CN214429521U - Filter circuit, filter and multiplexer - Google Patents

Abstract

The utility model discloses a filter circuit, wave filter and multiplexer. The filter circuit comprises at least four conductive layers which are stacked; at least two conductive layers are electrically connected to form an inductor and used for forming a capacitor; the capacitor is located between the inductors along the lamination direction of the conductive layers. On the basis of ensuring the capacitance value of the capacitor, the sum of the horizontal area occupied by the inductor and the horizontal area occupied by the capacitor is reduced, and the horizontal area occupied by the filter circuit is reduced. When the thickness of the filter circuit is unchanged, the size of the filter circuit can be reduced, the occupied space of the filter circuit is further reduced, and the miniaturization design of devices such as a filter, a multiplexer and the like formed by the filter circuit is facilitated. Meanwhile, the overall performance of the filter circuit can be ensured, and the overall performance of the filter circuit can be improved under the condition that the filter circuit occupies the same horizontal area.

Description

Filter circuit, filter and multiplexer

Technical Field

The embodiment of the utility model provides a relate to signal processing technology field, especially relate to a filter circuit, wave filter and multiplexer.

Background

Filter circuits are widely used in integrated circuits, for example, in filters, multiplexers, and the like of integrated circuits. The filter circuit often encounters a structure in which an inductor and a capacitor are connected in parallel for filtering. When different metal layers are adopted to respectively form the inductor and the capacitor and are connected in parallel, the filter circuit has a larger volume, so that the miniaturization design of the filter circuit is realized when the performance of the filter circuit is not ensured.

SUMMERY OF THE UTILITY MODEL

The utility model provides a filter circuit, wave filter and multiplexer to the realization reduces filter circuit's volume that occupies on the basis of guaranteeing the filter circuit performance, helps filter circuit's miniaturized design.

In a first aspect, an embodiment of the present invention provides a filter circuit, including at least four stacked conductive layers;

at least two conducting layers are electrically connected and used for forming an inductor, and at least two conducting layers are used for forming a capacitor; the capacitor is located between the inductors along the lamination direction of the conducting layers.

Optionally, along the stacking direction of the conductive layers, a vertical projection of the conductive layer for forming the inductor covers a vertical projection of the conductive layer for forming the capacitor.

Optionally, the filter circuit further includes an insulating layer disposed between different conductive layers; a first through hole is formed in the insulating layer and filled with a conductive material;

the conductive layer used for forming the inductor comprises a first connecting part, the vertical projection of the first connecting part is not overlapped with the vertical projection of the conductive layer used for forming the capacitor along the stacking direction of the conductive layers, the first connecting part is overlapped with the vertical projection of the first through hole, and the first connecting parts of at least two conductive layers used for forming the inductor are electrically connected through the conductive materials in the first through hole.

Optionally, a second through hole and a third through hole are further formed in the insulating layer, and the conductive material is filled in the second through hole and the third through hole;

the conducting layer used for forming the inductor comprises a first conducting layer and a second conducting layer which are provided with inductor ports, the conducting layer used for forming the capacitor comprises a third conducting layer and a fourth conducting layer which are provided with capacitor ports, the first conducting layer is electrically connected with the third conducting layer through the second through hole, and the second conducting layer is electrically connected with the fourth conducting layer through the third through hole.

Optionally, the conductive layer is a metal layer.

Optionally, in the stacking direction of the conductive layers, the filter circuit includes four stacked first metal layers, second metal layers, third metal layers, and fourth metal layers;

the first metal layer and the fourth metal layer are electrically connected to form the inductor, the second metal layer is used as a first polar plate of the capacitor, the third metal layer is used as a second polar plate of the capacitor, and the second metal layer and the third metal layer are used for forming the capacitor.

Optionally, the first metal layer and the fourth metal layer are electrically connected through the first via, the first metal layer is electrically connected with the third metal layer through the second via, and the fourth metal layer is electrically connected with the second metal layer through the third via; or, the first metal layer is electrically connected with the second metal layer through the second through hole, and the fourth metal layer is electrically connected with the third metal layer through the third through hole.

In a second aspect, the embodiment of the present invention further provides a filter, which includes the filter circuit provided in any of the embodiments of the first aspect.

In a third aspect, the embodiment of the present invention further provides a multiplexer, which includes the filter circuit provided in any embodiment of the first aspect.

Optionally, the multiplexer includes a first terminal, at least two second terminals, and at least two of the filter circuits;

each filter circuit is connected in series between the first end and any second end of the multiplexer.

According to the technical scheme of the embodiment of the utility model, at least four layers of conducting layers are arranged in a stacked manner; at least two conductive layers are electrically connected to form an inductor and used for forming a capacitor; the capacitor is located between the inductors along the lamination direction of the conductive layers. On the basis that the overlapping area of the conducting layer for forming the capacitor in the stacking direction of the conducting layer is not reduced and the capacitance value of the capacitor is guaranteed, the horizontal area occupied by the conducting layer for forming the capacitor and the horizontal area occupied by the conducting layer for forming the inductor are at least partially overlapped, so that the sum of the horizontal area occupied by the inductor and the horizontal area occupied by the capacitor can be reduced, and the horizontal area occupied by the filter circuit is reduced. When the thickness of the filter circuit is unchanged, the size of the filter circuit can be reduced, the occupied space of the filter circuit is further reduced, and the miniaturization design of devices such as a filter, a multiplexer and the like formed by the filter circuit is facilitated. Meanwhile, the structures of the inductor and the capacitor in the filter circuit can be kept unchanged, and the inductance value of the inductor and the capacitance value of the capacitor can be kept unchanged, so that the overall performance of the filter circuit can be ensured, and the filter circuit is favorable for improving the overall performance of the filter circuit under the condition that the filter circuit occupies the same horizontal area.

Drawings

Fig. 1 is a schematic diagram of a three-dimensional structure of a filter circuit provided in the prior art;

fig. 2 is a schematic diagram of a top view structure of a filter circuit provided in the prior art;

fig. 3 is a schematic diagram of a three-dimensional structure of a filter circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a top view structure of a filter circuit according to an embodiment of the present invention;

fig. 5 is a schematic filtering diagram of a filtering circuit provided in the prior art and a filtering circuit provided in the present application according to an embodiment of the present invention;

fig. 6 is a schematic three-dimensional structure diagram of another filter circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a multiplexer according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic diagram of a three-dimensional structure of a filter circuit provided in the prior art. As shown in fig. 1, the filter circuit includes an inductor L ' and a capacitor C ', the inductor L ' includes a first inductor L1 ' and a second inductor L2 ' connected in series, the first inductor L1 ' and the second inductor L2 ' are located on different metal layers, and an insulating layer (not shown in fig. 1) is disposed between the different metal layers. And a first connection hole V1 'is formed in the insulating layer, and the first connection hole V1' is filled with a conductive material. One end of the first inductor L1 ' is electrically connected to the first end of the second inductor L2 ' through the first connection hole V1 '. The capacitor C ' includes a first plate C1 ' and a second plate C2 ', the first plate C1 ' and the second plate C2 ' being located at different metal layers. A dielectric layer (not shown in fig. 1) is disposed between the first plate C1 'and the second plate C2'. The dielectric layer is provided with a second connection hole V2 'and a third connection hole V3', and the second connection hole V2 'and the third connection hole V3' are filled with a conductive material. The first polar plate C1 'is connected to the other end of the first inductor L1' through the second connection hole V2 ', and the second polar plate C2' is connected to the other end of the second inductor L2 'through the third connection hole V3', so that the parallel connection between the inductor L 'and the capacitor C' is realized. Fig. 2 is a schematic diagram of a top view structure of a filter circuit provided in the prior art. As shown in fig. 1 and fig. 2, the vertical projection area of the filter circuit in the horizontal plane includes a vertical projection area a of the capacitor C 'in the horizontal plane and a vertical projection area b of the inductor L' in the horizontal plane. At this time, the length l 'of the filter circuit is 0.7mm, the width b' is 0.65mm, and the horizontal area occupied by the filter circuit is 0.455mm². When the thickness of the filter circuit is constant, the capacitor C' is on the horizontal planeThe larger the sum of the vertical projection area a and the vertical projection area b of the inductor L' on the horizontal plane is, the larger the occupied space of the filter circuit is, that is, the larger the size of the filter circuit is, which is not beneficial to realizing the miniaturization design of the filter circuit while ensuring the performance of the filter circuit.

To the technical problem, the embodiment of the utility model provides a filter circuit is provided. Fig. 3 is a schematic diagram of a three-dimensional structure of a filter circuit according to an embodiment of the present invention. As shown in fig. 3, the filter circuit includes at least four conductive layers M stacked one on another; at least two conducting layers M are electrically connected and used for forming an inductor L, and at least two conducting layers M are used for forming a capacitor C; the capacitor C is located between the inductors L along the stacking direction X of the conductive layers.

Specifically, at least four conductive layers M in the filter circuit are stacked, and when the at least two conductive layers M are electrically connected to form the inductor L, the at least two conductive layers M may be electrically connected in sequence along the stacking direction X of the conductive layers. The inductor L can form a spiral structure with at least two conductive layers M, and the inductance value of the inductor L can be increased on the basis that the horizontal area occupied by the inductor L is not additionally increased. When two-layer at least conducting layer M is used for forming electric capacity C, every conducting layer M is as electric capacity C's capacitance polar plate for electric capacity C can be for the structure including the at least two-layer capacitance polar plate of range upon range of setting, can realize increasing electric capacity C's capacitance value on the basis that does not additionally increase electric capacity C and occupy the horizontal area. Moreover, the capacitor C is located between the inductors L, and on the basis that the overlapping area of the conductive layer M for forming the capacitor C in the stacking direction X of the conductive layers is not reduced, and the capacitance value of the capacitor C is ensured, the horizontal area occupied by the conductive layer M for forming the capacitor C and the horizontal area occupied by the conductive layer M for forming the inductor L are at least partially overlapped, so that the sum of the horizontal area occupied by the inductor L and the horizontal area occupied by the capacitor C can be reduced, and the horizontal area occupied by the filter circuit is reduced. When the thickness of the filter circuit is unchanged, the size of the filter circuit can be reduced, the occupied space of the filter circuit is further reduced, and the miniaturization design of devices such as a filter, a multiplexer and the like formed by the filter circuit is facilitated. Meanwhile, the structures of the inductor L and the capacitor C in the filter circuit can be kept unchanged, and the inductance value of the inductor L and the capacitance value of the capacitor C can be kept unchanged, so that the overall performance of the filter circuit can be ensured, and the filter circuit is favorable for improving the overall performance of the filter circuit under the condition that the filter circuit occupies the same horizontal area.

Exemplarily, as shown in fig. 3, fig. 3 shows that the filter circuit includes four conductive layers M, a first conductive layer M1, a second conductive layer M2, a third conductive layer M3 and a fourth conductive layer M4, which are stacked. The first conductive layer M1 and the fourth conductive layer M4 are electrically connected to form a two-layer spiral inductor L, and the second conductive layer M2 and the third conductive layer M3 respectively serve as two plates of a capacitor C. And the second conducting layer M2 is connected with the fourth conducting layer M4, and the third conducting layer M3 is connected with the first conducting layer M1, so that the parallel connection of the capacitor C and the inductor L is realized. Different from the filter circuit provided by the prior art (as shown in fig. 1), the conductive layer M for forming the capacitor C and the conductive layer M for forming the inductor L are stacked, so that the horizontal area occupied by the conductive layer M for forming the capacitor C and the horizontal area occupied by the conductive layer M for forming the inductor L are overlapped, and the horizontal area occupied by the filter circuit is reduced.

Fig. 4 is a schematic diagram of a top view structure of a filter circuit according to an embodiment of the present invention. As shown in fig. 4, when the capacitor C is located between the inductors L, the horizontal area occupied by the conductive layer M for forming the capacitor C overlaps with the horizontal area occupied by the conductive layer M for forming the inductors L, so that the horizontal area occupied by the filter circuit can be reduced. Referring to fig. 4, the length l of the filter circuit is 0.57mm, the width b is 0.65mm, and the horizontal area occupied by the filter circuit is 0.371mm². Fig. 5 is a schematic filtering diagram of a filter circuit provided by the prior art and a filter circuit provided by the present application. Wherein the abscissa is frequency and the ordinate is output amplitude. Curve 1 is a schematic curve of the center frequency of the filter circuit provided in the prior art, curve 2 is a schematic curve of the center frequency of the filter circuit provided in the present application, curve 3 is a schematic curve of the bandwidth within-3 dB of the filter circuit provided in the prior art, and curve 2 is a schematic curve of the bandwidth within-3 dB of the filter circuit provided in the present application. As shown in fig. 5, of curves 1 and 2The center frequencies are approximately equal and the bandwidths within-3 dB in curve 3 and curve 4 are approximately equal, so that the figures of merit of the filter circuit provided in the prior art and the filter circuit provided in the present application are approximately equal. Wherein the quality factor of the filter circuit is the ratio of the center frequency of the filter circuit to the-3 dB bandwidth, and is used for representing the capability of the filter circuit to separate adjacent frequency components. The higher the quality factor, the better the performance of the filter circuit. Therefore, when the horizontal area occupied by the conducting layer M for forming the capacitor C in the filter circuit is arranged and the horizontal area occupied by the conducting layer M for forming the inductor L is at least partially overlapped, the sum of the horizontal area occupied by the inductor L and the horizontal area occupied by the capacitor C can be reduced, the horizontal area occupied by the filter circuit is reduced, and the size of the filter circuit is further reduced. Meanwhile, the overall performance of the filter circuit can be ensured, and the overall performance of the filter circuit can be improved under the condition that the filter circuit occupies the same horizontal area. In addition, table 1 is the embodiment of the utility model provides a filter circuit that prior art provided and the filter circuit's that this application provided area occupied and performance comparison table. As shown in fig. 1 and 3, in the case that the position and shape of the conductive layer for forming the capacitor of the filter circuit provided in the prior art are different, the capacitance values are equal, and other conditions are the same as those of the filter circuit provided in the present application, as shown in table 1, the filter circuit provided in the prior art as a control group has a length of 0.7mm, a width of 0.65mm, and an occupied horizontal area of 0.455mm²And the figure of merit is 41. The application provides a filter circuit is as experimental group, and is 0.57mm long, and wide being 0.65mm, the horizontal area who occupies is 0.371mm²And the figure of merit is 39. Therefore, the horizontal area occupied by the filter circuit provided by the application is reduced compared with the horizontal area occupied by the filter circuit provided by the prior art, so that the size of the filter circuit can be reduced, and the miniaturization design of devices such as a filter, a multiplexer and the like formed by the filter circuit is facilitated. Meanwhile, the quality factor of the filter circuit provided by the application can be ensured, the overall performance of the filter circuit is ensured, and the overall performance of the filter circuit is improved under the condition that the filter circuit occupies the same horizontal area.

Table 1 the embodiment of the present invention provides a filter circuit provided by the prior art and a filter circuit provided by the present application, and a performance comparison table

	Long (mm)	Width (mm)	Horizontal area (mm)2)	Q value
					Control group	0.7	0.65	0.455	41
Experimental group	0.57	0.65	0.371	39

It should be noted that fig. 3 only exemplarily shows that the filter circuit includes four conductive layers M, and in other embodiments, the filter circuit may further include more than four conductive layers M. When the conductive layer M is more than four layers, the number of the conductive layer M for forming the inductor L and the conductive layer M for forming the capacitor C may be set according to the requirements of the filter circuit. Illustratively, the filter circuit may be provided to include 6 conductive layers M arranged in a stack. Along the stacking direction X of the conducting layers, the first conducting layer M and the last conducting layer M are electrically connected to form an inductor L, and the other middle conducting layers M form a capacitor C. In addition, when forming the filter circuit, the filter circuit may be implemented by a Low Temperature Co-fired Ceramic (LTCC) process, a Surface Mounted Device (SMD) process, and an Integrated Passive Device (IPD) process.

With continued reference to fig. 3 and 4, the vertical projection of the conductive layer M for forming the inductance L covers the vertical projection of the conductive layer M for forming the capacitance C along the stacking direction X of the conductive layers.

Specifically, when the vertical projection of the conductive layer M for forming the inductor L covers the vertical projection of the conductive layer M for forming the capacitor C, the horizontal area occupied by the conductive layer M for forming the capacitor C can be completely located within the horizontal area occupied by the conductive layer M for forming the inductor L, so that the sum of the horizontal area occupied by the capacitor C and the horizontal area occupied by the inductor L can be minimized, and further the horizontal area occupied by the filter circuit is minimized. The occupied space of the filter circuit is reduced, and the miniaturization design of devices such as a filter, a multiplexer and the like formed by the filter circuit is facilitated. Meanwhile, the overall performance of the filter circuit can be ensured, and the overall performance of the filter circuit can be improved under the condition that the filter circuit occupies the same horizontal area.

Fig. 6 is a schematic three-dimensional structure diagram of another filter circuit according to an embodiment of the present invention. As shown in fig. 6, the filter circuit further includes an insulating layer disposed between the different conductive layers M; a first through hole V1 is formed in the insulating layer, and a conductive material is filled in the first through hole V1; the conductive layer M for forming the inductance L includes a first connection portion L1, a vertical projection of the first connection portion L1 does not overlap a vertical projection of the conductive layer M for forming the capacitance C along the lamination direction X of the conductive layers, and overlaps a vertical projection of the first via hole V1, and the first connection portions L1 of the at least two conductive layers M for forming the inductance L are electrically connected through the conductive material in the first via holes V1.

Specifically, an insulating layer (not shown in fig. 6) is disposed between the different conductive layers M, for example, a dielectric material may be filled between the different conductive layers M, so as to form the insulating layer, and short circuit between the different conductive layers M may be avoided. The vertical projection of the first connection portion L1 is not overlapped with the vertical projection of the conductive layer M for forming the capacitor C, that is, along the stacking direction X of the conductive layers, only an insulating layer is arranged between at least two conductive layers M for forming the inductor L, and then the first through hole V1 is arranged on the insulating layer, so that the first connection portion L1 of at least two conductive layers M for forming the inductor L can be directly and electrically connected through the conductive material in the first through hole V1, and abnormal connection of the filter circuit caused by short circuit between the conductive layer in the first through hole V1 and the capacitor C arranged directly at the inductor L is avoided.

With continued reference to fig. 6, the insulating layer is further provided with a second through hole V2 and a third through hole V3, and the second through hole V2 and the third through hole V3 are filled with a conductive material; the conductive layer M for forming the inductor L includes a first conductive layer M11 and a second conductive layer M12 provided with an inductor port, the conductive layer M for forming the capacitor C includes a third conductive layer M13 and a fourth conductive layer M14 provided with a capacitor port, the first conductive layer M11 is electrically connected to the third conductive layer M13 through a second via V2, and the second conductive layer M12 is electrically connected to the fourth conductive layer M14 through a third via V3.

Specifically, fig. 6 exemplarily shows that the conductive layer M for forming the inductor L includes two layers, the first connection portion L1 of the first conductive layer M11 and the first connection portion L1 of the second conductive layer M12 are electrically connected through the first via hole V1, and the first conductive layer M11 and the second conductive layer M12 further include second connection portions L2, which respectively serve as two ports of the inductor L. In addition, fig. 6 exemplarily shows that the conductive layer M for forming the capacitor C includes two layers, and the third conductive layer M13 and the fourth conductive layer M14 serve as a first plate and a second plate of the capacitor C, respectively. The second connecting portion L2 of the first conductive layer M11 is electrically connected with the third conductive layer M13 through the second through hole V2, and the second connecting portion L2 of the second conductive layer M12 is electrically connected with the fourth conductive layer M14 through the third through hole V3, so that two ports of the inductor L are respectively connected with two plates of the capacitor C, and the inductor L and the capacitor C are connected in parallel.

Fig. 6 exemplarily shows that the conductive layer M for forming the inductor L is two layers, and the conductive layer M for forming the capacitor C is two layers. In other embodiments, when the conductive layer M for forming the inductor L is greater than two layers, and/or the conductive layer M for forming the capacitor C is greater than two layers, only the conductive layer M at which the port of the inductor L is located and the conductive layer M at which the port of the capacitor C is located are electrically connected, so that the parallel connection of the inductor L and the capacitor C is realized.

On the basis of the technical schemes, the conducting layer is a metal layer.

Specifically, the metal layer has strong conductive property, the requirement for forming an inductor and a capacitor can be met by arranging the thinner metal layer, and meanwhile, the size of a filter circuit formed by the capacitor and the inductor formed by the metal layer is smaller. Illustratively, the metal layer may be 8um thick.

Illustratively, the filter circuit includes, in a lamination direction of the conductive layers, four layers of a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer which are laminated; the first metal layer and the fourth metal layer are electrically connected to form an inductor, the second metal layer is used as a first pole plate of a capacitor, the third metal layer is used as a second pole plate of the capacitor, and the second metal layer and the third metal layer are used for forming the capacitor.

Specifically, the first metal layer and the fourth metal layer are electrically connected to form an inductor, and the first metal layer and the fourth metal layer are stacked, so that the inductance value of the inductor can be increased on the basis of not additionally increasing the horizontal area occupied by the inductor. In addition, the second metal layer and the third metal layer are respectively used as a first plate and a second plate of the capacitor and used for forming the capacitor. And second metal level and third metal level and first metal level and fourth metal level range upon range of setting, consequently along the range upon range of direction of metal level, the electric capacity that second metal level and third metal level formed sets up between inductance L, the horizontal area that the electric capacity occupies overlaps with the horizontal area that the inductance occupies to the horizontal area that can reduce filter circuit and occupy, and then reduced filter circuit's occupation space, be favorable to adopting the miniaturized design of devices such as filter and multiplexer that filter circuit formed. Meanwhile, the overall performance of the filter circuit can be ensured, and the overall performance of the filter circuit can be improved under the condition that the filter circuit occupies the same horizontal area.

Illustratively, the first metal layer and the fourth metal layer are electrically connected through a first via, the first metal layer is electrically connected with the third metal layer through a second via, and the fourth metal layer is electrically connected with the second metal layer through a third via; or the first metal layer is electrically connected with the second metal layer through the second through hole, and the fourth metal layer is electrically connected with the third metal layer through the third through hole.

Specifically, the first metal layer and the fourth metal layer may be electrically connected through the first via, the first metal layer is electrically connected through the second via and the third metal layer, and the fourth metal layer is electrically connected through the third via and the second metal layer, so that parallel connection between the inductor and the capacitor may be achieved. Or, the first metal layer is electrically connected with the second metal layer through the second through hole, and the fourth metal layer is electrically connected with the third metal layer through the third through hole, so that the parallel connection of the inductor and the capacitor can be realized.

The embodiment of the utility model provides a still provide a wave filter. This wave filter includes the utility model discloses the arbitrary filter circuit who provides.

Specifically, the filter includes at least the utility model discloses the filter circuit that the arbitrary embodiment provided, consequently has filter circuit's beneficial effect, and it is no longer repeated here. In addition, the filter can also comprise other filter circuits for improving the filtering function of the filter. Exemplarily, other filter circuit can be a low pass filter circuit, a high pass filter circuit or a band pass filter circuit, and the embodiment of the present invention is not limited.

The embodiment of the utility model provides a still provide a multiplexer. Fig. 7 is a schematic structural diagram of a multiplexer according to an embodiment of the present invention. As shown in fig. 7, the multiplexer includes a filter circuit 210 according to any embodiment of the present invention.

With continued reference to fig. 7, the multiplexer includes a first terminal IN, at least two second terminals, and at least two filter circuits 210; each of the filter circuits 210 is connected IN series between the first terminal IN and a second terminal of the multiplexer.

Specifically, fig. 7 exemplarily shows that the multiplexer includes a first terminal IN and n second terminals OUT1 and OUT2 … … OUTn, respectively. Each of the filter circuits 210 is connected IN series between the first terminal IN and a second terminal. For example, the first filter circuit 210 is connected IN series between the first terminal IN and the first second terminal OUT1, the second filter circuit 210 is connected IN series between the first terminal IN and the first second terminal OUT2 … …, and so on. Because the multiplexer has the filter circuit 210 that the utility model discloses arbitrary embodiment provided, consequently have filter circuit's beneficial effect, no longer describe here.

It should be noted that, the multiplexer can also include other filter circuit, and other filter circuit establish ties between first end IN and a second end, and other filter circuit can be low pass filter circuit, high pass filter circuit or band pass filter circuit, the embodiment of the utility model provides a do not restrict.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (10)

1. A filter circuit is characterized by comprising at least four conductive layers which are arranged in a stacking mode;

at least two conducting layers are electrically connected and used for forming an inductor, and at least two conducting layers are used for forming a capacitor; the capacitor is located between the inductors along the lamination direction of the conducting layers.

2. The filter circuit according to claim 1, wherein a vertical projection of the conductive layer on which the inductor is located covers a vertical projection of the conductive layer on which the capacitor is located along a stacking direction of the conductive layers.

3. The filter circuit of claim 2, further comprising an insulating layer disposed between different ones of the conductive layers; a first through hole is formed in the insulating layer and filled with a conductive material;

the conductive layer used for forming the inductor comprises a first connecting part, the vertical projection of the first connecting part is not overlapped with the vertical projection of the conductive layer used for forming the capacitor along the stacking direction of the conductive layers, the first connecting part is overlapped with the vertical projection of the first through hole, and the first connecting parts of at least two conductive layers used for forming the inductor are electrically connected through the conductive materials in the first through hole.

4. The filter circuit according to claim 3, wherein a second through hole and a third through hole are further formed in the insulating layer, and the conductive material is filled in the second through hole and the third through hole;

the conducting layer used for forming the inductor comprises a first conducting layer and a second conducting layer which are provided with inductor ports, the conducting layer used for forming the capacitor comprises a third conducting layer and a fourth conducting layer which are provided with capacitor ports, the first conducting layer is electrically connected with the third conducting layer through the second through hole, and the second conducting layer is electrically connected with the fourth conducting layer through the third through hole.

5. The filter circuit of claim 4, wherein the conductive layer is a metal layer.

6. The filter circuit according to claim 5, wherein the filter circuit includes, in a lamination direction of the conductive layers, four layers of a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer that are laminated;

the first metal layer and the fourth metal layer are electrically connected to form the inductor, the second metal layer is used as a first polar plate of the capacitor, the third metal layer is used as a second polar plate of the capacitor, and the second metal layer and the third metal layer are used for forming the capacitor.

7. The filter circuit of claim 6, wherein the first metal layer and the fourth metal layer are electrically connected by the first via, the first metal layer is electrically connected to the third metal layer by the second via, and the fourth metal layer is electrically connected to the second metal layer by the third via; or, the first metal layer is electrically connected with the second metal layer through the second through hole, and the fourth metal layer is electrically connected with the third metal layer through the third through hole.

8. A filter comprising a filter circuit as claimed in any one of claims 1 to 7.

9. A multiplexer, comprising the filter circuit of any one of claims 1 to 7.

10. The multiplexer of claim 9, wherein the multiplexer comprises a first terminal, at least two second terminals, and at least two of the filter circuits;

each filter circuit is connected in series between the first end and any second end of the multiplexer.

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