Broadband filtering power divider based on rectangular coaxiality

Abstract

The invention relates to the technical field of wireless communication, in particular to a broadband filtering power divider based on rectangular coaxial, which comprises a cavity structure formed by a rectangular coaxial outer conductor upper cavity and a rectangular coaxial outer conductor lower cavity, the cavity structure is used for installing an inner conductor circuit, and when the inner conductor circuit is installed, the rectangular coaxial outer conductor upper cavity and the rectangular coaxial outer conductor lower cavity are communicated with each other. And the inner conductor circuit is positioned in the center of the cavity structure by using the support body, and the inner conductor circuit is not in contact with the rectangular coaxial outer conductor upper cavity and the rectangular coaxial outer conductor lower cavity. The coupling distance is 0.21 mm, and compared with 0.06 mm of a traditional micro-strip form, the limitation caused by the machining size is reduced, and the use scene of the coupling line in a circuit is increased.

Description

Technical Field

[0001] The invention relates to the technical field of wireless communication, and in particular to a broadband filtering power divider based on rectangular coaxial. Background Art

[0002] With the rapid development of modern wireless communication technology, global communication business is increasing. Microwave and millimeter wave technology, as an engineering discipline with a long history, has been widely promoted and developed in the civil and military fields in recent years. Its application has involved satellite communications, radar detection, precision guidance, mobile communications, medical treatment and many other aspects.

[0003] Microwave radio frequency devices are developing towards high integration and multi-function. The traditional design method is to cascade independently designed filters and power dividers through additional matching networks. This cascade between devices will bring additional mismatch and loss, and make the circuit have a larger physical size. Therefore, the filter and power divider are usually designed as an integrated device, so that it has the characteristics of filter frequency selection and can distribute / synthesize power at the same time. How to better integrate the filter and power divider is the focus of research.

[0004] With the development of technology, the size of microwave devices continues to decrease, and the packaging of microwave millimeter wave circuits is becoming more dense, requiring devices that are suitable for large-scale integration and have high shielding properties. The microstrip lines used in existing designs have their own inherent disadvantages. As the frequency rises to the millimeter wave or even terahertz band, the dielectric loss of the printed circuit board greatly limits the transmission efficiency and power capacity of the microstrip lines. Moreover, since the microstrip is not closed, the coupling between the lines is large when the integration is high, so the planar process technology is not conducive to the realization of high-density integration and miniaturization of microwave systems. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention proposes a broadband filtering power divider based on rectangular coaxial, including a cavity structure composed of an upper cavity of a rectangular coaxial outer conductor and a lower cavity of a rectangular coaxial outer conductor, the cavity structure is used to install an inner conductor circuit, when installing the inner conductor circuit, a support body is used to make the inner conductor circuit be located at the center of the cavity structure, and the inner conductor circuit is not in contact with the upper cavity of the rectangular coaxial outer conductor and the lower cavity of the rectangular coaxial outer conductor.

[0006] Furthermore, the signal input port of the inner conductor circuit is connected to a Wilkinson quarter-wavelength impedance line, each output port of the Wilkinson quarter-wavelength impedance line is connected to one end of an impedance matching line, and a Wilkinson port isolation resistor is arranged between the impedance matching lines; the other end of the impedance matching line is connected to the high impedance line of the step impedance resonator, and the parallel coupling line and the impedance matching line are arranged perpendicularly at this end; the parallel coupling line is coupled and connected to the equally divided signal output port; the high impedance line of the step impedance resonator is connected to the low impedance line of the step impedance resonator.

[0007] Furthermore, the coupling area is adjusted by adjusting the line height of the parallel coupling line so as to control the impedance characteristics of the coupling line.

[0008] Furthermore, the supporting block is made of insulating Teflon material.

[0009] Furthermore, the inner conductor circuit, the rectangular coaxial outer conductor upper cavity and the rectangular coaxial outer conductor lower cavity are made of copper material.

[0010] Furthermore, the medium in the cavity structure is air.

[0011] Furthermore, the impedance characteristics of the broadband filtering power divider are controlled by adjusting the distance between the inner conductor circuit and the rectangular coaxial outer conductor.

[0012] Furthermore, the impedance ratio between the high impedance line of the step impedance resonator and the low impedance line of the step impedance resonator adjusts the bandwidth width of the broadband filter power divider.

[0013] Furthermore, the transmission position of the pole is adjusted by utilizing the coupling area of ​​the parallel coupling line.

[0014] The coupling spacing of the present invention is 0.21 mm, which reduces the limitation brought by the processing size and increases the use scenarios of the coupling line in the circuit compared to the 0.06 mm of the traditional microstrip form. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an exploded schematic diagram of a broadband filtering power divider based on rectangular coaxial according to the present invention;

[0016] Figure 2 This is a schematic diagram of the inner conductor circuit structure of a broadband filtering power divider based on rectangular coaxial in the present invention;

[0017] Figure 3 It is a simulation diagram of S11, S21 and S31 of a broadband filtering power divider based on rectangular coaxial according to the present invention;

[0018] Figure 4 It is a simulation diagram of S22 and S32 of a broadband filtering power divider based on rectangular coaxial according to the present invention;

[0019] Figure 5 It is a simulation diagram of phase / port imbalance of a broadband filter power divider based on rectangular coaxial according to the present invention;

[0020] Figure 6 It is a perspective structural schematic diagram of a broadband filtering power divider based on rectangular coaxial according to the present invention;

[0021] Among them: 1. Rectangular coaxial outer conductor upper cavity; 2. Inner conductor circuit; 3. Support body; 4. Rectangular coaxial outer conductor lower cavity; 5. Signal input port; 6. First equal-division signal output port; 7. Second equal-division signal output port; 8. Wilkinson quarter-wavelength impedance line; 9. Impedance matching line; 10. Wilkinson port isolation resistor; 11. Step impedance resonator high impedance line; 12. Step impedance resonator low impedance line; 13. Parallel coupling line. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The present invention provides a broadband filtering power divider based on rectangular coaxial, comprising a cavity structure composed of an upper cavity of a rectangular coaxial outer conductor and a lower cavity of a rectangular coaxial outer conductor, wherein the cavity structure is used to install an inner conductor circuit, and when installing the inner conductor circuit, a support body is used to make the inner conductor circuit be located at the center of the cavity structure, and the inner conductor circuit is not in contact with the upper cavity of the rectangular coaxial outer conductor and the lower cavity of the rectangular coaxial outer conductor.

[0024] Combination Figure 1 and Figure 6 The present invention proposes a broadband filtering power divider based on rectangular coaxial, which comprises, from top to bottom, a rectangular coaxial outer conductor upper cavity 1, an inner conductor circuit 2, a dielectric support block 3, and a rectangular coaxial outer conductor lower cavity 4.

[0025] Figure 2The diagram shows a schematic diagram of the inner conductor circuit of a broadband filter power divider, wherein the inner conductor circuit 2 includes a signal input port 5, two equally divided signal output ports, namely a first equally divided signal output port 6 and a second equally divided signal output port 7, a Wilkinson quarter-wavelength impedance line 8, an impedance matching line 9, a Wilkinson port isolation resistor 10, a step impedance resonator high impedance line 11, a step impedance resonator low impedance line 12, and a parallel coupling line 13; wherein: the Wilkinson quarter-wavelength impedance line 8 is connected in series with the impedance matching line 9 to achieve better matching of the circuit, and the Wilkinson port isolation resistor 10 is placed at the end of the series impedance matching line 9 to achieve port isolation. The overall internal circuit is placed on the dielectric support block 3 so that the circuit is in the middle of the rectangular coaxial outer conductor cavity, the dielectric support block 3 is made of insulating Teflon material, the rectangular coaxial outer conductor upper cavity 1, the rectangular coaxial outer conductor lower cavity 4 and the inner conductor circuit 2 are made of copper material, and the rectangular coaxial outer conductor cavity is air medium.

[0026] In this embodiment, a step impedance resonator (a step impedance resonator high impedance line 11, a step impedance resonator low impedance line 12) and a parallel coupling line 13 are connected in series in the circuit to broaden the signal equally divided by the Wilkinson circuit, and the transmission position of the pole is adjusted by adjusting the impedance ratio of the step impedance resonator (a step impedance resonator high impedance line 11, a step impedance resonator low impedance line 12) and the odd and even mode impedances of the parallel coupling line 13, thereby controlling the entire broadband filtering power divider to operate in a wider operating frequency range.

[0027] The dielectric support block 3 is placed at the bottom of the inner conductor circuit 2, so that the entire inner conductor circuit 2 is located in the center of the rectangular coaxial outer conductor cavity. The dielectric support blocks 3 should be placed reasonably, and the number should not be too much or too little, so as to ensure that the circuit can be transmitted normally within the working range and can support the circuit in the correct position. In this embodiment, a support body is set at the bottom of each structure of the inner conductor circuit, and the position is set just below the center of mass of the structure. After the inner conductor is installed on the support body, it is ensured that the distance from the upper surface of the inner conductor to the upper cavity of the rectangular coaxial outer conductor is equal to the distance from the lower surface of the inner conductor to the lower cavity of the rectangular coaxial outer conductor. Similarly, the distances from the left and right sides of the inner conductor to the upper cavity of the rectangular coaxial outer conductor and the lower cavity of the rectangular coaxial outer conductor are also equal. The impedance characteristics of the broadband filter power divider can be adjusted by adjusting the size of these two distances.

[0028] In this embodiment, the rectangular coaxial outer conductor (rectangular coaxial outer conductor upper cavity 1, rectangular coaxial outer conductor lower cavity 4) surrounds the entire circuit in the cavity, so that the circuit has a high shielding property, reduces the radiation loss of the circuit, and makes the circuit less likely to deform, thereby ensuring high stability.

[0029] In this embodiment, the characteristic impedance of the rectangular coaxial transmission structure is only related to the ratio of the inner and outer conductors in the cross section. By selecting different ratios of the inner and outer conductors to control the characteristic impedance of the rectangular coaxial transmission structure, the impedance requirements and power capacity requirements of different occasions can be met.

[0030] The working principle of a broadband filter power divider based on rectangular coaxial of the present invention is as follows: an input signal is input from an input port 5, and the input signal is equally divided through a Wilkinson quarter-wavelength impedance line 8, a port isolation resistor 10 is located at the end of an impedance matching line 9, and four poles are generated in the passband due to a step impedance resonator high impedance line 11, a step impedance resonator low impedance line 12 and a parallel coupling line 13, which effectively increases the bandwidth of the output signal, and the impedance matching line 9 enables the signal to have a better matching effect in the passband, and finally the signal is equally output from the first equally divided signal output port 6 and the second equally divided signal output port, and the resistance ratio of the step impedance resonator high impedance line 11 to the step impedance resonator low impedance line 12 can control the bandwidth width; in addition, the overlap degree of the parallel coupling line 13 can be controlled to control the characteristic impedance (including even-mode impedance and odd-mode impedance) to adjust the transmission position of the pole. After knowing the above two adjustment methods, those skilled in the art can make specific adjustments according to actual needs, thereby controlling the entire broadband filter power divider to work in a wider working frequency range.

[0031] The present invention adopts the structure of Wilkinson power divider cascade step impedance resonator and parallel coupling line, and uses rectangular coaxial transmission line for circuit implementation. A matching line is added to the output port of Wilkinson power divider to achieve better matching in the passband, and at the same time, step impedance resonator and parallel coupling line are cascaded on the basis of Wilkinson power divider, so that four transmission poles are generated in the band, and two zero points can be generated on the left and right sides outside the band respectively. Reasonable distribution of the resonance positions of these zero points and poles can effectively expand the passband bandwidth, so that the broadband power divider has good signal selection capability.

[0032] The simulation results of the filter power divider S11, S21, S31 are as follows Figure 3 From the simulation results, it can be seen that S11 is better than 17dB in the range of 3.57GHz-10.06GHz, and the insertion loss at the center frequency is 0.164dB / 0.152dB (S21 / S31). The filter power divider S22 and S32 are as follows Figure 4 As shown in the figure, S22 is better than 13dB in the passband range, indicating that there is a good matching effect between the three ports. The isolation between the two output ports is better than 10dB. The phase imbalance and port imbalance of the filter power divider are shown in Figure 5As shown, it means that the amplitude and phase of the output signals of the two ports remain basically the same, and there is a good port imbalance. Compared with the simulation effect of the filter power divider based on microstrip line transmission in the literature "Ultra-Wideband Power Divider With Good In-Band Splitting and Isolation Performances", the broadband filter power divider based on rectangular coaxial proposed in the present invention adds a section of impedance matching line and makes the circuit into a three-dimensional structure. It can control the coupling degree by changing the coupling area of ​​the coupling line to achieve better transmission effect, smaller insertion loss and more stable circuit structure.

[0033] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "outside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "rotation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A broadband filtering power divider based on rectangular coaxial, characterized in that: The invention comprises a cavity structure composed of a rectangular coaxial outer conductor upper cavity and a rectangular coaxial outer conductor lower cavity. The cavity structure is used to install an inner conductor circuit. When installing the inner conductor circuit, a support body is used to make the inner conductor circuit be located at the center of the cavity structure, and the inner conductor circuit is prevented from contacting the rectangular coaxial outer conductor upper cavity and the rectangular coaxial outer conductor lower cavity.

2. A broadband filtering power divider based on rectangular coaxial according to claim 1, characterized in that: The signal input port of the inner conductor circuit is connected to a Wilkinson quarter-wavelength impedance line, each output port of the Wilkinson quarter-wavelength impedance line is connected to one end of an impedance matching line, and a Wilkinson port isolation resistor is arranged between the impedance matching lines; the other end of the impedance matching line is connected to a high impedance line of a step impedance resonator, and a parallel coupling line is arranged perpendicularly to the impedance matching line at the end; The parallel coupling line is coupled to the equally divided signal output port; the high impedance line of the step impedance resonator is connected to the low impedance line of the step impedance resonator.

3. A broadband filtering power divider based on rectangular coaxial according to claim 2, characterized in that: The coupling area is adjusted by adjusting the line height of the parallel coupling line, thereby controlling the impedance characteristics of the coupling line.

4. The broadband filtering power divider based on rectangular coaxial according to claim 1, characterized in that: The support block is made of insulating Teflon material.

5. The broadband filtering power divider based on rectangular coaxial according to claim 1, characterized in that: The inner conductor circuit, the upper cavity of the rectangular coaxial outer conductor and the lower cavity of the rectangular coaxial outer conductor are made of copper material.

6. The broadband filtering power divider based on rectangular coaxial according to claim 1, characterized in that: The medium in the cavity structure is air.

7. The broadband filtering power divider based on rectangular coaxial according to claim 1, characterized in that: The impedance characteristics of the broadband filtering power divider are controlled by adjusting the distance between the inner conductor circuit and the rectangular coaxial outer conductor.

8. The broadband filtering power divider based on rectangular coaxial according to claim 2, characterized in that: The impedance ratio between the high impedance line of the step impedance resonator and the low impedance line of the step impedance resonator adjusts the bandwidth width of the broadband filter power divider.

9. The broadband filtering power divider based on rectangular coaxial according to claim 2, characterized in that: The transmission position of the pole is adjusted by using the coupling area of ​​the parallel coupled lines.

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