Power divider, phase shifter and base station antenna

Abstract

The application provides a power divider, a phase shifter and a base station antenna. The power divider comprises an input port, a plurality of output ports, at least one isolation resistor and a plurality of transmission lines. The input port is used for accessing an input signal. Adjacent output ports have a preset interval. An isolation resistor is arranged between any two adjacent output ports. Each transmission line is arranged between an adjacent output port and an isolation resistor. The length of each transmission line is 4λ / 9-5λ / 9, wherein λ is the wavelength of the center frequency point of the input signal. By arranging the transmission line with a certain length, the positions of the plurality of output ports and the isolation resistor can be flexibly set, the circuit design flexibility is improved, and the preset interval between adjacent output ports can be larger, so that the isolation degree of adjacent output ports is improved. By setting the length of the transmission line as 4λ / 9-5λ / 9, the input signal of the corresponding frequency point can be suppressed, and the filtering function is realized.

Description

Technical Field

[0001] This application relates to the field of power dividers, and more particularly to a power divider, a phase shifter, and a base station antenna. Background Technology

[0002] With increasingly scarce base station resources, base station antennas are rapidly developing towards multi-frequency, multi-port designs. Due to the limitations imposed by towers on the windward area of ​​base station antennas, the more integrated the multi-frequency, multi-port base station antenna, the denser the arrangement of its elements. This leads to a deterioration in the isolation of the radiating arrays between different frequency bands, affecting communication quality. Poor isolation between different frequency bands mainly occurs in multi-frequency, multi-port base station antennas with a frequency relationship of 2 times. For example, in base station antennas covering the 820-960MHz and 1710-2170MHz frequency bands, because the low-frequency element has a parasitic passband near its twice-center frequency, some high-frequency signals will flow in the low-frequency circuit, causing signal interference.

[0003] Currently, there are two main methods to optimize inter-frequency isolation. One is to add a band-stop filter structure to the radiating surface of the low-frequency vibrator to suppress high-frequency signals. This method is usually applicable to PCB (Printed Circuit Board) vibrators, but the structural reliability of PCB vibrators is not as good as that of die-cast vibrators. Most base station antennas from mainstream manufacturers in the industry use die-cast vibrators. The other method is to add a filter to the feed network to suppress inter-frequency signals. This method is applicable to both die-cast and PCB vibrators, but the newly introduced filter will bring additional circuit losses and reduce the radiation efficiency of the base station antenna. Summary of the Invention

[0004] To address the problems in the prior art, this application provides a power divider, a phase shifter, and a base station antenna to improve the isolation performance of the power divider and achieve the filtering effect of the power divider.

[0005] This application provides a power divider, the power divider comprising: Input port, used to connect input signals; Multiple output ports, with a preset interval between adjacent output ports; At least one isolation resistor is provided, and an isolation resistor is provided between two adjacent output ports; Multiple transmission lines are provided, each of which is located between an adjacent output port and an isolation resistor; the length of each transmission line is 4λ / 9 to 5λ / 9; where λ is the wavelength of the center frequency of the input signal.

[0006] In one embodiment, the power divider further includes an impedance transformer disposed between the input port and the plurality of output ports.

[0007] In one embodiment, the length of the impedance transformer is λ / 8 to λ / 4.

[0008] In one embodiment, the length of each of the transmission lines is λ / 2.

[0009] In one embodiment, the impedance of the transmission line is determined based on the power ratio of the two output ports adjacent to the transmission line and their characteristic impedance; the impedance of the isolation resistor is determined based on the power ratio of the two output ports adjacent to the isolation resistor and their characteristic impedance.

[0010] In one embodiment, the power divider includes a first output port, a second output port, a first isolation resistor, a first transmission line, and a second transmission line; The first end of the first transmission line is electrically connected to the first output port, and the second end of the first transmission line is electrically connected to the first end of the first isolation resistor; the first end of the second transmission line is electrically connected to the second output port, and the second end of the second transmission line is electrically connected to the second end of the first isolation resistor.

[0011] This application also proposes a phase shifter, which includes the power divider described above.

[0012] In one embodiment, the number of power dividers is multiple.

[0013] This application also proposes a base station antenna, which includes the phase shifter described above.

[0014] In one embodiment, the base station antenna further includes multiple vibrators.

[0015] This application allows for flexible placement of multiple output ports and isolation resistors by using a transmission line of a certain length. This enhances circuit design flexibility and allows for a larger preset interval between adjacent output ports, improving their isolation. By setting the transmission line length to 4λ / 9~5λ / 9, it can suppress input signals at corresponding frequencies, achieving a filtering function. Attached Figure Description

[0016] Figure 1 This is a structural diagram of an embodiment of the power divider of this application.

[0017] Figure 2 This is a structural diagram of another embodiment of the power divider component of this application.

[0018] Figure 3 This is an S-parameter curve of an embodiment of the power divider of this application.

[0019] Figure 4 This is a structural diagram of an embodiment of the phase shifter of this application.

[0020] Figure 5 This is a reflection coefficient curve of an embodiment of the phase shifter of this application.

[0021] Figure 6 This is a module structure diagram of an embodiment of the base station antenna of this application.

[0022] Explanation of main component symbols The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0023] The following description will refer to the accompanying drawings to provide a more complete picture of the present application. The drawings illustrate exemplary embodiments of the present application. However, the present application may be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. Similar reference numerals denote the same or similar components.

[0024] Currently, Wilkinson power dividers are used in phase shifters to achieve multi-port power distribution. However, conventional Wilkinson power dividers lack filtering characteristics, and the ends of the impedance transformers at the two power division terminals are close together, with the isolation resistors located at the ends of the impedance transformers. This circuit layout means that when used in phase shifters, the phase shifter circuit layout cannot achieve a compact effect, thus increasing the size of the phase shifter.

[0025] Reference Figure 1 and Figure 2 This application proposes a power divider 100, which includes an input port 110, a plurality of output ports 120, at least one isolation resistor R, and a plurality of transmission lines 130. The input port 110 is used to receive an input signal. The plurality of output ports 120 are spaced apart by a predetermined interval. An isolation resistor R is provided between two adjacent output ports 120. Each transmission line 130 is located between an adjacent output port 120 and the isolation resistor R; the length of each transmission line 130 is 4λ / 9 to 5λ / 9, where λ is the wavelength of the center frequency of the input signal.

[0026] In this embodiment, the power divider 100 can be mounted on a dielectric circuit board. The transmission line 130 can be implemented using a microstrip line. The output port 120 is connected to the isolation resistor R via the transmission line 130 of a certain length. The positions of adjacent output ports 120 and the isolation resistor R can be flexibly set, making the circuit design more flexible. The preset interval between adjacent output ports 120 can be set according to the actual application, for example, according to the width or length of the circuit board. Since the transmission line 130 has a certain length, the preset interval between adjacent output ports 120 can also increase with the increase of the length of the transmission line 130, thereby improving the isolation between the output ports 120, provided that the size requirements are met.

[0027] The length of transmission line 130 is set to 4λ / 9~5λ / 9, which is suitable for f / 2±10%. The f / 2 frequency band has a suppression effect, where f is the center frequency of the input signal. For example, if the length of transmission line 130 is set to λ / 2, then for the f / 2 frequency band, it is λ / 4. Odd-mode analysis shows that the f / 2 input signal undergoes impedance transformation through the λ / 4 transmission line 130, exhibiting an impedance of Z^2 / 50 (Z is the characteristic impedance), which can be considered as still high impedance, so the reflection coefficient is approximately 1. Even-mode analysis shows that the f / 2 input signal is transformed into a short circuit through the λ / 4 transmission line 130, at which point the reflection coefficient is approximately -1. Combining odd-mode and even-mode analysis, the gain of the f / 2 input signal passing through this point should be 1 + (-1) / 2, which is 0. Therefore, the λ / 2 transmission line 130 exhibits a suppression effect on the f / 2 input signal. Figure 3 The S-parameters of power divider 100 are shown at a center frequency of 1940MHz. It can be seen that the isolation between the two output ports 120 is greater than 18dB, and power divider 100 provides suppression around the 970MHz frequency point. Furthermore, the length of transmission line 130 can be set to 4λ / 9, 5λ / 9, or any value between 4λ / 9 and 5λ / 9 according to actual needs to achieve suppression at corresponding frequency points and achieve a filtering effect.

[0028] In one embodiment, the power divider 100 further includes an impedance transformer 140; the impedance transformer 140 is disposed between the input port 110 and the plurality of output ports 120.

[0029] In this embodiment, the impedance transformer 140 can be used to adjust the impedance matching between the input port 110 and the output port 120. The length of the impedance transformer 140 can be set according to actual needs, for example, λ / 8 to λ / 4. The width of the impedance transformer 140 can also be adjusted according to actual impedance requirements to achieve impedance matching between the input port 110 and the output port 120.

[0030] In one embodiment, the impedance of the transmission line 130 is determined based on the power ratio of the two output ports 120 adjacent to the transmission line 130 and their characteristic impedance; the impedance of the isolation resistor R is determined based on the power ratio of the two output ports 120 adjacent to the isolation resistor R and their characteristic impedance.

[0031] For example, two adjacent output ports 120 are output port m and output port n, respectively. The impedance of transmission line 130 is (Kmn+1 / Kmn). Z, Kmn^2 = Pm / Pn. Where Pm is the power of the m-th output port 120, Pn is the power of the n-th output port 120, and Z is the characteristic impedance between the m-th and n-th output ports 120. Similarly, the impedance of the isolation resistor R between the m-th and n-th output ports 120 is the same as the impedance of the transmission line 130 between them. This achieves impedance matching between the m-th and n-th output ports 120. Furthermore, the higher impedance of the isolation resistor R isolates the signals between adjacent output ports 120, preventing signal interference and improving the isolation between them.

[0032] In one embodiment, the power divider 100 includes a first output port 121, a second output port 122, a first isolation resistor R1, a first transmission line 131, and a second transmission line 132. A first end of the first transmission line 131 is electrically connected to the first output port 121, and a second end of the first transmission line 131 is electrically connected to a first end of the first isolation resistor R1. A first end of the second transmission line 132 is electrically connected to the second output port 122, and a second end of the second transmission line 132 is electrically connected to a second end of the first isolation resistor R1.

[0033] In this embodiment, the impedance of the first transmission line 131 is (K12+1 / K12). Z, K12^2 = P1 / P2. The impedance of the second transmission line 132 and the impedance of the first isolation resistor R1 are the same as the impedance of the first transmission line 131.

[0034] Reference Figure 2In one embodiment, the power divider 100 includes a first output port 121, a second output port 122, a third output port 123, a first isolation resistor R1, a second isolation resistor R2, a first transmission line 131, a second transmission line 132, a third transmission line 133, and a fourth transmission line 134. A first end of the first transmission line 131 is electrically connected to the first output port 121, and a second end of the first transmission line 131 is electrically connected to the first end of the first isolation resistor R1. A first end of the second transmission line 132 is electrically connected to the second output port 122, and a second end of the second transmission line 132 is electrically connected to the second end of the first isolation resistor R1. A first end of the third transmission line 133 is electrically connected to the second output port 122, and a second end of the third transmission line 133 is electrically connected to the first end of the second isolation resistor R2. A first end of the fourth transmission line 134 is electrically connected to the third output port 123, and a second end of the fourth transmission line 134 is electrically connected to the second end of the second isolation resistor R2.

[0035] In this embodiment, the impedance of the first transmission line 131 is (K12+1 / K12). Z, K12^2 = P1 / P2. The impedance of the second transmission line 132 and the impedance of the first isolation resistor R1 are the same as the impedance of the first transmission line 131. The impedance of the third transmission line 133 is (K23 + 1 / K23). Z, K23^2 = P2 / P3. The impedance of the fourth transmission line 134 and the impedance of the second isolation resistor R2 are the same as the impedance of the third transmission line 133.

[0036] This application allows for flexible configuration of multiple output ports 120 and isolation resistor R by setting a transmission line 130 of a certain length. This enables more flexible circuit design and allows for a larger preset interval between adjacent output ports 120, improving the isolation between them. By setting the length of the transmission line 130 to 4λ / 9~5λ / 9, it can suppress input signals at corresponding frequencies, achieving a filtering function.

[0037] Reference Figure 4 This application also proposes a phase shifter 10, which includes the power divider 100 described above.

[0038] The detailed structure of the power divider 100 can be referred to the above embodiments, and will not be repeated here. It is understood that since the power divider 100 is used in the phase shifter 10 of the present invention, the embodiments of the phase shifter 10 of the present invention include all the technical solutions of all the embodiments of the power divider 100, and the technical effects achieved are exactly the same, and will not be repeated here.

[0039] Figure 5The reflection coefficient curve of the input port 110 of the phase shifter 10 of this application is shown. It can be seen that while achieving good transmission of electromagnetic waves in the 1700-2100MHz range, the phase shifter 10 effectively suppresses signal transmission in the 820-960MHz range, reducing signal interference between different frequency bands.

[0040] In one embodiment, the number of power dividers 100 is multiple.

[0041] In this embodiment, the power divider 100 can be located at the end of the phase shifter 10. Multiple power dividers 100 can be cascaded. For example, the phase shifter 10 includes a first power divider 100, a second power divider 100, and a third power divider 100, each power divider 100 having one input port 110 and two output ports 120. The input terminal of the first power divider 100 is used to receive an input signal, and the two output terminals of the first power divider 100 are electrically connected to the input terminals of the second power divider 100 and the third power divider 100, respectively. Thus, through multi-stage power division, power distribution across multiple output ports 120 is achieved.

[0042] Reference Figure 6 This application also proposes a base station antenna 1, which includes the phase shifter 10 described above.

[0043] The detailed structure of the phase shifter 10 can be referred to the above embodiments, and will not be repeated here. It can be understood that since the above phase shifter 10 is used in the base station antenna 1 of the present invention, the embodiments of the base station antenna 1 of the present invention include all the technical solutions of all the embodiments of the above phase shifter 10, and the technical effects achieved are exactly the same, and will not be repeated here.

[0044] In one embodiment, the base station antenna 1 further includes a plurality of vibrators 20.

[0045] In this embodiment, the number of vibrator 20 components is the same as the number of output ports 120 of the phase shifter 10. After the input signal is power-divided and phase-shifted by the phase shifter 10, it is output to multiple vibrator 20 components to excite the vibrator 20 components to work. Since the multiple output ports 120 of the power divider 100 of the phase shifter 10 have a high degree of isolation, the mutual coupling between adjacent units of the vibrator 20 can be effectively reduced, the upper sidelobe suppression of the vertical plane of the base station antenna 1 can be optimized, and the directivity of the base station antenna 1 can be improved. At the same time, the isolation between different frequencies is optimized without introducing a filter.

[0046] The specific embodiments of this application have been described above with reference to the accompanying drawings. However, those skilled in the art will understand that various changes and substitutions can be made to the specific embodiments of this application without departing from the spirit and scope of this application. All such changes and substitutions fall within the scope defined by this application.

Claims

1. A power divider, characterized in that, The power divider includes: Input port, used to connect input signals; Multiple output ports, with a preset interval between adjacent output ports; At least one isolation resistor is provided, and an isolation resistor is provided between two adjacent output ports; Multiple transmission lines are provided, each of which is located between an adjacent output port and an isolation resistor; the length of each transmission line is 4λ / 9 to 5λ / 9; where λ is the wavelength of the center frequency of the input signal.

2. The power divider as described in claim 1, characterized in that, The power divider also includes an impedance transformer; the impedance transformer is located between the input port and the plurality of output ports.

3. The power divider as described in claim 2, characterized in that, The length of the impedance transformer is λ / 8 to λ / 4.

4. The power divider as described in claim 1, characterized in that, The length of each of the transmission lines is λ / 2.

5. The power divider as described in claim 1, characterized in that, The impedance of the transmission line is determined based on the power ratio of the two output ports adjacent to the transmission line and their characteristic impedance; the impedance of the isolation resistor is determined based on the power ratio of the two output ports adjacent to the isolation resistor and their characteristic impedance.

6. The power divider as described in claim 1, characterized in that, The power divider includes a first output port, a second output port, a first isolation resistor, a first transmission line, and a second transmission line; The first end of the first transmission line is electrically connected to the first output port, and the second end of the first transmission line is electrically connected to the first end of the first isolation resistor; the first end of the second transmission line is electrically connected to the second output port, and the second end of the second transmission line is electrically connected to the second end of the first isolation resistor.

7. A phase shifter, characterized in that, The phase shifter includes the power divider as described in any one of claims 1 to 6.

8. The phase shifter as described in claim 7, characterized in that, The number of power dividers is multiple.

9. A base station antenna, characterized in that, The base station antenna includes the phase shifter as described in claim 7 or 8.

10. The base station antenna as described in claim 9, characterized in that, The base station antenna also includes multiple vibrators.

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