A multi-layer filter

Abstract

The embodiment of the present invention provides a multilayer filter. By introducing open-circuit branches, N resonant units can generate more than N-2 zero points, and the out-of-band suppression is good. By adjusting the (electrical) length of the open-circuit branches, the position of the zero point can be flexibly controlled. Within the feasible range, the longer the line length, the weaker the low-end capacitive zero point (far away from the passband), the stronger the high-end inductive zero point (close to the passband), and vice versa. Through the connecting lines between the three-dimensional spiral inductors, on the one hand, strong coupling is achieved, and on the other hand, the difficulty of process implementation is reduced and the qualified rate of finished products is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of filters, and in particular to a multilayer filter. Background Art

[0002] Nowadays, whether it is military radar, electronic detection, electronic countermeasures, etc., or civilian mobile phone communications, television, and remote control, electronic signals need to be distributed and processed, which requires the use of an important microwave passive component - the filter.

[0003] With the rapid development of modern communication technology, small size, light weight, high performance, low cost and wide bandwidth have become the inevitable trend of the development of modern communication systems. As the core frequency selection device in the transceiver system, the filter is used to extract or filter out signals of different frequencies in the communication system. The traditional filter structure is large in size, and N resonant units can achieve N-2 out-of-band transmission zeros at most, which is not fully suppressed, limiting its use in communication systems. Therefore, the development of small, broadband and high-suppression filters has become an important technical task. Summary of the invention

[0004] The embodiment of the present invention provides a multi-layer filter, which is used to solve the problems of limited number of zero points, poor out-of-band suppression and weak coupling in the prior art.

[0005] An embodiment of the present invention provides a multilayer filter, comprising an input port and an output port, and a plurality of resonance units, wherein the resonance units comprise capacitors and three-dimensional spiral inductors; a filter channel is formed by coupling between the plurality of resonance units; and the input port and / or the output port are also connected to an open-circuit branch.

[0006] Preferably, the length of the open branch is adjustable.

[0007] Preferably, the open-circuit branch is led out and extended from a tap of the input port and / or the output port.

[0008] Preferably, a connecting line is provided between at least one group of adjacent or non-adjacent resonance units among the plurality of resonance units, and the connecting line is used to connect the adjacent or non-adjacent resonance units.

[0009] Preferably, the connecting line is led out from the three-dimensional spiral inductor of one resonance unit and connected to the three-dimensional spiral inductor of another resonance unit.

[0010] Preferably, the top and bottom layers of the multiple resonance units are grounded, and the resonance units include multiple layers of open-loop metal wires. Metallized vias are provided at both ends of the first layer of the metal wires, and the end of the upper metal wire is connected to the beginning of the lower metal wire through the metallized vias to form a spiral structural unit.

[0011] Preferably, the three-dimensional spiral inductor includes multiple layers of “∟”-shaped metal layers, and the endpoints of a metal arm of adjacent “∟”-shaped metal layers are connected to each other to form a closed “□”-shaped structure in the vertical direction, and the upper metal layer is higher than the lower metal layer, and the connection points of any “∟”-shaped metal layer with the upper and lower “∟”-shaped metal layers are located on different metal arms.

[0012] Preferably, the “∟”-shaped metal layer on the top layer is further provided with a bending arm, which is led out from an end point of a metal arm of the “∟”-shaped metal layer on the top layer, and the length of the bending arm is adjustable.

[0013] Preferably, the bending arm is parallel to a metal arm of an adjacent next “∟”-shaped metal layer.

[0014] The embodiment of the present invention provides a multilayer filter. By introducing open-circuit branches, N resonant units can generate more than N-2 zero points, and the out-of-band suppression is good; by adjusting the (electrical) length of the open-circuit branches, the position of the zero point can be flexibly controlled. Within the feasible range, the longer the line length, the weaker the low-end capacitive zero point (far away from the passband), the stronger the high-end inductive zero point (close to the passband), and vice versa; through the connecting lines between the three-dimensional spiral inductors, on the one hand, strong coupling is achieved, and on the other hand, the difficulty of process implementation is reduced and the qualified rate of finished products is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A perspective view of a multilayer filter provided by an embodiment of the present invention;

[0017] Figure 2 A top view of a multilayer filter provided by an embodiment of the present invention;

[0018] Figure 3 A side view of a multilayer filter in one direction provided by an embodiment of the present invention;

[0019] Figure 4 A side view of a multilayer filter provided by an embodiment of the present invention from another direction;

[0020] Figure 5 A circuit schematic diagram of a multilayer filter provided by an embodiment of the present invention;

[0021] Figure 6A perspective view of a single resonant unit in a multilayer filter provided by an embodiment of the present invention;

[0022] Figure 7 A full-wave three-dimensional electromagnetic simulation curve diagram of a multilayer filter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] With the rapid development of modern communication technology, small size, light weight, high performance, low cost and wide bandwidth have become the inevitable trend of the development of modern communication systems. As the core frequency selection device in the transceiver system, the filter plays the role of extracting or filtering signals of different frequencies in the communication system. The traditional filter structure is large in size, and N resonant units can achieve N-2 out-of-band transmission zeros at most, which is not fully suppressed, limiting its use in communication systems. Therefore, the development of small-volume, broadband and high-suppression filters has become an important technical task. The following will be explained and introduced through multiple embodiments.

[0027] Therefore, an embodiment of the present invention provides a multilayer filter. By introducing open-circuit branches, N resonant units can generate more than N-2 zero points, and the out-of-band suppression is good; by adjusting the (electrical) length of the open-circuit branches, the position of the zero point can be flexibly controlled. Within the feasible range, the longer the line length, the weaker the low-end capacitive zero point (far away from the passband), the stronger the high-end inductive zero point (close to the passband), and vice versa; through the connecting lines between the three-dimensional spiral inductors, on the one hand, strong coupling is achieved, and on the other hand, the difficulty of process implementation is reduced and the qualified rate of finished products is improved.

[0028] Figures 1 to 4 A multilayer filter provided in an embodiment of the present invention comprises an input port P1 and an output port P2, and a plurality of resonant units, wherein the resonant units comprise capacitors and three-dimensional spiral inductors; a filter channel is formed by coupling between the plurality of resonant units; the input port P1 and / or the output port P2 are further connected to open-circuit branches (TLO1, TLO2). In this embodiment, Figures 1 to 5 As shown in FIG. 1 , the transmission lines ( TL1 , TL2 ) of the input port P1 are connected to an open stub TLO1 , and the transmission lines ( TL4 , TL5 ) of the output port P2 are connected to an open stub TLO2 .

[0029] Figure 5 A circuit schematic diagram of a multilayer filter provided by an embodiment of the present invention, wherein Qn is a resonant circuit composed of Ln, Lnn and Cn, and Mmn represents the coupling between the resonant circuit m and the resonant circuit n.

[0030] In this embodiment, taking the LTCC filter as an example, the filter is composed of four resonant units (Q1-Q4), each of which includes a vertical three-dimensional spiral inductor (L1-L4, L11-44) and a capacitor (C1-C4). Multiple resonant units are spatially coupled to form a multi-layer LTCC filter structure. In this embodiment, Figure 5 As shown in the schematic diagram, by inserting open-circuit branches TLO1 / TLO2 at the input port P1 and / or the output port P2, source coupling / load coupling is introduced through this simple open-circuit branch, so that N resonant units can generate more than N-2 zero points, and the out-of-band suppression is good, such as Figure 7 As shown in FIG. 1 , the zero points generated by the open stub TLO1 and the open stub TLO2 are shown. The above structure is buried in a dielectric material.

[0031] Based on the above embodiments, there is also coupling between the open branch and the transmission line, such as Figure 5 As shown in the example, there is a coupling M between the open branch TLO1 and the transmission line TL2.

[0032] In other embodiments besides this embodiment, a multilayer filter with a PCB structure may also be used.

[0033] Based on the above embodiment, as a preferred implementation, the length of the above open-circuit branch is adjustable.

[0034] In this embodiment, by adjusting the (electrical) length of the open-circuit branch, the position of the zero point can be flexibly controlled. Within the feasible range, the longer the line length, the weaker the low-end capacitive zero point (far away from the passband), the stronger the high-end inductive zero point (close to the passband), and vice versa. In this embodiment, the open-circuit branch is an open-circuit transmission line, and the open-circuit transmission line can be set as an open-circuit transmission line with adjustable length to flexibly control the position of the zero point.

[0035] On the basis of the above embodiments, as a preferred implementation manner, the above open-circuit branches (TLO1, TLO2) are led out and extended from the taps of the input port P1 and / or the output port P2.

[0036] Based on the above embodiments, as a preferred implementation, a connecting line is provided between at least one group of adjacent or non-adjacent resonance units among the plurality of resonance units, and the connecting line is used to connect adjacent or non-adjacent resonance units.

[0037] In this embodiment, connecting lines are also provided between the three-dimensional spiral inductors to achieve strong coupling between adjacent or non-adjacent resonant units. The broadband filter requires strong coupling (the absolute value of the coupling coefficient is large), and strong coupling is achieved by connecting line TL3 between the three-dimensional spiral inductors (L2 and L3). By adding a suitable structure, on the one hand, strong coupling is achieved. On the other hand, due to the demand for miniaturization of the filter, in order to meet the coupling strength, it is often necessary to set the spacing between the resonant units very small, which increases the process difficulty. Therefore, by connecting lines to achieve strong coupling between adjacent or non-adjacent resonant units, the spacing between the corresponding two resonant units can be appropriately increased, the difficulty of process implementation can be reduced, and the qualified rate of finished products can be improved. Because the equipment generally has the minimum dimensional accuracy. The above structure is buried in the dielectric material.

[0038] Based on the above embodiments, as a preferred implementation manner, the connection line is led out from the three-dimensional spiral inductor of the adjacent resonance unit and connected to the three-dimensional spiral inductor of another adjacent resonance unit.

[0039] In this embodiment, for the sake of easy identification, after the corresponding three-dimensional spiral inductors (L1-L4) are connected, the connection point is connected to the ground terminal of the three-dimensional spiral inductor to form a section of inductance (L11-L44).

[0040] In this embodiment, based on actual needs, the connection line TL3 can be led out from the same layer of the corresponding two three-dimensional spiral inductors ( L2 and L3 ), or can be led out from different layers.

[0041] The top and bottom layers of the multiple resonance units are grounded, and the resonance units include multiple layers of open-loop metal wires. The first and second ends of the metal wires are also provided with metallized vias. The end of the upper metal wire is connected to the first end of the lower metal wire through the metallized vias to form a spiral structure unit.

[0042] Based on the above embodiments, as a preferred implementation, Figure 6 As shown in the figure, it is a perspective view of a single resonant unit. In this embodiment, taking 5 layers as an example, the three-dimensional spiral inductor includes multiple layers of "∟"-shaped metal layers (F1~F5), and the endpoints of a metal arm of adjacent "∟"-shaped metal layers are interconnected to form a closed "□"-shaped structure in the vertical direction, and the upper metal layer is higher than the lower metal layer, and the connection points of any "∟"-shaped metal layer and the upper and lower "∟"-shaped metal layers are located on different metal arms.

[0043] In this embodiment, the three-dimensional spiral inductor includes multiple stacked metal layers, wherein the metal layer is a "∟"-shaped metal layer. In this embodiment, the "∟"-shaped metal layer is integrally formed, and the two metal arms of the "∟"-shaped metal layer are at 90°; the endpoints of a metal arm of the adjacent "∟"-shaped metal layer are connected to form a closed "□"-shaped structure in the vertical direction, and the upper metal layer is higher than the lower metal layer, and the connection points of any "∟"-shaped metal layer and the upper and lower "∟"-shaped metal layers are located on different metal arms, and finally the multiple "∟"-shaped metal layers form a spiral structure. During the implementation process, a connector is provided between the corresponding upper and lower metal arms, and the connector has a set height, so that several layers of metal arms are stacked upward to finally form a three-dimensional spiral inductor with a vertical structure.

[0044] like Figure 6 As shown in the figure, one arm of the bottom "∟"-shaped metal layer is grounded through a connector, and the other arm is connected to the second "∟"-shaped metal layer through a connector. The other arm of the second layer continues to connect to the third "∟"-shaped metal layer through a connector, and this rule eventually forms a spiral structural unit in a rectangular winding manner.

[0045] On the basis of the above embodiments, the “∟”-shaped metal layer located on the top layer is further provided with a bending arm A', which is led out from an end point of a metal arm of the “∟”-shaped metal layer on the top layer, and the length of the bending arm A' is adjustable. In this embodiment, as another preferred implementation, the bending arm A' is parallel to a metal arm of the adjacent “∟”-shaped metal layer on the next layer. The length and extension direction of the bending arm A' are adjustable, and it is not connected to another metal arm of the “∟”-shaped metal layer on this layer to avoid forming a loop structure.

[0046] A multilayer filter provided by an embodiment of the present invention can generate more than N-2 zero points by introducing open-circuit branches, and has good out-of-band suppression; by adjusting the (electrical) length of the non-resonant structure, the position of the zero point can be flexibly controlled. Within the feasible range, the longer the line length, the weaker the low-end capacitive zero point (far away from the passband), the stronger the high-end inductive zero point (close to the passband), and vice versa; by connecting the lines between the three-dimensional spiral inductors, on the one hand, broadband coupling is achieved, and on the other hand, the difficulty of process implementation is reduced and the qualified rate of finished products is improved.

[0047] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multilayer filter, characterized in that: The invention comprises an input port and an output port, and a plurality of resonance units, wherein the resonance units comprise a capacitor and a three-dimensional spiral inductor; a filter channel is formed by coupling between the plurality of resonance units; the input port and / or the output port are connected with a transmission line, the transmission line is also connected with an open-circuit branch, coupling exists between the open-circuit branch and the transmission line, and a connecting line is provided between at least one group of adjacent or non-adjacent resonance units among the plurality of resonance units, and the connecting line is used to connect adjacent or non-adjacent resonance units.

2. The multilayer filter according to claim 1, characterized in that The length of the open branch is adjustable.

3. The multilayer filter according to claim 1, characterized in that The open-circuit branch is led out from a tap of the input port and / or the output port and extends.

4. The multilayer filter according to claim 1, characterized in that: The connecting line is led out from the three-dimensional spiral inductor of one resonance unit and connected to the three-dimensional spiral inductor of another resonance unit.

5. The multilayer filter according to claim 1, characterized in that: The top and bottom layers of the multiple resonance units are grounded, and the resonance units include multiple layers of open-loop metal wires. Metallized vias are provided at both ends of the metal wires. The end of the upper metal wire is connected to the beginning of the lower metal wire through the metallized vias to form a spiral structure unit.

6. The multilayer filter according to claim 1, characterized in that: The three-dimensional spiral inductor includes multiple layers of "∟"-shaped metal layers, and the endpoints of a metal arm of adjacent "∟"-shaped metal layers are connected to each other to form a closed "□"-shaped structure in the vertical direction, and the upper metal layer is higher than the lower metal layer, and the connection points of any "∟"-shaped metal layer with the upper and lower "∟"-shaped metal layers are located on different metal arms.

7. The multilayer filter according to claim 6, characterized in that: The "∟"-shaped metal layer located on the top layer is also provided with a bending arm, which is led out from an end point of a metal arm of the "∟"-shaped metal layer on the top layer, and the length of the bending arm is adjustable.

8. The multilayer filter according to claim 7, characterized in that: The bending arm is parallel to a metal arm of an adjacent "∟"-shaped metal layer.

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