CN216649635U - Miniaturized LTCC low pass filter - Google Patents

Abstract

The utility model relates to a miniaturized LTCC low-pass filter. It includes microwave component set in the ceramic body; the microwave assembly comprises an inductance assembly and a capacitance assembly which is in adaptive electric connection with the inductance assembly, a transmission first port is formed by one end of a first inductance, the other end of the first inductance is connected with one end of a second inductance and one end of a fourth inductance, and the other end of the fourth inductance is electrically connected with a ground reference layer in the ceramic body through the first capacitance; the other end of the second inductor is connected with one end of a third inductor and one end of a fifth inductor, the other end of the fifth inductor is electrically connected with a ground reference layer in the ceramic body through a second capacitor, and a transmission second port is formed by the other end of the third inductor; the first inductor, the second inductor, the third inductor, the fourth inductor and the inductor are all three-dimensional spiral inductors. The utility model can improve the suppression degree of the filter while reducing the size of the filter, and is safe and reliable.

Description

Miniaturized LTCC low pass filter

Technical Field

The utility model relates to a low-pass filter, in particular to a miniaturized LTCC low-pass filter.

Background

The filter is a filter circuit consisting of a capacitor, an inductor and a resistor. The filter can effectively filter the frequency point of the specific frequency in the power line or the frequencies except the frequency point to obtain a power signal of the specific frequency or eliminate the power signal of the specific frequency. The filter is a frequency selection device, which can pass specific frequency components in signals and greatly attenuate other frequency components, and the frequency selection function of the filter can be used for filtering interference noise or performing spectrum analysis. In other words, any device or system that can pass a specific frequency component of a signal and greatly attenuate or suppress other frequency components is called a filter.

A filter is a device that filters waves. "wave" is a very broad physical concept, and in the field of electronics, is narrowly limited to refer specifically to processes that describe the variation of values of various physical quantities over time. This process is converted into a time function of voltage or current, called time waveform of various physical quantities, or called signal, by the action of various sensors. Since the argument time is continuously valued, it is called a continuous time signal, which is also conventionally called an analog signal.

With the development of communication technology, the demand for mobile communication devices is increasing, and the demand for mobile communication devices is also increasing. The industry is also working on miniaturization, high performance, and light weight of products. The filter is used as a key component of the radio frequency front section, and the performance of the filter directly influences the performance of the whole product. In all mobile communication devices, the filter is a passive component that must be reduced. Therefore, the filter device has wide market prospect in realizing miniaturization and high performance.

LTCC (Low Temperature Co-fired Ceramic technology) is a multilayer circuit made by laminating unsintered cast Ceramic materials together with printed interconnecting conductors, components and circuitry, and sintering the structure into an integrated Ceramic multilayer material. LTCC utilizes conventional thick film dielectric material casting rather than screen printing the dielectric paste. Cutting the raw porcelain strips into proper sizes, punching alignment holes and inner cavities, and forming the interconnection through holes by adopting laser drilling or mechanical drilling; screen printing or photo etching the conductors together with the required resistors, capacitors and inductors onto the respective ceramic sheets; then, the ceramic plates are aligned, laminated and co-fired at 850 ℃, and the substrate is assembled and surface-mounted by using the existing thick film circuit production technology.

The filter is integrated in the LTCC, so that the internal space can be fully utilized, the size and the area of a passive device of a radio frequency system are effectively reduced, and high integration of the device is realized. LTCC low pass filters generally provide smaller size, smaller insertion loss, but their rejection is generally not high. If the suppression degree of the filter is to be improved, the order of the filter needs to be increased, and the size of the LTCC low-pass filter is sacrificed. Therefore, how to improve the suppression degree of the LTCC low-pass filter is a technical problem at present.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art and provide a miniaturized LTCC low-pass filter which can improve the suppression degree of the filter and is safe and reliable when the size of the filter is reduced.

According to the technical scheme provided by the utility model, the miniaturized LTCC low-pass filter comprises a microwave assembly arranged in a ceramic body; the microwave assembly comprises an inductance assembly and a capacitance assembly which is in adaptive electric connection with the inductance assembly, wherein the inductance assembly comprises a first inductance, a second inductance, a third inductance, a fourth inductance and a fifth inductance, and the capacitance assembly comprises a first capacitance and a second capacitance;

a transmission first port is formed by one end of a first inductor, the other end of the first inductor is connected with one end of a second inductor and one end of a fourth inductor, and the other end of the fourth inductor is electrically connected with a ground reference layer in the ceramic body through a first capacitor; the other end of the second inductor is connected with one end of a third inductor and one end of a fifth inductor, the other end of the fifth inductor is electrically connected with a ground reference layer in the ceramic body through a second capacitor, and a transmission second port is formed by the other end of the third inductor; the first inductor, the second inductor, the third inductor, the fourth inductor and the fifth inductor are all three-dimensional spiral inductors.

The first inductor comprises a first inductor top metal layer, a first inductor bottom metal layer and a plurality of first inductor middle metal layers, wherein the first inductor middle metal layers are positioned between the first inductor top metal layer and the first inductor bottom metal layer, and the first inductor top metal layers, the first inductor middle metal layers and the first inductor bottom metal layers are sequentially connected in series;

and a first transmission port is formed by utilizing the head end of the top metal layer of the first inductor, and the tail end of the bottom metal layer of the first inductor is in adaptive electric connection with the fourth inductor and the second inductor.

The second inductor comprises a second inductor top metal layer, a second inductor bottom metal layer and a plurality of second inductor middle metal layers, wherein the second inductor middle metal layers are positioned between the second inductor top metal layers and the second inductor bottom metal layers, and each second inductor top metal layer comprises an inductor first connecting sheet and an inductor second connecting sheet;

one end of the first inductor connecting sheet is electrically connected with the tail end of the first inductor bottom metal layer in the first inductor through the first inductor connecting column, and the other end of the first inductor connecting sheet is sequentially connected with the second inductor middle metal layer and the second inductor bottom metal layer in series; the tail end of the bottom metal layer of the second inductor is connected with one end of the second connecting piece of the inductor through an inter-inductor third connecting column penetrating through the middle metal layer of the second inductor, and the other end of the second connecting piece of the inductor is in adaptive connection with the third inductor through the inter-inductor second connecting column.

The third inductor comprises a third inductor top metal layer, a third inductor bottom metal layer and a plurality of third inductor middle metal layers, and the third inductor top metal layer, the third inductor middle metal layer and the third inductor bottom metal layer are sequentially connected in series;

and a transmission second port is formed by utilizing the head end of the top metal layer of the third inductor, and the tail end of the bottom metal layer of the third inductor is electrically connected with the second connecting column between inductors.

The fourth inductor comprises a fourth inductor top metal layer, a fourth inductor bottom metal layer and a plurality of fourth inductor middle metal layers, the fourth inductor middle metal layers are positioned between the fourth inductor top metal layer and the fourth inductor bottom metal layer, and the fourth inductor top metal layer, the fourth inductor middle metal layers and the fourth inductor bottom metal layers are sequentially connected in series;

the head end of the top metal layer of the fourth inductor is electrically connected with the tail end of the bottom metal layer of the first inductor, and the tail end of the bottom metal layer of the fourth inductor is electrically connected with the first capacitor.

The fifth inductor comprises a fifth inductor top metal layer, a fifth inductor bottom metal layer and a plurality of fifth inductor middle metal layers, the fifth inductor middle metal layer is positioned between the fifth inductor top metal layer and the fifth inductor bottom metal layer, and the fifth inductor top metal layer, the fifth inductor middle metal layer and the fifth inductor bottom metal layer are sequentially connected in series;

the fifth inductor top metal layer is electrically connected with the tail end of the third inductor bottom metal layer, and the tail end of the fifth inductor bottom metal layer is electrically connected with the second capacitor.

The first capacitor comprises a first capacitor first polar plate, a first capacitor second polar plate and a first capacitor middle isolating plate, the first capacitor middle isolating plate is positioned between the first capacitor first polar plate and the first capacitor second polar plate, the first capacitor middle isolating plate and the first capacitor first polar plate are sequentially distributed above the ground reference layer;

the first capacitor first pole plate is electrically connected with the first capacitor second pole plate through the first capacitor inter-pole connecting column, the first capacitor middle isolation plate is electrically connected with the ground reference layer, and the first capacitor first pole plate is in adaptive electric connection with the fourth inductor.

The second capacitor comprises a second capacitor first polar plate, a second capacitor second polar plate and a second capacitor middle isolating plate, the second capacitor middle isolating plate is positioned between the second capacitor first polar plate and the second capacitor second polar plate, the second capacitor middle isolating plate and the second capacitor first polar plate are sequentially distributed above the ground reference layer;

the first pole plate of the second capacitor is electrically connected with the second pole plate of the second capacitor through the connecting column between the second capacitor pole plates, the middle isolation plate of the second capacitor is electrically connected with the ground reference layer, and the first pole plate of the second capacitor is in adaptive electric connection with the fifth inductor.

The first inductor and the fourth inductor have opposite or same spiral directions in the ceramic body.

The spiral direction of the first inductor and the spiral direction of the third inductor are in mirror symmetry or rotational symmetry with respect to the second inductor.

The utility model has the advantages that: the microwave assembly comprises an inductance assembly and a capacitance assembly which is in adaptive electric connection with the inductance assembly, the inductance assembly comprises a first inductance, a second inductance, a third inductance, a fourth inductance and a fifth inductance, and the capacitance assembly comprises a first capacitance and a second capacitance; a transmission first port is formed by one end of a first inductor, the other end of the first inductor is connected with one end of a second inductor and one end of a fourth inductor, and the other end of the fourth inductor is electrically connected with a ground reference layer in the ceramic body through a first capacitor; the other end of the second inductor is connected with one end of a third inductor and one end of a fifth inductor, the other end of the fifth inductor is electrically connected with a ground reference layer in the ceramic body through a second capacitor, and a transmission second port is formed by the other end of the third inductor; the first inductor, the second inductor, the third inductor, the fourth inductor and the inductor are all three-dimensional spiral inductors; the suppression degree of the filter can be improved when the size of the filter is reduced.

Drawings

Fig. 1 is an equivalent circuit schematic diagram of the present invention.

Fig. 2 is a perspective view of the present invention.

Fig. 3 is a perspective view of a first inductor according to the present invention.

Fig. 4 is a perspective view of a fourth inductor according to the present invention.

Fig. 5 is a perspective view of a third inductor according to the present invention.

Fig. 6 is a perspective view of a fifth inductor according to the present invention.

Fig. 7 is a perspective view of a second inductor according to the present invention.

Fig. 8 is a perspective view of a sixth capacitor and a seventh capacitor according to the present invention.

FIG. 9 is a schematic representation of a first layer within a ceramic body of the present invention.

FIG. 10 is a schematic representation of a second layer within a ceramic body of the present invention.

FIG. 11 is a schematic representation of a third layer within a ceramic body of the present invention.

FIG. 12 is a schematic view of a fourth layer in a ceramic body according to the present invention.

FIG. 13 is a schematic illustration of a fifth layer in a ceramic body according to the present invention.

FIG. 14 is a schematic representation of a sixth layer in a ceramic body of the present invention.

FIG. 15 is a schematic representation of a seventh layer within a ceramic body of the present invention.

FIG. 16 is a schematic view of an eighth layer in a ceramic body according to the present invention.

FIG. 17 is a schematic view of a ninth layer in a ceramic body according to the present invention.

FIG. 18 is a schematic representation of the tenth layer in a ceramic body of the present invention.

FIG. 19 is a schematic representation of the eleventh layer in a ceramic body of the present invention.

FIG. 20 is a schematic representation of a twelfth layer in a ceramic body of the present invention.

Description of reference numerals: 1-first inductor, 2-second inductor, 3-third inductor, 4-fourth inductor, 5-fifth inductor, 6-first capacitor, 7-second capacitor, 8-ground reference layer, 9-transmission first port, 10-transmission second port, 11-inter-inductor first connection column, 12-inter-inductor second connection column, 13-first inductor top metal layer, 14-first inductor middle first metal layer, 15-first inductor inner first connection column, 16-first inductor middle second metal layer, 17-first inductor bottom metal layer connection tail end, 18-first inductor inner second connection column, 19-first inductor inner third connection column, 20-first inductor bottom metal layer, 21-fourth inductor top metal layer, 22-fourth inductor inner first connection column, 23-fourth inductor bottom metal layer, 24-fourth inductor inner second connection column, 25-fourth inductor inner third connection column, 26-third inductor top metal layer, 27-third inductor middle first metal layer, 28-third inductor middle second metal layer, 29-third inductor bottom metal layer, 30-third inductor inner first connection column, 31-third inductor inner second connection column, 32-third inductor inner third connection column, 33-fifth inductor top metal layer, 34-fifth inductor inner first connection column, 35-fifth inductor bottom metal layer, 36-fifth inductor inner second connection column, 37-fifth inductor inner third connection column, 38-inductor first connection sheet, 39-inductor second, 40-second inductor inner first connection column, 41-second inductor inner second connection column, 42-second inductor intermediate first connection layer, 43-second inductor intermediate second connection layer, 44-second inductor intermediate third connection layer, 45-second inductor bottom metal layer, 46-inductor intermediate third connection column, 47-second inductor inner fourth connection column, 48-first capacitor first pole plate, 49-second capacitor first pole plate, 50-first capacitor intermediate isolation plate, 51-second capacitor intermediate isolation plate, 52-first capacitor pole plate intermediate connection column, 53-first capacitor separator ground connection column, 54-first capacitor second pole plate, 55-second capacitor second pole plate, 56-second capacitor separator ground connection column, 57-second capacitor inter-pole connection column, 58-transmission second port first connection column, 59-transmission first port first connection piece, 60-ceramic body first layer first connection piece, 61-ceramic body first layer second connection piece, 62-transmission first port bottom connection piece, 63-transmission second port bottom connection piece, 64-ceramic body bottom layer first connection piece and 65-ceramic body bottom layer second connection piece.

Detailed Description

The utility model is further illustrated by the following specific figures and examples.

As shown in fig. 1 and 2: in order to reduce the size of the filter and improve the suppression degree of the filter, the microwave component is arranged in the ceramic body; the microwave assembly comprises an inductance assembly and a capacitance assembly which is in adaptive electric connection with the inductance assembly, wherein the inductance assembly comprises a first inductance 1, a second inductance 2, a third inductance 3, a fourth inductance 4 and a fifth inductance 5, and the capacitance assembly comprises a first capacitance 6 and a second capacitance 7;

a first transmission port is formed by one end of a first inductor 1, the other end of the first inductor 1 is connected with one end of a second inductor 2 and one end of a fourth inductor 4, and the other end of the fourth inductor 4 is electrically connected with a ground reference layer 8 in the ceramic body through a first capacitor 6; the other end of the second inductor 2 is connected with one end of a third inductor 3 and one end of a fifth inductor 5, the other end of the fifth inductor 5 is electrically connected with a ground reference layer 8 in the ceramic body through a second capacitor 7, and a transmission second port is formed by the other end of the third inductor 3; the first inductor 1, the second inductor 2, the third inductor 3, the fourth inductor 4 and the fifth inductor 5 are all three-dimensional spiral inductors.

Specifically, the microwave component is prepared in the ceramic body, and the process for preparing the microwave component in the ceramic body is consistent with the prior art, and is well known to those skilled in the art, and is not described herein again. The microwave assembly comprises an inductance assembly and a capacitance assembly, and the inductance assembly is electrically connected and matched with the capacitance assembly.

In the embodiment of the utility model, in the inductor assembly, the inductor L1 can be formed through the first inductor 1, the inductor L2 can be formed through the second inductor 2, the inductor L3 can be formed through the third inductor 3, the inductor L4 can be formed through the fourth inductor 4, and the inductor L5 can be formed through the fifth inductor 5; in the capacitor assembly, a capacitor C1 can be formed through the first capacitor 6, a capacitor C2 can be formed through the second capacitor 7, and the corresponding circuit schematic diagram in fig. 1 can be formed after the inductor assembly and the capacitor assembly are connected in a matched mode. The first inductor 1, the second inductor 2, the third inductor 3, the fourth inductor 4 and the inductor 5 are all three-dimensional spiral inductors, and as shown in fig. 2, the matching of the inductor assembly and the capacitor assembly is utilized, so that the suppression degree of the filter can be improved when the size of the filter is reduced.

Further, the first inductor 1 includes a first inductor top metal layer 13, a first inductor bottom metal layer 20, and a plurality of first inductor middle metal layers, where the first inductor middle metal layers are located between the first inductor top metal layer 13 and the first inductor bottom metal layer 20, and the first inductor top metal layer 13, the first inductor middle metal layer, and the first inductor bottom metal layer 20 are sequentially connected in series;

the first end of the first inductor top metal layer 13 is used to form a first transmission port 9, and the tail end of the first inductor bottom metal layer 20 is adapted and electrically connected with the fourth inductor 4 and the second inductor 2.

In specific implementation, the first inductor top metal layer 13 is located above the first inductor middle metal layer and the first inductor bottom metal layer 20, the number of the first inductor middle metal layers in the first inductor 1 may be selected according to actual needs, and when the number of the first inductor middle metal layers in the first inductor 1 is different, the inductance values of the first inductor 1 are different, which is known to those skilled in the art and is not described herein again. Fig. 3 shows a schematic diagram of an embodiment of the first inductor 1, wherein the first inductor intermediate metal layer includes a first inductor intermediate first metal layer 14 and a first inductor intermediate second metal layer 16, the first inductor intermediate first metal layer 14 is located between the first inductor top metal layer 13 and the first inductor intermediate second metal layer 16, and the first inductor intermediate second metal layer 16 is located between the first inductor intermediate first metal layer 14 and the first inductor bottom metal layer 20.

The first inductor top metal layer 13, the first inductor middle first metal layer 14, the first inductor middle second metal layer 16, and the first inductor bottom metal layer 20 are in the shape of a chip. The first transmission port 9 is formed by the head end of the first inductor top metal layer 13, and the first transmission port 9 is made of one metal material of gold, silver or copper. When the first inductor top metal layer 13, the first inductor middle metal layer and the first inductor bottom metal layer 20 are sequentially connected in series, the tail end of the first inductor top metal layer 13 is connected with the head end of the first inductor middle first metal layer 14 through the first inductor inner first connecting post 15, the tail end of the first inductor middle first metal layer 14 is connected with the head end of the first inductor middle second metal layer 16 through the first inductor inner second connecting post 18, the tail end of the first inductor middle second metal layer 16 is connected with the head end of the first inductor bottom metal layer 20 through the first inductor inner third connecting post 19, the tail end of the first inductor bottom metal layer 20 forms a first inductor bottom metal layer connecting tail end 17, and the first inductor 1, the second inductor 2 and the fourth inductor 4 can be conveniently electrically connected through the first inductor bottom metal layer connecting tail end 17.

Further, the second inductor 2 includes a second inductor top metal layer, a second inductor bottom metal layer 45, and a plurality of second inductor middle metal layers, where the second inductor middle metal layers are located between the second inductor top metal layer and the second inductor bottom metal layer 45, and the second inductor top metal layers include an inductor first connection pad 38 and an inductor second connection pad 39;

one end of the first inductor connecting sheet 38 is electrically connected with the tail end of the first inductor bottom metal layer 20 in the first inductor 1 through the first inductor connecting column 11, and the other end of the first inductor connecting sheet 38 is sequentially connected with the second inductor middle metal layer and the second inductor bottom metal layer 45 in series; the tail end of the second inductor bottom metal layer 45 is connected with one end of the inductor second connecting piece 39 through an inductor third connecting post 46 penetrating through the second inductor middle metal layer, and the other end of the inductor second connecting piece 39 is connected with the third inductor 3 in a matching mode through the inductor second connecting post 12.

Specifically, similar to the case of the first inductor 1, the number of the second inductor intermediate metal layers may be selected according to actual needs, and fig. 7 shows a specific case of the second inductor intermediate metal layers in the second inductor 2, specifically, the second inductor intermediate metal layers are the second inductor intermediate first metal layer 42, the second inductor intermediate second metal layer 43, and the second inductor intermediate third metal layer 44, the second inductor intermediate second metal layer 43, and the second inductor first metal layer 42 are sequentially distributed over the second inductor bottom metal layer 45, and the second inductor first metal layer 42 is adjacent to the second inductor top metal layer.

In order to be electrically connected with the first inductor 1 and the third inductor 3, the second inductor top metal layer includes an inductor first connection pad 38 and an inductor second connection pad 39, and the inductor first connection pad 38 and the inductor second connection pad 39 are located on the same layer but do not contact each other. One end of the inductor first connection tab 38 is electrically connected to the first inductor bottom metal layer connection tail 17 of the first inductor bottom metal layer 20 in the first inductor 1 through the inductor first connection stud 11. The other end of the inductor first connection piece 38 is electrically connected with the head end of the second inductor middle first metal layer 42 through the second inductor inner first connection post 40, the tail end of the second inductor middle first metal layer 42 is electrically connected with the head end of the second inductor middle second metal layer 43 through the second inductor inner second connection post 41, the tail end of the second inductor middle second metal layer 43 is electrically connected with the head end of the second inductor middle third metal layer 44 through the second inductor inner third connection post, and the tail end of the second inductor middle third metal layer 44 is connected with the head end of the second inductor bottom metal layer 45 through the second inductor inner fourth connection post 47; the tail end of the second inductor bottom metal layer 45 is connected with one end of the inductor second connecting piece 39 through an inductor third connecting post 46 penetrating through the second inductor middle metal layer, and the other end of the inductor second connecting piece 39 is connected with the third inductor 3 in a matching mode through the inductor second connecting post 12.

The first connecting column 11, the second connecting column 12 and the third connecting column 46 are parallel to each other in the ceramic body.

Further, the third inductor 3 includes a third inductor top metal layer 26, a third inductor bottom metal layer 29, and a plurality of third inductor middle metal layers, and the third inductor top metal layer 26, the third inductor middle metal layer, and the third inductor bottom metal layer 29 are sequentially connected in series;

wherein, the second transmission port 10 is formed by the head end of the third inductor top metal layer 26, and the tail end of the third inductor bottom metal layer 29 is electrically connected to the second connection post 12.

Specifically, the number of the middle metal layers of the third inductor in the third inductor 3 may be selected according to actual needs, and specific reference is made to the above description, which is not described herein again. One specific implementation of the third inductor 3 is shown in fig. 5, and fig. 5 shows that the third inductor intermediate metal layer of the third inductor 3 includes a third inductor intermediate first metal layer 27 and a third inductor intermediate second metal layer 28, wherein the third inductor intermediate first metal layer 27 is adjacent to the third inductor top metal layer 26, and the third inductor intermediate second metal layer 28 is adjacent to the third inductor bottom metal layer 29.

The second transmission port 10 can be formed by using the head end of the top metal layer 26 of the third inductor, the tail end of the top metal layer 26 of the third inductor is electrically connected with the head end of the middle first metal layer 27 of the third inductor through the first connection post 30 in the third inductor, the tail end of the middle first metal layer 27 of the third inductor is connected with the head end of the middle second metal layer 28 of the third inductor through the second connection post 31 in the third inductor, the tail end of the middle second metal layer 28 of the third inductor is connected with the head end of the bottom metal layer 29 of the third inductor through the third connection post 32 in the third inductor, the tail end of the bottom metal layer 29 of the third inductor is electrically connected with the second connection post 12 between inductors, that is, the electrical connection between the third inductor 3 and the second inductor 2 is realized, and meanwhile, the tail end of the bottom metal layer 29 of the third inductor is also electrically connected with the fifth inductor 5.

In specific implementation, the first inductor 1 and the third inductor 3 are distributed on two sides of the second inductor 2 in a mirror image manner, that is, the first transmission port 9 and the second transmission port 10 point to corresponding outer sides respectively.

Further, the fourth inductor 4 includes a fourth inductor top metal layer 21, a fourth inductor bottom metal layer 23, and a plurality of fourth inductor middle metal layers, the fourth inductor middle metal layers are located between the fourth inductor top metal layer 21 and the fourth inductor bottom metal layer 23, and the fourth inductor top metal layer 21, the fourth inductor middle metal layer, and the fourth inductor bottom metal layer 23 are sequentially connected in series;

the head end of the fourth inductor top metal layer 21 is electrically connected to the tail end of the first inductor bottom metal layer 20, and the tail end of the fourth inductor bottom metal layer 23 is electrically connected to the first capacitor 6.

Specifically, the number of the fourth inductor intermediate metal layers in the fourth inductor 4 may be selected according to actual needs, and fig. 4 shows a schematic diagram that the fourth inductor intermediate metal layers are not disposed in the fourth inductor 4. The head end of the fourth inductor top metal layer 21 is provided with a first connecting post 22 in the fourth inductor, and the head end of the fourth inductor top metal layer 21 is electrically connected with the tail end of the first inductor bottom metal layer 20 through the first connecting post 22 in the fourth inductor. The fourth inductor top metal layer 21 is electrically connected to the head end of the fourth inductor bottom metal layer 23 through a second connection pin 24 in the fourth inductor, and the tail end of the fourth inductor bottom metal layer 23 can be electrically connected to the first capacitor 6 through a third connection pin 25 in the fourth inductor.

In specific implementation, the spiral directions of the first inductor 1 and the fourth inductor 4 in the ceramic body are opposite, the specific spiral directions of the first inductor 1 and the fourth inductor 4 can be selected according to actual needs, and certainly, the spiral direction of the second inductor 2 can also be selected according to actual needs, but after the spiral direction of the first inductor 1 is determined, the spiral direction of the third inductor 3 can be determined because the third inductor 3, the first inductor 1 and the second inductor 2 are mirror-symmetrical. The spiral direction of the third inductor 3 is opposite to the spiral direction of the fifth inductor 5, specifically, the spiral directions of the first inductor 1 and the fourth inductor 4 in the ceramic body are consistent, so that the spiral direction of the fifth inductor 5 can be determined after the spiral direction of the third inductor 3 is determined.

In specific implementation, the relationship among the first inductor 1, the second inductor 2, the third inductor 3, the fourth inductor 4, and the fifth inductor 5 in the rotation direction in the ceramic body may also adopt other matching forms. The method specifically comprises the following steps:

the spiral direction of the first inductor 1 and the spiral direction of the third inductor 3 may be rotationally symmetrical with respect to the second inductor 2, the spiral direction of the first inductor 1 is opposite to the spiral direction of the fourth inductor 4, and the spiral direction of the third inductor 3 is opposite to the spiral direction of the fifth inductor 5. The spiral direction of the first inductor 1 and the spiral direction of the third inductor 3 are rotationally symmetrical with respect to the second inductor 2, specifically, the third inductor 3 can be obtained by rotating the first inductor 1 by 180 degrees;

the spiral direction of the first inductor 1 and the spiral direction of the third inductor 3 are in mirror symmetry with respect to the second inductor 2, the spiral direction of the first inductor 1 is the same as that of the fourth inductor 4, and the spiral direction of the third inductor 3 is the same as that of the fifth inductor 5;

the spiral direction of the first inductor 1 and the spiral direction of the third inductor 3 are mirror symmetry with respect to the second inductor 2, the spiral direction of the first inductor 1 is opposite to the spiral direction of the fourth inductor, and the spiral direction of the third inductor 3 is the same as the spiral direction of the fifth inductor 5.

Specifically, the relationship among the rotation directions of the first inductor 1, the second inductor 2, the third inductor 3, the fourth inductor 4 and the fifth inductor 5 in the ceramic body can be specifically selected according to needs, and is not listed here.

Further, the fifth inductor 5 includes a fifth inductor top metal layer 33, a fifth inductor bottom metal layer 35, and a plurality of fifth inductor middle metal layers, the fifth inductor middle metal layer is located between the fifth inductor top metal layer 33 and the fifth inductor bottom metal layer 35, and the fifth inductor top metal layer 33, the fifth inductor middle metal layer, and the fifth inductor bottom metal layer are sequentially connected in series;

the fifth inductor top metal layer 33 is electrically connected to the tail end of the third inductor bottom metal layer 29, and the tail end of the fifth inductor bottom metal layer 35 is electrically connected to the second capacitor 7.

Specifically, the specific case of the fifth inductance intermediate metal layer in the fifth inductance 5 is as described above, and fig. 6 shows the case where the fifth inductance intermediate metal layer is not provided in the fifth inductance 5, that is, only the fifth inductance top metal layer 33 and the fifth inductance bottom metal layer 35 are included in the fifth inductance 5. In the embodiment of the present invention, the head end of the fifth inductor top metal layer 33 is electrically connected to the tail end of the third inductor bottom metal layer 29 of the third inductor 3 through the fifth inductor inner first connection pillar 34, the tail end of the fifth inductor top metal layer 33 is connected to the head end of the fifth inductor bottom metal layer 35 through the fifth inductor inner second connection pillar 36, and the tail end of the fifth inductor bottom metal layer 35 is electrically connected to the second capacitor 7 through the fifth inductor inner third connection pillar 37.

As shown in fig. 8, the first capacitor 6 includes a first capacitor first plate 48, a first capacitor second plate 54, and a first capacitor intermediate isolating plate 50, the first capacitor intermediate isolating plate 50 is located between the first capacitor first plate 48 and the first capacitor second plate 54, the first capacitor intermediate isolating plate 50, and the first capacitor first plate 48 are sequentially distributed above the ground reference layer 8;

the first capacitor first plate 48 is electrically connected with the first capacitor second plate 54 through the first capacitor inter-plate connection post 52, the first capacitor intermediate isolation plate 50 is electrically connected with the ground reference layer 8, and the first capacitor first plate 48 is electrically connected with the fourth inductor 4 in a matching manner.

The second capacitor 7 comprises a second capacitor first polar plate 49, a second capacitor second polar plate 55 and a second capacitor intermediate isolating plate 51, the second capacitor intermediate isolating plate 51 is positioned between the second capacitor first polar plate 49 and the second capacitor second polar plate 55, the second capacitor intermediate isolating plate 51 and the second capacitor first polar plate 49 are sequentially distributed above the ground reference layer 8;

the second capacitor first plate 49 is electrically connected with the second capacitor second plate 55 through the second capacitor inter-plate connecting post 57, the second capacitor intermediate isolating plate 51 is electrically connected with the ground reference layer 8, and the second capacitor first plate 49 is electrically connected with the fifth inductor 5 in a matching manner.

Specifically, when the fourth inductor 4 is electrically connected to the first capacitor 6, the third connection pin 25 in the fourth inductor 4 is electrically connected to the first plate 48 of the first capacitor. Similarly, the third connecting post 37 in the fifth inductor 5 is electrically connected to the first plate 49 of the second capacitor. The ground reference layer 8 can be used as a reference potential layer of the whole filter, and the specific function of the ground reference layer 8 is consistent with the prior art, and is well known to those skilled in the art, and will not be described herein again.

Fig. 9 to 20 show the layered decomposition of the ceramic body according to the present invention, the ceramic body includes twelve layers, wherein a transmission second port first connection piece 58, a transmission first port first connection piece 59, a ceramic body first layer first connection piece 60, and a ceramic body first layer second connection piece 61 are disposed on a first layer of the ceramic body, wherein the transmission second port first connection piece 58 is adapted to be electrically connected to the transmission second port 10, the transmission port first connection piece 59 is adapted to be electrically connected to the transmission first port 9, and the ceramic body first layer first connection piece 60 and the ceramic body first layer second connection piece 61 are used for forming a ground at the upper end of the ceramic body.

As can be seen from fig. 9 to 20, the first inductor 1 and the third inductor 3 are distributed in the second layer to the fifth layer; the second inductors 2 are distributed on a second layer to a sixth layer; the fourth inductor 4 and the fifth inductor 5 are both positioned on the sixth layer to the seventh layer; the first capacitor 6 and the second capacitor 7 are located on the eighth layer to the tenth layer of the metal layer, and the specific distribution of the first inductor 1, the second inductor 2, the third inductor 3, the fourth inductor 4, the fifth inductor 5, the first capacitor 6 and the second capacitor 7 is related to the corresponding structure, which can be referred to the above description and is known to those skilled in the art specifically, and is not described herein again.

In addition, a transmission first port bottom connecting piece 62, a transmission second port bottom connecting piece 63, a first connecting piece 64 of the ceramic body bottom layer and a second connecting piece 65 of the ceramic body bottom layer are arranged on the twelfth layer, and the distribution and the function of the twelfth layer are similar to those of the first layer, and the description is omitted here.

In the embodiment of the present invention, the fourth inductor 4 and the first capacitor 6 form a first series resonant circuit, the fifth inductor 5 and the second capacitor 7 form a second series resonant circuit, and the first series resonant circuit and the second series resonant circuit are both connected in parallel; one end of the first series resonant circuit is connected to one end of the first inductor 1 and one end of the second inductor 2; one end of the second series resonant circuit is electrically connected with the other end of the second inductor 2 and one end of the third inductor 3; and the other end of the first series resonant circuit and the other end of the second series resonant circuit are both grounded.

In specific implementation, the working frequency band of the low-pass filter is DC-850 MHz; the low-pass filter reduces attenuation from-2.91 db to-43.12 db at a frequency range of 1GHz-1.55GHz, and has a degree of suppression greater than 35.1dBc at a frequency range of 1.55GHz-5 GHz.

Claims (10)

1. A miniaturized LTCC low pass filter comprises a microwave component arranged in a ceramic body; the method is characterized in that: the microwave assembly comprises an inductance assembly and a capacitance assembly which is in adaptive electrical connection with the inductance assembly, wherein the inductance assembly comprises a first inductance (1), a second inductance (2), a third inductance (3), a fourth inductance (4) and a fifth inductance (5), and the capacitance assembly comprises a first capacitance (6) and a second capacitance (7);

a first transmission port is formed by one end of a first inductor (1), the other end of the first inductor (1) is connected with one end of a second inductor (2) and one end of a fourth inductor (4), and the other end of the fourth inductor (4) is electrically connected with a ground reference layer (8) in the ceramic body through a first capacitor (6); the other end of the second inductor (2) is connected with one end of the third inductor (3) and one end of the fifth inductor (5), the other end of the fifth inductor (5) is electrically connected with a ground reference layer (8) in the ceramic body through a second capacitor (7), and a transmission second port is formed by the other end of the third inductor (3); the first inductor (1), the second inductor (2), the third inductor (3), the fourth inductor (4) and the fifth inductor (5) are all three-dimensional spiral inductors.

2. The miniaturized LTCC low pass filter of claim 1, wherein: the first inductor (1) comprises a first inductor top metal layer (13), a first inductor bottom metal layer (20) and a plurality of first inductor middle metal layers, wherein the first inductor middle metal layers are positioned between the first inductor top metal layer (13) and the first inductor bottom metal layer (20), and the first inductor top metal layer (13), the first inductor middle metal layer and the first inductor bottom metal layer (20) are sequentially connected in series;

a first transmission port is formed by the head end of the first inductor top metal layer (13), and the tail end of the first inductor bottom metal layer (20) is in adaptive electrical connection with the fourth inductor (4) and the second inductor (2).

3. The miniaturized LTCC low pass filter of claim 2, wherein: the second inductor (2) comprises a second inductor top metal layer, a second inductor bottom metal layer (45) and a plurality of second inductor middle metal layers, wherein the second inductor middle metal layers are located between the second inductor top metal layer and the second inductor bottom metal layer (45), and each second inductor top metal layer comprises an inductor first connecting sheet (38) and an inductor second connecting sheet (39);

one end of the first inductor connecting sheet (38) is electrically connected with the tail end of the first inductor bottom metal layer (20) in the first inductor (1) through the first inductor connecting column (11), and the other end of the first inductor connecting sheet (38) is sequentially connected with the second inductor middle metal layer and the second inductor bottom metal layer (45) in series; the tail end of the second inductor bottom metal layer (45) is connected with one end of the inductor second connecting piece (39) through an inductor third connecting column (46) penetrating through the second inductor middle metal layer, and the other end of the inductor second connecting piece (39) is connected with the third inductor (3) in an adaptive mode through the inductor second connecting column (12).

4. The miniaturized LTCC low pass filter of claim 3, wherein: the third inductor (3) comprises a third inductor top metal layer (26), a third inductor bottom metal layer (29) and a plurality of third inductor middle metal layers, and the third inductor top metal layer (26), the third inductor middle metal layer and the third inductor bottom metal layer (29) are sequentially connected in series;

and a transmission second port is formed by utilizing the head end of the third inductor top metal layer (26), and the tail end of the third inductor bottom metal layer (29) is electrically connected with the inductor second connecting column (12).

5. The miniaturized LTCC low pass filter of claim 2, wherein: the fourth inductor (4) comprises a fourth inductor top metal layer (21), a fourth inductor bottom metal layer (23) and a plurality of fourth inductor middle metal layers, the fourth inductor middle metal layers are located between the fourth inductor top metal layer (21) and the fourth inductor bottom metal layer (23), and the fourth inductor top metal layer (21), the fourth inductor middle metal layer and the fourth inductor bottom metal layer (23) are sequentially connected in series;

the head end of the fourth inductance top metal layer (21) is electrically connected with the tail end of the first inductance bottom metal layer (20), and the tail end of the fourth inductance bottom metal layer (23) is electrically connected with the first capacitor (6).

6. The miniaturized LTCC low pass filter of claim 4, wherein: the fifth inductor (5) comprises a fifth inductor top metal layer (33), a fifth inductor bottom metal layer (35) and a plurality of fifth inductor middle metal layers, the fifth inductor middle metal layers are positioned between the fifth inductor top metal layer (33) and the fifth inductor bottom metal layer (35), and the fifth inductor top metal layer (33), the fifth inductor middle metal layer and the fifth inductor bottom metal layer are sequentially connected in series;

the fifth inductor top metal layer (33) is electrically connected with the tail end of the third inductor bottom metal layer (29), and the tail end of the fifth inductor bottom metal layer (35) is electrically connected with the second capacitor (7).

7. The miniaturized LTCC low pass filter according to any of the claims 1 to 6, wherein: the first capacitor (6) comprises a first capacitor first polar plate (48), a first capacitor second polar plate (54) and a first capacitor middle isolating plate (50), the first capacitor middle isolating plate (50) is positioned between the first capacitor first polar plate (48) and the first capacitor second polar plate (54), the first capacitor middle isolating plate (50) and the first capacitor first polar plate (48) are sequentially distributed above the ground reference layer (8);

the first capacitor first plate (48) is electrically connected with the first capacitor second plate (54) through a first capacitor inter-plate connecting column (52), the first capacitor middle isolating plate (50) is electrically connected with the ground reference layer (8), and the first capacitor first plate (48) is in adaptive electric connection with the fourth inductor (4).

8. The miniaturized LTCC low pass filter of claim 7, wherein: the second capacitor (7) comprises a second capacitor first polar plate (49), a second capacitor second polar plate (55) and a second capacitor middle isolating plate (51), the second capacitor middle isolating plate (51) is positioned between the second capacitor first polar plate (49) and the second capacitor second polar plate (55), the second capacitor middle isolating plate (51) and the second capacitor first polar plate (49) are sequentially distributed above the ground reference layer (8);

the first polar plate (49) of the second capacitor is electrically connected with the second polar plate (55) of the second capacitor through a connecting post (57) between the polar plates of the second capacitor, the middle isolating plate (51) of the second capacitor is electrically connected with the ground reference layer (8), and the first polar plate (49) of the second capacitor is electrically connected with the fifth inductor (5) in a matching mode.

9. The miniaturized LTCC low pass filter according to any of the claims 1 to 6, wherein: the first inductor (1) and the fourth inductor (4) have opposite or same spiral directions in the ceramic body.

10. The miniaturized LTCC low pass filter of claim 9, wherein: the spiral direction of the first inductor (1) and the spiral direction of the third inductor (3) are in mirror symmetry or rotational symmetry with respect to the second inductor (2).

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