Disclosure of Invention
The invention aims to provide a powder microwave filter and a preparation method thereof, which are used for overcoming the defects and shortcomings existing when a powder filter is prepared by only adopting a powder filtering material.
An aspect of the present invention provides a powder microwave filter, wherein the powder microwave filter includes:
a filter cavity body having a length;
the first accommodating cavity is arranged in the filter cavity body along the axial direction of the length direction of the filter cavity body, and the first accommodating cavity and the filter cavity body are coaxially arranged;
the conducting wire is arranged in the first accommodating cavity along the axial direction of the first accommodating cavity;
the colloidal metal powder filtering material is filled in the first accommodating cavity around the conducting wire;
the two connecting terminals are detachably arranged on two opposite sides of the filter cavity body, are respectively used for sealing one end part of the first accommodating cavity and are respectively and electrically connected with one end part of the conducting wire.
In the above powder microwave filter, preferably, the filter chamber body has a cylindrical shape or a rectangular parallelepiped shape.
The powder microwave filter as described above, preferably, the first accommodating cavity is a cylindrical cavity, and the conductive wire is in a spiral column shape.
The powder microwave filter as described above, wherein preferably, the conductive wire presents a diameter of the spiral column smaller than a diameter of the first accommodation cavity, and the conductive wire presents a diameter of the spiral column larger than a radius of the first accommodation cavity.
The powder microwave filter as described above, wherein preferably, the conductive wire presents a length of the spiral column that is greater than a length of the first accommodation cavity.
The powder microwave filter as described above, wherein, preferably, the colloidal metal powder filter material comprises the following components by weight:
20-36% of epoxy resin potting adhesive and 66-80% of copper powder with oxidized surface;
and uniformly mixing the epoxy resin potting adhesive and the surface oxidized copper powder.
The powder microwave filter as described above, wherein, preferably, the epoxy resin potting is two-component epoxy resin potting StyCAST 1266A and 1266B;
wherein: 1266A and 1266B are in a weight ratio of 3: 0.8.
The homogeneous mixing process of the 1266A, the 1266B and the copper powder is as follows:
the 1266B is added with the 1266A and stirred to be uniform and liquid to obtain a mixed solution;
and adding the copper powder into the mixed solution, and stirring the mixture uniformly to obtain the uniformly mixed colloidal metal powder filtering material.
In the above powder microwave filter, preferably, the colloidal metal powder filter material does not contain air therein.
In the above powder microwave filter, preferably, two opposite end faces of the filter cavity body in the length direction are symmetrically provided with grooves for accommodating and fixing the connection terminals.
Another aspect of the present invention provides a method for preparing a powder microwave filter, including the steps of:
assembling a conductive wire into a first accommodating cavity in the filter cavity body, wherein two ends of the conductive wire are respectively and electrically connected with a connecting terminal;
fixing one connecting terminal on the filter cavity body, and reserving a first gap between the other connecting terminal and the filter cavity body to open the end part of the first accommodating cavity corresponding to the connecting terminal;
injecting the colloidal metal powder filtering material into the first accommodating cavity through the first gap in an injection mode until the first accommodating cavity is filled with the colloidal metal powder filtering material;
and fixing the connecting terminal corresponding to the first gap to the filter cavity body.
Compared with the prior art, the colloidal metal powder filtering material which is colloidal integrally is adopted, and the colloidal metal powder filtering material is filled into the filtering cavity after being prepared outside the filtering cavity. The measure is used for preparing the filtering material outside the filtering cavity, so that the preparation operation control of the filtering material is facilitated, and the colloidal metal powder filtering material with the bonding performance in the filtering cavity ensures the stability of the filtering material.
Detailed Description
The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
As introduced by the background art, the applicant finds that the powder microwave filter is directly prepared by adopting the powder filtering material through a large amount of use research and experiments, and in the preparation process, the filling of the powder filtering material is difficult to control due to the fact that the adopted filtering material is powder (generally, um-level copper powder), so that the problems of waste, air pollution, damage to the physical health of workers and the like are easily caused; meanwhile, the filling degree of the powdery filtering material in the filtering cavity can not be directly observed in the filling process, and the filling process is carried out by the working experience and feeling of workers, so that the tightness degree and the integral uniformity of the inside of the powdery filtering material and the uniformity among the powdery filtering materials can not be ensured, and the factors influence the working performance of the powdery microwave filter. Based on the vision of preparing a powder microwave filter with better performance and better performance more suitable for the quantum computing field, the inventors of the present application have conducted a targeted study in the face of a great deal of problems found using investigations and experiments, and have proposed a powder microwave filter.
The embodiment of the invention provides a powder microwave filter, which adopts a whole colloidal filter material, and the colloidal filter material is prepared outside a filter cavity and then filled into the filter cavity. The measure is used for preparing the filtering material outside the filtering cavity, so that the preparation operation control of the filtering material is facilitated, and the colloidal filtering material with the adhesive property in the filtering cavity ensures the stability of the filtering material.
The powder microwave filter of this embodiment includes filter chamber body 1, first holding chamber 2, conductor wire 3, colloidal metal powder filtering material and two connecting terminal 4. The first accommodating cavity 2 is axially arranged in the filter cavity body 1 along the length of the filter cavity body 1, and the first accommodating cavity and the filter cavity body are coaxially arranged; the conductive wire 3 is arranged in the first accommodating cavity 2 along the axial direction of the first accommodating cavity 2; the colloidal metal powder filtering material is filled in the first accommodating cavity 2 around the conducting wire 3; two connecting terminal 4 can dismantle the setting at the double-phase offside of filter chamber body 1 to be used for sealed one end of first holding chamber 2 respectively, and connect the tip of conductor wire 3 respectively electrically.
For unfolding, the material of the filter cavity body 1 is oxygen-free copper, and the shape is regular and has a certain length; for example, the shape may be a cylinder or a rectangular parallelepiped. As shown in fig. 1.
It should be noted that the length of the filter chamber body 1 is the basis for constructing the effective signal transmission path length, and the shape of the filter chamber body 1 can be set as required on the basis of satisfying the effective signal transmission path length, and is not particularly limited herein.
The first accommodating cavity 2 is arranged in the filter cavity body 1 along the axial direction of the length direction of the filter cavity body 1, and the filter cavity body 1 and the first accommodating cavity 2 are coaxially arranged.
Specifically, first holding chamber 2 is used for holding conductor wire 3 and gelatineous metal powder filtering material, and when setting up, first holding chamber 2 sets up in filter chamber body 1 along filter chamber body 1's length axial, and the inner space that can make full use of filter chamber body 1 guarantees the construction of signal transmission path length. Of course, the first receiving chamber 2 may be constructed in a shorter direction in the filter chamber body 1 without considering the volume of the entire filter chamber body 1. In this embodiment, the filter cavity body 1 is an entity that is configured to form the first receiving cavity 2, and the shape and size of the filter cavity body are required to be set according to the required first receiving cavity 2. And the shape parameters of the first accommodating cavity 2 need to be reasonably set according to the frequency band, the bandwidth and the like of the signal to be filtered.
The conductive wire 3 is disposed in the first accommodation chamber 2 in the axial direction of the first accommodation chamber 2.
Specifically, the conductive wire 3 is a carrier for transmitting signals to be filtered, the signals passing through when the conductive wire 3 is electrified are the signals to be filtered, the signals to be filtered are electromagnetic waves radiated by electromagnetic induction, and when the electromagnetic waves are transmitted in the first accommodating cavity 2 filled with the colloidal metal powder filtering material, most of high-frequency electromagnetic waves are absorbed by the metal powder and lost due to the skin effect of the metal powder conductor, so that the effects of low-frequency signal loss, namely low-frequency signal passing, and high-frequency signal loss, namely high-frequency signal blocking, can be realized.
In order to ensure sufficient contact of the conductive wire 3 with the colloidal metal powder filter material at the time of implementation, the conductive wire 3 is generally prepared in a spiral cylindrical shape or the like, for example, a spiral cylindrical shape. As shown in fig. 2.
It should be noted that the shape of the conductive wire 3 as a whole generally substantially corresponds to the shape of the first accommodating cavity 2, and in the present embodiment, given a specific example which does not limit the inventive concept, the shapes of the two are described as follows: the first accommodating cavity 2 is a cylindrical cavity, and the conductive wire 3 is in a spiral column shape. The size relationship between the two is that the diameter of the spiral column is smaller than that of the first accommodating cavity 2, and the diameter of the spiral column is larger than the radius of the first accommodating cavity 2; the length of the spiral column is larger than that of the first accommodating cavity 2. Meanwhile, if the two are coaxially assembled, a better high-frequency signal blocking effect can be provided.
The colloidal metal powder filtering material is filled in the first containing cavity 2 around the conductive wire 3.
Specifically, the colloidal metal powder filter material is obtained by uniformly mixing the metal powder filter material and the potting adhesive, and when the colloidal metal powder filter material and the potting adhesive are mixed, the colloidal metal powder filter material and the potting adhesive are preferably uniformly mixed. Also, it is preferable to ensure that the interior of the mixed filter material contains no air or as little air as possible by vacuum stirring or slow stirring.
In the aspect of efficacy, signal loss is achieved by means of the skin effect of the metal powder, and the effects of facilitating packaging of the metal powder, fixing the metal powder, guaranteeing stability, reducing air among the metal powder and the like are achieved by means of the glue pouring glue.
In the specific embodiment, the metal powder is copper powder, and the copper powder refers to surface oxidized copper powder with a diameter of several micrometers to several tens of micrometers. In the present embodiment, copper powder of 10um in diameter is preferable. The selection of the glue filling needs to consider not only the bonding effect of the glue, but also the requirements of the low-temperature and superconducting environments of the quantum computing experimental system on the glue filling. In this embodiment, the preferred potting is epoxy potting, especially two-component epoxy potting StyCAST 1266A/1266B.
The selected two-component epoxy potting adhesive StyCAST 1266A/1266B is a transparent, low viscosity, room temperature curable epoxy potting/casting adhesive with excellent moisture resistance, good electrical resistance, and impact strength. StyCAST 1266A/1266B can be used for adhering various metals, glass and plastics. After curing, the material has little flexibility and can not generate stress. Meanwhile, the potting adhesive has low magnetic susceptibility and high thermal conductivity. The application of quantum computing has extremely strict requirements on low-temperature environment, and the high thermal conductivity of the potting adhesive plays a significant role in the application of the powder microwave filter in the low-temperature environment. Meanwhile, the low magnetic susceptibility of the potting adhesive provides guarantee for diamagnetic signals required by quantum computation; moreover, the shrinkage rate of the potting adhesive at 4K ℃ is only 1.1%, and the performance effectively ensures the stability of the filtering material in the filtering cavity.
When the colloidal metal powder filtering material is prepared, the raw materials are prepared according to the weight ratio of epoxy resin potting adhesive to surface oxidized copper powder of 20-36 percent and the weight ratio of surface oxidized copper powder of 66-80 percent, the epoxy resin adhesive is two-component epoxy resin potting adhesive StyCAST 1266A/1266B, and the weight ratio of the 1266A component to the 1266B component in the two-component is 3: 0.8. 1266A, 1266B and copper powder were mixed homogeneously as follows: 1266B adding 1266A, stirring to uniform and liquid state to obtain mixed solution; and adding the copper powder into the mixed solution, and stirring uniformly to obtain the uniformly mixed colloidal metal powder filtering material. The arrangement is obtained by the inventor of the application through a large number of experiments, and the powder microwave filter manufactured in the range has a good filtering effect.
In this embodiment, for a first receiving cavity 2 with a diameter of 5.6mm and a length of 55mm, a 0.2 mm copper paint wire is wound into a spiral cylindrical conductive wire 3 with a 4mm cylindrical rod, the pitch is 1mm, and the weight of each component of the corresponding colloidal metal powder filter material is 1266A 9g, 1266B 2.4g, and copper powder 30 g. The performance of the prepared powder microwave filter is tested, the obtained test index is 3dB of attenuation, and the corresponding filtering cut-off frequency is about 40MHz, namely the powder microwave filter can pass low frequency below 40MHz and even direct current.
Two connecting terminal 4 are used for connecting external circuit, and connecting terminal 4 is the SMA connector, as shown in fig. 3, two SMA connectors can dismantle the setting at the double-phase offside of filter chamber body 1 to be used for the tip of sealed first holding chamber 2 respectively, and connect the tip of conductor wire 3 electrically respectively. When the filter chamber is specifically arranged, grooves for containing the fixed connecting terminals 4 can be symmetrically arranged on two opposite end faces in the length direction of the filter chamber body.
Another embodiment of the present invention further provides a method for manufacturing a powder microwave filter, including the steps of:
step S1: assembling a conductive wire 3 into a first accommodating cavity 2 in a filter cavity body 1, wherein two ends of the conductive wire 3 are respectively and electrically connected with a connecting terminal 4;
step S2: fixing one connecting terminal 4 on the filter cavity body 1, and reserving a first gap between the other connecting terminal 4 and the filter cavity body 1 to open the end part of the first accommodating cavity 2 corresponding to the connecting terminal 4;
step S3: injecting the colloidal metal powder filtering material into the first accommodating cavity 2 through the first gap in an injection mode until the first accommodating cavity 2 is filled with the colloidal metal powder filtering material;
step S4: the connection terminal 4 corresponding to the first slit is fixed.
In the above process, the colloidal metal powder filtering material is injected into the first accommodating cavity 2 through the first gap in an injection manner until the first accommodating cavity 2 is filled with the colloidal metal powder filtering material; prepare colloidal metal powder filtering material in first holding chamber 2 outside promptly, made things convenient for colloidal metal powder filtering material's preparation and control on the one hand, on the other hand has effectively guaranteed the state of the inside colloidal metal powder filtering material in first holding chamber 2.
In practice, the selection of the components of the colloidal metal powder filter and the preparation method are described in the above examples, and will not be described herein.
It should be noted that, in the implementation of the method, after the conductive wire 3 is assembled in the first accommodating cavity 2 in the filter cavity body 1, and the two ends of the conductive wire 3 are respectively electrically connected to the connection terminals 4, it is necessary to measure the electrical connection effect between the conductive wire 3 and the connection terminals 4, and to ensure the communication between the conductive wire 3 and the connection terminals 4, where the test of the electrical connection effect, i.e., the test of whether the circuit is connected or not, is not described herein too much. After the assembly is completed, the electrical connectivity of the line between the two quantum terminals needs to be tested, i.e. the electrical connection between the conductive wire 3 and the connection terminal 4 needs to be confirmed again.
The construction, features and functions of the present invention have been described in detail for the purpose of illustration and description, but the invention is not limited to the details of construction and operation, and is capable of other embodiments without departing from the spirit and scope of the invention.