WO2015043300A1

WO2015043300A1 - Dielectric filter and method of assembling same

Info

Publication number: WO2015043300A1
Application number: PCT/CN2014/082744
Authority: WO
Inventors: 卜伟; 康玉龙
Original assignee: 中兴通讯股份有限公司
Priority date: 2013-09-25
Filing date: 2014-07-22
Publication date: 2015-04-02
Also published as: CN203721860U

Abstract

Disclosed are a dielectric filter and a method of assembling the same. The dielectric filter comprises: dielectric resonant columns, a metal cavity, a sealing cover plate and a tuning screw, wherein the dielectric resonant columns are located inside a sealed space formed by the sealing cover plate and the metal cavity, and the tuning screw is mounted on the sealing cover plate. The dielectric filter further comprises elastic conductive washers. A bottom face in the metal cavity is provided with snap-fit grooves matching a lower surface of the dielectric resonant columns. The elastic conductive washers are located at the bottom part of the snap-fit grooves, and the dielectric resonant columns are fitted into the snap-fit grooves.

Description

Dielectric filter and assembly method thereof

The present invention relates to the field of filter technologies for mobile communication devices, and in particular, to a dielectric filter and a device method thereof. BACKGROUND OF THE INVENTION When electromagnetic waves propagate in a high dielectric constant material, the wavelength thereof can be shortened. With this theory, a dielectric material can be used instead of a conventional metal material, and the volume of the filter can be reduced under the same index. Research on dielectric filters has been a hot topic in the communications industry. As an important component of wireless communication products, dielectric filters are of particular importance for the miniaturization of communication products.

A related art TM (Transverse Magnetic) mode dielectric filter structure is shown in Fig. 1. Generally, a TM mode dielectric filter is mainly composed of a dielectric resonator column 103, a sealing cover 102, a tuning screw 101, and a metal cavity 104. According to the working principle of the cavity of the TM mode dielectric filter, during normal operation, the dielectric resonator column 103 is of a hollow cylinder type, and a high electric field distribution exists at the joint portion of the upper and lower surfaces and the metal cavity 104. The upper surface of the dielectric resonator column 103 is in close contact with or suspended from the metal cavity 104, and the lower surface is in a short-circuited state in contact with the metal cavity 104. If the contact of the lower surface is insufficient, the impedance will be discontinuous, the field energy cannot be transmitted, and the high dielectric constant and high quality factor of the medium will not be exerted, and even the dielectric resonator column 103 will be burned. Therefore, it is particularly important that the surface of the dielectric resonator column 103 in the TM mode dielectric filter is in good contact with the surface of the metal cavity 104.

The lower surface of the dielectric resonator column 103 is in contact with the bottom surface of the metal cavity 104, and the upper surface of the dielectric resonator column 103 is in contact with the bottom surface of the sealing cover 102. The sealing cover 102 and the metal cavity 104 are fixed by ordinary mounting screws. The force is applied to ensure that the upper and lower surfaces of the dielectric resonator column 103 are tightly pressed against the bottom surfaces of the sealing cover 102 and the metal cavity 104, respectively, and are in full contact with each other to form a closed cavity. Since the dielectric resonator column 103 and the metal cavity 104 need to be tightly coupled to ensure the continuity of the impedance, when the temperature is expanded or contracted by the temperature, the linear expansion coefficients of the dielectric resonator column 103 and the metal cavity 104 are greatly different and two The hardness of the material is high and the elasticity is poor, and a large shear force is generated to easily damage the tightness of the original combination, which may result in deterioration of the performance of the dielectric filter, or even physical damage. SUMMARY OF THE INVENTION The technical problem to be solved by the embodiments of the present invention is how to realize a medium resonant column and a metal cavity of a dielectric filter capable of releasing stress and achieving good contact under the condition of high and low temperature changes in the environment.

In order to solve the above problems, an embodiment of the present invention provides a dielectric filter, including: a dielectric resonator column, a metal cavity, a sealing cover, and a tuning screw, wherein the dielectric resonator column is located in a closed portion composed of a sealing cover plate and a metal cavity a tuning screw is mounted on the sealing cover, the dielectric filter further includes an elastic conductive gasket, and a bottom surface of the metal cavity is provided with a card slot matching the lower surface of the dielectric resonator column; A gasket is located at the bottom of the card slot, and the dielectric resonator column is assembled in the card slot.

Preferably, the depth of the card slot is at least guaranteed to limit the dielectric resonator column. The elastic conductive gasket has one surface flat and the other surface has an elastic protrusion, and the flat surface is in contact with the lower surface of the metal cavity, and the elastic convex surface is in contact with the dielectric resonator column. Preferably, the elastic projections are uniformly arranged zigzag protrusions; the size of the elastic conductive gasket matches the size of the card slot.

Preferably, the elastic conductive gasket is tightly coupled to the dielectric resonator column by a crimping method. The elastic conductive gasket is fixed in the card slot by fixing or fixing by threading or by an interference fit.

Preferably, the dielectric resonator column is a dielectric resonator column which is silver plated on at least the lower surface. The elastic conductive gasket is an elastic conductive gasket made of copper or a silicone rubber filled with conductive particles.

An embodiment of the present invention further provides a method for assembling a dielectric filter, including:

Inserting the elastic conductive gasket into the bottom of the card slot on the bottom surface of the metal cavity or at the bottom of the card slot fixed on the bottom surface of the metal cavity;

Inserting the dielectric resonator column into the card slot on the bottom surface of the metal cavity;

Assembling the sealing cover plate, tightening the common mounting screw through the sealing cover to lock the sealing cover plate and pressing the crimping force downward, so that the dielectric resonant column is in close contact with the elastic conductive gasket and the fixing of the dielectric resonant column is completed;

Assemble and adjust the tuning screw to control the resonant frequency by adjusting the depth of the screw into the cavity. Preferably, the dielectric resonator column is a dielectric resonator column which is silver plated on at least the lower surface. Preferably, the elastic conductive gasket is an elastic conductive gasket made of copper or a silicone rubber filled with conductive particles.

上述With the above technical solution, the dielectric resonator column can be in good contact with the bottom surface of the metal cavity to ensure the continuity of the impedance; at the same time, in the case of changing the ambient temperature, the stress caused by the temperature change between the dielectric resonator column and the metal cavity is ensured. Reasonable release, thereby improving the reliability of the dielectric filter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a related art mode dielectric filter;

2 is a schematic structural diagram of a dielectric filter according to an embodiment of the present invention;

FIG. 3 is a schematic structural view of an elastic conductive gasket inside a dielectric filter according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

As shown in FIG. 2, a dielectric filter according to an embodiment of the present invention includes the following components: a dielectric resonator column 103, a metal cavity 204, a sealing cover 102, a tuning screw 101, and an elastic conductive gasket 205, wherein the medium The resonant column 103 is located inside the closed space composed of the sealing cover 102 and the metal cavity 204. The closed space is a resonant cavity, and the sealing cover 102 is mounted with a tuning screw 101 for adjusting the resonant frequency. The bottom surface of the metal cavity 204 is provided with a card slot matching the lower surface of the dielectric resonator column 103; the elastic conductive gasket 205 is located at the bottom of the card slot, and the dielectric resonator column 103 is assembled in the card slot; when the sealing cover 102 is fixed to the metal cavity After the body 204 is applied downward, the dielectric resonator column 103 is applied downward to the elastic conductive gasket 205, so that the lower surface of the dielectric resonator column 103 is in close contact with the elastic conductive gasket and the dielectric resonator column 103 is fixed. . The depth of the card slot is at least guaranteed to limit the dielectric resonator column 103.

Figure 3 shows a schematic view of the structure of the elastic conductive gasket, wherein the elastic conductive gasket is flat on one side and has elastic projections on the other side. As shown in the figure: 301 is a flat surface of the elastic conductive gasket; 302 is a resiliently convex side of the elastic conductive gasket, and 303 is a hollow region between the convex and the entire surface. When assembled, the flat side is in direct contact with the bottom surface of the metal cavity, and the elastic convex side is in direct contact with the dielectric resonator column. The elastic projections are zigzag, or trapezoidal, or other shapes, which may be evenly arranged or non-uniformly arranged. When the dielectric resonator is crimped downward, the first end of the elastic protrusion is contacted, and the convex end is rebounded downward. When the dielectric resonator and the metal cavity material shrink due to temperature drop, the contact surface will A void is generated, at which time the elastic protrusion relaxes, and the gap can be filled, so that the dielectric resonator column and the metal cavity remain in good contact, thereby ensuring continuity of the impedance; when the dielectric resonator column and the metal cavity material expand due to temperature rise When pressed together, the elastic protrusions are further contracted, thereby buffering the stress on the contact faces of the two materials and improving the reliability of the filter.

In the first embodiment of the invention, the size of the resilient conductive gasket 205 matches the size of the card slot to ensure the accuracy of the placement of the resilient conductive gasket. The assembly steps can be carried out as follows:

1) the upper and lower surfaces of the dielectric resonator column 103 are plated with silver;

2) inserting the elastic conductive gasket 205 into the bottom of the card groove on the bottom surface of the metal cavity 204;

3) loading the dielectric resonator column 103 into the card slot on the bottom surface of the metal cavity 204;

4) assembling the sealing cover 102, tightening the common mounting screw by the sealing cover 102 to lock the sealing cover 102 and performing a crimping force downward, so that the dielectric resonator 103 is in close contact with the elastic conductive gasket 205 and completes the dielectric resonant column 103. Fixed

5) Assemble and adjust the tuning screw 101 to control the resonant frequency by adjusting the depth of the screw into the cavity.

In a second embodiment of the present invention, the elastic conductive gasket 205 is fixed in the card slot, and may be fixed by means of adhesive fixing, threaded snapping, interference fit fixing or other suitable fixing means. The assembly steps can be carried out according to the following process:

2) fixing the elastic conductive gasket 205 to the bottom of the card groove on the bottom surface of the metal cavity 204; 3) loading the dielectric resonator column 103 into the card slot on the bottom surface of the metal cavity 204;

4) assembling the sealing cover 102, tightening the common mounting screw by the sealing cover 102 to lock the sealing cover 102 and performing a crimping force downward, so that the dielectric resonator 103 is in close contact with the elastic conductive gasket 205 and completes the dielectric resonant column 103. fixed; 5) Assemble and adjust the tuning screw 101 to control the resonant frequency by adjusting the depth of the screw into the cavity.

In the above embodiment, the dielectric resonator column 103 may be a dielectric resonator column having a silver plating treatment on at least the lower surface. The elastic conductive gasket 205 may be an elastic conductive gasket made of copper or a silicone rubber filled with conductive particles, but is not limited to these two materials.

The dielectric resonator provided by the embodiment of the invention has the advantages of ensuring reasonable release of the stress generated by the dielectric resonator due to temperature change in the case of environmental temperature change, thereby improving the reliability of the filter without affecting the filter performance. The entire assembly operation is simple in production process and low in cost. It is also possible to compensate for the temperature drift coefficient of the entire filter by adjusting the material temperature expansion coefficient or the sawtooth size of the elastic conductive gasket. For example, when the temperature drift of the filter needs to compensate more to the low frequency, the elastic conductive gasket uses a material having a high linear expansion coefficient; conversely, a material having a low linear expansion coefficient is used.

The technical means and functions of the present invention for achieving the intended purpose can be more deeply and specifically understood by the description of the specific embodiments. However, the accompanying drawings are only for the purpose of reference and description, and are not intended to be Limit it.

Industrial applicability

The dielectric filter of the embodiment of the invention can make the dielectric resonator column have good contact with the bottom surface of the metal cavity to ensure the continuity of the impedance; and at the same time, when the ambient temperature changes, the temperature between the dielectric resonator column and the metal cavity is ensured. The stress generated by the change is reasonably released, thereby improving the reliability of the dielectric filter.

Claims

claims

1. A dielectric filter, including: a dielectric resonant column, a metal cavity, a sealing cover plate and a tuning screw, wherein the dielectric resonant column is located inside a closed space composed of a sealing cover plate and a metal cavity, and the sealing cover plate Tuning screws installed;

The dielectric filter also includes an elastic conductive washer, and the inner bottom surface of the metal cavity is provided with a slot that matches the lower surface of the dielectric resonance column; the elastic conductive washer is located at the bottom of the slot, and the dielectric resonance column Assembled in the slot.

2. The dielectric filter according to claim 1, wherein the depth of the slot can at least ensure the limitation of the dielectric resonance column.

3. The dielectric filter according to claim 1, wherein one side of the elastic conductive gasket is flat, and the other side has elastic protrusions. The flat side is in contact with the lower bottom surface of the metal cavity, and the elastic protrusion side is in contact with the bottom surface of the metal cavity. The dielectric resonant column contacts.

4. The dielectric filter according to claim 3, wherein the elastic protrusions are uniformly arranged zigzag protrusions or trapezoidal protrusions.

5. The dielectric filter according to any one of claims 1 to 4, wherein the size of the elastic conductive gasket matches the size of the slot.

6. The dielectric filter according to claim 5, wherein the elastic conductive gasket is tightly combined with the dielectric resonant column through crimping.

7. The dielectric filter according to any one of claims 1 to 4, wherein the elastic conductive gasket is fixed in the slot.

8. The dielectric filter according to claim 7, wherein the fixing method is by adhesion, thread engagement, or interference fit.

9. The dielectric filter according to any one of claims 1 to 4, wherein the dielectric resonant column is a dielectric resonant column with at least a lower surface treated with silver plating.

10. The dielectric filter according to claim 9, wherein the elastic conductive gasket is an elastic conductive gasket made of copper or silicone rubber filled with conductive particles.

11. An assembly method of a dielectric filter, including: Install the elastic conductive gasket into the bottom of the slot on the inner bottom of the metal cavity or fix it on the bottom of the slot on the inner bottom of the metal cavity;

Install the dielectric resonant column into the slot on the bottom surface of the metal cavity;

Assemble the sealing cover, tighten the ordinary installation screws through the sealing cover to lock the sealing cover and apply a downward crimping force to make the dielectric resonant column closely contact the elastic conductive gasket and complete the fixation of the dielectric resonant column;

Assemble and adjust the tuning screw, and control the resonant frequency by adjusting the depth of screwing into the resonant cavity.

12. The method according to claim 11, wherein the dielectric resonant column is a dielectric resonant column with at least a lower surface plated with silver.

13. The method according to claim 11, wherein the elastic conductive gasket is an elastic conductive gasket made of copper or silicone rubber filled with conductive particles.