A rotary microwave filter power divider

Abstract

The present invention discloses a rotary microwave filter power divider, which resonates with TM 010 The choke slot loaded circular waveguide cavity of the mode and the circular symmetric loaded circular waveguide cavity of the coaxial probe are coupled through a common metal ring. 010 The circular symmetry of the mode field, the external quality factor control of the output coaxial probe and the coupled equal-amplitude and in-phase field, and the internal field continuity provided by the choke slot simultaneously achieve the functions of filtering, power division and stable output signal during rotation, forming a rotary filter power divider with the characteristics of low cost, small size, low loss and simple structure.

Description

Technical Field

[0001] The present invention relates to a microwave communication device, in particular to a rotary microwave filtering power divider. Background Art

[0002] Rotating devices are microwave devices that maintain stable signal transmission during mechanical rotation. They can be used in mechanically scanned antenna systems, radar systems, and test turntables. In addition to ensuring stable signal transmission during rotation, rotatable antenna systems also require other considerations. For example, antenna systems typically consist of multiple antenna elements in an array, requiring a power splitter network to feed each element at a specified power ratio. Furthermore, antenna systems need to filter out-of-band spurious signals to minimize their impact on the system itself or to filter out-of-band signals generated by the system to prevent interference with other systems. Therefore, filtering devices are required to suppress out-of-band spurious signals. Traditionally, the rotating device, power splitter network, and filtering devices are designed independently and then cascaded. This approach offers the advantages of relatively independent and easy design, achieving their respective performance limits. However, its disadvantages include large overall size, weight, high losses, high cost, and the potential need for matching circuits between the devices. Combining the three functions of rotation, power splitting, and filtering into a single device, creating a rotating filter power splitter, would significantly reduce system size, weight, losses, and cost, offering significant research and engineering value.

[0003] At present, there are no reports on rotating filter power dividers that integrate the three functions of rotation, power division and filtering. There are only filter power dividers that integrate filtering and power division functions, which are mainly of two types. One is a filter power divider based on microstrip implementation, which mainly integrates microstrip resonators into microstrip power dividers. The overall structure is placed on a substrate made of high-frequency dielectric material. Its advantages are low cost, simple structure and easy integration. However, its field distribution does not have circular symmetry, which makes it impossible to integrate with rotating devices. The frequency selectivity of the filter is poor, and the linear arrangement of the power branches when increased is not conducive to reducing the space occupied during rotation. The other is a filter power divider based on substrate integrated waveguide implementation, which mainly integrates substrate integrated waveguide resonators with power division networks. Compared with the previous method, the frequency selectivity of the filter is improved, but other problems still exist. In summary, the existing technology cannot integrate the three functions of rotation, power division and filtering into one device, and needs to be implemented separately. Therefore, it has disadvantages such as large size, heavy weight, high loss and high cost. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned existing technologies, a rotary microwave filtering power divider is proposed, which can simultaneously realize the three functions of rotation, power division and filtering, so as to achieve the purpose of reducing cost, size, loss and structural complexity.

[0005] Technical solution: A rotary microwave filter power divider, comprising: a first metal circular waveguide cavity, a second metal circular waveguide cavity, a common metal wall, an input coaxial line, and an output coaxial line;

[0006] The first metal circular waveguide cavity includes a metal circular waveguide 1, a choke slot, a metal circular waveguide 2, and a metal disc; the choke slot separates the coaxially arranged metal circular waveguide 1 and the metal circular waveguide 2; the metal disc is arranged at the lower end of the metal circular waveguide 2; a circular hole is opened in the center of the metal disc, and is connected to the input end coaxial line;

[0007] The second metal circular waveguide cavity includes a metal circular waveguide 3 and a metal disc; the metal disc is arranged at the upper end of the metal circular waveguide 3, and the metal disc is provided with four circular holes symmetrically distributed around the center of the circle, each circular hole is connected to an output end coaxial line;

[0008] The common metal wall is located between the lower end of the metal circular waveguide three and the upper end of the metal circular waveguide one, and is a common structure of the first metal circular waveguide cavity and the second metal circular waveguide cavity; the common metal wall is composed of a thin metal ring and concentric circular holes;

[0009] The first metal circular waveguide cavity, the second metal circular waveguide cavity and the common metal wall are coaxially arranged. The inner diameter of the first metal circular waveguide cavity is larger than the inner diameter of the second metal circular waveguide cavity. The first metal circular waveguide cavity and the second metal circular waveguide cavity both work in TM 010 model.

[0010] Furthermore, the inner diameters of the first metal circular waveguide cavity and the second metal circular waveguide cavity are both between 0.74-0.78λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0011] Furthermore, the diameter of the circular hole in the shared metal wall is between 0.58-0.62λ0, where λ0 is the free space wavelength corresponding to the center frequency. The operating bandwidth of the rotary filter power divider is controlled by adjusting the diameter of the circular hole in the shared metal wall.

[0012] Furthermore, the radius of the circle where the four output coaxial lines are located is between 0.25-0.3λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0013] Furthermore, the external quality factors of the four output ends are equal and four times the external quality factor of the input end. The external quality factor of the input end is adjusted by the length of the coaxial line probe at the input end extending into the cavity, and the external quality factor of the output end is adjusted by the position of the coaxial line at the output end from the center of the resonant cavity and the length of the coaxial line probe at the output end extending into the cavity.

[0014] Beneficial effect: The present invention will resonate with TM 010The choke slot loaded circular waveguide cavity of the mode and the circular symmetric loaded circular waveguide cavity of the coaxial probe are coupled through a common metal ring. 010 The circular symmetry of the mode field, the external quality factor control of the output coaxial probe and the coupled equal-amplitude and in-phase field, and the internal field continuity provided by the choke slot simultaneously achieve the functions of filtering, power division and stable output signal during rotation, forming a rotary filter power divider with the characteristics of low cost, small size, low loss and simple structure.

[0015] Four coaxial probes are loaded symmetrically on the resonant TM 010 The circular waveguide cavity of the mode ensures that the four signals are output with equal amplitude and in phase. At the same time, the extension length of the coaxial core and the position of the coaxial probe from the center of the resonant cavity are used to adjust the external quality factor of the output resonator to make it equal to four times the external quality factor of the input end, which is used to maintain filtering and matching.

[0016] The two circular waveguide cavities share a metal wall with a metal ring and a circular hole. The centers of the two circles coincide with each other, which is used to couple the TM of the two circular waveguide cavities. 010 The mode field and coupling strength are controlled by the inner diameter, which can adjust the working bandwidth of the rotating filter power divider.

[0017] A coaxial probe is loaded at the center of one end of the input circular waveguide cavity, and a choke slot is loaded on the metal ring wall. The length of the coaxial probe core can be adjusted to 010 The excitation of the mode is used to control the external quality factor of the input end. The choke slot ensures that the external impedance at the operating frequency is equivalent to an open circuit, avoiding energy leakage during rotation and maintaining stable signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a front cross-sectional structural diagram of the rotary filter power divider of the present invention;

[0019] Figure 2 A top view of the rotary filter power divider of the present invention;

[0020] Figure 3 The S parameter comparison of the rotary filter power divider rotated 0° and 90°, where (a) is S 11 and S 21 , (b) is S 11 and S 31 , (c) is S 11 and S 41 , (d) is S 11 and S 51 . DETAILED DESCRIPTION

[0021] The present invention will be further explained below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, a rotary microwave filter power divider includes: a first metal circular waveguide cavity 1, a second metal circular waveguide cavity 2, a common metal wall 3, an input end coaxial line 4 and an output end coaxial line 5.

[0023] The first metal circular waveguide cavity 1 comprises a metal circular waveguide 1 11, a choke slot 12, a metal circular waveguide 2 13, and a metal disc 14. The choke slot 12 separates the coaxially arranged metal circular waveguides 1 11 and 13. The metal disc 14 is located at the lower end of the metal circular waveguide 13. A circular hole is formed in the center of the metal disc 14, connecting it to the input coaxial line 4. Specifically, the metal circular waveguide 1 11 is a double-ring structure with a downward step. The metal circular waveguide 2 13 is divided into two parts: the upper part is a double-ring metal structure, and the lower part is a single-ring metal structure. In practical applications, these two parts can be relatively fixed by flanges or other external components.

[0024] The second metal circular waveguide cavity 2 includes a metal circular waveguide 3 21 and a metal disc 22. The metal disc 22 is arranged at the upper end of the metal circular waveguide 3 21. The metal disc 22 is provided with four circular holes symmetrically distributed around the center of the circle. Each circular hole is connected to an output end coaxial line 5. Figure 2 shown.

[0025] The shared metal wall 3 is located between the lower end of the metal circular waveguide 3 21 and the upper end of the metal circular waveguide 1 11 and is a common structure for the first metal circular waveguide cavity 1 and the second metal circular waveguide cavity 2. The shared metal wall 3 is composed of a thin metal ring 31 and a concentric circular hole 32.

[0026] The first metal circular waveguide cavity 1 , the second metal circular waveguide cavity 2 and the common metal wall 3 are coaxially arranged. The inner diameter of the first metal circular waveguide cavity 1 is greater than the inner diameter of the second metal circular waveguide cavity 2 .

[0027] In the present invention, the lengths of the first metal circular waveguide cavity 1 and the second metal circular waveguide cavity 2 are equal, ranging from 0.65 to 0.70λ0. The inner diameters of the first metal circular waveguide cavity 1 and the second metal circular waveguide cavity 2 are both between 0.74 and 0.78λ0. The diameter of the circular hole 32 of the common metal wall 3 is between 0.58 and 0.62λ0. The radius of the circular ring where the four output end coaxial lines 5 are located is between 0.25 and 0.3λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0028] For the rotary filter power divider of the present invention, the signal is fed from the input coaxial line 4, passes through the metal circular waveguide cavity 1 loaded by the choke slot, the common metal wall 3 and the metal circular waveguide cavity 2, and is output through the output coaxial line 5, forming a rotary filter power divider under the action of the overall structure.

[0029] In this structure, the first metal circular waveguide cavity 1 and the second metal circular waveguide cavity 2 both operate in TM 010 The mode resonant frequency is controlled by the inner diameter of each circular waveguide cavity. At the same time, the coupling between the two circular waveguide cavity modes is adjusted by the inner diameter of the common metal wall 3, thereby controlling the working bandwidth of the rotary filter power divider. The four output coaxial lines 5 are symmetrically distributed on the concentric circles of the metal disk 22. 010 The circularly symmetric field distribution of the resonant mode in the cross section inside the resonant cavity enables the current of the same intensity to be coupled to the probe inside the coaxial line, ensuring that the signal is distributed in equal proportion to the four output ends.

[0030] To ensure overall filtering characteristics, the external quality factors of the four output ports are equal and four times that of the input port. The input port's external quality factor is adjusted by the length of the probe extending into the cavity through input coaxial line 4. The output port's external quality factor is adjusted by the distance of output coaxial line 5 from the center of the resonant cavity and the length of the probe extending into the cavity through output coaxial line 5. The choke slot loaded into the metal circular waveguide cavity 1 utilizes the half-wavelength conversion period of impedance, current, and voltage in the transmission line. This makes the external impedance of the resonant cavity slot equivalent to an open circuit at the operating frequency, thereby maintaining field continuity within the resonant cavity, avoiding energy leakage during rotation, and maintaining the filtering power-sharing characteristics.

[0031] An embodiment of the present invention is listed below, and its structure is as follows Figure 1 As shown. The outer diameter of the rotary filter power divider is 32.1mm, the length is 38.4mm, the length of the two internal circular waveguide cavities is 19mm, the inner diameter of the first metal circular waveguide cavity is 21.1mm, the inner diameter of the second metal circular waveguide cavity is 21.36mm, the inner diameter of the shared metal wall circular hole is 17mm, and the radius of the circular ring where the four output end coaxial lines are located is 7.5mm. The S parameters of this embodiment are shown as follows Figure 3 As shown, this embodiment achieves equal power splitting ratios for input from port one and output from ports two, three, four, and five. Each power split path achieves a filtering response, demonstrating good out-of-band suppression. Each path has a -10dB matching bandwidth of 10.5-10.9 GHz, a center frequency of 10.7 GHz, a relative bandwidth of 4%, and an insertion loss of less than 0.15 dB. Furthermore, filtering and power splitting functions are maintained even when rotated to different angles, and the transmitted frequency response is very stable at different rotation angles.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A rotary microwave filter power divider, characterized in that: include: A first metal circular waveguide cavity (1), a second metal circular waveguide cavity (2), a common metal wall (3), an input end coaxial line (4), and an output end coaxial line (5); The first metal circular waveguide cavity (1) includes a metal circular waveguide 1 (11), a choke slot (12), a metal circular waveguide 2 (13), and a first metal disk (14); the choke slot (12) separates the coaxially arranged metal circular waveguide 1 (11) and the metal circular waveguide 2 (13); the first metal disk (14) is arranged at the lower end of the metal circular waveguide 2 (13); a circular hole is opened in the center of the first metal disk (14) and is connected to the input end coaxial line (4); The second metal circular waveguide cavity (2) comprises a metal circular waveguide three (21) and a second metal disc (22); the second metal disc (22) is arranged at the upper end of the metal circular waveguide three (21), and the second metal disc (22) is provided with four circular holes symmetrically distributed around the center of the circle, each circular hole being connected to an output end coaxial line (5); The shared metal wall (3) is located between the lower end of the metal circular waveguide three (21) and the upper end of the metal circular waveguide one (11), and is a shared structure of the first metal circular waveguide cavity (1) and the second metal circular waveguide cavity (2); the shared metal wall (3) is composed of a metal thin ring (31) and concentric circular holes (32); The first metal circular waveguide cavity (1), the second metal circular waveguide cavity (2), and the shared metal wall (3) are coaxially arranged, and the inner diameter of the first metal circular waveguide cavity (1) is smaller than the inner diameter of the second metal circular waveguide cavity (2); The first metal circular waveguide cavity (1) and the second metal circular waveguide cavity (2) both operate in TM 010 model.

2. The rotary microwave filter power divider according to claim 1, characterized in that: The inner diameters of the first metal circular waveguide cavity (1) and the second metal circular waveguide cavity (2) are both between 0.74-0.78λ0, where λ0 is the free space wavelength corresponding to the center frequency.

3. The rotary microwave filter power divider according to claim 1, characterized in that: The diameter of the circular hole (32) of the shared metal wall (3) is between 0.58 and 0.62λ0, where λ0 is the free space wavelength corresponding to the center frequency. The operating bandwidth of the rotary microwave filter power divider is controlled by adjusting the diameter of the circular hole (32) of the shared metal wall (3).

4. The rotary microwave filter power divider according to claim 1, characterized in that: The radius of the circle where the four output coaxial lines (5) are located is between 0.25-0.3λ0, where λ0 is the free space wavelength corresponding to the center frequency.

5. The rotary microwave filter power divider according to claim 1, characterized in that: The external quality factors of the four output ends are equal and are four times the external quality factor of the input end. The external quality factor of the input end is adjusted by the length of the probe of the input end coaxial line (4) extending into the cavity. The external quality factor of the output end is adjusted by the position of the output end coaxial line (5) from the center of the resonant cavity and the length of the probe of the output end coaxial line (5) extending into the cavity.

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