CN210111011U

CN210111011U - Band-pass filter

Info

Publication number: CN210111011U
Application number: CN201921355483.1U
Authority: CN
Inventors: 高慧; 刘汉玉; 王晓宇
Original assignee: China Communications Polytron Technologies Inc
Current assignee: China Communications Polytron Technologies Inc
Priority date: 2019-08-21
Filing date: 2019-08-21
Publication date: 2020-02-21
Anticipated expiration: 2029-08-21

Abstract

The utility model discloses a band-pass filter, including the cavity with place in the cavity inside and outside part, there is three resonant cavity in the cavity, be provided with between two adjacent resonant cavities and realize capacitive coupling window, place the skeleton in the resonant cavity, and the spiral coil dress is on the skeleton, and the skeleton passes through self tapping screw to be fixed on the apron. One end of the spiral coil is open-circuit, the other end of the spiral coil is welded on the cover plate, one end of the tap is welded on the spiral coil, and the other end of the tap is welded with a cable with a plug, which is welded on the cover plate. The utility model discloses has following effect: the 381MHz to 396MHz band-pass filter has small volume, the insertion loss is less than 1.2dB, stopband attenuation which is not less than 44dB is arranged below the stopband 344 MHz and above the stopband 436MHz, and the no-load Q value is relatively high.

Description

Band-pass filter

Technical Field

The utility model belongs to the technical field of the radio, mainly relate to a 381MHz ~ 396MHz band pass filter's design.

Background

Filters are important components commonly used in communications engineering, have frequency selectivity for signals, pass or block, separate or synthesize signals of certain frequencies in communications systems, and are widely used in various telecommunications equipment and control systems. In the very high frequency and ultra high frequency bands, it is very difficult to realize a small, low insertion loss and high selectivity narrow band filter with lumped-parameter inductors and capacitors. With the spread of the operating parameter filter and the emergence of the spiral resonator, the spiral filter is beginning to be widely used in the electronic devices of the very high frequency and ultrahigh frequency bands. However, in the previous design, the same-frequency band spiral band-pass filter is often large in size, complex in structural process, not beneficial to processing and not beneficial to the realization of miniaturization of the whole machine.

Disclosure of Invention

An object of the utility model is to provide a small, do not have a load Q value high, electrical property is good and easy processing's a band-pass filter.

The utility model discloses a task is accomplished like this, its characterized in that: including the cavity with place in the inside and outside part of cavity, there is three resonant cavity in the cavity, be provided with between two adjacent resonant cavities and realize capacitive coupling window, place the skeleton in the resonant cavity, and helical coil dress is on the skeleton, and the skeleton passes through self tapping screw to be fixed on the apron. One end of the spiral coil is open-circuit, the other end of the spiral coil is welded on the cover plate, one end of the tap is welded on the spiral coil, and the other end of the tap is welded with a cable with a plug, which is welded on the cover plate.

The inner cavity wall of the cavity is plated with silver, and the size of the cavity is 45mm multiplied by 16mm multiplied by 20 mm.

The framework is in a spiral pipe shape and is smaller than the coaxial line resonator in size, and the framework is made of polytetrafluoroethylene materials.

The coupling window is selectively arranged at the open end of the spiral pipe, the opening height of the coupling window is 12mm, and the thickness of the cover plate is 1.5 mm.

The utility model discloses has following effect: the 381MHz to 396MHz band-pass filter has small volume, the insertion loss is less than 1.2dB, stopband attenuation which is not less than 44dB is arranged below the stopband 344 MHz and above the stopband 436MHz, and the no-load Q value is relatively high.

Drawings

Fig. 1 is a schematic top view of the cavity of the present invention; FIG. 2 is a schematic view of the coupling window in the cavity; FIG. 3 is a schematic view of the structure placed inside the chamber; fig. 4 is a schematic structural diagram of the present invention.

Description of the drawings: 1. the device comprises a resonant cavity, 2, a coupling window, 3, a framework, 4, a spiral coil, 5, a tap, 6, a cover plate, 7, the other end of the tap, 8, a self-tapping screw, 9, a cable, 10 and a tuning screw.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the specific embodiment, as shown in fig. 1 and 3, the band-pass filter includes a cavity and components disposed inside and outside the cavity, three resonant cavities 1 are disposed in the cavity, a capacitive coupling window 2 is disposed between two adjacent resonant cavities, a framework 3 is disposed in the resonant cavities, a spiral coil 4 is mounted on the framework, and the framework is fixed on a cover plate 6 through a tapping screw 8. One end of the spiral coil is open-circuit, and the other end of the spiral coil is welded on the cover plate. One end of the tap 5 is welded on the spiral coil 4, and the other end 7 of the tap is welded with a cable 9 with a plug welded on the cover plate.

The inner cavity wall of the cavity is plated with silver to reduce radiation loss, and the size of the cavity is 45mm multiplied by 16mm multiplied by 20 mm.

The framework is in a spiral tube shape, is smaller than the coaxial line resonator in size, and has no radiation loss because the electric field and the magnetic field are all limited in the cavity by the metal surface. The framework is made of polytetrafluoroethylene materials, the cavity wall is plated with silver, the lead is properly selected, and the metal loss of the resonant cavity is small. The quality factor of the spiral filter is still high, about 1000.

The coupling window 2 is selectively arranged at the open end of the spiral tube, namely capacitive coupling, according to the size of insertion loss, combined with practical application, and through multiple verification and modification, the height of the opening of the coupling window 2 is 12mm, and the thickness of the cover plate 6 is 1.5 mm.

The spiral coil 4 is formed by winding silver-plated optical copper wires with the gap of 1.25mm, the diameter of a mould of 7.2mm and the wire diameter of 0.7 mm.

The present solution achieves high and low impedance matching by changing the position of the tap 5, which can be calculated approximately at 1/2 of the spiral coil 4.

The band-pass filter has an insertion loss not more than 1.2dB at the working frequency range of the transmitter of 381MHz to 396 MHz; when the frequency is less than 340MHz, the stop band attenuation is not less than 40 dB; at frequencies greater than 436MHz, the stopband attenuation is not less than 40 dB.

The 381MHz to 396MHz band-pass filter is characterized in that three frameworks with spiral coils are placed in a closed cavity formed by three resonant cavities, and the technical indexes of the band-pass filter are realized by arranging a tuning screw 10 which can move up and down along the axial direction of a spiral pipe on a cover at the open end of the spiral pipe and changing tap positions 5 at two ends. The volume is small, and the processing is relatively easy.

The utility model discloses an adopt spiral resonator to realize the parallel resonance return circuit in the coupling syntonizer wave filter to be connected test technical index through the cable of taking the plug and instrument.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected, and may communicate between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Claims

1. A band-pass filter, characterized by: including the cavity with place in the cavity inside and outside part, there is three resonant cavity in the cavity, be provided with between two adjacent resonant cavities and realize capacitive coupling window, place the skeleton in the resonant cavity, and spiral coil dress is on the skeleton, and the skeleton passes through self-tapping screw to be fixed on the apron, spiral coil's one end open circuit, spiral coil's the other end welds on the apron, takes a percentage one end and welds on the spiral coil, and the other end of taking a percentage and the cable weld that has the plug on the apron are in the same place.

2. A bandpass filter as recited in claim 1, wherein: the inner cavity wall of the cavity is plated with silver, and the size of the cavity is 45mm multiplied by 16mm multiplied by 20 mm.

3. A bandpass filter as recited in claim 1, wherein: the framework is in a spiral pipe shape and is smaller than the coaxial line resonator in size, and the framework is made of polytetrafluoroethylene materials.

4. A bandpass filter as recited in claim 1, wherein: the coupling window is selectively arranged at the open end of the spiral pipe, the opening height of the coupling window is 12mm, and the thickness of the cover plate is 1.5 mm.