CN215010185U

CN215010185U - LC filter structure

Info

Publication number: CN215010185U
Application number: CN202121459296.5U
Authority: CN
Inventors: 程小军; 李昂; 李开文
Original assignee: Anhui Falcon Wave Technology Co ltd
Current assignee: Anhui Falcon Wave Technology Co ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2021-12-03
Anticipated expiration: 2031-06-29

Abstract

The utility model relates to a filter, in particular to an LC filter structure, which comprises a shielding cover and an installation bottom plate, wherein a circuit board dielectric layer is arranged between the shielding cover and the installation bottom plate, the circuit board dielectric layer is respectively provided with top layer copper-clad layer and bottom layer copper-clad layer, the circuit board dielectric layer, the top layer copper-clad layer and the bottom layer copper-clad layer are electrically connected through metallized holes, a coupling resonant cavity filter circuit is welded on the top layer copper-clad layer, the bottom of the installation bottom plate is provided with a conductive copper block which is electrically connected with an input terminal or an output terminal of the coupling resonant cavity filter, and the conductive copper block is connected with the installation bottom plate through a dielectric glass insulating layer; the utility model provides a technical scheme can effectively overcome the great, the relatively poor defect of insulating properties of volume and filtering performance that prior art exists.

Description

LC filter structure

Technical Field

The utility model relates to a wave filter, concretely relates to LC wave filter structure.

Background

For the mainstream LC filters existing in the market, most of them adopt SMA connection or insulator welding type, and surface mount type LC filters are not particularly common. The traditional LC filter has a series of defects that the size is large, and a special structure needs to be designed according to the external form in practical application. In comparison, the surface-mounted LC filter can be directly soldered in the microstrip line, which is simple and convenient. In addition, the existing LC filter has a large space for improving the insulation performance and the filtering performance.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

To the above-mentioned shortcoming that prior art exists, the utility model provides a LC filter structure can effectively overcome the great, the relatively poor defect of insulating properties of volume and filtering performance that prior art exists.

(II) technical scheme

In order to achieve the above purpose, the utility model discloses a following technical scheme realizes:

an LC filter structure comprises a shielding cover and an installation bottom plate, wherein a circuit board dielectric layer is arranged between the shielding cover and the installation bottom plate, a top layer copper-clad layer and a bottom layer copper-clad layer are respectively arranged on the circuit board dielectric layer, the top layer copper-clad layer and the bottom layer copper-clad layer are electrically connected through metallized holes, and a coupling resonant cavity filter circuit is welded on the top layer copper-clad layer;

and the bottom of the mounting base plate is provided with a conductive copper block which is electrically connected with an input or output terminal of the coupled resonant cavity filter, and the conductive copper block is connected with the mounting base plate through a dielectric glass insulating layer.

Preferably, the coupled cavity filter circuit comprises inductors L1-L7, capacitors C1-C15 and two input or output terminals, wherein the capacitors C1, C3, C5, C7, C9, C11, C13 and C15 are sequentially connected in series between the input or output terminals;

a capacitor C2 and an inductor L1 are connected in parallel between the capacitors C1 and C3, a capacitor C4 and an inductor L2 are connected in parallel between the capacitors C3 and C5, a capacitor C6 and an inductor L3 are connected in parallel between the capacitors C5 and C7, a capacitor C8 and an inductor L4 are connected in parallel between the capacitors C7 and C9, a capacitor C10 and an inductor L5 are connected in parallel between the capacitors C9 and C11, an inductor L4, a capacitor C12 and an inductor L6 are connected in parallel between the capacitors C11 and C13, and a capacitor C14 and an inductor L7 are connected in parallel between the capacitors C13 and C15.

Preferably, the coupled resonator filter circuit has a symmetrical structure.

Preferably, the top copper clad includes a two-sided ground region and a plurality of intermediate pads.

Preferably, the mounting bottom plate is provided with a mounting groove matched with the shielding cover and the circuit board dielectric layer.

Preferably, the mounting bottom plate is provided with a mounting screw hole.

Preferably, the shielding case and the mounting base plate are both made of hard aluminum materials.

(III) advantageous effects

Compared with the prior art, the LC filter structure provided by the utility model changes the traditional SMA connection and high-frequency insulator input/output mode, adopts a special patch type structure, effectively reduces the device volume, saves a large amount of internal space, is more convenient in structural design and easier to install and operate; the conductive copper block is connected with the mounting bottom plate through the dielectric glass insulating layer, so that the insulating property is effectively improved; the whole device adopts a coupling resonant cavity filter circuit, and the filtering quality is further improved.

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 invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is an exploded view of the structure of the present invention;

fig. 2 is a schematic top view of the mounting base of fig. 1 according to the present invention;

fig. 3 is a schematic bottom view of the mounting base of fig. 1 according to the present invention;

fig. 4 is a schematic diagram of the middle coupled resonator filter circuit of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

An LC filter structure is shown in fig. 1 to 3 and comprises a shielding cover 1 and an installation bottom plate 5, wherein a circuit board dielectric layer 3 is arranged between the shielding cover 1 and the installation bottom plate 5, a top layer copper clad 2 and a bottom layer copper clad 4 are respectively arranged on the circuit board dielectric layer 3, the top layer copper clad 2 and the bottom layer copper clad 4 are electrically connected through a metalized hole 9, and a coupling resonant cavity filter circuit is welded on the top layer copper clad 2;

the bottom of the mounting bottom plate 5 is provided with a conductive copper block 7 which is electrically connected with an input or output terminal of the coupled resonant cavity filter, and the conductive copper block 7 is connected with the mounting bottom plate 5 through a dielectric glass insulating layer 6.

The mounting bottom plate 5 is provided with a mounting groove 10 matched with the shielding case 1 and the circuit board dielectric layer 3. The shield case 1 is mounted on the mounting base plate 5 and the circuit board to protect the circuit on the circuit board in a closed cavity.

In the technical scheme, the circuit board comprises a circuit board dielectric layer 3, a top layer copper-clad layer 2 and a bottom layer copper-clad layer 4, the two layers of boards are standard, the bottom layer is large-area copper-clad and is electrically connected with the top layer copper-clad layer 2 through a metallized hole 9, and meanwhile, a signal network is ensured not to be short-circuited with the ground.

The conductive copper blocks 7 are arranged on two opposite corners of the bottom of the mounting bottom plate 5 and are parallel to each other, and the mounting screw holes 8 are arranged on the other two opposite corners of the bottom of the mounting bottom plate 5. The conductive copper block 7 is similar to a half-convex shape, and the periphery of the conductive copper block is insulated from the whole structure by the dielectric glass insulating layer 6.

The shielding case 1 and the mounting bottom plate 5 are both made of hard aluminum materials, and the surfaces of the shielding case and the mounting bottom plate are all subjected to silver plating treatment.

The top layer copper-clad 2 comprises two side grounding areas and a plurality of middle bonding pads, and the middle bonding pads are more in arrangement and support the welding manufacture of the multi-order LC filter. As can be seen from the bottom layer copper clad 4, copper is clad in a large area in a region other than the input or output terminal, and is electrically connected to the top layer copper clad 2 through the metallized hole 9, so that they are in a state of being connected to each other in the circuit.

As shown in fig. 4, the coupled cavity filter circuit includes inductors L1-L7, capacitors C1-C15, and two input or output terminals, wherein the capacitors C1, C3, C5, C7, C9, C11, C13, and C15 are connected in series between the input or output terminals in sequence.

A capacitor C2 and an inductor L1 are connected between the capacitors C1 and C3 in parallel, a capacitor C4 and an inductor L2 are connected between the capacitors C3 and C5 in parallel, a capacitor C6 and an inductor L3 are connected between the capacitors C5 and C7 in parallel, a capacitor C8 and an inductor L4 are connected between the capacitors C7 and C9 in parallel, a capacitor C10 and an inductor L5 are connected between the capacitors C9 and C11 in parallel, an inductor L4 is connected between the capacitors C11 and C13 in parallel, a capacitor C12 and an inductor L6 are connected between the capacitors C13 and C15 in parallel, and a capacitor C14 and an inductor L7 are connected between the capacitors C13 and C15 in parallel.

In the technical scheme of the application, the structure and the circuit of the coupling resonant cavity filter circuit are symmetrical, so that specific input and output terminals do not need to be distinguished, and a designer can change the values of capacitance and inductance in the circuit according to the indexes of a specific LC filter. In practical application, a designer does not need to be bound by the LC filter and the top copper clad 2 in this form, and can manufacture different circuit boards according to the order and form of the designed LC filter circuit, but needs to ensure the size of the whole circuit board and the positions of the input or output terminals so as to prevent the phenomenon that the circuit boards cannot be butted or even short-circuited in the installation process.

The fabrication of the entire LC filter can be performed as follows. In the first mode, the circuit board is firstly welded on the mounting base plate 5, then the coupling resonant cavity filter circuit is welded on the surface of the circuit board, the shielding cover 1 is covered after debugging, and the shielding cover 1 is fixed by using a laser seal welding technology. In the process, when the circuit board is installed, a layer of molten soldering tin needs to be fully paved in the mounting groove 10 on the installation bottom plate 5 except for the dielectric glass insulating layer, and then the circuit board is placed in the mounting groove 10 and lightly pressed to ensure that no air bubbles are in close contact with the inside of the circuit board. Furthermore, the circuit board is placed in a centered position, so that soldering faults are avoided and the shielding case 1 cannot be mounted. After the circuit board is installed, when the circuit is welded on the surface of the circuit board, attention should be paid to the fact that the edges of components cannot exceed the circuit board, and the height of the components should be smaller than the internal height of the shielding case 1, so that the phenomenon that the performance of the LC filter is changed due to the fact that the circuit touches the inner wall is avoided.

In the second mode, the coupling resonant cavity filter circuit is firstly welded to the circuit board by high-temperature soldering tin, then the circuit board is welded to the mounting bottom plate 5 by low-temperature soldering tin, and debugging is carried out after cooling. After debugging, the installation bottom plate 5 and the circuit board welded with components are heated, then the shielding case 1 is covered, and the whole structure is fixed by using soldering tin. Compared with the first mode, the second mode can finish a series of operations only by the constant-temperature heating table, laser sealing welding is not needed, and the production cost is low.

For the installation of whole LC wave filter, can directly with electrically conductive copper billet 7 welding on the microstrip line can, also can reserve the mounting hole of suitable position in structural design according to the position of installation screw 8, utilize the screw to fix after the welding. When the whole LC filter is designed, the dielectric glass insulating layer 6 on the bottom surface of the mounting bottom plate 5 occupies a large area, so that the phenomena of short circuit and the like can be effectively avoided.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims

1. An LC filter structure, characterized by: the circuit board comprises a shielding cover (1) and a mounting bottom plate (5), wherein a circuit board dielectric layer (3) is arranged between the shielding cover (1) and the mounting bottom plate (5), a top layer copper-clad layer (2) and a bottom layer copper-clad layer (4) are respectively arranged on the circuit board dielectric layer (3), the top layer copper-clad layer (2) and the bottom layer copper-clad layer (4) are electrically connected through a metalized hole (9), and a coupling resonant cavity filter circuit is welded on the top layer copper-clad layer (2);

the bottom of the mounting base plate (5) is provided with a conductive copper block (7) which is electrically connected with an input or output terminal of the coupling resonant cavity filter, and the conductive copper block (7) is connected with the mounting base plate (5) through a dielectric glass insulating layer (6).

2. The LC filter structure of claim 1, wherein: the coupled resonant cavity filter circuit comprises inductors L1-L7, capacitors C1-C15 and two input or output terminals, wherein the capacitors C1, C3, C5, C7, C9, C11, C13 and C15 are sequentially connected in series between the input or output terminals;

3. The LC filter structure of claim 2, wherein: the coupling resonant cavity filter circuit is of a symmetrical structure.

4. The LC filter structure of claim 2, wherein: the top copper clad (2) layer comprises two side grounding areas and a plurality of middle bonding pads.

5. The LC filter structure of claim 1, wherein: and the mounting bottom plate (5) is provided with a mounting groove (10) matched with the shielding cover (1) and the circuit board dielectric layer (3).

6. The LC filter structure of claim 5, wherein: and the mounting bottom plate (5) is provided with a mounting screw hole (8).

7. The LC filter structure of claim 5, wherein: the shielding case (1) and the mounting bottom plate (5) are both made of hard aluminum materials.