CN108365331A - A kind of high isolation Bipolarization antenna for base station unit towards 5G applications - Google Patents

Abstract

The invention relates to a high-isolation dual-polarization base station antenna unit for 5G applications, including a dielectric board, a coaxial feeder, a backplane and an SMA feeder arranged in sequence from bottom to bottom, and the front and back of the dielectric board are etched with ±45 ° a first bow-tie dipole antenna and a second bow-tie dipole antenna placed vertically, each of the bow-tie dipole antennas is composed of two symmetrically arranged dipole antenna arms, and the dipoles Antenna arms include optimized fragmented parasitic structures. The advantage of the present invention is that: the high-isolation dual-polarized base station antenna unit for 5G applications, by optimizing the fragmented parasitic structure, forms a base station antenna unit with low loss and high isolation characteristics, low loss and high isolation, and can reduce the size of the antenna self-loss and reduce self-interference between antennas.

Description

A high-isolation dual-polarization base station antenna unit for 5G applications

technical field

The invention relates to a dual-polarized base station antenna unit, in particular to a high-isolation dual-polarized base station antenna unit for 5G applications.

Background technique

In recent years, with the rapid development of wireless communication technology, people's desire for data rate is increasing day by day. Dual-polarized antennas are widely used in base station systems because they can achieve greater channel capacity and faster transmission rates. However, in a communication system, there is often a strong mutual coupling between the dual-polarized antennas of the base station antenna unit, and the self-interference caused by this will degrade the performance of the base station system. Therefore, it is essential to design a base station antenna unit with high polarization isolation.

Research on high-isolation dual-polarization base station antenna units is ongoing at home and abroad, literature [1] (Mao Jianjun, Yu Daqun, Jiao Yongchang. A massive MIMO antenna array design for 5G. Modern Radar, 2 (2016) , 66-69.) Using orthogonal H-shaped slot coupling feeding, a dual-polarized antenna unit with isolation higher than 23dB was designed; literature [2] (K-L.Wu, C.Wei, X.Mei and Z. Zhang, Array-Antenna Decoupling Surface, IEEE Trans.AntennasPropag., 12(2017), 6728–6738.) uses decoupling and surface cancellation coupling wave to realize a dual-polarized base station antenna unit with isolation higher than 30dB; literature [3 ](K.Mak,H.Lai and K.Luk,A 5G Wideband Patch Antenna withAntisymmetric L-shaped Probe Feeds,IEEE Trans.Antennas Propag.,2017.) using orthogonal L-shaped probe coupling feeds, designed Dual polarized base station antenna unit with isolation higher than 30dB.

At present, higher-performance dual-polarized base station antenna units that accurately cover the 5G frequency band (3.4-3.6GHz) are still blank. The invention adopts the dipole antenna placed vertically at ±45° to realize dual polarization, and realizes higher isolation performance by optimizing the fragmented parasitic structure. Facing the background of 5G applications, the present invention designs a dual-polarized base station antenna unit working in the 3.4-3.6GHz frequency band. The return loss of the base station antenna unit in the working frequency band is higher than 20dB, and the isolation between dual-polarized antennas is higher than 40dB.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-isolation dual-polarization base station antenna unit for 5G applications that can achieve higher isolation performance.

In order to solve the above technical problems, the technical solution of the present invention is: a high-isolation dual-polarization base station antenna unit for 5G applications. SMA feeding, the first bow-tie dipole antenna and the second bow-tie dipole antenna placed vertically at ±45° are etched on the front and back of the dielectric plate, and each bow-tie dipole antenna is composed of two symmetrical The dipole antenna arm is configured, and the dipole antenna arm includes an optimized fragmented parasitic structure.

Further, the two dipole antenna arms of the first bow-tie dipole antenna in the base station antenna unit are respectively etched on the upper and lower surfaces of the dielectric board, and the two dipole arms of the second bow-tie dipole antenna are respectively etched on the upper and lower surfaces of the dielectric board. The antenna arms are all etched on the lower surface of the dielectric plate, and the two dipole antennas are vertical to achieve dual polarization.

Further, the coaxial feeder includes a first coaxial feeder and a second coaxial feeder respectively connected to two dipole antennas and arranged in parallel, the inner conductor of the first coaxial feeder is connected to the first collar dipole The sub-antenna is arranged on the dipole patch on the upper surface of the dielectric board, and the outer conductor of the first coaxial feeder is connected to the dipole patch and the back of the first collar dipole antenna arranged on the lower surface of the dielectric board. Plate connection; the inner conductor of the second coaxial feeder is connected to the transmission line on the upper surface of the dielectric plate with the second collar dipole antenna, and the transmission line on the upper surface is arranged on the medium through the through hole and the second collar dipole antenna. A dipole patch on the lower surface of the board is connected, and the outer conductor of the second coaxial feeder is connected to another dipole patch on the lower surface of the dielectric board and the backplane of the second collar dipole antenna.

Further, the dipole antenna arm is a combined structure of an isosceles triangle and a fragmented parasitic structure.

Further, the fragmented parasitic structure in the dipole antenna arm is optimized through a multi-objective optimization algorithm.

The advantages of the present invention are:

(1) The high-isolation dual-polarization base station antenna unit for 5G applications of the present invention forms a base station antenna unit with low-loss, high-isolation characteristics, low-loss and high-isolation characteristics by optimizing the fragmented parasitic structure, thereby reducing the loss of the antenna itself, And reduce the self-interference between antennas; compared with traditional base station antenna units, the return loss of the antenna unit of the present invention is higher than 20dB, and the isolation between dual-polarized antennas is higher than 40dB. As a 5G base station antenna unit, the present invention will further Improve the performance of future 5G base station systems;

(2) The high-isolation dual-polarization base station antenna unit for 5G applications of the present invention, the fragmented parasitic structure in the dipole patch is optimized by a multi-objective optimization algorithm, and based on the multi-objective optimization algorithm, the parasitic structure with low loss and high isolation is searched .

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 is an overall schematic diagram of a ±45° dual-polarized base station antenna unit in an embodiment of the present invention.

Fig. 2 is a side sectional view of the base station antenna unit in the embodiment of the present invention.

3 and 4 are diagrams of a dipole antenna etched on a dielectric plate in an embodiment of the present invention.

5 to 9 are schematic diagrams of the design process of the fragmented parasitic structure model in the embodiment of the present invention.

10 and 11 are optimized parasitic structures and dipole antenna models in the embodiments of the present invention, respectively.

Fig. 12 is the simulated S parameter of the antenna unit of the base station in the embodiment of the present invention.

13 and 14 are radiation patterns simulated at 3.5 GHz for the base station antenna unit in the embodiment of the present invention.

Detailed ways

The following examples can enable those skilled in the art to understand the present invention more comprehensively, but the present invention is not limited to the scope of the described examples.

Example

The high-isolation dual-polarized base station antenna unit for 5G applications in this embodiment, as shown in Figures 1 and 2, includes a dielectric board 1, a coaxial feeder 2, a backplane 3 and an SMA feeder arranged in sequence from bottom to bottom. The first bow-tie dipole antenna 4 and the second bow-tie dipole antenna 5 placed vertically at ±45° are etched on the front and back of the board 1, and the first bow-tie dipole antenna 4 includes symmetrically arranged dipole antennas Arm 41 and dipole antenna arm 42, the second bow-tie type dipole antenna 5 includes dipole antenna arm 51 and dipole antenna arm 52 that are arranged symmetrically, and each dipole antenna arm includes optimized fragmented parasitic structure .

As shown in Figures 3 and 4, the dipole antenna arm 41 of the first bow tie type dipole antenna 4 is etched on the upper surface of the dielectric plate 1, and the dipole antenna arm 42 of the first bow tie type dipole antenna 4 Etched on the lower surface of the dielectric plate 1, the two dipole antenna arms of the second tie-type dipole antenna 5 are all etched on the lower surface of the dielectric plate 1, and the inner end of the dipole antenna arm 41 is connected with a dipole The pole patch 43 and the inner end of the dipole antenna arm 51 are connected to the dipole patch 53 through a through hole.

The coaxial feeder 2 includes a first coaxial feeder 21 and a second coaxial feeder 22 which are respectively connected to two dipole antennas and arranged in parallel. As shown in FIGS. 2 and 3 , the inner conductor of the first coaxial feeder 21 and the second A collar-type dipole antenna 4 is arranged on the connection of the dipole patch 43 on the upper surface of the dielectric board 1, and the outer conductor of the first coaxial feeder 21 and the first collar-type dipole antenna 4 are arranged under the dielectric board 1 The dipole patch 42 (dipole antenna arm 42 inner end) on the surface is connected with the backboard 3; as shown in Figure 4, the inner conductor of the second coaxial feeder 22 is arranged with the second collar type dipole antenna 5 The transmission line on the upper surface of the dielectric board 1 is connected, the upper surface transmission line is connected with the dipole patch 53 arranged on the lower surface of the dielectric board 1 by the second collar dipole antenna 5 through the through hole 6, and the second coaxial feeder 22 The outer conductor is connected to the dipole patch 52 (inner end of the dipole antenna arm 52 ) disposed on the lower surface of the dielectric plate 1 and the back plate 3 of the second collar dipole antenna 5 .

In the embodiment, the dipole antenna arms are all combined structures of an isosceles triangle and a fragmented parasitic structure, and the four identical rectangular areas in FIG. 4 are design regions of the fragmented parasitic structure. The fragmented structure can also be applied to the design of other areas of the antenna such as isosceles triangles and backplanes.

Due to the symmetry of the antenna, as shown in Figure 5, the rectangular area can be divided into two identical rectangles; as shown in Figure 6, each rectangle can be discretized into rectangular fragments with m rows and n columns, and the fragment structure unit It can also exist in various forms such as circle, square, triangle, polygon, ring, etc. The unit arrangement density can be adjusted according to the actual situation, and then each fragment is assigned "0" or "1"; if "0" means non-metallic Unit, "1" indicates a metal unit, and the fragmented structure can be expressed as the shape of Figure 7; the symmetrical operation along the dotted line can obtain the design structure shown in Figure 8; the design structure can be etched to the corresponding area of the dielectric plate, and the following can be obtained: Antenna shown in Figure 9.

The design of the low-loss and high-isolation 5G base station antenna unit in this embodiment is a multi-objective optimization problem. The fragmented structure transforms the antenna structure optimization problem into the optimization of a two-dimensional matrix. The setting of the objective function is extremely important in the entire optimization design process. link. For the design of dual-polarized high-performance 5G base station antennas, the return loss is the primary consideration. According to the symmetry of the antenna, it is described as follows:

Among them, [ω ₁ , ω ₂ ] represent the working frequency band of the antenna, and S ₁₁ represents the return loss. To design a 5G base station antenna unit with high matching performance, the target value _Q1 can be set to 20.

In addition to return loss, isolation is also an important indicator that needs to be considered by the base station antenna, which is described as follows:

Among them, S ₁₂ represents the isolation between dual-polarized antennas in the antenna unit, and the target value Q ₂ can be set to 40 to achieve a high isolation design.

This design takes low loss and high isolation as an example, and optimizes the fragmented parasitic structure through a multi-objective optimization algorithm to achieve a return loss of 20dB and an isolation of 40dB. In addition, the base station antenna unit also has certain requirements on beam width, cross-polarization ratio, and front-to-back ratio. It is only necessary to add an objective function to the multi-objective optimization algorithm to optimize the radiation characteristics of the antenna.

Fixed antenna parameters: L1＝8.4mm, L2＝14mm, L3＝7mm, L4＝6.5mm, L5＝7.4mm, L6＝1.8mm, α＝87°, W＝60mm, H＝22mm, h＝4mm. [ω ₁ ,ω ₂ ] is set to the 5G working frequency band [3.4GHz, 3.6GHz], and the final structure and antenna structure obtained from the search are shown in Figures 10 and 11. As shown in Figure 12, the return loss of the antennas in the 3.4-3.6GHz frequency range is higher than 20dB, and the isolation between dual-polarized antennas is higher than 40dB. As shown in Figures 13 and 14, the axial cross-polarization of the antenna H plane is lower than -25dB, the half-power beamwidth is 90°, and the cross-polarization is lower than -18dB in the range of ±60°; the half-power beamwidth of the E-plane is 70°; the antenna gain is 8.1dB, and the front-to-back ratio is higher than 23dB.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. a kind of high isolation Bipolarization antenna for base station unit towards 5G applications, it is characterised in that：Including from and under be sequentially arranged Dielectric-slab, coaxial feeder, backboard and SMA feeds, the dielectric-slab positive and negative etched ± 45 ° of first knots being disposed vertically Type dipole antenna and the second bow-tie type dipole antenna, each bow-tie type dipole antenna is by two symmetrically arranged dipoles Sub-antenna arm is constituted, and the dipole antenna arm includes optimization fragment type parasitic structure.

2. the high isolation Bipolarization antenna for base station unit according to claim 1 towards 5G applications, it is characterised in that：It is described Two dipole antenna arms of the first bow-tie type dipole antenna in base station antenna unit etch respectively in dielectric-slab upper surface and Two dipole antenna arms of lower surface, the second bow-tie type dipole antenna are etched in dielectric-slab lower surface, and two dipole days Line vertically realizes dual polarization.

3. wanting the high isolation Bipolarization antenna for base station unit applied towards 5G described in 2 according to right, it is characterised in that：It is described same Feeder shaft includes connecting respectively with two dipole antennas and the first coaxial feeder disposed in parallel and the second coaxial feeder, and described the The inner wire of one coaxial feeder is connect with the dipole patch that the first collar dipole antenna is arranged in dielectric-slab upper surface, described Dipole patch and the back of the body in dielectric-slab lower surface is arranged in the outer conductor of first coaxial feeder and the first collar dipole antenna Plate connects；The transmission line in dielectric-slab upper surface is arranged in the inner wire of second coaxial feeder and the second collar dipole antenna The dipole patch in dielectric-slab lower surface is arranged by through-hole and the second collar dipole antenna for connection, upper surface transmission line Connection, another dipole in dielectric-slab lower surface is arranged in the outer conductor of second coaxial feeder and the second collar dipole antenna Sub- patch and backboard connection.

4. the high isolation Bipolarization antenna for base station unit according to claim 1 towards 5G applications, it is characterised in that：It is described Dipole antenna arm is the composite structure of isosceles triangle and fragment type parasitic structure.

5. the high isolation Bipolarization antenna for base station unit according to claim 1 towards 5G applications, it is characterised in that：It is described Fragment type parasitic structure optimizes to obtain by multi-objective optimization algorithm in dipole antenna arm.