainstream form of base station antenna development today because of their ability to accommodate antennas of multiple frequency bands in a compact space and reduce operating costs.

[0003] Although multi-band co-aperture base station antenna arrays have many application advantages, the problem of cross-band scattering coupling between antennas in different frequency bands needs to be solved urgently in actual applications. At present, there are several layout architectures and solutions to solve the cross-band scattering coupling problem in multi-band common aperture base station antenna arrays: 1. Embedded layout / cavity-backed layout. In this type of array layout, the high-frequency antenna is embedded in the low-frequency antenna or the high-frequency antenna and the low-frequency antenna radiation structure are reused. In this layout, the low-frequency antenna greatly reduces the shielding area of ​​the high-frequency antenna, so the cross-band scattering coupling problem is solved. However, this design has significant disadvantages. It can only be applied under a fixed frequency ratio and the working bandwidth and array formation of the high-frequency antenna are limited; 2. Stacked layout, the high-frequency antenna is installed above the low-frequency antenna, and a frequency selective surface with low-pass and high-resistance characteristics is inserted between the low-frequency antenna and the high-frequency antenna. At this time, the frequency selective surface only allows low-frequency electromagnetic waves to pass through. The high-frequency antenna is equivalent to an electrically small structure relative to the low-frequency antenna, and the shielding and scattering effect on the directional pattern of the low-frequency antenna is small. At the same time, the frequency selective surface shows reflection characteristics for high-frequency electromagnetic waves, which can realize the role of the high-frequency antenna floor, so that the high-frequency antenna pattern will not be affected by the high-frequency induced current scattering waves generated on the low-frequency antenna. However, the array structure is more complex and the overall profile of the array is higher under this layout. 3. Staggered layout: high-frequency antennas are arranged around low-frequency antennas, and low-frequency antennas are blocked above high-frequency antennas. However, the low-frequency antennas can be specially designed, such as based on FSS units / equivalent circuits, reverse current structures, etc. to make them electromagnetically transparent to solve their impact on the high-frequency antenna radiation pattern, thereby achieving a compact and miniaturized array. However, these current methods are difficult to perform multi-order design to achieve broadband electromagnetic transparency, and will also cause the working bandwidth of the low-frequency antenna to deteriorate and decrease.

[0004] In view of the above problems, the present invention discloses a broadband electromagnetic transparent base station antenna based on irregular fragmentation design. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention proposes a base station antenna unit and a multi-frequency common-aperture antenna array based on irregular fragmentation design which does not destroy the antenna's own working bandwidth and can achieve good electromagnetic transparency in a wider frequency band.

[0006] The technical solution of the present invention to achieve the above-mentioned purpose is as follows: a broadband electromagnetic transparent base station antenna and array based on irregular fragmentation design, which includes a low-frequency antenna, a high-frequency antenna and a reflective floor with multiple electromagnetic transparent effects;

[0007] The low-frequency antenna with multiple electromagnetic transparent effects includes low-frequency irregular fragmented patch dipoles located at four diagonal positions on the lower surface of the low-frequency antenna dielectric substrate, a Y-shaped feed line located at a diagonal position on the upper surface of the dielectric substrate, the Y-shaped feed line for feeding the low-frequency antenna is connected to the inner conductor at one end of the low-frequency feeding coaxial line, and the outer conductor at the other end of the low-frequency feeding coaxial line is connected to the reflective floor, and the low-frequency antenna dielectric substrate is fixed on the reflective floor dielectric substrate through the low-frequency antenna nylon column.

[0008] The low-frequency irregular fragmented patch dipole has an irregular fragmentation design for the patch, retaining the complete electrical connection of the edge of the low-frequency patch dipole. The interior is composed of multiple groups of fragmented metal patches of different sizes. The fragmented metal patches reduce the shielding and scattering effect on the high-frequency antenna. At the same time, the integrity of the edge of the low-frequency patch ensures the parasitic coupling between the patches, making it equivalent to a frequency selective surface unit with electromagnetic transparency in the high-frequency band. At the same time, by regulating the fragmented metal patch and the semi-closed gap formed with the edge of the low-frequency patch, the high-frequency induced current on the above two structures can be reversed. Therefore, the low-frequency fragmented patch dipole with an irregular fragmentation design can have multiple electromagnetic transparency effects in the high-frequency band, realizing broadband electromagnetic transparency characteristics.

[0009] The high-frequency antenna is arranged around the bottom of the low-frequency antenna with multiple electromagnetic transparent effects. The high-frequency antenna includes a high-frequency patch dipole cross-distributed on the lower surface of the high-frequency antenna dielectric substrate and a Y-shaped feeding line cross-distributed on the upper surface of the high-frequency antenna dielectric substrate. One end of the high-frequency feeding coaxial line is connected to the Y-shaped feeding line, and the other end is connected to the square metal patch on the upper surface of the reflective floor dielectric substrate. The high-frequency antenna dielectric substrate is fixed on the reflective floor dielectric substrate through the high-frequency antenna nylon column.

[0010] The high-frequency patch dipole is subjected to patch angle cutting, and the size of the high-frequency patch dipole can be adjusted by changing the size of the angle cutting, thereby adjusting the working frequency of the high-frequency patch dipole.

[0011] The reflective floor comprises a metal floor printed on the lower layer of a dielectric substrate and four square metal patches printed on the upper layer of the dielectric substrate. The center of the square metal patch is connected to a high-frequency feeding coaxial line, and a bent microstrip line is extended from the other end. The end of the microstrip line is connected to a metallized via to achieve connection with the metal floor of the lower layer of the dielectric substrate.

[0012] In summary, compared with the prior art, the present invention has the following significant advantages:

[0013] 1. The irregular fragmentation design of the present invention retains the integrity of the edge of the low-frequency patch dipole, so that the parasitic coupling effect between the low-frequency patch dipoles is not destroyed, ensuring that the working bandwidth of the low-frequency antenna with multiple electromagnetic transparency effects will not deteriorate due to the destruction of the original structure, so that it can obtain good broadband impedance matching characteristics.

[0014] 2. The present invention makes the low-frequency antenna structure tend to be fragmented, and the small-sized fragmented structure effectively reduces the shielding and scattering effects of the low-frequency patch dipoles; the low-frequency antenna with irregular fragmentation design has a complete patch edge so that the parasitic coupling between the patch dipoles is not destroyed, and the generated parasitic coupling capacitance can make it have an equivalent frequency selective surface passband characteristic in the high frequency band; at the same time, the induced current on the two side structures of the semi-closed gap formed by the irregular fragmentation patch and the edge of the low-frequency patch dipole further reduces the cross-band scattering coupling. Therefore, a low-frequency antenna structure obtained by an irregular fragmentation design method can achieve multiple electromagnetic transparency effects, realize the broadband electromagnetic transparency characteristics of the low-frequency antenna, and very effectively weaken the cross-band scattering coupling to other high-frequency antennas.

[0015] 3. The present invention does not need to design and load any structure other than the low-frequency irregular fragmented patch dipole to improve the radiation performance and wave transmission characteristics of the low-frequency antenna, nor does it need to design and load any additional structure to improve the performance of the high-frequency antenna, which significantly reduces the difficulty of product design and assembly, and is suitable for solving the cross-band scattering coupling problem of large-scale base station antenna arrays. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a broadband electromagnetic transparent base station antenna based on irregular fragmentation design according to the present invention;

[0017] Figure 2 It is a side view of a broadband electromagnetic transparent base station antenna structure based on irregular fragmentation design according to the present invention;

[0018] Figure 3 It is a top view of a low-frequency antenna structure with multiple electromagnetic transparency effects;

[0019] Figure 4 is a top view of the high frequency antenna structure;

[0020] Figure 5 It is the S parameter result of the low frequency antenna with multiple electromagnetic transparent effects;

[0021] Figure 6 It is the main polarization gain curve of the low-frequency antenna with multiple electromagnetic transparency effects;

[0022] Figure 7 This is a simulation result diagram of the transmission coefficient-frequency of a low-frequency antenna structure with multiple electromagnetic transparency effects;

[0023] Figure 8 yes Figure 4 The high frequency antenna is Figure 3 The comparison results of the directional patterns of the low-frequency antenna under the occlusion;

[0024] Fig. 9 is the S parameter result of the high frequency antenna;

[0025] Fig.10 It is the radiation pattern of a low-frequency antenna with multiple electromagnetic transparency effects. Fig.10 (a), (b), and (c) are the radiation patterns of the low-frequency antenna at 690MHz, 820MHz, and 960MHz, respectively;

[0026] Fig.11 is the radiation pattern of the high-frequency antenna, Fig.11 (a), (b), and (c) are the radiation patterns of the high-frequency antenna at 1.65 GHz, 2.2 GHz, and 2.8 GHz, respectively;

[0027] In the attached figure: 1. low-frequency irregular fragmented patch dipole, 2. low-frequency antenna Y-shaped feed line, 3. low-frequency antenna dielectric substrate, 4. low-frequency feeding coaxial line, 5. high-frequency patch dipole, 6. high-frequency antenna Y-shaped feed line, 7. high-frequency antenna dielectric substrate, 8. high-frequency feeding coaxial line, 9. reflecting floor, 10. reflecting floor dielectric substrate, 11. square metal patch, 12. bent microstrip line, 13. low-frequency antenna nylon column, 14. high-frequency antenna nylon column. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention application clearer, the following will be further described in detail in conjunction with the drawings in the examples of the present invention. It should be noted that the described examples are only part of the embodiments of the present invention for describing and explaining the present application, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] A broadband electromagnetically transparent base station antenna based on irregular fragmentation design includes a low-frequency antenna with multiple electromagnetic transparent effects, a high-frequency antenna and a reflective floor. The operating frequency band of the low-frequency antenna with multiple electromagnetic transparent effects is 0.69-0.96 GHz, and the operating frequency band of the high-frequency antenna is 1.65-2.80 GHz. The low-frequency antenna with irregular fragmentation design can significantly reduce the cross-band scattering coupling to the high-frequency antenna within a wider frequency band, and effectively weaken the negative impact of the low-frequency antenna on the high-frequency antenna radiation pattern.

[0030] like Figure 1 , Figure 2 and Figure 3 As shown, the low-frequency antenna with multiple electromagnetic transparent effects includes a low-frequency irregular fragmented patch dipole 1 located at four diagonal positions on the lower surface of the low-frequency antenna dielectric substrate 3, a Y-shaped feeding line 2 located at a diagonal position on the upper surface of the dielectric substrate 3, the Y-shaped feeding line 2 for feeding the low-frequency antenna is connected to the inner conductor at one end of the low-frequency feeding coaxial line 4, and the outer conductor at the other end of the low-frequency feeding coaxial line 4 is connected to the reflective floor 9, and the low-frequency antenna dielectric substrate 3 is fixed on the reflective floor dielectric substrate 10 through the low-frequency antenna nylon column 13.

[0031] The low-frequency antenna Y-shaped feeding line 2 is connected to the low-frequency feeding coaxial line 4 to realize coupled feeding of the low-frequency irregular fragmented patch dipole 1. The coupled feeding method enables the antenna to be well matched in a wider frequency band, achieving a reflection coefficient of <-11dB in the 0.69-0.96GHz frequency band, and the polarization isolation between antenna ports is higher than 22dB.

[0032] Furthermore, the low-frequency antenna is designed to be an irregularly fragmented low-frequency patch dipole 1, which is composed of multiple groups of fragmented metal patches of different sizes and metal thin wires at the edge of the low-frequency dipole, including 4 groups of 2×2 small metal patches at the center, 12 groups of 2×2 small metal patches at the periphery, 4 metal patches at the four corners, and 4 thin metal thin wires connected to the metal patches at the four corners. The fragmented patches and the thin metal thin wires have very small structural sizes, which greatly reduce the scattering and shielding effect of the low-frequency antenna on the high-frequency antenna. The metal patches at the four corners and the thin metal thin wires have a very small size. The connection ensures the parasitic coupling effect between the low-frequency irregular fragmented patch dipole 1, ensures that its own working bandwidth is not deteriorated, and also enables it to have the high-pass characteristics of an equivalent frequency selective surface in the high-frequency band. At the same time, the small metal patches located on the surroundings and the small spacing between the edges of the low-frequency irregular fragmented patch dipole 1 make the high-frequency induced currents thereon reverse and the scattered fields cancel each other, further realizing the electromagnetic transparency characteristics of the low-frequency irregular fragmented patch dipole 1. The above-mentioned multiple transparency effects combine to make the low-frequency irregular fragmented patch dipole have an electromagnetic transparency effect in a wide bandwidth range, solving the cross-band scattering coupling problem faced by high-frequency antennas working under a common aperture array.

[0033] like Figure 1 , Figure 2 and Figure 4 As shown, the high-frequency antenna is arranged around the bottom of the low-frequency electromagnetic transparent antenna. The high-frequency antenna includes a high-frequency patch dipole 5 cross-distributed on the lower surface of the high-frequency antenna dielectric substrate 7 and a high-frequency antenna Y-shaped feeding line 6 cross-distributed on the upper surface of the high-frequency antenna dielectric substrate 7. One end of the high-frequency feeding coaxial line 8 is connected to the high-frequency antenna Y-shaped feeding line 6, and the other end is connected to the square metal patch 11 on the upper surface of the reflective floor dielectric substrate 10. The high-frequency antenna dielectric substrate 7 is fixed on the reflective floor dielectric substrate 10 through a high-frequency antenna nylon column 14.

[0034] Furthermore, the high-frequency patch dipole 5 is subjected to a patch angle cutting process. Changing the size of the angle cutting can adjust the size of the high-frequency patch dipole 5 , thereby adjusting the operating frequency of the high-frequency patch dipole 5 .

[0035] When the low-frequency antenna is working, it will excite the outer conductor of the high-frequency feeding coaxial line 8, causing it to generate an induced current, resulting in common-mode resonance problems, leading to the deterioration of the low-frequency antenna matching and radiation pattern. The introduction of the square metal patch 11 and the bent microstrip line 12 can change the direct grounding of the high-frequency antenna, extend the induced current path on the outer conductor of the high-frequency feeding coaxial line 8, thereby moving the common-mode resonance frequency out of the low-frequency band, and suppressing the negative impact of the induced current on the low-frequency antenna matching and radiation pattern.

[0036] The performance of low-frequency antennas with multiple electromagnetic transparency effects is as follows Figure 5 , Figure 6 As shown, the antenna operating frequency band is 0.69-0.96 GHz, the reflection coefficient is less than -11 dB, the port polarization isolation is greater than 22 dB, and the antenna gain is stable at about 7 dBi. Figure 5 In the figure, curve S(1,1) represents the reflection coefficient of low-frequency antenna port 1 with multiple electromagnetic transparency effects, curve S(2,2) represents the reflection coefficient of low-frequency antenna port 2 with multiple electromagnetic transparency effects, and curve S(1,2) represents the polarization isolation between low-frequency antenna ports 1 and 2 with multiple electromagnetic transparency effects. Figure 6 In FIG. 1 , curves Port 1 and Port 2 respectively represent the gains of ports 1 and 2 of the low-frequency antenna with multiple electromagnetic transparency effects.

[0037] like Figure 7 As shown, the transmission coefficient of the low-frequency irregular fragmented patch dipole 1 obtained by the irregular fragmentation design is kept within 0.6 dB in the high frequency band 1.6-2.8 GHz, and has good electromagnetic transparency characteristics within a relative bandwidth range of more than 50%.

[0038] like Figure 8 As shown in the figure, the directional pattern of the high-frequency antenna has different changes under the shielding of different low-frequency antenna structures. Under the traditional low-frequency antenna structure, the directional pattern of the high-frequency antenna is seriously distorted, the gain deteriorates significantly, and the gain decreases by more than 10dBi. When the traditional low-frequency antenna structure is specially designed with irregular fragmentation to form a low-frequency irregular fragmented patch dipole 1, the directional pattern of the high-frequency antenna is significantly repaired under the irregular fragmented low-frequency antenna, which is almost the same as the directional pattern when the high-frequency antenna works alone. Figure 1 In the figure, the curve Only HB Array represents the directional pattern of the high-frequency antenna when working alone, the curve HB+Conventional LB represents the directional pattern of the high-frequency antenna in the traditional low-frequency patch dipole antenna structure, and the curve HB+Fragmented LB represents the directional pattern of the high-frequency antenna in the low-frequency irregular fragmented patch dipole 1 antenna structure.

[0039] like Fig. 9 As shown, the S parameter results of the high-frequency antenna in the 1.65-2.80GHZ frequency band are displayed. The reflection coefficient of the antenna port is lower than -11dB, and the polarization isolation between ports is higher than 29dB. Fig.10 and Fig.11The radiation patterns of the low-frequency antenna and high-frequency antenna with multiple electromagnetic transparency effects are given respectively. It can be seen that the radiation pattern of the low-frequency antenna with multiple electromagnetic transparency effects is stable, without deflection distortion, and the cross-polarization suppression ratio is higher than 20dB. The radiation pattern of the high-frequency antenna is not distorted by the obstruction of the low-frequency antenna. The radiation pattern has a good shape and the cross-polarization suppression ratio is higher than 20dB. The high-frequency antenna has good radiation characteristics in the common-aperture array environment.

[0040] The examples described and shown above are only some preferred examples of the present invention and do not constitute any limitation to the patent scope of the present invention. For those skilled in the art, the present application may have various improvements and changes without departing from the concept of the present application. Therefore, the modifications and changes based on the concept of the present invention are within the scope of protection of the claims of the present invention.

Claims

1. A broadband electromagnetically transparent base station antenna based on irregular fragmentation design, characterized in that: It comprises a low-frequency antenna with multiple electromagnetic transparency effects, a high-frequency antenna and a reflective floor; the low-frequency antenna with multiple electromagnetic transparency effects comprises a low-frequency irregular fragmented patch dipole (1) located at four diagonal positions on the lower surface of a low-frequency antenna dielectric substrate (3), a Y-shaped feeder (2) located at a diagonal position on the upper surface of the dielectric substrate (3), the Y-shaped feeder (2) for feeding the low-frequency antenna is connected to an inner conductor at one end of a low-frequency feeding coaxial line (4), the outer conductor at the other end of the low-frequency feeding coaxial line (4) is connected to a reflective floor (9), and the low-frequency antenna dielectric substrate (3) is fixed on the reflective floor dielectric substrate (10) via a low-frequency antenna nylon column (13); The high-frequency antenna is arranged around the bottom of the low-frequency antenna with multiple electromagnetic transparent effects. The high-frequency antenna comprises high-frequency patch dipoles (5) cross-distributed on the lower surface of the high-frequency antenna dielectric substrate (7) and high-frequency antenna Y-shaped feed lines (6) cross-distributed on the upper surface of the high-frequency antenna dielectric substrate (7). One end of the high-frequency feeding coaxial line (8) is connected to the high-frequency antenna Y-shaped feed line (6), and the other end is connected to a square metal patch (11) on the upper surface of the reflective floor dielectric substrate (10). The high-frequency antenna dielectric substrate (7) is fixed on the reflective floor dielectric substrate (10) via a high-frequency antenna nylon column (14); The reflective floor comprises a metal floor printed on the lower layer of a reflective floor dielectric substrate (10) and four square metal patches (11) and a bent microstrip line (12) printed on the upper layer of the dielectric substrate (10); the center of the square metal patch (11) is connected to a high-frequency feeding coaxial line (8); and the end of the microstrip line is connected to a metallized via hole to achieve connection with the metal floor of the lower layer of the dielectric substrate (10).

2. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 1, characterized in that: The high-frequency patch dipole (5) is subjected to patch angle cutting, and the size of the high-frequency patch dipole (5) can be adjusted by changing the size of the angle cutting, thereby adjusting the operating frequency of the high-frequency patch dipole (5).

3. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 1, characterized in that: The introduction of the square metal patch (11) and the bent microstrip line (12) in the reflective floor can change the direct grounding mode of the high-frequency antenna, extend the induced current path on the outer conductor of the high-frequency feeding coaxial line (8), thereby moving the common mode resonant frequency out of the low-frequency band, and suppressing the negative impact of the induced current on the matching and radiation pattern of the low-frequency antenna.

4. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 1, characterized in that: The low-frequency irregular fragmented patch dipole (1) formed by the irregular fragmentation design of the low-frequency antenna with multiple electromagnetic transparent effects is composed of multiple groups of fragmented metal patches of different sizes and metal thin wires at the edge of the low-frequency dipole, including 4 groups of 2×2 small metal patches located at the center, 12 groups of 2×2 small metal patches located at the periphery, 4 metal patches located at the four corners, and 4 thin and long metal thin wires connected to the metal patches at the four corners. The irregularly fragmented multiple groups of patches and the thin and long metal thin wires have very small structural sizes, which greatly reduces the shielding and scattering effects of the low-frequency antenna on the high-frequency antenna.

5. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 4, characterized in that: The connection between the metal patches located at the four corners of the low-frequency irregular fragmented patch dipole (1) and the slender metal wires ensures the parasitic coupling effect between the low-frequency irregular fragmented patch dipole (1), ensuring that the working bandwidth of the low-frequency antenna itself will not be deteriorated due to the damage to the original structure, and also enables it to have the high-pass characteristics of an equivalent frequency selective surface in the high frequency band.

6. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 4, characterized in that: The small metal patches distributed around the low-frequency irregular fragmented patch dipole (1) and the metal thin wires at its edges form a semi-closed gap. By adjusting the size of the semi-closed gap structure, the high-frequency induced currents on the two structures can be reversed, so that the scattering field is cancelled and the electromagnetic transparency effect of the low-frequency antenna is realized.

7. The broadband electromagnetically transparent base station antenna based on irregular fragmentation design according to claim 1, characterized in that: A low-frequency antenna structure with an irregular fragmentation design includes substructures such as small patches of different sizes, slender metal wires and semi-closed gaps, so that it has the multiple electromagnetic transparency effects of claims 4-6 at the same time, achieving broadband electromagnetic transparency characteristics within a wide frequency band.

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