阅读说明：本技术 一种抑制宽带双极化基站天线间耦合的级联型裂环谐振器 (Cascade split ring resonator for inhibiting coupling between broadband dual-polarized base station antennas ) 是由 刘震国 李茜 陆卫兵 于 2021-06-17 设计创作，主要内容包括：本发明公开了一种抑制宽带双极化基站天线间耦合的级联型裂环谐振器,包括,裂环谐振器、金属条带和介质基片；其中,两个所述裂环谐振器通过所述金属条带桥接,并印刷于所述介质基片上。通过本发明可以利用裂环谐振器的带隙滤波的原理,降低了双极化基站天线间的耦合,同时扩展了去耦结构的带宽,实现了1.71GHz-2.69GHz宽带双极化基站天线间的解耦,还能够缩小天线阵列的3dB波宽,为未来4G、5G宽带双极化基站阵列的解耦提供帮助。(The invention discloses a cascade split-ring resonator for inhibiting coupling between broadband dual-polarized base station antennas, which comprises a split-ring resonator, a metal strip and a dielectric substrate, wherein the split-ring resonator is arranged on the dielectric substrate; wherein two of the split-ring resonators are bridged by the metal strip and printed on the dielectric substrate. The invention can utilize the band gap filtering principle of the split ring resonator, reduce the coupling between the dual-polarized base station antennas, simultaneously expand the bandwidth of the decoupling structure, realize the decoupling between the 1.71GHz-2.69GHz broadband dual-polarized base station antennas, also can reduce the 3dB wave width of the antenna array, and provide help for the decoupling of the future 4G, 5G broadband dual-polarized base station arrays.)

1. A cascaded split-ring resonator for inhibiting coupling between broadband dual-polarized base station antennas is characterized in that: the split ring resonator comprises a split ring resonator (1), a metal strip (2) and a dielectric substrate (3); wherein two split ring resonators (1) are bridged by the metal strip (2) and printed on the dielectric substrate (3).

2. The cascaded split-ring resonator for suppressing coupling between wideband dual-polarized base station antennas of claim 1, wherein: the split-ring resonator (1) further comprises a first small split-ring resonator (1-1) and a second small split-ring resonator (1-2), the second small split-ring resonator (1-2) is arranged inside the first small split-ring resonator (1-1), the first small split-ring resonator (1-1) and the second small split-ring resonator (1-2) are both rectangular structures, and a notch is formed in the center of one side of the first small split-ring resonator and the second small split-ring resonator.

3. The cascaded split-ring resonator for suppressing coupling between antennas of a wideband dual-polarized base station as claimed in claim 1 or 2, wherein: the dielectric constant of the dielectric substrate (3) is 4.4, the loss tangent value is 0.02, the dielectric substrate (3) is an FR4 plate, the thickness of the FR4 plate is 1mm, and gaps with the width of 1mm and the height of 25mm are arranged at the positions of 0.5mm away from the edge at two sides of the FR4 plate.

4. The cascaded split-ring resonator for suppressing coupling between wideband dual-polarized base station antennas of claim 3, wherein: the split-ring antenna comprises two base station antennas (4), and is characterized by further comprising a base station antenna (4), wherein the split-ring resonator (1) is arranged between the two base station antennas (4), one base station antenna (4) is a cascaded split-ring resonator, and the distance between the split-ring resonator (1) and the center of the base station antenna (4) is 76 mm.

5. The cascaded split-ring resonator for suppressing coupling between wideband dual-polarized base station antennas of claim 4, wherein: the base station antenna (4) is a 2 x 2 array, the distance is 0.6 lambda, the frequency band is 1.71GHz-2.69GHz, the base station antenna (4) is arranged on a rectangular metal reflecting plate (5) with the thickness of 300mm x 600mm, and the center of the base station antenna (4) is the center of the metal reflecting plate (5).

Technical Field

The invention relates to the technical field of microwave devices, in particular to a cascade split-ring resonator for inhibiting coupling between broadband dual-polarized base station antennas.

Background

A multi-antenna system is an important trend in the development of mobile communication antennas. However, mutual coupling between closely spaced antenna elements can result in increased antenna pattern correlation and reduced communication capacity. For a base station antenna, the coupling between the antenna elements is strengthened and the 3dB bandwidth of the H-plane of the array is spread.

Many studies have been made at home and abroad to reduce the mutual coupling between antennas, but most decoupling methods are directed to microstrip antenna arrays. Such as Decoupled Ground (DG) structures, to eliminate free space coupling by introducing out-of-phase surface coupling; for example, a propagating coupled wave is converted into an evanescent wave using a super-surface of negative permeability.

Some solutions have also been proposed for base station antennas, but the bandwidth is generally very narrow. For example, the proposed Array Decoupling Surface (ADS) of the dual-polarized base station Antenna Array (k.wu, c.wei, x.mei and z.zhang, "Array-Antenna Decoupling Surface," in IEEE Transactions on Antennas and propagation, vol.65, no,12, pp,6728 + 6738, Dec,2017, doi: 10.1109/tap.2017.2712818) inevitably increases the Array profile and is only applicable to narrow bands.

One approach to Microstrip antenna array decoupling is to directly suppress the surface waves of the antenna by adding a resonant structure Between the two antenna elements to achieve high isolation, such as a Slotted Complementary Split-Ring resonator-SCSRR (m.m.bait-Suwailam, o.f.siddiqui and o.m.ramahi, "structural Coupling Reduction of the antenna Microstrip antenna Using Slotted-Complementary Split-Ring Resonators," IEEE Antennas Wireless performance. The SCSRR consists of two complementary split-ring resonators (CSRR) connected by an additional slot. The band gap filter characteristic of the CSRR is used for realizing decoupling, and the broadband characteristic of a decoupling structure can be realized by two CSRR cascades. In recent years, a scholars loads a Split Ring Resonator (SRR) structure on a baffle of a base station antenna to realize the conversion from a microstrip decoupling scheme to a base station antenna decoupling scheme, but the existing broadband base station antenna array decoupling scheme is rare, so that the concept of converting the microstrip decoupling scheme into the base station array decoupling scheme is worthy of further research.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides the cascade split-ring resonator for inhibiting the coupling between the broadband dual-polarized base station antennas, the invention can realize the decoupling between the broadband dual-polarized base station array units, the structure is simple, and the 3dB wave width of the antenna array can be reduced.

The technical scheme is as follows: in order to achieve the above object, the present invention provides a cascaded split-ring resonator for suppressing coupling between broadband dual-polarized base station antennas, comprising a split-ring resonator, a metal strip and a dielectric substrate; wherein two of the split-ring resonators are bridged by the metal strip and printed on the dielectric substrate.

Further, in the present invention: the split ring resonator further comprises a first small split ring resonator and a second small split ring resonator, the second small split ring resonator is arranged inside the first small split ring resonator, the first small split ring resonator and the second small split ring resonator are both rectangular structures, and a notch is formed in the center of one side of the first small split ring resonator and the second small split ring resonator.

Further, in the present invention: the dielectric constant of the dielectric substrate is 4.4, the loss tangent value is 0.02, the dielectric substrate is an FR4 plate, the thickness of the dielectric substrate is 1mm, and gaps with the width of 1mm and the height of 25mm are arranged at the positions of two sides 0.5mm away from the edge.

Further, in the present invention: the split-ring antenna comprises two base station antennas, and is characterized by further comprising a base station antenna, wherein the split-ring resonators are arranged between the two base station antennas, one base station antenna is a cascaded split-ring resonator, and the distance between the split-ring resonator and the center of the base station antenna is 76 mm.

Further, in the present invention: the base station antenna is a 2 x 2 array, the spacing is 0.6 lambda, the frequency band is 1.71GHz-2.69GHz, the base station antenna is arranged on a rectangular metal reflecting plate with the thickness of 300mm x 600mm, and the center of the base station antenna array is the center of the metal reflecting plate.

Has the advantages that: compared with the prior art, the invention has the beneficial effects that:

(1) the cascaded split-ring resonator is printed on the dielectric substrate and loaded between the antenna units of the base station, so that decoupling between the antenna units of the broadband base station can be realized, and the 3dB wave width of the array is reduced;

(2) the invention utilizes the band gap filtering principle of the split ring resonator, reduces the coupling between the dual-polarized base station antenna units, and can effectively improve the same polarization and vertical polarization isolation between the dual-polarized base station antennas;

(3) the invention utilizes the principle that the cascade split-ring resonator is equivalent to two cascade filters, expands the band gap of a decoupling structure and realizes the decoupling between the array units of the broadband dual-polarized base station with the relative bandwidth of between 1.71 and 2.69GHz and 44.5 percent.

Drawings

Fig. 1 is a schematic view of an overall structure of a cascaded split-ring resonator for suppressing coupling between broadband dual-polarized base station antennas according to the present invention;

FIG. 2 is a schematic structural diagram of a cascaded split-ring resonator according to the present invention;

FIG. 3 is a schematic structural diagram of a split-ring resonator according to the present invention;

fig. 4 is a comparison graph of simulation results of S parameters of the dual-polarized base station array before and after loading the cascaded split-ring resonator according to the present invention;

fig. 5 is a comparison diagram of the H-plane (i.e., XOZ-plane) 3dB wave widths of the dual-polarized base station array before and after loading the cascaded split-ring resonator according to the present invention;

fig. 6 is a schematic diagram showing a comparison of main polarization and cross polarization directional diagrams of a dual-polarized base station array before and after loading the cascaded split-ring resonator according to the present invention.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the attached drawings:

the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

As shown in fig. 1, a schematic diagram of an overall structure of a cascaded split-ring resonator for suppressing coupling between broadband dual-polarized base station antennas according to the present invention specifically includes a split-ring resonator 1, a metal strip 2, and a dielectric substrate 3;

referring to the schematic diagram of fig. 2, the schematic diagram is a structural schematic diagram of a cascaded split-ring resonator, where the cascaded split-ring resonator is formed by bridging two split-ring resonators 1 through the metal strip 2, and is printed on the dielectric substrate 3.

Specifically, the dielectric constant of the dielectric substrate 3 is 4.4, the loss tangent value is 0.02, the dielectric substrate 3 is an FR4 plate, the thickness of the dielectric substrate is 1mm, and a gap with the width of 1mm and the height of 25mm is arranged at the position 0.5mm away from the edge on two sides.

Further, the dielectric substrate 3 can be regarded as a perfect magnetic conductor PMC approximately at the boundary of the four side walls, and the cascade split-ring resonator can be effectively excited.

Referring to the schematic diagram of fig. 3, the split-ring resonator 1 further includes a first small split-ring resonator 1-1 and a second small split-ring resonator 1-2, the second small split-ring resonator 1-2 is disposed inside the first small split-ring resonator 1-1, and the first small split-ring resonator 1-1 and the second small split-ring resonator 1-2 are both rectangular structures, and a notch is disposed in the center of one side of the first small split-ring resonator 1-1 and the second small split-ring resonator 1-2.

Specifically, the first small split ring resonator 1-1 and the second small split ring resonator 1-2 are different in size, and the second small split ring resonator 1-2 is smaller, so that the second small split ring resonator 1-2 can be arranged in the first small split ring resonator 1-1 without contacting with the first small split ring resonator 1-1, referring to fig. 3, the notch of the first small split ring resonator 1-1 and the notch of the second small split ring resonator 1-2 are arranged in opposite directions, that is, the opposite side of the side where the notch of the first small split ring resonator 1-1 is arranged is close to the side where the notch of the second small split ring resonator 1-2 is arranged, and the opposite side of the side where the notch of the second small split ring resonator 1-2 is arranged is close to the side where the notch of the first small split ring resonator 1-1 is arranged.

Further, in the present embodiment, the width of each of the first small split ring resonator 1-1 and the second small split ring resonator 1-2 is 2.25mm, wherein the length and width of the notch of the first small split ring resonator 1-1 is 3.75mm and 2.25mm, and the length and width of the notch of the second small split ring resonator 1-2 is 6.56mm and 2.25 mm.

The split-ring resonator 1 generates resonance with a center frequency f_cComprises the following steps:

l and C are respectively the inductance and the capacitance of the split ring resonator 1, the inductance L is related to the width and the height of the first small split ring resonator 1-1 and the second small split ring resonator 1-2, and the capacitance C is related to the length and the width of the gap of the first small split ring resonator 1-1 and the second small split ring resonator 1-2. When the central resonance frequency of the split-ring resonator 1 is outside the working frequency band of the antenna, the split-ring resonator 1 is equivalent to a filter, and filtering and harmonic suppression can be realized.

Furthermore, the cascade split ring resonator is equivalent to two filters in cascade connection, and can realize broadband filtering and harmonic suppression. By optimizing the size of the cascade split-ring resonator, the same polarization and vertical polarization coupling between the dual-polarization base station antennas can be effectively inhibited. For best effect, in the present embodiment, the width of the split-ring resonator 1 is 28mm, the height thereof is 24mm, and the length of the metal strip 2 for bridging between two split-ring resonators 1 is 11mm, and the width thereof is 3.5 mm.

Furthermore, the cascaded split-ring resonator for inhibiting coupling between broadband dual-polarized base station antennas further comprises base station antennas 4, the split-ring resonator 1 is arranged between the two base station antennas 4, one base station antenna 4 is a cascaded split-ring resonator, and the distance between the split-ring resonator 1 and the center of each base station antenna 4 is 76 mm.

The base station antenna 4 is a 2 x 2 array, the spacing is 0.6 lambda, lambda corresponds to the wavelength of the central frequency 2.2GHz, the frequency band is 1.71GHz-2.69GHz, the base station antenna 4 is arranged at the center of the metal reflector 5 with the size of 300mm x 600mm, and the center of the base station antenna 4 is the center of the metal reflector 5. Referring to the schematic of fig. 1, the ports of the base station antenna 4 are labelled in fig. 1 and are designated P1-P8, where the ports P1 and P5 feed.

In order to verify the beneficial effects of the invention, referring to the schematic diagram of fig. 4, which is a comparison schematic diagram of simulation results of S parameters of dual-polarized base station arrays before and after loading the cascaded split-ring resonator, it can be seen that after the cascaded split-ring resonator provided by the invention is loaded, homopolar between adjacent units of the dual-polarized base station array 4The polarization and vertical polarization isolation degree is obviously improved, the position of each port refers to the label in the figure 1, and in addition, in the frequency band of 1.71GHz-2.69GHz, the same polarization isolation degree | S between the adjacent units₃₁Less than-20.5 dB, 5.2dB lower than that before baffle plate is added, and polarized isolation is different₄₁The | is lower than-23.3 dB, and is reduced by 3.2dB compared with the situation before the baffle is added, so that the requirement of the practical engineering application is met; moreover, after the cascade split-ring resonator provided by the invention is loaded, the return loss S of the antenna can be caused₁₁I is reduced by 0.58dB, | S₂₂Decrease | by 2.55dB, although make | S₂₁The improvement is about 3dB, but this part of the error is acceptable due to the improved isolation between antenna elements.

Further, referring to the schematic diagrams of fig. 5 and fig. 6, fig. 5 is a schematic diagram showing the comparison of the 3dB wave widths of the dual-polarized base station arrays before and after loading the cascaded split-ring resonator, that is, the XOZ plane, and fig. 6 is a schematic diagram showing the comparison of the main polarization and cross polarization directional diagrams of the dual-polarized base station arrays before and after loading the cascaded split-ring resonator, because the problem of 3dB wave width expansion of the H plane of the array is caused by coupling between the base station antenna units, the 3dB wave widths of the array can be reduced by loading the cascaded split-ring resonator provided by the present invention, and the maximum wave width can reach 28 °; in addition, after the cascade split-ring resonator provided by the invention is loaded, the array main polarization directional diagram is kept stable, and meanwhile, the cross polarization is also kept at a lower level, so that a stable radiation directional diagram is obtained.

It should be noted that the above-mentioned examples only represent some embodiments of the present invention, and the description thereof should not be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various modifications can be made without departing from the spirit of the present invention, and these modifications should fall within the scope of the present invention.