Patent Description:
Filters are widely applied to a microwave communication system, a radar navigation system, an electronic countermeasure system, a satellite communications system, a missile guidance system, a meter testing system, and the like. As development of communications, more channels can be selected by a system. This imposes higher requirements on design of the filter. In addition, the filter is an important part of a communications system, and performance of the filter greatly influences quality of the communications system.

The filter is a device with a frequency selection function that allows a specific frequency component in a signal to pass therethrough while greatly attenuating other frequency components, thereby filtering out interference. There are many types of filters. A cavity filter, because of its features of high power, a low loss, and a robust structure, availability for a microwave frequency band, and the like, is widely applied to various communications systems. In addition, communication frequency bands are increasingly high, operating bandwidth is becoming wider, and an advantage of the cavity filter is getting obvious.

Performance indicators and reliability of the cavity filter have a strong correlation with the structure of the cavity filter. An existing cavity filter includes a cavity, a cover, and a tuning screw. The cover is usually fastened to the cavity by using the screw, and a degree of fastening thereof is uncontrollable, directly affecting filter frequency selectivity. In addition, the tuning screw is mounted on the cover, and it is relatively time-consuming to adjust a resonance characteristic of the filter by screwing the tuning screw. Assembly and tuning processes of the filter are complex.

<CIT> describes a phase shifter having a chamber in flat-shaped solid state, one side of which is recessed to form a holding space, and a lower coupling circuit board, assembled into the holding space. The lower coupling surface of the lower coupling circuit board is fitted with two coupling strips arranged at interval. One end of the coupling strips is provided with a cable coupling portion. An upper coupling strip is overlapped onto the lower coupling circuit board in a U-shaped pattern. The upper coupling strip is provided with an upper coupling surface for coupling with the coupling strips of the lower coupling circuit board. A slider has a driving end and a driven end, the driving end being used to connect and drive the upper coupling strip, and the driven end protrudes out of the chamber's holding space. A cover plate is used to seal the chamber's holding space. <CIT> discloses a low-pas filter with a strip resonant structure included in a housing and with bendable flaps to tune the resonance frequency of the filter.

In view of this, embodiments of this application provide a filtering device, to effectively simplify assembly and tuning processes.

According to a first aspect, a filtering device is provided according to the claims of the application.

It can be learned that, based on the housing provided in this application, complex steps of mounting a cover and walls can be omitted. The resonant conductor is plugged in the inner cavity of the housing. This facilitates an adjustment or replacement of the resonant conductor. The pressing element provided in this application is closely connected to the housing, and the resonant frequency is adjusted by pressing or drawing, thereby simplifying a tuning method. In conclusion, it can be learned that the filtering device provided in this application effectively simplifies the assembly and tuning processes.

Apparently, the described embodiments are merely some rather than all of the embodiments of this application.

"A plurality" refers to two or more than two. The term "and/or" describes an association relationship for describing associated objects and represents that three relationships may exist. The character "/" generally indicates an "or" relationship between the associated objects.

The terms in this application are described above, to facilitate understanding by a person skilled in the art.

<FIG> is a schematic structural diagram of a filter <NUM> in the prior art. As shown in <FIG>, the filter <NUM> in the prior art includes: a cavity <NUM>, a cover <NUM>, a support member <NUM>, a resonant element <NUM>, a fastening screw <NUM>, a tuning screw lever <NUM>, and the like. There are one or more single resonant cavities <NUM> in the cavity <NUM>. The cavity <NUM> may be formed as an integral component by machining or casting, and the cover <NUM> is formed by casting or by machining using a molding plate. During assembly, the support member <NUM> is first assembled as a component to be fastened inside the cavity <NUM>. Next, the resonant element <NUM> is fastened at a central position of the single resonant cavity <NUM> in the cavity <NUM> to form a resonant unit. Then, the tuning screw lever <NUM> is fastened on the cover <NUM>. Finally, a cover component and a cavity component that are assembled are mounted together by using the fastening screw <NUM>.

It can be learned that, a manufacturing and assembly process of the existing filter is relatively complex, and resonance performance of the filter may be affected by a degree of fastening between the cover <NUM> and the cavity <NUM>, and may also be affected by stability of grounding of the tuning screw lever <NUM>. In addition, it is relatively time-consuming to implement tuning by screwing the tuning screw lever <NUM>.

In view of this, an embodiment of this application provides a filter (which is also referred to as a filtering device) that can simplify an assembly process and a tuning process, and can effectively improve filtering performance of the filter.

The filtering device provided in this embodiment of this application is applicable to various communications systems, for example, <NUM> communications systems such as a Global System for Mobile Communications (GSM, Global System for Mobile Communications) and a general packet radio service (GPRS, General Packet Radio Service) system; <NUM> communications systems such as a Code Division Multiple Access (CDMA, Code Division Multiple Access) system, a Time Division Multiple Access (TDMA, Time Division Multiple Access) system, a Wideband Code Division Multiple Access (WCDMA, Wideband Code Division Multiple Access Wireless) system; and a Long Term Evolution (LTE, Long Term Evolution) system and an LTE-Advanced system.

The filtering device provided in this embodiment of this application is applicable to a plurality of communications devices that need to select a signal frequency, for example, may be used in a base station device.

<FIG> is a schematic structural diagram of a filtering device <NUM> according to the subject-matter of the present claims. The filtering device <NUM> includes.

The filtering device further includes a cavity terminal <NUM>, configured to electrically connect a short circuit end of the resonant conductor220 to the housing210, and further configured to support the resonant conductor.

Based on the foregoing structure, in a process of assembling the filtering device, a cover does not need to be assembled, an assembly process of the filtering device is simple, and impact of assembly of the cover on performance of the filtering device is reduced. In addition, tuning can be implemented by pressing or drawing the pressing element <NUM>, thereby simplifying a tuning process, and reducing a tuning time.

Optionally, <FIG> is a schematic structural diagram of a filtering device <NUM>. As shown in <FIG>, in addition to a housing <NUM>, a resonant conductor <NUM>, and a pressing element <NUM> that are included in the filtering device shown in <FIG>, and an optionally included cavity terminal <NUM>, the filtering device may further include:.

It can be learned that for the filtering device having the fastening terminal and the wiring port, it can be very convenient to fasten the filtering device on another device, and it is convenient to connect to a signal input or output wire.

The following further describes, with reference to <FIG> that is a schematic diagram of a resonant conductor <NUM> according to an embodiment of this application, a structure of the resonant conductor <NUM>. As shown in <FIG>, the resonant conductor <NUM> includes:.

The resonant conductor <NUM> may be disposed inside an inner cavity of a filtering device by plugging in. In the filtering device shown in <FIG> or <FIG>, the resonant conductor is horizontally disposed inside the inner cavity. Alternatively, the resonant conductor may be vertically disposed inside the inner cavity.

It should be noted that the resonant conductor <NUM> in the figure is merely an example, and a quantity of open-circuit ends, a quantity of short circuit ends, and a quantity of wiring ends are not limited herein. The resonant conductor <NUM> is a conductor with resonance performance, for example, may be a metal strip, a microstrip, a strip line, or a printed circuit board (printed circuit board, PCB). A specific implementation form of the resonant conductor is not limited herein.

The following further describes, with reference to <FIG> that is a schematic structural diagram of a pressing element500 according to an embodiment of this application, a structure of the pressing element <NUM>. As shown in <FIG>, in this embodiment, the pressing element <NUM> is of a sheet-shaped structure having one end disposed on a housing <NUM>, and other three ends suspended.

<FIG> is a schematic diagram of another pressing element according to this application. As shown in <FIG>, the pressing element <NUM> is of a pin-shaped structure, including a pin cap <NUM> and a pin bar <NUM>, and is connected to a housing <NUM> of the filtering device by using the pin cap <NUM> of the pin-shaped structure, and extends into an inner cavity of the housing by using the pin bar <NUM> of the pin-shaped structure.

It should be noted that the foregoing pressing element is merely an example, and a specific shape of the pressing element is not limited in this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the claims shall fall within the protection scope of this application. Any method for adjusting a resonance characteristic by pressing or drawing a pressing element shall fall within the protection scope of the claims of this application.

For the filtering device shown in the foregoing embodiment, a housing including one inner cavity is used as an example. Optionally, the housing may include a plurality of inner cavities, such as a combiner. <FIG> is a schematic structural diagram of another filtering device <NUM> according to an embodiment of this application. As shown in <FIG>, the filtering device <NUM> has a housing including two inner cavities, such as an inner cavity <NUM> and an inner cavity <NUM> in <FIG>. One resonant conductor is disposed inside each inner cavity, that is, a resonant conductor <NUM> is disposed inside the inner cavity <NUM>, and a resonant conductor <NUM> is disposed inside the inner cavity <NUM>. For other components such as a pressing element and a cavity terminal, refer to <FIG>.

When the housing includes a plurality of inner cavities, resonant conductors in the plurality of inner cavities may be electrically connected. For example, the electrical connection is implemented by using a metal pin, a metal probe, or a printed circuit board (PCB). For example, the resonant conductor <NUM> and the resonant conductor <NUM> in <FIG> may be electrically connected by using a metal pin, a metal probe, or a PCB.

It should be noted that in the filtering device <NUM> in the foregoing embodiment, only a case in which one resonant conductor is disposed inside each inner cavity is illustrated. Optionally, a plurality of resonant conductors may be disposed inside each inner cavity.

Regardless of one or more inner cavities that a single housing includes in a filtering device, the pressing element, the cavity terminal, the fastening terminal, or the wiring port may be integrally formed with the housing. An advantage of the integral forming is that a grounding characteristic of the element, the terminal, or the port is good.

Claim 1:
A filtering device, comprising:
a housing (<NUM>), comprising an inner cavity;
a resonant conductor (<NUM>), disposed inside the inner cavity, wherein the resonant conductor (<NUM>) is disposed inside the cavity by plugging in, and the resonant conductor is vertically or horizontally disposed inside the inner cavity;
a pressing element (<NUM>), having one end disposed on the housing (<NUM>) and another end suspended, and facing a position of an open-circuit end of the resonant conductor (<NUM>), wherein a distance between the pressing element (<NUM>) and the resonant conductor (<NUM>) is changeable by pressing or drawing the pressing element (<NUM>), to thereby adjust a resonant frequency; and
a cavity terminal (<NUM>) integrally formed with the housing (<NUM>), wherein the cavity terminal (<NUM>) is configured to electrically connect a short circuit end of the resonant conductor (<NUM>) to the housing (<NUM>), and configured to support the resonant conductor (<NUM>), when the resonant conductor (<NUM>) is disposed inside the inner cavity.