阅读说明：本技术 一种实现温度自补偿的谐振腔结构及腔体滤波器 (Resonant cavity structure for realizing temperature self-compensation and cavity filter ) 是由 王浩 陈勇 唐波 姚将锋 钟琳 于 2020-03-23 设计创作，主要内容包括：本发明涉及无线通信技术领域,公开了一种实现温度自补偿的谐振腔结构及腔体滤波器,即通过在谐振腔腔体中固定具有悬置部的温度补偿装置,并使该悬置部由至少两层具有不同热膨胀系数的导电体紧密贴合而成,可以在温度变化时,利用不同材料的膨胀量或收缩量会不同的特点,使该悬置部因外形产生弯曲变形而改变在谐振腔内的位置,进而对腔内的电磁场产生微扰,导致谐振腔的谐振频率发生变化,最终在悬置部的构成材料、大小、位置、摆放方向及个数等合适时,可使结构形变对谐振频率的影响与谐振腔腔体的热胀冷缩对谐振频率的影响刚好抵消,得到完全的温度补偿,实现零温漂目的。(The invention relates to the technical field of wireless communication, and discloses a resonant cavity structure and a cavity filter for realizing temperature self-compensation, namely, a temperature compensation device with a suspension part is fixed in a resonant cavity, and the suspension part is formed by tightly attaching at least two layers of electric conductors with different thermal expansion coefficients, so that when the temperature changes, the position of the suspension part in the resonant cavity is changed due to the fact that the expansion amount or the contraction amount of different materials is different, the suspension part generates bending deformation due to the appearance, and further generates micro-disturbance on an electromagnetic field in the cavity, so that the resonant frequency of the resonant cavity is changed, finally, when the forming materials, the size, the position, the placing direction, the number and the like of the suspension part are proper, the influence of the structural deformation on the resonant frequency and the influence of the thermal contraction on the resonant frequency of the resonant cavity are just counteracted, and complete temperature compensation is obtained, the purpose of zero temperature drift is realized.)

1. A resonant cavity structure for achieving temperature self-compensation, comprising a resonant cavity (1) defined by conductive wall surfaces and having a resonance frequency, characterized in that: the temperature compensation device (2) is arranged in the resonant cavity body (1) in a built-in mode, wherein the temperature compensation device (2) comprises a fixing part (201) and a suspension part (202);

the fixed part (201) is connected to the inner wall of the resonant cavity (1), and the suspension part (202) is connected with the fixed part (201) and is separated from the inner wall of the resonant cavity (1) at intervals;

the suspension part (202) is formed by tightly attaching at least two layers of electric conductors with different thermal expansion coefficients.

2. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: when the fixing part (201) is one end of the temperature compensation device (2) in a strip shape, the suspension part (202) is the other end of the temperature compensation device (2) in the strip shape;

or, when the fixing part (201) is two strip-shaped ends or the peripheral edge of the temperature compensation device (2), the suspension part (202) is the middle part of the temperature compensation device (2);

or, when the fixing part (201) is the middle part of the temperature compensation device (2), the suspension part (202) is two strip-shaped ends or the peripheral edge of the temperature compensation device (2).

3. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the resonant cavity (1) is defined by a box body (101) and a cover plate (102) used for covering the box body (101).

4. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the resonant cavity body (1) is in a rectangular cavity, a circular cavity, a coaxial cavity or an irregular cavity.

5. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the shape of the temperature compensation device (2) is a strip shape, a square shape, a trapezoid shape, a cross shape, a circular shape, an oval shape, a U-shaped shape, a V-shaped shape or a Y-shaped shape.

6. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the fixing part (201) is connected to the bottom wall, the top wall or the side wall of the inner cavity of the resonant cavity body (1) in a welding, bonding or screw fastening mode.

7. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the initial normal temperature state of the suspension part (202) is a straight state or a pre-bending state.

8. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: the amount of deformation of the free end of the suspension (202) due to temperature changes is the greatest relative to other portions of the temperature compensation device.

9. The resonator structure for realizing temperature self-compensation according to claim 1, wherein: a plurality of said temperature compensation means (2) are arranged in said resonator cavity (1).

10. A cavity filter, characterized in that: the resonant cavity structure comprises a plurality of resonant cavity structures which are used for realizing temperature self-compensation according to any one of claims 1-9, wherein resonant cavity bodies (1) in the plurality of resonant cavity structures are sequentially arranged in sequence, a coupling structure is arranged between every two adjacent resonant cavity bodies (1), the resonant cavity body (1) at the head of the sequence is connected with an input coupling structure, and the resonant cavity body (1) at the tail of the sequence is connected with an output coupling structure.

Technical Field

The invention belongs to the technical field of wireless communication, and particularly relates to a resonant cavity structure and a cavity filter for realizing temperature self-compensation.

Background

With the rapid development of communication technology, channels become more and more congested. To prevent interference between adjacent channels, higher and higher requirements are also placed on the frequency selectivity and temperature stability of the filter. The cavity filter has the advantages of high Q value, low loss, high band rejection degree, high power capacity and the like, and is widely applied to various communication systems.

Due to the influence of expansion caused by heat and contraction caused by cold of the metal material, the structural size of the resonant cavity in the cavity filter can change along with the change of temperature, so that the resonant frequency of the resonant cavity generates temperature drift, the electrical property of the cavity filter is deteriorated, and the normal work of the cavity filter is influenced. Especially for narrow band cavity filters, this temperature drift is more pronounced and may even cause it to be inoperable. Therefore, how to eliminate the temperature drift and ensure the resonant frequency of the resonant cavity to be constant within a certain temperature range becomes an urgent subject.

In order to provide the resonant cavity with good temperature stability, there are three methods commonly used at present, but there are also respective disadvantages.

The first approach is to fabricate the resonator cavity from a material with a low coefficient of thermal expansion, such as invar, which is typically about 0.9 ppm/c and is about 20 times smaller than the coefficient of thermal expansion of aluminum (which is a commonly used material). The purpose of reducing temperature drift is achieved by reducing the variable quantity of the structure size of the resonant cavity caused by temperature change. However, invar materials have many disadvantages, such as high price, heavy weight, high processing cost, difficult welding, poor thermal conductivity, and the like, and are not suitable for large-scale application. In addition, in practical application, the inner wall of the cavity made of invar steel must be plated with silver for use, and due to the large difference between the thermal expansion coefficients of silver and invar steel, when the cavity is subjected to repeated temperature changes in the use process, the silver plated layer attached to the invar steel can fall off. Therefore, when the power is high, if a silver coating layer at a certain position falls off to form burrs, a local electromagnetic field is abnormally increased, ignition is caused, and accordingly damage to the cavity is accelerated.

The second method is to flexibly adopt materials with different thermal expansion coefficients for different parts of the resonant cavity, so that the influence of the structural deformation of the different parts on the resonant frequency of the resonant cavity is mutually counteracted when the temperature changes. In the chinese utility model patent of the publication number CN206163680U, a low temperature drift coaxial resonator is disclosed, wherein the cavity material adopts aluminum, the upper half material of the resonance rod adopts copper, the lower half material of the resonance rod adopts aluminum, the tuning screw material adopts copper, the difference of the influence of different structures on the resonance frequency is utilized, and the difference of the thermal expansion coefficient between different metal materials is combined to reduce the temperature drift of the resonance frequency. However, the temperature compensation effect of this method is proportional to the capacitive loading strength, and if the capacitive loading is too strong, the Q value of the resonant cavity is reduced, thereby increasing the insertion loss of the filter. Therefore, in the case where the filter is required to have a low loss and a high Q value, the temperature compensation effect is not ideal.

The third method is to arrange a mechanical structure with a temperature sensor outside the resonant cavity, and the mechanical structure drives a metal rod or a medium block connected with the mechanical structure according to the sensed environmental temperature change, and changes the length of the metal rod extending into the cavity or the position of the medium block in the cavity, thereby changing the resonant frequency of the resonant cavity and realizing temperature compensation. In the chinese utility model patent of the publication number CN203013899U, a temperature compensation mechanism for a resonant cavity is disclosed, which is externally arranged at a suitable position of the resonant cavity, and a metal rod of the temperature compensation mechanism extends into the resonant cavity, and when the temperature changes, a paraffin power source in the mechanism can drive the metal rod to change the length of the cavity, thereby adjusting the resonant frequency of the resonant cavity and playing the effect of temperature compensation. However, this method requires more space due to additional mechanical structure loaded outside the resonator, which increases the size and weight of the filter, and increases the complexity of design and production, and increases the manufacturing cost.

Disclosure of Invention

The invention aims to solve the problems that in the current resonant cavity temperature compensation technology, a resonator is expensive and heavy due to the adoption of invar materials, the temperature compensation effect of the resonator is not ideal when a high Q value is required due to the adoption of various materials with different thermal expansion coefficients, and the volume, the weight and the manufacturing cost of a filter are increased due to the fact that the resonator is provided with a mechanical structure with a temperature sensor.

The technical scheme adopted by the invention is as follows:

a resonant cavity structure for realizing temperature self-compensation comprises a resonant cavity defined by a conductive wall surface and having a certain resonant frequency, and further comprises a temperature compensation device arranged in the resonant cavity, wherein the temperature compensation device comprises a fixed part and a suspension part;

the fixed part is connected to the inner wall of the resonant cavity, and the suspension part is connected with the fixed part and is separated from the inner wall of the resonant cavity at intervals;

the suspension part is formed by tightly attaching at least two layers of electric conductors with different thermal expansion coefficients.

Preferably, when the fixing part is one end of the temperature compensation device in a strip shape, the suspension part is the other end of the temperature compensation device in the strip shape;

or when the fixed part is two strip-shaped ends or the peripheral edge of the temperature compensation device, the suspension part is the middle part of the temperature compensation device;

or, when the fixing part is the middle part of the temperature compensation device, the suspension part is two strip-shaped ends or the peripheral edge of the temperature compensation device.

Preferably, the resonant cavity is enclosed by a box body and a cover plate for covering the box body.

Preferably, the resonant cavity is rectangular, circular, coaxial or irregular.

Preferably, the shape of the temperature compensation device is a strip, a square, a trapezoid, a cross, a circle, an ellipse, a U-shaped, a V-shaped or a Y-shaped.

Preferably, the fixing part is connected to the bottom wall, the top wall or the side wall of the inner cavity of the resonant cavity body, and the connecting mode is welding, bonding or screw fastening.

Preferably, the initial normal temperature state of the suspension part is a straight state or a pre-bending state.

Preferably, the amount of deformation of the suspended end of the suspension due to temperature change is the largest relative to other portions of the temperature compensation device.

Preferably, a plurality of temperature compensation devices are arranged in the resonant cavity.

The other technical scheme adopted by the invention is as follows:

a cavity filter comprises a plurality of resonant cavity structures which are as described above and realize temperature self-compensation, wherein the resonant cavity bodies in the plurality of resonant cavity structures are sequentially arranged, a coupling structure is arranged between every two adjacent resonant cavity bodies, the resonant cavity body at the head of the sequence is connected with an input coupling structure, and the resonant cavity body at the tail of the sequence is connected with an output coupling structure.

The invention has the beneficial effects that:

(1) the invention provides a novel resonant cavity structure for realizing temperature self-compensation by arranging a temperature compensation device inside, namely, the temperature compensation device with a suspension part is fixed in a resonant cavity body, and the suspension part is formed by tightly laminating at least two layers of electric conductors with different thermal expansion coefficients, so that when the temperature changes, the position of the suspension part in the resonant cavity is changed due to the fact that the expansion amount or the contraction amount of different materials can be different, the electromagnetic field in the cavity is subjected to perturbation, the resonant frequency of the resonant cavity is changed, and finally when the forming materials, the size, the position, the arrangement direction, the number and the like of the suspension part are proper, the influence of the structural deformation on the resonant frequency and the influence of the thermal contraction on the resonant frequency of the resonant cavity body are just counteracted to obtain complete temperature compensation, the purpose of zero temperature drift is realized;

(2) compared with the existing temperature compensation scheme adopting an invar material, the loaded temperature compensation device has a good temperature compensation effect, so that the resonant cavity body can be processed and manufactured by adopting materials with large thermal expansion coefficient, low price and small weight, such as aluminum and even metallized plastic, thereby increasing the range of material selection, improving the flexibility of material selection, being beneficial to reducing the production cost and reducing the product weight;

(3) compared with the existing temperature compensation scheme adopting the mechanical structure with the external temperature sensor, the adopted temperature compensation device has the advantages of simple structure, low cost, less consumption and the like, can effectively reduce the size and weight of a filter or other radio frequency devices, and simultaneously reduces the complexity of design and production, thereby reducing the manufacturing cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a perspective structural schematic diagram of a first resonant cavity structure provided by the present invention.

Fig. 2 is a schematic cross-sectional structural diagram of a first resonant cavity structure provided by the present invention when temperature changes.

Fig. 3 is a perspective structural diagram of a second resonant cavity structure provided by the present invention.

Fig. 4 is a perspective structural diagram of a third resonant cavity structure provided by the present invention.

Fig. 5 is a perspective structural diagram of a fourth resonant cavity structure provided by the present invention.

Fig. 6 is a schematic cross-sectional structural diagram of a fifth resonant cavity structure provided by the present invention when the temperature is unchanged.

Fig. 7 is a schematic cross-sectional structural diagram of a sixth resonant cavity structure provided by the present invention when the temperature is unchanged.

In the above drawings: 1-a resonant cavity; 101-a box body; 102-a cover plate; 2-a temperature compensation device; 201-a fixed part; 202-suspension.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. Specific structural and functional details disclosed herein are merely illustrative of example embodiments of the invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention.

It should be understood that, for the term "and/or" as may appear herein, it is merely an associative relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, B exists alone, and A and B exist at the same time; for the term "/and" as may appear herein, which describes another associative object relationship, it means that two relationships may exist, e.g., a/and B, may mean: a exists independently, and A and B exist simultaneously; in addition, for the character "/" that may appear herein, it generally means that the former and latter associated objects are in an "or" relationship.

It will be understood that when an element is referred to herein as being "connected," "connected," or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to herein as being "directly connected" or "directly coupled" to another element, it is not intended that an intervening element be present. In addition, other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between … …" versus "directly between … …", "adjacent" versus "directly adjacent", etc.).

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, quantities, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, and/or groups thereof.

It should also be noted that, in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed substantially concurrently, or the figures may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

It should be understood that specific details are provided in the following description to facilitate a thorough understanding of example embodiments. However, it will be understood by those of ordinary skill in the art that the example embodiments may be practiced without these specific details. For example, systems may be shown in block diagrams in order not to obscure the examples in unnecessary detail. In other instances, well-known processes, structures and techniques may be shown without unnecessary detail in order to avoid obscuring example embodiments.