A coaxial cavity electrically tunable filter

Abstract

The application discloses a coaxial cavity electrically tunable filter and belongs to the technical field of wireless communication. The coaxial cavity electrically tunable filter comprises an input-output coupling structure, a transmission structure, a frequency compensation device and a coupling compensation device; a cavity mainly comprises resonant cavities and a coupling structure; the resonant cavities are arranged in a linear array mode, and adjacent resonant cavities are communicated through the coupling structure; the top of each resonant cavity is provided with a choke structure, and the bottom of each resonant cavity is provided with a frequency compensation hole; the outer wall of the resonant cavities at the two ends of the linear array is provided with an input-output structure; the input-output coupling structure mainly comprises a coupling plate, a coupling ring and a radio frequency plug; the coupling ring is arranged on one side of the coupling plate, and the radio frequency plug is arranged on the other side of the coupling plate; and the coupling ring is located in the input-output structure. The frequency tuning column of the application reduces frictional resistance in the frequency adjustment process and improves the reliability of the electrically tunable filter.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication, in particular to a coaxial cavity electrically tunable filter, which is particularly suitable for realizing constant filter bandwidth and freely adjusting the center frequency in a wide frequency range in a C-band communication system. BACKGROUND

[0002] The electromagnetic environment faced by modern military communication is becoming increasingly complex, and electronic countermeasures are becoming stronger. In view of electronic jamming, an electrically tunable filter is an important component for realizing electronic anti-jamming.

[0003] The Chinese patent CN104393383B of the prior art discloses a wide tuning coaxial electrically tunable filter and a debugging method. The overall structure of the electrically tunable filter is relatively complex, the number of cavities is even, and it lacks generality. In the transmission structure, the screw rod is connected with the filter through an annular elastic comb, which is difficult to realize in process and has low reliability. There is a lack of inter-cavity coupling compensation device, and the debugging is difficult. In view of the deficiencies in the prior art, the present application provides a coaxial cavity electrically tunable filter with constant bandwidth and freely adjustable center frequency in a wide frequency range. SUMMARY

[0004] To solve the above technical problems, the present application provides a coaxial cavity electrically tunable filter, which reduces the frictional resistance in the frequency adjustment process and improves the reliability of the electrically tunable filter.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A coaxial cavity electrically tunable filter, comprising a cavity 5, further comprising an input-output coupling structure 6, a transmission structure 2, a frequency compensation device 8 and a coupling compensation device 9;

[0007] The cavity 5 is mainly composed of a resonant cavity 10 and a coupling structure 11. A plurality of resonant cavities 10 are arranged in a straight line, and adjacent resonant cavities are connected through the coupling structure 11. The top of each resonant cavity is provided with a choke structure 12, and the bottom is provided with a frequency compensation hole 13. The outer wall of the resonant cavities at both ends of the straight line array is provided with an input-output structure 14;

[0008] The input-output coupling structure 6 is mainly composed of a coupling plate 15, a coupling ring 16 and a radio frequency plug 17. The coupling ring 16 is arranged on one side of the coupling plate, and the radio frequency plug is arranged on the other side of the coupling plate 15. The coupling ring 16 is located in the input-output structure 14;

[0009] The outer end of the choke structure 12 is provided with a shaft sleeve. The shaft sleeve is provided with a frequency adjustment column 24 with the same central axis, and the frequency adjustment column can move up and down along the shaft sleeve. The transmission plate is arranged above the frequency adjustment column, and the transmission plate is fixedly connected with the top end of each frequency adjustment column below.

[0010] The action end of the transmission structure is fixedly connected with the transmission plate, and is used for driving the transmission plate to move up and down; the transmission plate 21 drives the frequency adjusting column 24 to move up and down along the shaft sleeve.

[0011] Further, the plane where the coupling ring 16 is located and the coupling plate are perpendicular to each other.

[0012] Further, the transmission structure mainly comprises a stepping motor 18, a transmission adapter plate 20 and a sliding plate 25; the transmission adapter plate is a bent structure, one end of which is fixedly connected with the transmission plate;

[0013] The shell of the stepping motor is fixed to the outer wall of the cavity 5; the output end of the stepping motor is fixedly connected with one end of the lead screw; the other end of the lead screw is connected with the lead screw fixed seat bearing; the sliding plate 25 is threadedly connected with the lead screw, and the other end of the sliding plate is connected with the adapter plate.

[0014] Further, the stepping motor is fixed to the outer wall of the cavity 5 through the fixing plate 19.

[0015] Further, the transmission adapter plate is fixedly connected with the transmission plate 21 through the adapter plate 23.

[0016] Further, a limiting column is further arranged between the lead screw fixed seat and the outer wall of the stepping motor, and a limiting hole is arranged on the transmission adapter plate; the lead screw fixed seat is located directly above the transmission adapter plate, and the limiting column is located in the limiting hole; the output shaft of the stepping motor rotates to drive the lead screw to rotate, and the lead screw further drives the sliding plate to drive the transmission adapter plate to move up and down along the limiting column.

[0017] Further, the depth of the resonant cavity 10 is three quarters of a wavelength, and the coupling structure 11 is a metal plate with a rectangular hole structure, and the rectangular hole structure penetrates through adjacent resonant cavities.

[0018] Further, the frequency compensation device 8 and the coupling compensation device are both combined structures of a frequency compensation screw and a frequency compensation nut, the frequency compensation screw enters the inside 10 of the resonant cavity through the frequency compensation hole 13, and the frequency compensation nut is located outside the frequency compensation hole 13 and is used for locking the frequency compensation screw; the part of the frequency compensation screw entering the resonant cavity is a smooth surface.

[0019] Further, the coupling compensation device 9 is a combined structure of a coupling compensation screw and a coupling compensation nut, the coupling compensation screw enters the rectangular hole structure of the coupling structure through the coupling compensation hole, and the coupling compensation nut is located outside the coupling compensation hole and is used for locking the coupling compensation screw; the part of the frequency compensation screw entering the rectangular hole structure is a smooth surface.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] The coaxial cavity electrically tunable filter of the present application is designed in an integrated structure, the filter and the transmission structure are matched and connected, the length of the tuning column entering the resonant cavity is changed by rotating the driving stepper motor, the constant working bandwidth of the filter is realized, and the center frequency is freely adjusted. The depth of the resonant cavity is three-fourth of the wavelength, the adjustment stroke of the filter is increased, and the sensitivity of the frequency change of the filter is reduced; the filter is designed with a frequency compensation device and a coupling compensation device, which can compensate the frequency and coupling offset during the center frequency adjustment.

[0022] The choke structure and the shaft sleeve of the present application form an absorption cavity, the tuning column does not directly contact the absorption cavity when passing through the absorption cavity and entering the resonant cavity, the frictional resistance during the frequency adjustment is reduced, and the reliability of the electrically tunable filter is improved. The transmission structure is matched and designed according to the filter structure, and the overall structure is small and precise.

[0023] The coaxial cavity electrically tunable filter adopts the form of a coaxial cavity filter, the resonant cavity structure, the input and output coupling structure, the coupling structure and the choke structure of the filter cavity are optimized and designed, and the technical requirements of the electrically tunable filter are realized, that is, when the center frequency of the filter changes in a wide frequency range, the bandwidth of the filter is constant and unchanged.

[0024] The filter, the transmission structure and the assembly relationship are optimized and designed, the practicability and reliability of the electrically tunable filter are greatly improved, and the requirements of the communication equipment on the coaxial cavity electrically tunable filter, that is, the constant bandwidth and the free adjustment of the center frequency in a wide frequency range, are met. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a front view of the cavity of the present application;

[0026] Figure 2 is a front view of the cavity of the present application;

[0027] Figure 3 is a side view of the cavity of the present application;

[0028] Figure 4 is a filter structure diagram of the present application;

[0029] Figure 5 is an input and output coupling structure diagram of the present application;

[0030] Figure 6 is an assembly relationship diagram of the present application;

[0031] Figure 7 is a rear view of the present application;

[0032] Figure 8 is a working mode principle block diagram of the present application. DETAILED DESCRIPTION

[0033] The application will be described in further detail below with reference to the drawings:

[0034] The coaxial cavity electrically tunable filter comprises a cavity 5, and further comprises an input / output coupling structure 6, a transmission structure 2, a frequency compensation device 8 and a coupling compensation device 9.

[0035] The cavity 5 mainly comprises resonant cavities 10 and coupling structures 11; the resonant cavities 10 are arranged in a straight line, and adjacent resonant cavities are connected through the coupling structures 11; the top of each resonant cavity is provided with a choke structure 12, and the bottom of each resonant cavity is provided with a frequency compensation hole 13; the outer wall of the resonant cavities at the two ends of the straight line array is provided with an input / output structure 14;

[0036] The input / output coupling structure 6 mainly comprises a coupling plate 15, a coupling ring 16 and a radio frequency plug 17; the coupling ring 16 is arranged on one side of the coupling plate, and the radio frequency plug is arranged on the other side of the coupling plate 15; the coupling ring 16 is located in the input / output structure 14;

[0037] The outer end of the choke structure 12 is provided with a shaft sleeve; the shaft sleeve is provided with a frequency tuning column 24 with the same central axis, and the frequency tuning column can move up and down along the shaft sleeve; the transmission plate is arranged above the frequency tuning column, and the top end of each frequency tuning column below the transmission plate is fixedly connected with the transmission plate;

[0038] The action end of the transmission structure is fixedly connected with the transmission plate, and is used for driving the transmission plate to move up and down; the transmission plate 21 drives the frequency tuning column 24 to move up and down along the shaft sleeve.

[0039] Further, the plane where the coupling ring 16 is located and the coupling plate are perpendicular to each other.

[0040] Further, the transmission structure mainly comprises a stepping motor 18, a transmission adapter plate 20 and a sliding plate 25; the transmission adapter plate is a bent structure, and one end of the transmission adapter plate is fixedly connected with the transmission plate;

[0041] The shell of the stepping motor is fixed to the outer wall of the cavity 5; the output end of the stepping motor is fixedly connected with one end of a lead screw; the other end of the lead screw is connected with a lead screw fixed seat bearing; the sliding plate 25 is threadedly connected with the lead screw, and the sliding plate is connected with the other end of the adapter plate.

[0042] Further, the stepping motor is fixed to the outer wall of the cavity 5 through the fixing plate 19.

[0043] Further, the transmission adapter plate is fixedly connected with the transmission plate 21 through the adapter plate 23.

[0044] Further, the limiting post is arranged between the outer wall of the screw rod fixing seat 66 and the stepper motor, and the limiting hole is arranged on the transmission adapter plate; the screw rod fixing seat is located directly above the transmission adapter plate, and the limiting post is located in the limiting hole; the stepper motor output shaft rotates to drive the screw rod to rotate, and the screw rod further drives the sliding plate to drive the transmission adapter plate to move up and down along the limiting post.

[0045] Further, the resonant cavity 10 has a depth of three quarters of a wavelength, and the coupling structure 11 is a metal plate with a rectangular hole structure, and the rectangular hole structure penetrates the adjacent resonant cavities.

[0046] Further, the frequency compensation device 8 and the coupling compensation device are both combined structures of a frequency compensation screw and a frequency compensation nut, the frequency compensation screw enters the resonant cavity 10 through the frequency compensation hole 13, and the frequency compensation nut is located outside the frequency compensation hole 13 and is used for locking the frequency compensation screw; the part of the frequency compensation screw entering the resonant cavity is a smooth surface.

[0047] Further, the coupling compensation device 9 is a combined structure of a coupling compensation screw and a coupling compensation nut, the coupling compensation screw enters the rectangular hole structure of the coupling structure through the coupling compensation hole, and the coupling compensation nut is located outside the coupling compensation hole and is used for locking the coupling compensation screw; the part of the frequency compensation screw entering the rectangular hole structure is a smooth surface.

[0048] The following is a specific embodiment:

[0049] Figure 1 、 Figure 2 and Figure 3 are respectively a schematic front view, a schematic front cross-sectional view and a schematic side view of the cavity of the present application; including 5 resonant cavities 10, 4 coupling structures 11, 5 choke structures 12, 5 frequency compensation holes 13 and 2 input / output structures 14. The cavity 5 is a linear arrangement structure, and the arrangement is in turn input / output structure to resonant cavity to coupling structure to resonant cavity to coupling structure to resonant cavity to coupling structure 11 to resonant cavity to coupling structure to resonant cavity 10 to input / output structure 14; the choke structure 12 is located at the top of the resonant cavity 10; the frequency compensation hole 13 is located at the bottom of the resonant cavity 10; the resonant cavity 10 has a depth of three quarters of a wavelength, and the coupling structure 11 is a metal plate with a rectangular hole structure, and the rectangular hole structure is located outside the metal plate and is connected to one side of the cover plate 7.

[0050] Figure 4The filter structure schematic diagram of the application; including cavity 5, input and output coupling structure 6, cover plate 7, frequency compensation device 8 and coupling compensation device 9. Input and output coupling structure 6 is connected with input and output structure 14 of cavity 5; cover plate 7 is connected with the side of cavity 5; frequency compensation device 8 is screw and nut combination, screw enters the inside 10 of resonant cavity through frequency compensation hole 13, nut and screw combination, located outside frequency compensation hole 13, locking; coupling compensation device 9 is screw and nut combination, screw enters the inside of coupling structure 11 through coupling compensation hole, nut and screw combination, located outside coupling compensation hole, locking. Figure 5 The input and output coupling structure schematic diagram: including coupling plate 15, coupling ring 16 and RF plug 17.

[0051] Figure 6 And Figure 7 The assembly relationship schematic diagram of filter 1 and transmission structure 2; transmission structure 2 is composed of stepper motor 18, fixed plate 19, transmission adapter plate 20, transmission plate 21, shaft sleeve 22, adapter plate 23, frequency tuning column 24. Assembly relationship 3 is connected with filter 1 respectively, and connected with transmission structure 2; stepper motor 18 is fixed on fixed plate 19, fixed plate 19 is fixed on the side wall of filter 1; 5 shaft sleeves 22 are fixed on 5 choke structures 12 respectively; 5 frequency tuning columns 24 are fixed on transmission plate 21 mounting hole and connected with nut respectively; transmission adapter plate 20 is fixed on the sliding plate 25 of stepper motor 18 at one end, and is fixed on transmission plate 21 through adapter plate 23 at one end; frequency tuning column 24 enters the inside of resonant cavity 10 through shaft sleeve 22 and choke structure 12;

[0052] Figure 8 The principle block diagram of coaxial cavity electrically tunable filter working mode 4; working mode 4 is connected with filter 1 respectively, and connected with transmission structure 2; stepper motor 18 bearing moves outward, driving sliding plate 25 to move outward, sliding plate 25 drives transmission plate 21 to move outward through transmission connecting plate 20 and connecting plate 23, transmission plate 21 drives frequency tuning column 24 to move outward, frequency tuning column 24 is in the inside of resonant cavity 10, the length becomes shorter, the center frequency of filter moves to high frequency; stepper motor 18 bearing moves inward, driving sliding plate 25 to move inward, sliding plate 25 drives transmission plate 21 to move inward through transmission connecting plate 20 and connecting plate 23, transmission plate 21 drives frequency tuning column 24 to move inward, screw 24 is in the inside of resonant cavity 1, the length becomes longer, the center frequency of filter moves to low frequency.

Claims

1. A coaxial cavity electrically tunable filter comprising a cavity (5), characterized in that, It also includes input-output coupling structure (6), transmission structure (2), frequency compensation device (8) and coupling compensation device (9); The cavity (5) is mainly composed of resonant cavity (10) and coupling structure (11); a plurality of resonant cavities (10) are arranged in a straight line, and adjacent resonant cavities are communicated through the coupling structure (11); the top of each resonant cavity is provided with a choke structure (12), and the bottom is provided with a frequency compensation hole (13); the outer wall of the resonant cavity at both ends of the straight line array is provided with an input-output structure (14); The input-output coupling structure (6) includes a coupling plate (15), a coupling ring (16) and a radio frequency plug (17); the coupling ring (16) is arranged on one side of the coupling plate, and the radio frequency plug is arranged on the other side of the coupling plate (15); the coupling ring (16) is located in the input-output structure (14); The outer end of the choke structure (12) is provided with a shaft sleeve; a frequency modulation column (24) with the same central axis is arranged in the shaft sleeve, and the frequency modulation column can move up and down along the shaft sleeve; a transmission plate is arranged above the frequency modulation column, and the transmission plate is fixedly connected with the top end of each frequency modulation column below; The action end of the transmission structure is fixedly connected with the transmission plate, for driving the transmission plate to move up and down; the transmission plate (21) drives the frequency modulation column (24) to move up and down along the shaft sleeve; The transmission structure includes a stepping motor (18), a transmission adapter plate (20) and a sliding plate (25); the transmission adapter plate is a bent structure, one end of which is fixedly connected with the transmission plate; The shell of the stepping motor is fixed to the outer wall of the cavity (5); the output end of the stepping motor is fixedly connected with one end of a lead screw; the other end of the lead screw is connected with a screw rod fixed seat bearing; the sliding plate (25) is threadedly connected with the screw rod, and the sliding plate is connected with the other end of the adapter plate; The transmission adapter plate is fixedly connected with the transmission plate (21) through the adapter plate (23); A limiting column is further arranged between the screw rod fixed seat and the outer wall of the stepping motor, and a limiting hole is arranged on the transmission adapter plate; the screw rod fixed seat is located directly above the transmission adapter plate, and the limiting column is located in the limiting hole; the output shaft of the stepping motor rotates to drive the lead screw to rotate, and the screw rod further drives the transmission adapter plate to move up and down along the limiting column by driving the sliding plate; The resonant cavity (10) has a depth of three-quarters of a wavelength, and the coupling structure (11) is a metal plate with a rectangular hole structure, and the rectangular hole structure penetrates through the adjacent resonant cavities.

2. The coaxial cavity electrically tunable filter of claim 1, wherein, The plane where the coupling ring (16) is located and the coupling plate are perpendicular to each other.

3. The coaxial cavity electrically tunable filter of claim 1, wherein, The stepping motor is fixed to the outer wall of the cavity (5) through a fixed plate (19).

4. The coaxial cavity electrically tunable filter of claim 1, wherein, The frequency compensation device (8) and the coupling compensation device are both combined structures of a frequency compensation screw column and a frequency compensation nut, the frequency compensation screw column enters the inside of the resonant cavity (10) through the frequency compensation hole (13), and the frequency compensation nut is located outside the frequency compensation hole (13) for locking the frequency compensation screw column; the part of the frequency compensation screw column entering the resonant cavity is a smooth surface.

5. The coaxial cavity electrically tunable filter of claim 1, wherein, The coupling compensation device (9) is a combination of a coupling compensation screw column and a coupling compensation nut, the coupling compensation screw column enters the rectangular hole structure of the coupling structure through the coupling compensation hole, and the coupling compensation nut is located outside the coupling compensation hole for locking the coupling compensation screw column. The part of the frequency compensation stud entering the rectangular hole structure is smooth.

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