AU2017375168A1

AU2017375168A1 - High-performance band-stop filter and communications cavity device thereof

Info

Publication number: AU2017375168A1
Application number: AU2017375168A
Authority: AU
Inventors: Yingjie Di; Chunbo GUO; Zhenxiong XIE
Original assignee: Comba Telecom Technology Guangzhou Ltd; Comba Telecom Systems China Ltd; Tianjin Comba Telecom Systems Co Ltd
Current assignee: Comba Telecom Technology Guangzhou Ltd
Priority date: 2016-12-14
Filing date: 2017-04-20
Publication date: 2019-07-04
Anticipated expiration: 2037-04-20
Also published as: BR112019011886A2; WO2018107633A1; AU2017375168B2; CN106602191A

Abstract

Provided in the present invention is a high-performance band-stop filter, comprising a cavity body and a cover plate covering the cavity body; the cavity body is provided with a longitudinal hollow cavity, two connection ports being formed in two ends of the hollow cavity in a longitudinal direction, a transmission wire used to realize an electrical connection between the two connection ports and a transmission wire cavity used to accommodate the transmission wire being provided in the hollow cavity, one side of the transmission wire cavity is provided with multiple resonant cavities arranged in sequence, each resonant cavity having provided therein a resonant post, each resonant post being provided with an accommodation hole accommodating a resonance-adjusting screw, the transmission wire having provided thereon impedance converter structures corresponding to the resonant posts and capacitively coupled to said resonant posts; resonance-adjusting screws corresponding to each resonant post are suspended on the cover plate, said resonance adjusting screws having non-contact connections to the resonant posts. The present high-performance band-stop filter can realize good results in narrow relative bandwidth, wide pass band and stop band bandwidth, high stop band suppression and low insertion loss. Also provided in the present invention is a communications cavity device including the present high-performance band-stop filter.

Description

HIGH PERFORMANCE BAND-STOP FILTER AND ITS

COMMUNICATION CAVITY DEVICE

FIELD OF THE INVENTION [0001] The present invention relates to the field of communications technologies, and in particular to a high performance band-stop filter and a communication cavity device thereof.

BACKGROUD OF THE INVENTION io [0002] With the development of LTE communication technology, system expansion has become an important part of network construction. System expansion enhances the use of frequency band resources, but at the same time, frequency bands are becoming more and more crowded. In order to ensure sufficient isolation between systems during system expansion, higher requirements are placed on filter performance.

[0003] Prior art filters can achieve faster out-of-band degradation and higher out-of-band suppression. A good isolation effect can be achieved in case where an interval between a pass band and a stop band is large and stop band suppression is not high. However, in case where the interval between the pass band and the stop band is small, the pass band and the stop band have a wide bandwidth, and the stop band suppression is high, the prior art filter cannot achieve good isolation.

[0004] Therefore, there is a need in the industry for a filter or filter path that can solve the above technical problems.

SUMMARY OF THE INVENTION [0005] The present invention is intended to provide a band-stop filter and its communication cavity device, which can achieve good isolation in case where the interval between the pass band and the stop band is small, the 5 pass band and the stop band have a wide bandwidth, and the stop band suppression requirement is high.

[0006] In order to achieve the above object, the present invention provides the following technical solution.

[0007] In a first aspect, a high performance band-stop filter is provided, io The high performance band-stop filter includes a cavity and a cover plate mounted with the cavity. An elongated cavity is formed in the cavity, and a connection port is formed at each end of the cavity in the longitudinal direction. A transmission line for realizing electrical connection between the two connection ports and a transmission line chamber for accommodating the transmission line are provided in the cavity.

[0008] One side of the transmission line chamber is provided with a plurality of resonant cavities arranged in sequence, and each resonant cavity is provided with a resonant post. Each resonant post is provided with a receiving hole for accommodating a tuning screw, and an impedance 20 conversion structure capacitively coupled to a respective resonant post is disposed on the transmission line at a location corresponding to said resonant post.

[0009] A tuning screw is suspended on the cover plate at a location corresponding to a respective resonant post. The tuning screw is non-contactly connected to a corresponding resonant post.

[0010] Specifically, the transmission line is provided with a plurality of impedance conversion structures, and the plurality of impedance conversion structures are respectively arranged in correspondence with respective ones of the plurality of resonance posts.

[0011] Preferably, the resonant posts and the impedance conversion nodes are sequentially arranged along the linear transmission line in equally spaced intervals.

[0012] Specifically, the impedance conversion structure includes a high impedance line electrically connected to the transmission line and a coupling io disk connected to the high impedance line. An end surface of the coupling disk faces the resonant post.

[0013] Preferably, the end surface of the coupling disk is circular or rectangular.

[0014] Specifically, the plurality of resonant cavities are formed by 15 connecting a plurality of metal separation plates disposed in parallel with each other, a bottom plate and side plates of the cavity [0015] Preferably, each resonant cavity is a square cavity having bottom sides of a same length.

[0016] Specifically, the resonant post does not contact with the cover 20 plate to form a capacitance there-between.

[0017] Specifically, the resonant post is electrically connected to a bottom of the cavity [0018] Preferably, the transmission line is secured within the transmission line chamber by means of a dielectric supporting member.

[0019] In a second aspect, a communication cavity device is provided.

The communication cavity device comprises the high performance band-stop filter of the first aspect described above.

[0020] Compared with the prior art, the solution of the invention has the following advantages.

[0021] According to the high performance band-stop filter of the present invention, one side of the transmission line chamber is provided with a plurality of resonant cavities arranged in sequence, and each resonant cavity is provided with a resonant post. Each resonant post is provided with a receiving hole for accommodating a tuning screw. An impedance io conversion structure capacitively coupled to the resonant post is disposed on the transmission line at a location corresponding to the resonant post, so that performance of the band-stop filter is greatly improved. It can effectively achieve narrow gap between pass-band and stop-band, wide bandwidth of pass-band and stop-band, high degree of stop-band suppression, and good 15 insertion loss. In addition, the high-performance band-stop filter has simple structure, a suitable size, and good consistency, which is advantageous for mass production and improved production efficiency.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description, which follows.

BRIEF DESCRIPTION OF THE DRAWINGS [0023] The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the description in connection with the drawings, wherein:

[0024] Figure 1 is a schematic structural view of an embodiment of a high performance band-stop filter according to the present invention; and [0025] Figure 2 is a top plan view of the cavity of figure f showing the locational relationship of the impedance conversion structure and the resonant post.

DETAILED DESCRIPTION OF THE INVENTION [0026] The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer io to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

[0027] As shown in figure 1, the present invention provides a high 15 performance band-stop filter 100 capable of achieving a narrow gap between pass-band and stop-band, wide bandwidth of pass-band and stop-band, high degree of stop-band suppression, and good insertion loss. In addition, as the high performance band-stop filter 100 has simple structure, it is advantageous for mass production.

[0028] With reference to figure 2, the high performance band stop filter

100 includes a cavity 2 and a cover plate 1 assembled with the cavity 2. An elongated cavity 21 is formed in the cavity 2, and two connection ports 51, 52 are formed at two ends of the cavity respectively in a longitudinal direction. A transmission line 3 for realizing electrical connection between the two connection ports 51, 52 and a transmission line chamber 31 for accommodating the transmission line 3 are provided in the cavity 21. The cover plate 1 is fixedly connected to the cavity 2 by screws 9 to form a sealed space for signal transmission.

[0029] One side of the transmission line chamber 31 is provided with a 5 plurality of resonant cavities 7 arranged in sequence. The plurality of resonant cavities 7 are formed by connecting a plurality of metal separation plates 10 disposed in parallel with each other, a bottom plate and side plates of the cavity 2. Preferably each resonant cavity 7 is a square cavity having bottom sides of a same length in order to better arrange them, improve space io utilization, optimize space layout. Further, each of the resonant cavities 7 is provided with a resonant post 71, which is of an arbitrary cylindrical structure, and each of the resonant posts 71 is provided with a receiving hole for accommodating a tuning screw 6 therein.

[0030] Correspondingly, the cover plate 1 is provided with a plurality 15 of mounting holes for a corresponding tuning screw 6 to pass through, and each mounting hole is formed corresponding to a respective one of the resonant posts 71. The tuning screw 6 is suspended on a corresponding resonant post 71 through a corresponding mounting hole on the cover plate 1 and can extend into the receiving hole of a corresponding resonant post 71. 20 However, the tuning screw 6 and a corresponding resonant post 71 are always in a non-contact connection.

[0031] The resonance frequency of a resonator defined by the cavity 7 and a corresponding resonance post 71 is adjusted by adjusting a corresponding tuning screw 6, thereby limiting the resonance frequency of 25 the resonator in the frequency band of stop band. In addition, the resonant post 71 is non-contacted with the cover plate 1 to form a capacitance there-between, which is the equivalent capacitance of the corresponding resonator. The resonant post 71 electrically connected to the bottom of the cavity 2 forms an inductance, which is the equivalent inductance of the resonator. An impedance conversion structure 4 capacitively coupled to a respective resonant post 71 is disposed on the transmission line 3 at a location corresponding to said resonant post 71.

[0032] The impedance conversion structure 4, the transmission line 3 located halfway between two adjacent impedance conversion structures 4 on io both sides of the impedance conversion structure 4, and the resonance post 71 capacitively coupled to the impedance conversion structure 4 and the resonant cavity 7 where the resonant post 71 is located together define a basic unit of the high performance band-stop filter 100. The impedance conversion structure 4 in the high performance band stop filter 100 15 contributes to the high performance of the high performance filter 100, while having a simple structure and being easy to produce and layout.

[0033] Specifically, the transmission line 3 is provided with a plurality of impedance conversion structures 4, and the plurality of impedance conversion structures 4 are disposed corresponding to the plurality of 20 resonance posts 71. Meanwhile, the length of the transmission line between the adjacent two impedance conversion structures 4 is not necessarily constrained to conventional 1/4 or 1/8 wavelength, and the length may be different. In addition, the distance between the resonant post 71 and the transmission line 3 may be different, and the structural size of the impedance conversion structures 4 may be different.

[0034] Referring to figure 2, the impedance conversion structure 4 includes a high impedance line 41 electrically connected to the transmission line 3 and a coupling disk 42 connected to the high impedance line 41. An end surface of the coupling disk 42 faces a side wall of the resonant posts 71, 5 and is not in a contact relationship with the resonant post 71 to form a coupling capacitor. A side surface of the resonant post 71 may be a plane or a curved surface, such as a square or a cylindrical surface. The end surface of the coupling disk 42 can be adjusted according to the side surface of the resonant post 71.

io [0035] Preferably, the side surface of the resonant post 71 is a plane surface, and correspondingly, the end surface of the coupling disk 42 is circular or rectangular, thereby facilitating adjustment the shape and size of the end face of the coupling disk 42 according to the structure and size inside the cavity 2 and/or the area of the side surface of the resonant post 71. In the high performance band stop filter 100 of the present embodiment, by elastically adjusting the shape and size of the coupling disk 42, on the one hand, it is advantageous to improve the electrical performance of the high performance band stop filter 100, and on the other hand, it is advantageous for the structural layout of the high performance band-stop filter 100.

[0036] In addition, the transmission line 3 is built in the transmission line chamber 31, and two ends of the transmission line 3 are respectively connected with inner conductors (not labeled) of the two connection ports 51, 52 to realize signal transmission between the two connection ports 51, 52. Here, the shape of the cross section of the transmission line 3 may be any shape. The shapes and sizes of the cross sections at different axial locations may be different from each other, and may be adjusted according to actual needs and according to the shape at the connection ports 51, 52.

[0037] Preferably, the high performance band-stop filter 100 further includes a dielectric supporting member 8. The transmission line 3 is fixed in 5 the transmission line chamber 31 by means of the dielectric supporting member 8, ensuring that the location of transmission line 3 does not move, avoiding the influence on the capacitance formed between the impedance conversion structure 4 on it and the resonance post 71 corresponding to the impedance conversion structure 4, and avoiding influence on the electrical io performance of the high performance band stop filter 100.

[0038] In order to ensure the high utilization of space and convenience of cavity arrangement, the resonant cavity 7 is preferably a square cavity of equal length and width under the basis of ensuring the electrical performance of the high performance band stop filter 100. Obviously, when the resonant 15 cavity 7 is a square cavity, its utilization of space is the highest. At the same time, the transmission line between two adjacent impedance conversion structures 4 is laid in a straight line. The length of the transmission line is equal to the sum of the length of the side of the resonant cavity 7 and thickness of the metal separation plate 10 between the two resonant cavities 20 7. That is to say, the resonant posts 71 and the impedance conversion structures 4 are arranged in equally spaced intervals along the linear transmission line 3.

[0039] In the high performance band stop filter 100 described in the present invention, the performance of the corresponding band-stop filter is 25 greatly improved using the impedance conversion structure 4 with simple structure. The high performance band stop filter 100 can achieve an insertion loss of <0.5 dB when the pass band is 0-1880 MHz, and a suppression of >60 dB for the stop band of the 1920-2170MHz.

[0040] It should be noted that some embodiments of the high 5 performance band-stop filter 100 described in the present invention do not constitute a limitation on the use manner of the present invention. In addition to the case where the low-end band of the stop band shown in the embodiment has a pass band, the high-performance band stop filter 100 can also realize the case where the high-end band of the stop band also has a io pass band, and the high and low ends of the stop band both have a pass band.

[0041] In addition, the present invention also provides a communication cavity device. The communication cavity device includes the above-described high performance band stop filter 100.

[0042] The above is only part of the embodiments of the present 15 invention, and it should be noted that those skilled in the art can also make several improvements without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

Claims

1. A high performance band-stop filter, comprising: a cavity; and a cover plate mounted with the cavity;

5 an elongated cavity being formed in the cavity, and two connection ports being formed respectively at two ends of the cavity in a longitudinal direction; a transmission line for realizing electrical connection between the two connection ports and a transmission line chamber for accommodating the transmission line being provided in the io cavity; wherein one side of the transmission line chamber is provided with a plurality of resonant cavities arranged in sequence, and each resonant cavity is provided with a resonant post;

each resonant post is provided with a receiving hole for 15 accommodating a tuning screw;

an impedance conversion structure capacitively coupled to a respective resonant post is disposed on the transmission line at a location corresponding to said resonant post;

a tuning screw is suspended on the cover plate at a location 20 corresponding to a respective resonant post; and the tuning screw is non-contactly connected to a corresponding resonant post.
2. The high performance band-stop filter as recited in claim 1, wherein the transmission line is provided with a plurality of said

25 impedance conversion structures, which are respectively arranged in correspondence with respective ones of the plurality of resonance posts.
3. The high performance band-stop filter as recited in claim 1, wherein the resonant posts and the impedance conversion structures are sequentially arranged along the linear transmission line in equally spaced intervals.
4. The high performance band-stop filter as recited in any one of 5 claims 1-3, wherein each impedance conversion structure includes a high impedance line electrically connected to the transmission line and a coupling disk connected to the high impedance line; and an end surface of the coupling disk faces a corresponding resonant post.
5. The high performance band-stop filter as recited in claim 4, io wherein the end surface of the coupling disk is circular or rectangular.
6. The high performance band-stop filter as recited in claim 1, wherein the plurality of resonant cavities are formed by connecting a plurality of metal separation plates disposed in parallel with each other, a bottom plate and side plates of the cavity.

15
7. The high performance band-stop filter as recited in claim 6, wherein each resonant cavity is a square cavity having bottom sides of a same length.
8. The high performance band-stop filter as recited in claim 1, wherein the resonant post is non-contacted with the cover plate to form

20 a capacitance there-between.
9. The high performance band-stop filter as recited in claim 1, wherein the resonant post is electrically connected to a bottom of the cavity.
10. The high performance band-stop filter as recited in claim 1, 25 wherein the transmission line is secured within the transmission line chamber by a dielectric supporting member.
11. A communication cavity device comprising a high performance band-stop filter as recited in any one of claims 1-10