CN205211944U - Differential broadband dual-polarized base station antenna with improved cross-polarization ratio - Google Patents

Abstract

The utility model discloses a difference broadband dual-polarized base station antenna for improving cross polarization ratio, which comprises a reflecting plate, a cross feed structure, four radiating elements and four coaxial lines, wherein after the upper ends of the four coaxial lines pass through the reflecting plate, the outer conductors at the upper ends of the four coaxial lines are connected with the four radiating elements in a one-to-one correspondence manner, and the inner conductor at the upper end of each coaxial line is connected with the cross feed structure after passing through the corresponding radiating element; the lower ends of the four coaxial lines are connected with the SMA heads; the four coaxial lines form two pairs of differential feed ports, the four radiating units form two pairs of dipoles, and the two pairs of differential feed ports feed the two pairs of dipoles. The utility model has the characteristics of broadband, high cross polarization ratio, high isolation have realized stable radiation pattern, stable half power beam width and stable gain, simple structure, functional moreover, adopt the foundry goods structure, but increase of service life.

Description

Differential broadband dual-polarized base station antenna with improved cross-polarization ratio

technical field

The utility model relates to a differential broadband dual-polarization base station antenna, in particular to a differential broadband dual-polarization base station antenna with improved cross polarization ratio, which belongs to the technical field of wireless mobile communication.

Background technique

In the past 20 years, the mobile communication industry has achieved rapid development. As of the beginning of 2012, the number of mobile phone users in the world reached 6 billion. According to statistics from the Ministry of Industry and Information Technology of China, as of the end of March 2013, China had a total of 1.146 billion mobile communication service users. According to data from the International Telecommunication Union, in early 2014, there were more than 7 billion mobile phone users worldwide. The development of the mobile communication industry in the future will be immeasurable, and it will have a significant impact on the national economy and people's lives. In China, on December 4, 2013, the Ministry of Industry and Information Technology promulgated the "LTE/Fourth Generation Digital Cellular Mobile Communication Service (TD-LTE)" business plan to China Mobile Communications Corporation, China Telecom Corporation, and China United Network Communications Corporation license. China Mobile obtained 130MHz spectrum resources, respectively 1880-1900MHz, 2320-2370MHz, 2575-2635MHz; China Unicom obtained 40MHz spectrum resources, respectively 2300-2320MHz, 2555-2575MHz; China Telecom obtained 40MHz spectrum resources, respectively 2370-2390MHz , 2635-2655MHz. This marks that my country has entered the 4G era. Therefore, the research on base station antennas has entered an era of "broadband" and "multi-frequency" along with the development of communication systems. On the one hand, the evolution of the mobile communication system is a long-term and gradual process. It is expected that the coexistence of 2G, 3G and 4G systems will be maintained for a long time in the future. Multi-system shared base stations and multi-system shared antennas are feasible. Effective solutions; on the other hand, as people pay more and more attention to visual pollution and electromagnetic radiation pollution, coupled with the high maintenance cost of base station antennas, there is an urgent need to reduce the number. The broadband/multi-frequency antenna can provide services for multiple systems with one antenna, effectively reducing the number of antennas and occupying space, and has very broad application space and practical value.

The ever-increasing demand for communication requires continuous expansion of the communication system. Designing the communication system using the orthogonal polarization characteristics of electromagnetic waves can enable the dual-polarization system to obtain higher system capacity. In order to increase the system capacity and reduce the impact of multipath fading, the receiving end of the system generally adopts ±45 dual-polarized base station antennas to receive signals, and its diversity gain improves system performance.

At present, RF circuits usually use differential technology to transmit signals, and many RF front-end devices can be directly integrated into transceiver chips. However, as an important component of the RF front-end circuit, most antennas are designed as single-port devices and cannot be directly integrated with differential circuits. Usually, a balun is required to convert the differential signal into a single-port signal and then feed it into the antenna. The use of the balun will cause loss, reduce the system efficiency, and increase the number of independent devices, which is not conducive to the high integration and miniaturization of the system.

According to the investigation and understanding, the currently disclosed prior art is as follows:

1) In 2013, YingLiu, HaoYi, Fu-WeiWang and Shu-XiGong et al published an article titled "ANovelMiniaturizedBroadbandDual-PolarizedDipoleAntennaforBaseStation" in "IEEEANTENNASANDWIRELESSPROPAGATIONLETTERS", using the traditional single-port antenna design method, which basically meets the parameter requirements of the base station antenna , a square ring and a square plate are introduced into the antenna as a parasitic radiation ring and a director, respectively, so that the antenna has a smaller electrical size. However, the half-power beam width is too large, and the cross-polarization ratio of the antenna is not discussed. On the other hand, the introduction of parasitic radiation loops and directors will make the antenna structure too complicated and the processing difficulty will be increased.

2) In 2012, ZengdiBao, ZaipingNie and Xianzheng Zong et al published an article entitled "A Novel Broadband Dual-Polarization Antenna Utilizing Strong Mutual Coupling" in "IEEETRANSACTIONSONANTENNASANDPROPAGATION", using the traditional single-port design method, using the mode generated by the dipole itself and the relationship between the two pairs of dipoles The coupling produces another mode to achieve a wider bandwidth. However, the shape of the reflector of this antenna is too complicated, the size is large, and the appropriate half-power beam width is not achieved, and the cross-polarization ratio within the range of 60 degrees in the horizontal plane is not discussed.

Utility model content

The purpose of this utility model is to solve the defects of the above-mentioned prior art, and provide a differential broadband dual-polarization base station antenna with improved cross-polarization ratio, which realizes a stable radiation pattern and a stable half-power beam width And stable gain, with the advantages of simple structure and good performance.

The purpose of this utility model can be achieved by taking the following technical solutions:

A differential broadband dual-polarized base station antenna with improved cross-polarization ratio, including a reflector, a cross-shaped feed structure, four radiating elements and four coaxial lines, the upper ends of the four coaxial lines pass through the reflector , the outer conductors at the upper ends of the four coaxial lines are connected to the four radiation units one by one, and the inner conductors at the upper end of each coaxial line are connected to the cross-shaped feed structure after passing through the corresponding radiation units; the four The lower end of the coaxial line is connected to four SMA heads in one-to-one correspondence; the four coaxial lines form two pairs of differential feed ports, the four radiation units form two pairs of dipoles, and the two pairs of differential feed ports Feed two pairs of dipoles.

As a preferred solution, the four radiating units are respectively the first radiating unit, the second radiating unit, the third radiating unit and the fourth radiating unit, and the first radiating unit and the third radiating unit are in a direction of -45 degrees placed, the second radiating unit and the fourth radiating unit are placed in a direction of +45 degrees; the four coaxial lines are respectively the first coaxial line, the second coaxial line, the third coaxial line and the fourth coaxial line line, the first coaxial line corresponds to the first radiating unit, the second coaxial line corresponds to the second radiating unit, the third coaxial line corresponds to the third radiating unit, and the fourth coaxial line corresponds to the fourth Radiation unit; a pair of differential feeding ports formed by the first coaxial line and the third coaxial line feeds a pair of dipoles formed by the first radiating unit and the third radiating unit, and the second coaxial line A pair of differential feeding ports formed with the fourth coaxial line feeds a pair of dipoles formed by the second radiating unit and the fourth radiating unit.

As a preferred solution, it also includes a supporting structure, the supporting structure is arranged between the reflecting plate and the four radiating units, and is used to support the four radiating units; the upper ends of the four coaxial lines pass through the reflecting plate, After supporting the structure, the outer conductors at the upper ends of the four coaxial lines are connected to the four radiation units one by one, and the inner conductors at the upper end of each coaxial line are connected to the cross-shaped feed structure after passing through the corresponding radiation units; The lower ends of the four coaxial cables are connected to the four SMA heads one by one.

As a preferred solution, the reflector is a square box-shaped structure, and there is a flange inside the reflector, and the flange forms a square box-shaped structure inside the reflector, and the support structure is located at the edge surrounded by the flange. into the center of a square box-like structure.

As a preferred solution, the shape of the support structure is a cylinder.

As a preferred solution, the support structure is made of polytetrafluoroethylene plastic.

As a preferred solution, both the reflecting plate and the flange are made of aluminum alloy.

As a preferred solution, the shapes of the four radiation units are all square; or the shapes of the four radiation units are all square with corners cut.

As a preferred solution, the cross-shaped feed structure and the four radiation units are all made of copper material.

As a preferred solution, the four coaxial wires are all 50Ω coaxial wires.

Compared with the prior art, the utility model has the following beneficial effects:

1. In the differential broadband dual-polarized base station antenna of the present utility model, the outer conductors of four coaxial lines are connected to four radiation units, and the inner conductors pass through the radiation units and are connected to the cross-shaped feed structure, that is, four Two pairs of differential feed ports formed by a coaxial line provide differential feeds to two pairs of dipoles formed by four radiating elements, and the impedance bandwidth of the antenna is 1.65-2.77GHz when SWR (StandingWaveRatio, standing wave ratio) < 1.5 , and the cross-shaped feed structure makes the differential signal isolation between the two pairs of differential feed ports of the antenna very high. Due to the introduction of differential feed, the antenna can be directly connected to the differential circuit without additionally designing a balun. It can also effectively suppress the common mode noise signal.

2. The differential feed adopted by the differential broadband dual-polarization base station antenna of the present invention can form a relatively wide impedance bandwidth composed of two resonance modes, and the two modes in the impedance bandwidth can be controlled by controlling the size of the radiation unit and the spacing between the radiating elements to achieve the desired impedance bandwidth.

3. In the differential broadband dual-polarization base station antenna of the present utility model, a support structure is set between the reflector and the radiation unit, and the parameters of the reflector and the support structure are optimized, so that the antenna can maintain a stable horizontal plane and vertical position in the entire frequency band. Surface radiation pattern, and the half power beam width (HBPW) meets the requirements of the base station antenna, with high and stable gain.

4. In the differential broadband dual-polarized base station antenna of the present utility model, the flanging is introduced into the reflector, so that the cross-polarization ratio (XPD) of the antenna is better improved, and the axial XPD>50dB, the horizontal plane ± XPD > 10dB within 60 degrees, which fully meets the requirements of the base station antenna for the cross-polarization ratio.

5. The differential broadband dual-polarized base station antenna of the present utility model has the characteristics of wide frequency band, high cross polarization ratio, and high isolation, and realizes a stable radiation pattern, stable half-power beam width and stable gain, and The structure is simple, the performance is good, and the casting structure can prolong the service life.

Description of drawings

FIG. 1 is a structural diagram of a differential broadband dual-polarization base station antenna in Embodiment 1 of the present invention.

Fig. 2 is a structural diagram of the relationship among the cross-shaped feeding structure, supporting structure, four coaxial cables and four radiation units in Embodiment 1 of the utility model.

FIG. 3 is a graph of the standing wave ratio of the differential feed ports Port1 and Port2 in Embodiment 1 of the present invention.

FIG. 4 is a diagram of the current distribution on the cross-shaped feed structure when the differential feed port Port1 of Embodiment 1 of the present invention is excited.

FIG. 5 is a curve diagram of differential mode signal isolation of differential feed ports Port1 and Port2 in Embodiment 1 of the present invention.

FIG. 6 is a horizontal plane radiation pattern when the differential feed port Port1 is excited in Embodiment 1 of the present utility model.

Fig. 7 is a vertical plane radiation pattern when the differential feed port Port1 is excited in Embodiment 1 of the present utility model.

Fig. 8 is a comparison diagram of the half-power beam width curves of the horizontal plane and the vertical plane when the differential feed port Port1 is excited in Embodiment 1 of the present utility model.

FIG. 9 is a gain curve diagram of the antenna when the differential feed port Port1 is excited in Embodiment 1 of the present utility model.

Fig. 10 is a comparison diagram of cross polarization ratio curves at 1.7 GHz, 2.2 GHz and 2.7 GHz when the differential feed port Port1 is excited by the differential feed port Port1 in Embodiment 1 of the present utility model at +45 degree direction of the antenna.

Fig. 11 is a structural diagram of four radiation units in Embodiment 2 of the present invention.

Among them, 1-reflector, 2-cross feed structure, 3-support structure, 4-flange, 5-first radiating unit, 6-second radiating unit, 7-third radiating unit, 8-fourth Radiation unit, 9 - the first coaxial line, 10 - the second coaxial line, 11 - the third coaxial line, 12 - the fourth coaxial line.

detailed description

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto.

Example 1:

As shown in Figures 1 and 2, the differential broadband dual-polarized base station antenna of this embodiment includes a reflector 1, a cross-shaped feed structure 2, a support structure 3, four radiation units, and four coaxial lines;

The reflector 1 is a square box-shaped structure, and the reflector 1 has a flanging 4, and the flanging 4 forms a square box-like structure in the reflector 1. The side lengths of the reflector 1 are Lg1, height is H1, the side length of flanging 4 is Lg2, and the height is H2. Reflector 1 is used to form a better and stable radiation pattern, gain and half-power beam width in the entire bandwidth. The chemical ratio has been greatly improved;

The shape of the support structure 3 is a cylinder, which is arranged between the reflector 1 and the four radiation units, and is located in the center of the square box-shaped structure surrounded by the flange 4, and is used to support the four radiation units;

Both the reflector 1 and the support structure 3 have a part cut out for the coaxial line to pass through, and each radiation unit has a part cut out for the coaxial inner conductor to pass through;

The shapes of the four radiating units are all square, which are respectively the first radiating unit 5, the second radiating unit 6, the third radiating unit 7 and the fourth radiating unit 8, and the first radiating unit 5 and the third radiating unit 7 is placed in a direction of -45 degrees to form a linear polarization in the direction of -45 degrees, that is, a pair of dipoles is formed, and the second radiation unit 6 and the fourth radiation unit 8 are placed in a direction of +45 degrees to form a line in the direction of +45 degrees Polarization, the whole can form a ±45-degree dual-polarized antenna, which also constitutes a pair of dipoles;

The four coaxial wires are all 50Ω coaxial wires, which are respectively the first coaxial wire 9, the second coaxial wire 10, the third coaxial wire 11 and the fourth coaxial wire 12; the first coaxial wire 9. After the upper ends of the second coaxial line 10, the third coaxial line 11 and the fourth coaxial line 12 pass through the reflector 1 and the support structure 3 in sequence, the outer conductor at the upper end of the first coaxial line 9 and the first radiation unit 5 connection, the outer conductor at the upper end of the second coaxial line 10 is connected with the second radiation unit 6, the outer conductor at the upper end of the third coaxial line 11 is connected with the third radiating unit 7, and the outer conductor at the upper end of the fourth coaxial line 12 is connected with the The fourth radiating unit 8 is connected, and the inner conductors at the upper ends of the first coaxial line 9, the second coaxial line 10, the third coaxial line 11 and the fourth coaxial line 12 pass through their respective corresponding first radiating units 5, The second radiating unit 6, the third radiating unit 7, and the fourth radiating unit 8 are then connected to the cross-shaped feeding structure 2; the first coaxial line 9, the second coaxial line 10, the third coaxial line 11 and the The lower ends of the four coaxial lines 12 are connected to the four SMA heads in one-to-one correspondence; the second coaxial line 10 and the fourth coaxial line 12 form a pair of differential feed ports Port1 (Port1-, Port1+), differential feed The port Port1 feeds a pair of dipoles formed by the second radiating unit 6 and the fourth radiating unit 8, and the first coaxial line 9 and the third coaxial line 11 form a pair of differential feeding ports Port2 (Port2-, Port2+), the differential feed port Port2 feeds a pair of dipoles formed by the first radiating unit 5 and the third radiating unit 7, forming a wide impedance bandwidth and a high isolation composed of two resonant modes; Different from the general single-port feed, the differential feed port Port1 and the differential feed port Port2 in this embodiment feed in differential signals with equal amplitudes and opposite phases.

The two 45-degree linear polarizations of the antenna in this embodiment are completely symmetrical. The standing wave ratios of the two pairs of differential feed ports Port1 and Port2 are shown in Figure 3. The curves basically coincide completely. Since the differential feed ports Port1 and Port2 are completely symmetrical , the following electromagnetic simulation curves (Figure 6-Figure 10) are all the curves with the differential feed port Port1 as the excitation, and the differential feed port Port2 is similar when the differential feed port Port2 is excited; the side length L of each radiation unit only affects the low frequency mode, and the low frequency mode With the increase of the side length L, it will move to the low frequency, and the distance g between the radiating elements will affect the two modes at the same time. When the distance g increases, the two modes will be far away, the impedance bandwidth will increase, but the matching will become Difference.

The cross-shaped feed structure 2 includes two vertical feed parts. When the port Port1- and port Port1+ feed differential signals, the black line in FIG. The current in the line direction is very weak when the current reaches Port2- and Port2+, and the current on Port1- and Port1+ is theoretically infinitesimal, so the antenna has a high isolation, and the differential signal isolation in the entire frequency band is greater than 60dB, as shown in Figure 5.

The height of the reflector 1 from the radiation unit, that is, the height H3 of the support structure 3, and the parameters of the reflector 1 (Lg1, Lg2, H1, H2) have a great influence on the radiation pattern of the antenna, and the height H3 is generally taken as impedance The bandwidth center frequency of 2.2GHz corresponds to 1/4 of the free space wavelength. Optimizing parameters H3, Lg1, Lg2, H1 and H2 can make the antenna have a better and stable radiation pattern in the entire frequency band, as shown in Figure 6 and Figure 7 The half-power beam width is controlled within the range of 66°±3.5°, as shown in Figure 8; the gain is controlled within a relatively high range of 9.1±0.2dB, as shown in Figure 9; the axial cross-polarization ratio is much greater than 15dB , Theta(θ) with a cross-polarization ratio greater than 10dB in the horizontal plane is at least 65 degrees. Figure 10 shows the cross-polarization ratios at +45 degrees at 1.7GHz, 2.2GHz and 2.7GHz when the differential feed port Port1 is excited, satisfying The base station antenna requires that the range of ±60 degrees in the horizontal plane is greater than 10dB. The most critical thing is the flange 4 in the reflector 1, which greatly improves the cross-polarization ratio of the antenna.

Therefore, the antenna of this embodiment utilizes the differentially fed dipole to generate two resonant modes to realize a working broadband of 1.65-2.77GHz (SWR<1.5); Symmetrical, the characteristics of the antenna are exactly the same when the differential feed ports Port1 and Port2 are respectively excited, and the differential feed also ensures that the antenna has a better radiation pattern; the special cross-shaped feed structure 2 makes the differential feed port Port1 of the antenna and the There is a high differential signal isolation between Port 2; reflector 1 and the appropriate distance between reflector 1 and the radiation unit can make the antenna obtain stable half-power beam width and stable gain, and the flange in reflector 1 4, the antenna can meet the requirement that the axial cross-polarization ratio is much greater than 15dB and the ±60-degree range in the plane is greater than 10dB on the ±45-degree plane; the movement of the low-frequency mode can be controlled by adjusting the length of the radiation unit, and the radiation unit can be adjusted The distance between them can simultaneously control the movement of the two modes in order to obtain the required bandwidth.

Example 2:

As shown in Figure 11, the main feature of this embodiment is that the shapes of the four radiation units (the first radiation unit 5, the second radiation unit 6, the third radiation unit 7 and the fourth radiation unit 8) are all The corner-cut square, other parts are the same as those in Embodiment 1, and the target characteristics can also be achieved, meeting the requirements of the base station antenna for various parameters.

In the above embodiment, the reflector 1 and the flange 4 are both made of aluminum alloy, the support structure 3 is made of polytetrafluoroethylene plastic (the king of plastics "Teflon"), and the cross-shaped feed structure 2 and four radiating elements are made of copper material.

In summary, the differential broadband dual-polarized base station antenna of the present invention has the characteristics of wide frequency band, high cross polarization ratio, and high isolation, and realizes a stable radiation pattern, stable half-power beam width and stable Gain, and simple structure, good performance, using casting structure, can prolong the service life.

The above is only a preferred embodiment of the utility model patent, but the scope of protection of the utility model patent is not limited thereto, any skilled person familiar with the technical field within the disclosed scope of the utility model patent, according to The technical scheme of the utility model patent and the equivalent replacement or change of the utility model concept all belong to the protection scope of the utility model patent.

Claims (10)

1. The differential broadband dual-polarized base station antenna that improves the cross-polarization ratio, including a reflector, is characterized in that: it also includes a cross-shaped feed structure, four radiation elements and four coaxial lines, and the four coaxial lines After the upper end of the line passes through the reflector, the outer conductors at the upper ends of the four coaxial lines are connected to the four radiation units one by one, and the inner conductors at the upper end of each coaxial line are connected to the cross-shaped feeder after passing through its corresponding radiation unit. Electrical structural connection; the lower ends of the four coaxial cables are connected to the four SMA heads in one-to-one correspondence; the four coaxial cables form two pairs of differential feed ports, and the four radiating units form two pairs of dipoles, The two pairs of differential feed ports feed the two pairs of dipoles. 2. The differential broadband dual-polarized base station antenna for improving cross-polarization ratio according to claim 1, characterized in that: the four radiating elements are respectively the first radiating element, the second radiating element, and the third radiating element and the fourth radiating unit, the first radiating unit and the third radiating unit are placed in a direction of -45 degrees, the second radiating unit and the fourth radiating unit are placed in a direction of +45 degrees; the four coaxial lines are respectively are the first coaxial line, the second coaxial line, the third coaxial line and the fourth coaxial line, the first coaxial line corresponds to the first radiation unit, and the second coaxial line corresponds to the second radiation unit, so The third coaxial line corresponds to the third radiating unit, and the fourth coaxial line corresponds to the fourth radiating unit; the pair of differential feed ports formed by the first coaxial line and the third coaxial line is paired with the first radiating unit The pair of dipoles formed by the second coaxial line and the fourth coaxial line are fed to the pair of dipoles formed by the third radiating unit, and the pair of differential feed ports formed by the second coaxial line and the fourth coaxial line is fed to the pair of dipoles formed by the second radiating unit and the fourth radiating unit. The poles are fed. 3. The differential wide-band dual-polarized base station antenna for improving cross-polarization ratio according to claim 1, characterized in that: it also includes a support structure, and the support structure is arranged between the reflector and the four radiation units, with To support four radiating units; after the upper ends of the four coaxial lines pass through the reflector and the supporting structure in turn, the outer conductors at the upper ends of the four coaxial lines are connected with the four radiating units one by one, and each coaxial line The inner conductor at the upper end is connected to the cross feed structure after passing through the corresponding radiation unit; the lower ends of the four coaxial cables are connected to the four SMA heads one by one. 4. The differential broadband dual-polarized base station antenna for improving the cross-polarization ratio according to claim 3, characterized in that: the reflector is a square box-shaped structure, and there is a flanging in the reflector, and the flanging is A square box-shaped structure is formed inside the reflecting plate, and the support structure is located at the center of the square box-shaped structure surrounded by the flange. 5. The differential broadband dual-polarized base station antenna with improved cross-polarization ratio according to claim 3 or 4, characterized in that: the shape of the support structure is a cylinder. 6. The differential broadband dual-polarized base station antenna with improved cross-polarization ratio according to claim 3 or 4, characterized in that: the supporting structure is made of polytetrafluoroethylene plastic. 7. The differential broadband dual-polarized base station antenna with improved cross-polarization ratio according to claim 4, characterized in that: the reflector and the flange are both made of aluminum alloy. 8. The differential broadband dual-polarized base station antenna for improving cross-polarization ratio according to any one of claims 1-4, characterized in that: the shapes of the four radiating elements are all square; or the four The shapes of the radiation units are all squares with corners cut. 9. The differential broadband dual-polarized base station antenna for improving cross-polarization ratio according to any one of claims 1-4, characterized in that: the cross-shaped feed structure and the four radiating elements are all made of copper materials become. 10. The differential broadband dual-polarized base station antenna with improved cross-polarization ratio according to any one of claims 1-4, wherein the four coaxial lines are all 50Ω coaxial lines.