VHF-band high-power resonator and electrically tunable band-pass filter

Abstract

The invention discloses a VHF (very high frequency) high-power resonator and an electrically tunable band-pass filter. The electrically tunable resonator comprises an outer cavity, an inner conductor, a loading capacitor, a linear stepping motor, an upper limiting proximity switch and a lower limiting proximity switch, the inner conductor comprises a fixed bottom cylinder and a sliding upper cylinder, a guide rod support, a guide rod and a tuning rod are arranged in the fixed bottom cylinder, the tuning rod is connected with the sliding upper cylinder and the motor, and linear tuning of the sliding upper cylinder is achieved; a tight contact reed is arranged at the joint of the sliding upper cylinder and the fixed bottom cylinder, so that good contact between the sliding upper cylinder and the fixed bottom cylinder is ensured; and a guide medium is arranged between the outer side of the sliding upper cylinder and the loading capacitor cylinder, so that the sliding upper cylinder and the wall of the loading capacitor cylinder are kept parallel in the tuning process. The electrically tunable band-pass filter is composed of four electrically tunable resonators and a coupling structure. The electrically tunable band-pass filter is stable in working performance, large in power capacity and wide in tuning stroke.

Description

Technical Field

[0001] The invention relates to a VHF frequency band high-power electric rate regulation resonator and an electric regulation bandpass filter, belonging to the technical field of microwave bandpass filters. Background Art

[0002] At present, it is difficult to realize the kilowatt-class filters used in VHF band due to the frequency band problem. The coaxial cavity structure can meet the power requirements, but the volume is too large and inconvenient to install; the inner conductor of the spiral structure can greatly reduce the volume of the filter, but its stability is poor, and the spiral structure is greatly affected by the change of ambient temperature, and its filter index will also be greatly deteriorated. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a strongly loaded VHF band high-power resonator and an electrically tunable bandpass filter.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A VHF band high-power electrically tuned resonator comprises an outer cavity (1), an inner conductor (2), a loading capacitor (3) and a linear stepping motor (4); the inner conductor and the loading capacitor are both located in the outer cavity, and are respectively connected to the inner top wall and the inner bottom wall of the outer cavity (1); the linear stepping motor (4) is installed outside the outer cavity and fixed to the top of the outer cavity via a motor support block (8); a linear stepping motor screw (15) penetrates the wall of the outer cavity (1) and extends into the inner conductor;

[0006] The inner conductor (2) comprises a fixed bottom cylinder (6) and a sliding upper cylinder (7); the top of the fixed bottom cylinder (6) is fixedly connected to the inner top wall of the outer cavity, and a tuning rod (12) is installed inside the fixed bottom cylinder, and the tuning rod (12) has the freedom to slide along the central axis of the inner conductor; the electric screw is threadedly assembled with the top plate of the tuning rod (12), the sliding upper cylinder is installed at the bottom of the tuning rod and the two are fixedly connected, and a tight contact spring (15) is installed at the connection position between the sliding upper cylinder (7) and the fixed bottom cylinder (6) to ensure good contact between the sliding upper cylinder (7) and the fixed bottom cylinder (6);

[0007] The loading capacitor is provided with a space for the sliding upper cylinder to move.

[0008] Furthermore, a guide medium (14) is installed between the outer side of the sliding upper cylinder (7) and the loading capacitor (3) to ensure that the sliding upper cylinder (7) and the loading capacitor (3) remain parallel during the tuning process.

[0009] Furthermore, the guide medium (14) is a non-metallic hard material.

[0010] Furthermore, it also includes an upper limit switch (5) and a lower limit switch (11); the upper limit switch (5) is located at the bottom of the motor, and the switch sensing part of the upper limit switch is located in the hollow part of the motor support block (8); the lower limit switch (11) is located at the bottom of the guide rod support (9), and the switch sensing part of the lower limit switch is located in the hollow part of the inner conductor (2).

[0011] Furthermore, a guide rod support (9) and a guide rod (10) are also provided inside the fixed bottom cylinder (6);

[0012] The guide rod support is fixedly connected to the inside of the fixed bottom cylinder (6), which is in the form of a cylinder and is provided with two semicircular grooves parallel to the tuning rod; the guide rod is two metal cylinders, and the two metal cylinders are respectively fixed in the corresponding semicircular grooves by screws; and another semicircular groove corresponding to the metal cylinder is provided on both sides of the tuning rod.

[0013] A VHF band high-power electrically tunable filter, comprising an input / output coupling structure (18), adjacent inter-cavity coupling holes (17), and four low-frequency high-power resonators (16) as claimed in any one of claims 1 to 5; characterized in that the four resonators (16) are arranged in a rectangular array, two adjacent external cavities are coupled via the inter-cavity coupling holes (17), and the two resonators at both ends are provided with the input / output coupling structure (18).

[0014] Furthermore, the input and output coupling structure (18) is a rectangular coupling ring, the inner conductors of the rectangular coupling ring are parallel, and the coupling ring is made of silver-plated aluminum plates.

[0015] Furthermore, there is a capacitive coupling disk (19) between the input and output resonant cavities, and the capacitive coupling disk (19) is made of silver-plated aluminum;

[0016] Furthermore, the capacitive coupling disk (19) is fixed on a common cavity wall of the input and output resonant cavities, and the common cavity wall is provided with equidistant fixing holes (20).

[0017] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0018] 1. Two guide rods are used inside the inner conductor of the present invention to ensure the linear tuning of the inner conductor sliding cylinder; a non-metallic medium guide is designed between the sliding cylinder and the loading cylinder to ensure the linear tuning of the sliding conductor cylinder in the loading cylinder; the double guide prevents the sliding cylinder from tilting slightly during the tuning process;

[0019] 2. The present invention designs proximity switches as limit switches at both ends of the tuning stroke. The proximity switches are non-contact switches, which realize limit through electromagnetic induction, and are convenient for tuning program control. The structural parts of the VHF band electric tuning filter are relatively large, and the impact force is also relatively large. The contact switch is easy to be damaged, and the non-contact switch can avoid this problem. And the limit switches are designed inside the inner conductor, without any interference to the electromagnetic field in the resonant cavity;

[0020] 3. The present invention fills a medium between the sliding conductor and the loading capacitor tube, which can not only guide the sliding conductor but also greatly reduce the volume of the cavity;

[0021] 4. A capacitive cross-coupling structure is designed between the input and output resonant cavities. This structure can form a transmission zero point outside the band, greatly improving the near-end suppression of the passband. Equidistant mounting holes are designed on the cavity wall. The cross-coupling structure can be adjusted up and down without affecting the filter waveform, which is suitable for zero point requirements at different positions outside the band. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the internal structure of a single electrically tuned resonator.

[0023] Figure 2 It is a structural diagram of the guide rod support;

[0024] Figure 3 This is the internal structure diagram of the electronically tunable bandpass filter;

[0025] Figure 4 This is a cross-sectional diagram of the electrically tunable bandpass filter. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0027] A low-frequency, high-power electrically tuned resonator, the resonator comprises an outer cavity 1, an inner conductor 2, a loading capacitor 3, a linear stepping motor 4, an upper limit proximity switch 5, and a lower limit proximity switch 11; the inner conductor 2 comprises a fixed bottom cylinder 6 and a sliding upper cylinder 7, the fixed bottom cylinder 6 is provided with a guide rod support 9, a guide rod 10, and a tuning rod 12, the tuning rod 12 connects the sliding upper cylinder 7 and a motor screw 15, so as to realize the linear tuning of the sliding upper cylinder 7; a close contact spring 15 is provided at the connecting position of the sliding upper cylinder 7 and the fixed bottom cylinder 6, so as to ensure good contact between the sliding upper cylinder 7 and the fixed bottom cylinder 6; the linear stepping motor 4 is fixed to the top of the outer cavity through a motor support block 8, the linear stepping motor screw 15 enters the outer cavity 1 through the wall of the outer cavity 1, enters the inner conductor 2 through the inner conductor fixed bottom cylinder 6, and is threadedly assembled with the top plate of the tuning rod 12, and the motor screw 15 is installed in parallel with the inner conductor 2.

[0028] In the coaxial cavity resonator, a guide medium 14 is installed between the outer side of the sliding upper cylinder 7 and the loading capacitor 3. The guide medium 14 is a non-metallic hard material; the guide medium 14 is a cylindrical structure, the inner diameter of which is slightly larger than the outer diameter of the sliding upper cylinder 7, and the outer diameter is slightly smaller than the inner diameter of the loading capacitor cylinder, and is filled between the sliding upper cylinder and the loading capacitor cylinder. It can ensure that the sliding upper cylinder 7 and the loading capacitor 3 maintain parallel movement during the tuning process, and greatly reduce the cavity volume.

[0029] The upper limit switch 5 is located at the bottom of the motor, and the switch sensing part is in the hollow part of the linear motor support block 8; the lower limit switch 11 is located at the bottom of the guide rod support 9, and the switch sensing part is in the hollow part of the inner conductor 2.

[0030] A VHF band high-power electrically tunable filter is composed of an input and output coupling structure 18, four low-frequency high-power resonators 16, and adjacent inter-cavity coupling holes 17. The four resonators 16 are arranged in a grid, and there is an inter-cavity coupling hole 17 between two adjacent cavities to achieve coupling. The two resonators at both ends have an input and output coupling structure 18. The input and output coupling structure 18 is a rectangular coupling ring, the inner conductors of the rectangular coupling ring are parallel, and the coupling ring is spliced ​​with silver-plated aluminum plates. There is a capacitive coupling disk 19 between the input and output resonant cavities, and the capacitive coupling disk 19 is made of aluminum silver-plated. The capacitive coupling disk 19 is fixed on the common cavity wall of the input and output resonant cavities, and the common cavity wall is designed with equidistant fixing holes 20.

[0031] The following is a more specific embodiment:

[0032] Combined with Figure 1 , Figure 2 A VHF band high-power electrically tuned resonator includes an outer cavity 1, an inner conductor 2, a loading capacitor 3, a linear stepping motor 4, an upper limit proximity switch 5, and a lower limit proximity switch 11; the outer cavity 1 is formed by splicing aluminum plates due to its large volume;

[0033] The inner conductor 2 is composed of a fixed bottom cylinder 6 and a sliding upper cylinder 7. The fixed bottom cylinder 6 is welded and fixed to the outer cavity 1. A guide rod support 9, a guide rod 10 and a tuning rod 12 are installed inside the fixed bottom cylinder 6. The guide rod support is designed as a cylinder, and a semicircular groove is designed for the guide rod. The guide rod support and the fixed bottom cylinder are screwed and installed. The guide rod 10 is two metal cylinders, which are screwed in the groove of the guide rod support 9. The tuning rod 12 connects the sliding upper cylinder 7 and the motor screw 15 to achieve linear tuning of the sliding upper cylinder 7. The contact part of the tuning rod 12 and the guide rod 10 is designed with a semicircular groove. A close contact spring 15 is installed at the connecting position of the sliding upper cylinder 7 and the fixed bottom cylinder 6 to ensure good contact between the sliding upper cylinder 7 and the fixed bottom cylinder 6.

[0034] The linear stepper motor 4 is fixed to the top of the outer cavity through the motor support block 8, the linear stepper motor screw 15 enters the cavity through the wall of the outer cavity 1, enters the inner conductor 2 through the inner conductor fixing bottom cylinder 6, and is threadedly assembled with the top plate of the tuning rod 12, and the motor screw 15 is installed parallel to the inner conductor 2;

[0035] A guide medium 14 is installed between the outer side of the sliding upper cylinder 7 and the loading capacitor 3 to ensure that the sliding upper cylinder 7 and the loading capacitor 3 remain parallel during the tuning process, and the guide medium 14 is a non-metallic hard material;

[0036] The upper limit switch 5 is located at the bottom of the motor, and is threadedly mounted on the side surface 8 of the linear motor support. The switch sensing part is located in the hollow part of the linear motor support block 8. The lower limit switch 11 is located at the bottom of the guide rod support 9, and the switch sensing part is located in the hollow part of the inner conductor 2. The sensing blocks of the upper and lower limit switches are both on the top plate of the guide rod, respectively located on both sides.

[0037] Combination Figure 3 , Figure 4 From the perspective of the electronically tunable filter, it is composed of an input and output coupling structure 18, four VHF band high-power resonators 16, and adjacent inter-cavity coupling holes 17. The four resonators 16 are arranged in a grid, and there is an inter-cavity coupling hole 17 between two adjacent cavities to achieve coupling, and the two resonators at both ends have an input and output coupling structure 18. The input and output coupling structure 18 is a rectangular coupling ring, which is assembled in parallel with the inner conductor, and the coupling ring is spliced ​​with silver-plated aluminum plates. There is a capacitive coupling disk 19 between the input and output resonant cavities, and the capacitive coupling disk 19 is made of silver-plated aluminum. The capacitive coupling disk 19 is supported by a non-metallic medium and fixed on the common cavity wall of the input and output resonant cavities. The common cavity wall is designed with upper and lower equidistant fixing holes 20; the upper and lower equidistant fixing holes can be used to tune the position of the capacitive coupling disk 19. The present invention belongs to a single-cavity monotonic electronically tunable filter, each resonant cavity is equipped with a linear motor, and the tuning structure and limit switch are almost concentrated inside the inner conductor, which simplifies the tuning mechanical structure to the maximum extent and reduces the volume of the entire filter. The invention has stable structural performance and is less affected by the external environment; it has high out-of-band suppression and small in-band insertion loss, and is suitable for high-power communication systems in the VHF frequency band.

Claims

1. A VHF band high-power electrically tuned resonator, characterized in that: The invention comprises an outer cavity (1), an inner conductor (2), a loading capacitor (3) and a linear stepping motor (4); the inner conductor and the loading capacitor are both located in the outer cavity, and are respectively connected to the inner top wall and the inner bottom wall of the outer cavity (1); the linear stepping motor (4) is installed outside the outer cavity and fixed to the top of the outer cavity via a motor support block (8); and the linear stepping motor screw (15) penetrates the wall of the outer cavity (1) and extends into the inner conductor; The inner conductor (2) comprises a fixed bottom cylinder (6) and a sliding upper cylinder (7); the top of the fixed bottom cylinder (6) is fixedly connected to the inner top wall of the outer cavity, and a tuning rod (12) is installed inside the fixed bottom cylinder, and the tuning rod (12) has the freedom to slide along the central axis of the inner conductor; the electric screw is threadedly assembled with the top plate of the tuning rod (12), the sliding upper cylinder is installed at the bottom of the tuning rod and the two are fixedly connected, and a tight contact spring (15) is installed at the connection position between the sliding upper cylinder (7) and the fixed bottom cylinder (6) to ensure good contact between the sliding upper cylinder (7) and the fixed bottom cylinder (6); The loading capacitor is provided with a space for the sliding upper cylinder to move.

2. A VHF band high-power electrically tunable resonator according to claim 1, characterized in that: A guide medium (14) is arranged between the outer side of the sliding upper cylinder (7) and the loading capacitor (3) to ensure that the sliding upper cylinder (7) and the loading capacitor (3) remain parallel during the tuning process.

3. A VHF band high-power electrically tuned resonator according to claim 2, characterized in that: The guide medium (14) is a non-metallic hard material.

4. A VHF band high-power electrically tuned resonator according to claim 1, characterized in that: It also includes an upper limit switch (5) and a lower limit switch (11); the upper limit switch (5) is located at the bottom of the motor, and the switch sensing part of the upper limit switch is located in the hollow part of the motor support block (8); the lower limit switch (11) is located at the bottom of the guide rod support (9), and the switch sensing part of the lower limit switch is located in the hollow part of the inner conductor (2).

5. A VHF band high-power electrically tunable resonator according to claim 1, characterized in that: A guide rod support (9) and a guide rod (10) are also provided inside the fixed bottom cylinder (6); The guide rod support is fixedly connected to the inside of the fixed bottom cylinder (6), which is in the form of a cylinder and is provided with two semicircular grooves parallel to the tuning rod; the guide rod is two metal cylinders, and the two metal cylinders are respectively fixed in the corresponding semicircular grooves by screws; and another semicircular groove corresponding to the metal cylinder is provided on both sides of the tuning rod.

6. A VHF band high-power electrically tunable filter, comprising an input and output coupling structure (18) and four low-frequency high-power resonators (16) as claimed in any one of claims 1 to 5; characterized in that: The four resonators (16) are arranged in a rectangular array, two adjacent external cavities are coupled via an inter-cavity coupling hole (17), and the two resonators at both ends are provided with the input and output coupling structures (18).

7. A VHF band high power electrically tunable filter according to claim 6, characterized in that: The input and output coupling structure (18) is a rectangular coupling ring, the inner conductors of the rectangular coupling ring are parallel, and the coupling ring is made of silver-plated aluminum plates.

8. A VHF band high power electrically tunable filter according to claim 6, characterized in that: A capacitive coupling disk (19) is provided between the input and output resonant cavities, and the capacitive coupling disk (19) is made of silver-plated aluminum.

9. A VHF band high power electrically tunable filter according to claim 8, characterized in that: The capacitive coupling disk (19) is fixed on the common cavity wall of the input and output resonant cavities, and the common cavity wall is provided with equidistant fixing holes (20).

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