Oscillator unit and base station antenna

Abstract

The present invention provides a vibrator unit and a base station antenna. The vibrator unit of the present invention filters out radio waves of antennas of other frequency bands radiated in space by loading a filtering circuit on an antenna dielectric substrate, and the filtering circuit is linearly distributed on the antenna dielectric substrate. By adjusting the linearity and linear size of the filtering circuit, the radio waves of antennas of other frequency bands radiated in space can be filtered out, thereby solving the cross-band interference problem of the antenna in the base station antenna. At the same time, the antenna radiation surface of the present invention includes two pairs of antenna radiation units, each antenna radiation unit is distributed in a square area on the antenna dielectric substrate, and the plurality of filtering circuits and strip lines included in the antenna radiation units are continuously arranged along the edge of the square area, which not only achieves the filtering of external radio waves of other frequency bands, but also increases the electrical length of the antenna radiator circuit on the basis of reducing the antenna size, realizes the design of a full-wave dipole antenna, and thus increases the gain of the antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of base station antennas, and in particular relates to a vibrator unit and a base station antenna. Background Art

[0002] With the rapid development of 5G communication technology, the integration of 3G, 4G, and 5G base stations is becoming increasingly important. This not only significantly improves space utilization, but also significantly reduces costs and enhances base station intelligence. However, when multiple types of antennas for multiple frequency bands are compactly packed onto a small power splitter board, the electromagnetic environment within the base station becomes quite complex, and antennas in different frequency bands interfere with each other, with antennas in higher frequency bands having a particularly significant impact on antennas in lower frequency bands.

[0003] In order to solve the problem of cross-band interference between antenna array elements, many scholars at home and abroad have conducted research on it and published many articles and patents. For example, in 2011, the domestic Mobi company published a dual-frequency dual-polarization antenna vibrator loaded with a filter, which can filter out certain radio waves in a smaller frequency band. However, the antenna gain failed to meet the requirements of the industry, and the filtering band was narrow; in 2019, the University of Technology Sydney published an article loading a choke circuit on the radiating surface of the vibrator. The proposed antenna can filter out incoming waves from 1.7 to 2.2 GHz and work well from 0.69 to 0.96 GHz, but it still has the problem of a narrow filtering band. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a vibrator unit and a base station antenna to solve the cross-band interference problem of an antenna used in a certain working frequency band to an antenna working in other frequency bands in a 3G / 4G / 5G base station antenna.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an oscillator unit, including a radiating element and a balun support, the radiating element includes an antenna dielectric substrate and an antenna radiating surface arranged on the antenna dielectric substrate, the antenna radiating surface includes two pairs of antenna radiating units, each antenna radiating unit includes a plurality of dispersed filter circuits and strip lines for connecting adjacent filter circuits, the plurality of filter circuits are connected in series through strip lines, and the filter circuits are linearly distributed on the antenna dielectric substrate, and by adjusting the linear shape and linear size of the filter circuit, the radio waves of antennas of other frequency bands radiated in space can be filtered out.

[0006] Furthermore, the two pairs of antenna radiation units are orthogonally distributed on the antenna dielectric substrate.

[0007] Furthermore, each antenna radiation unit is distributed in a square area on the antenna dielectric substrate, and the plurality of filter circuits and strip lines included in the antenna radiation unit are continuously arranged along the edge of the square area.

[0008] Furthermore, at least two filter circuits are directly connected in line to achieve current splitting.

[0009] Furthermore, the linear distribution of the filter circuit includes but is not limited to any one or more of a meander line, a spiral line, a sine distribution line, and a cosine distribution line.

[0010] Furthermore, the filtering circuit is distributed on the same or different layers of the antenna dielectric substrate.

[0011] Furthermore, the width of the strip line is not less than the line width of the filter circuit.

[0012] Furthermore, the balun support includes two orthogonally arranged balun dielectric substrates, and each balun dielectric substrate is provided with a balun and a corresponding matching circuit.

[0013] Furthermore, the matching circuit, filter circuit and stripline are all realized by printing a copper layer on the antenna dielectric substrate / balun dielectric substrate.

[0014] The base station antenna of the present invention comprises the above-mentioned vibrator unit, and a base for mounting the vibrator unit on the base station antenna is provided at the bottom of the vibrator unit.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention loads an antenna radiating unit composed of several dispersed filter circuits and striplines connecting adjacent filter circuits onto an antenna dielectric substrate. The filter circuits are linearly distributed on the antenna dielectric substrate. By adjusting the linear shape and linear size of the filter circuits, radio waves radiated from antennas of other frequency bands in space are filtered out. This can solve the problem of cross-band interference between antennas operating in a certain operating frequency band and antennas operating in other frequency bands in 3G / 4G / 5G base station antennas.

[0017] 2. The antenna radiating surface of the present invention includes two pairs of antenna radiating elements orthogonally distributed on the antenna dielectric substrate. Each antenna radiating element is distributed within a square area on the antenna dielectric substrate, and the plurality of filter circuits and strip lines included in the antenna radiating element are continuously arranged along the edge of the square area. This not only achieves the filtering of external radio waves of other frequency bands, but also increases the electrical length of the antenna radiator circuit while reducing the antenna size, realizing the design of a full-wave dipole antenna, thereby increasing the antenna gain.

[0018] 3. At least two filter circuits are directly connected linearly in the antenna radiation unit to achieve current splitting, thereby increasing the isolation and cross-polarization ratio while ensuring that the filter bandwidth is not reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A complete model diagram of the vibrator unit provided in an embodiment of the present invention;

[0020] Figure 2 Graph showing the S12 parameter simulation results of a 7th-order band-stop filter loaded on the antenna radiating surface in an example of the present invention;

[0021] Figure 3 This is the S12 parameter simulation result of the overall stripline after connecting four sections of 7th-order band-stop filters through four sections of stripline;

[0022] Figure 4 For the general Figure 1 The Z parameter curve obtained by simulating the example given in the present invention and connecting it with a complete matching circuit;

[0023] Figure 5 For the general Figure 1 The RCS simulation results of the embodiment of the present invention are measured at 1.4~2.7GHz after connecting with the complete matching circuit;

[0024] Figure 6 This is a diagram of the array topology of an example given in the present invention;

[0025] Figure 7 for Figure 6 The voltage standing wave ratio diagram of the array shown is obtained by simulation at 1.4~2.7GHz;

[0026] Figure 8 for Figure 6 The radial pattern of the array simulated from 1.4 to 2.7 GHz when stimulating the 45° polarization ports HP1 and HP2 is shown.

[0027] Figure 9 A schematic diagram of an array consisting of 16 antennas operating at 1.4-2.7 GHz (element A in the figure) and 4 antennas operating at 0.69-0.96 GHz (element B in the figure) according to an embodiment of the present invention;

[0028] Figure 10 A schematic diagram of an array consisting of eight antennas operating at 1.4 to 2.7 GHz (element A in the figure) and four antennas operating at 0.69 to 0.96 GHz (element B in the figure) according to an embodiment of the present invention;

[0029] Figure 11This is a schematic diagram of an array consisting of 16 antennas operating at 1.4-2.7 GHz (array element A in the figure) and 4 antennas operating at 0.69-0.96 GHz (array element B in the figure), equipped with an example of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] The vibrator unit of the present invention includes a radiating element and a balun support. The radiating element includes an antenna dielectric substrate and an antenna radiating surface arranged on the antenna dielectric substrate. The antenna radiating surface includes two pairs of antenna radiating units. The two pairs of antenna radiating units are orthogonally distributed on the antenna dielectric substrate. Each antenna radiating unit includes a plurality of dispersed filter circuits and a strip line for connecting adjacent filter circuits. The plurality of filter circuits are connected in series through the strip line, and the filter circuits are linearly distributed on the antenna dielectric substrate. By adjusting the linear size of the filter circuit, the radio waves of antennas of other frequency bands radiated in space can be filtered out.

[0032] The linear distribution mode of the filter circuit includes but is not limited to any one or more of a meander line, a spiral line, a sine-distributed line, and a cosine-distributed line. It should be noted that a variety of different linear distribution modes can also be used in combination. If a meander line mode is adopted, when adjusting the linear size of the filter circuit, you can choose to load a meander line circuit with different lengths and widths, or different gap thicknesses, or different shapes, and connect them with strip lines. This can filter out radio waves radiated from the space within a very wide frequency band. It should be noted here that the meander line is only one way to connect capacitors and inductors in parallel. Any method of evenly or unevenly distributing meander lines of different sizes in different spaces, or distributing them in different layers of a dielectric substrate, or using various methods such as spiral / sine / cosine distributed lines / metal tubes in a plane or space to manufacture meander line / meant tube combinations with different size parameters falls within the scope of protection of this application.

[0033] Furthermore, each antenna radiating unit is distributed in a square area on the antenna dielectric substrate, and the several filtering circuits and strip lines included in the antenna radiating unit are continuously arranged along the edge of the square area, thereby not only filtering out external radio waves of other frequency bands, but also increasing the electrical length of the antenna radiator circuit on the basis of reducing the antenna size, realizing the design of a full-wave dipole antenna, and thereby increasing the gain of the antenna.

[0034] Furthermore, at least two filter circuits are directly connected linearly in the antenna radiation unit to achieve shunting. The present invention adopts the circuit shunting method to increase the isolation and cross-polarization ratio while ensuring that the filtering bandwidth is not reduced.

[0035] Furthermore, the width of the stripline is not less than the line width of the filter circuit.

[0036] Furthermore, the balun support includes two orthogonally arranged balun dielectric substrates, and each balun dielectric substrate is provided with a balun and a corresponding matching circuit.

[0037] The matching circuit, the filtering circuit and the strip line in the present invention are all realized by printing a copper layer on the antenna dielectric substrate / balun dielectric substrate.

[0038] The following invention takes an orthogonal dual-polarized dipole antenna with a filter circuit for 0.69~0.96GHz as an example to describe the technical solution of the present invention in detail:

[0039] like Figure 1 The figure shows the complete model of the oscillator unit in the cross-dual-polarized dipole antenna, where 1-1 is the antenna radiation surface, 1-2 is the antenna dielectric substrate, 1-3(a) and 1-3(b) are the baluns responsible for inputting two polarized electric fields and the corresponding matching circuits, respectively, and 1-4 is the balun dielectric substrate that carries the two baluns and the corresponding matching circuits.

[0040] The two baluns and corresponding matching circuits indicated by 1-3(a) and 1-3(b) are located in planes that are orthogonal to each other in space, thus controlling the antenna to radiate a + / -45° polarized electric field in space. The length and width of the antenna radiation surface 1-1 are both 117mm, and the overall height of the antenna is 83mm. The antenna dielectric substrate 1-2 is a single-sided board with only one layer of copper. The other dielectric substrates in this example are double-sided boards. The minimum width of the copper wire used is 0.7mm, and the maximum width is 6mm. The material can be determined according to the manufacturer's specific production conditions. Figure 1 In the example shown, the material of the substrate 1-2 used for the antenna radiation surface 1-1 is a FR4 series substrate with a dielectric constant of 4.4; the material used for the balun dielectric substrate 1-4 is an ARLON series substrate with a dielectric constant of 3.0.

[0041] like Figure 1 As shown, the antenna radiation surface 1-1 is composed of four circuits, named 1-1(a), 1-1(b), 1-1(c), and 1-1(d). 1-1(a) and 1-1(c) form the radiation surface of one dipole antenna, and 1-1(b) and 1-1(d) form the radiation surface of another dipole antenna. The two dipole antennas are orthogonal to each other and are compactly combined together. The four circuits on the antenna radiation surface 1-1 are exactly the same. Each circuit consists of four strip lines and four 7th-order band-stop filters. The principle of the filtering branch can be explained as follows: the 7th-order filter circuit in the antenna radiation surface 1-1 is composed of four curved strip lines of different lengths and gap widths. The line can be regarded as a circuit that connects the inductor and the capacitor in parallel; there is a wider strip line between two adjacent curved strip lines. The line can be regarded as a circuit that connects the capacitor, inductor and resistor in series to ground; connecting the above parallel circuit and series circuit can produce a wider stop band; by modifying the capacitance value and the inductance value, the stop band can be achieved in different frequency bands. Therefore, by combining the band-stop filter circuits with different capacitance and inductance values, filtering can be achieved in a very wide frequency band. Since the higher the filter order, the greater the insertion loss, after a series of simulations, it is concluded that the 7th-order filter circuit has the best effect. The simulation results of the above filter circuit are as follows. Figure 2 As shown in the figure, when the current at 1.4~2.7GHz enters the 7th-order band-stop filter through the port, only very little energy reaches the other port, and its S12 parameter is below -40dB within the frequency band.

[0042] The purpose of combining the four filter circuits mentioned above is to increase the electrical length of the circuit so that the current paths of the two dipole radiation surfaces on the radiator in the example given by the present invention can reach 1 wavelength. The "1 wavelength" mentioned here refers to the period length of the radio wave at a frequency of 0.823GHz. The circuit simulation results of combining the four 7th-order band-stop filters mentioned above with four strip lines of different widths are shown in the figure below. Figure 3 shown.

[0043] The four circuits are combined into a square radiating surface as a single antenna radiating unit of a full-wave dipole, and then the four square radiating surfaces are combined to form the following: Figure 1 The Z parameter simulation results of the dual-polarized antenna radiation surface 1-1 with a complete matching circuit are as follows: Figure 4 The RCS simulation results are shown in Figure 5 As shown, it can be seen that the present invention can achieve normal operation at 0.69~0.96GHz while filtering at 1.4~2.7GHz.

[0044] To achieve optimal performance, two perpendicular zigzag lines are connected at the ends of the dipole's radiating surface (i.e., the two outermost ends). This allows current to flow through the outermost ends along two orthogonal paths, significantly optimizing the antenna's cross-polarization ratio and isolation. The cross-polarization ratio at 0° in the radiation direction is 40dB, and at 60° is 23dB. The isolation between the two ports is -35dB, resulting in even better isolation and cross-polarization ratio in this example.

[0045] This example is used in a multi-band dual-polarization reused base station antenna array that includes multiple generations of antennas such as 3G / 4G / 5G. To verify the reliability of this example, it is preferably simulated together with four dual-polarization base station antennas (hereinafter referred to as HP antennas) operating at 1.4~2.7GHz. The topology is as follows: Figure 6 As shown in the figure, the voltage standing wave ratio simulation results are as follows: Figure 7 As shown, when a row of HP antennas is excited, the radial pattern of the array at some frequency points is as follows Figure 8 This proves that the example given in the present invention can be normally used in a base station and the design is feasible.

[0046] The present invention aims to eliminate cross-band interference in an array composed of multiple antennas for different frequency bands. For the example given in the present invention, the purpose is to eliminate the interference caused by antennas operating at 0.69-0.96 GHz in the array to antennas operating at 1.4-2.7 GHz. Figure 9 As shown, an array consists of 16 antennas operating at 1.4~2.7GHz (array element A in the figure) and 4 antennas operating at 0.69~0.96GHz (array element B in the figure). Array element B is equipped with the present invention. After simulation and testing, the array can operate well and efficiently at 1.4~2.7GHz.

[0047] remove Figure 9 Outside the array shown, Figure 10 、 Figure 11 The following arrays can all use this technology. This technology can be used in multiple frequency bands such as 0.69~0.96GHz, 1.4~2.7GHz, 3.3~3.8GHz, etc., and can be used to filter specific frequency bands.

[0048] Figure 10 For the array of the present invention, which consists of 8 antennas operating at 1.4-2.7 GHz (element A in the figure) and 4 antennas operating at 0.69-0.96 GHz (element B in the figure), it is worth noting that: Figure 10 and Figure 9Although the array topology is different, the array element B equipped with the present invention can effectively filter out the radio waves emitted by the array element A operating at 1.4-2.7 GHz, so that no scattering or refraction occurs on the array element A.

[0049] Figure 11 For an array equipped with the present invention consisting of 16 antennas operating at 1.4-2.7 GHz (element A in the figure) and 4 antennas operating at 0.69-0.96 GHz (element B in the figure), it is worth noting that: Figure 11 The array element A is equipped with the present invention. After targeted design, it can effectively filter out the radio waves emitted by the array element B operating at 0.69~0.96GHz, so that no scattering or refraction occurs on the array element A.

[0050] In summary, this example is to load a high-order band-stop filter structure on the vibrator working at 0.69~0.96GHz to filter out the waves emitted by the vibrator working at 1.4~2.7GHz; similarly, the vibrator working at 1.4~2.7GHz is targetedly loaded with a high-order band-stop filter similar to the present invention to filter out the waves emitted by the vibrator working at 0.69~0.96GHz. Therefore, loading a high-order band-stop filter structure similar to the present invention on the vibrator working at any frequency band to filter out the waves emitted by the vibrator working at any frequency band, such technical means should be covered within the scope of protection of the present invention. In addition, the gain of the example given by the present technical solution is higher than that of similar antennas, the size is smaller, the cross-polarization ratio is high, the height is low, the cost is low, and it is easy to produce, and it has strong competitiveness in the market.

[0051] The examples of the present invention also have the following technical effects:

[0052] 1. By utilizing a broadband dual-polarization filtering antenna, the multi-frequency multiplexing base station array antenna can achieve good and distortion-free directional patterns when operating in the 1.4-2.7 GHz range. Compared with current technologies in the same field at home and abroad, the present invention can achieve a wider filtering bandwidth and better filtering effect.

[0053] 2. The example given in this invention uses a square radiating surface, and the dipole on the radiating surface is a full-wavelength dipole, so that the gain is around 10dBi within the operating frequency band, and the half-power beamwidth is maintained in the range of 65+ / -5°, reaching the industry's first-class level.

[0054] 3. By using the circuit orthogonal shunting method, the dual-port isolation of the dual-polarization antenna reaches -35dB and the cross-polarization ratio reaches 40dB.

[0055] 4. The antenna size is only 117mm*117mm*83mm, the material is cheap and the process is simple.

[0056] 5. When the present invention is used in a compact base station array that integrates multiple antennas, it will hardly cause any cross-band interference to other antennas. Furthermore, the required cost is very low, making it suitable for mass production.

[0057] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dipole unit, comprising a radiating element and a balun support, wherein the radiating element comprises an antenna dielectric substrate and an antenna radiating surface disposed on the antenna dielectric substrate, the antenna radiating surface comprising two pairs of antenna radiating elements, the two pairs of antenna radiating elements being orthogonally distributed on the antenna dielectric substrate to form two orthogonal dipole antennas, characterized in that: Each antenna radiating unit includes a number of dispersed filter circuits and strip lines for connecting adjacent filter circuits. The filter circuits are connected in series via the strip lines, and the filter circuits are linearly distributed on the antenna dielectric substrate. By adjusting the linear shape and linear size of the filter circuits, radio waves radiated from the antenna in other frequency bands in space can be filtered out. Each antenna radiating element is distributed in a square area on the antenna dielectric substrate, and the plurality of filter circuits and strip lines included in the antenna radiating element are continuously arranged along the edge of the square area; The width of the stripline is not less than the linear width of the filter circuit; At the two outermost ends of the radiation surface of the dipole antenna, two folded lines of two filters placed perpendicular to each other are connected together to split the current into two orthogonal paths.

2. The vibrator unit according to claim 1, characterized in that: The linear distribution of the filter circuit includes any one or more of a meander line, a spiral line, a sine distribution line, and a cosine distribution line.

3. The vibrator unit according to claim 2, characterized in that: The filtering circuit is distributed on the same or different layers of the antenna dielectric substrate.

4. The vibrator unit according to claim 3, characterized in that: The balun support includes two orthogonally arranged balun dielectric substrates, and each balun dielectric substrate is provided with a balun and a corresponding matching circuit.

5. The vibrator unit according to claim 4, characterized in that: The matching circuit, filter circuit and strip line are all realized by printing a copper layer on the antenna dielectric substrate / balun dielectric substrate.

6. Base station antenna, characterized in that: The device comprises at least one vibrator unit according to any one of claims 1 to 5, wherein the bottom of the vibrator unit is provided with a base for mounting the vibrator unit on a base station antenna.

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