Common mode filters and terminal devices

Abstract

This application relates to the field of filter technology and provides a common mode filter and a terminal device. The common mode filter includes a first winding and a second winding. A portion of the first winding and a portion of the second winding are formed by rotating them around the same axis in a first coil layer. Another portion of the first winding and another portion of the second winding are formed by rotating them around another same axis in a second coil layer stacked with the first coil layer. In the first coil layer and the second coil layer, one turn of the second winding is located between every two adjacent turns of the first winding. In the first coil layer, the first winding and the second winding are arranged so that the outer turns surround the inner turns of the winding, and the second winding is located on the outer turn relative to the first winding. In the second coil layer, the first and second windings are arranged so as to surround each other from the inner turn to the outer turn, and the second winding is located on the inner turn of the first winding. The surrounding direction of the first and second windings in the second coil layer is the same as the surrounding direction of the first and second windings in the first coil layer.

Description

[Technical field]

[0001] This application relates to the field of filter technology, and in particular to common mode filters and terminal devices. [Background technology]

[0002] In mobile communication terminal devices, the Mobile Device Industrial Processor Interface is used as a data transmission standard to connect processors and multimedia devices (displays, cameras, etc.). ( The D-PHY and C-PHY protocols for MIPI (Multi-Integrated Physics Instrumentation) are widely used in the industry.

[0003] To suppress interference with the high-speed signals transmitted to the display and camera, these terminal devices are equipped with common-mode filters. ( CMF) and the 5th generation mobile communication technology ( With the development of 5G, antennas with wider frequency bands are being introduced. In 5G high-frequency high-speed application scenarios, the overlap between the power spectrum of high-speed signals and antenna frequency bands will be wider. As the noise frequency increases, the mode conversion of common mode filters will cause an increasing impact. More common mode noise will be converted into differential mode noise and superimposed on the differential signal. This will greatly deteriorate the transmission quality of high-speed signals. For example, the mode conversion of common mode filters will cause large noise noise on the high-speed interface of antennas coupled to structures such as displays, cameras, etc. The current of , on high speed signals through mode conversion To Overlay As a result, Too many bit errors but occurrence do This can cause interference such as display distortion or streaking on the camera, display, and other modules.

[0004] In addition, since the conventional common mode filter has a low suppression bandwidth (also called the suppression center frequency), the suppression effect against common mode noise in the 5G high frequency band is poor, and the anti-interference effect on each interface circuit in the terminal device in the 5G frequency band is not significant.

[0005] In addition, as the transmission speed increases, the insertion loss on high-frequency signals caused by traditional common-mode filters becomes larger, which greatly limits the improvement of link bandwidth and affects high-speed signal quality. Summary of the Invention

[0006] The present invention provides a common mode filter and a terminal device, which mainly provides a common mode filter which can reduce mode conversion loss, reduce high frequency insertion loss and enlarge common mode suppression bandwidth.

[0007] This application uses the following technical solutions:

[0008] According to a first aspect, the application provides a common mode filter. The common mode filter includes a first winding and a second winding. A part of the first winding and a part of the second winding are formed in a first coil layer by rotating around the same axis. Another part of the first winding and another part of the second winding are formed in a second coil layer stacked with the first coil layer by rotating around another same axis. In the first coil layer and the second coil layer, one turn of the second winding is present between each two adjacent turns of the first winding. In the first coil layer, the first winding and the second winding are arranged so as to surround the winding of the inner turn from the outer turn, and the second winding is located on the outer turn with respect to the first winding. In the second coil layer, the first winding and the second winding are arranged so as to surround the winding of the inner turn from the inner turn, and the second winding is located on the inner turn with respect to the first winding. The surrounding direction of the first winding and the second winding in the second coil layer is the same as the surrounding direction of the first winding and the second winding in the first coil layer.

[0009] According to the common mode filter provided in this application, the first winding and the second winding in each coil layer rotate around the same axis, and two adjacent turns of the first winding are spaced apart by one turn of the second winding. Thus, in any coil layer, the first winding and the second winding are spaced apart along the radial direction of the spiral. arrangement As a result, the common-mode coupling inductance between the first winding and the second winding is strengthened, and the balance of the common-mode magnetic coupling between the first winding and the second winding is improved.

[0010] Additionally, in the first coil layer, the first winding and the second winding are arranged so as to surround from the outer turn to the inner turn, and the second winding is located on the outer turn relative to the first winding. In the second coil layer, the first winding and the second winding are arranged so as to surround from the inner turn to the outer turn, and the second winding is located on the inner turn relative to the first winding. The surrounding direction of the first winding and the second winding in the second coil layer is the same as the surrounding direction of the first winding and the second winding in the first coil layer. In this way, the sum of the lengths of the first windings in all coil layers is essentially equal to the sum of the lengths of the second windings in all coil layers. This eliminates the latency difference in signal transmission between the first winding and the second winding and reduces the conversion between differential mode signals and common mode signals, thereby reducing the mode conversion loss of the common mode filter, reducing the high-frequency insertion loss, and widening the common-mode suppression bandwidth.

[0011] In a possible implementation of the first aspect, the first winding and the second winding are arranged in a staggered manner in a direction perpendicular to the stacking direction of the first coil layer and the second coil layer. arrangement When the common mode filter is connected in series, the parasitic distributed capacitance between two adjacent coil layers can be reduced, thereby further improving the suppression bandwidth of the common mode filter and reducing the mode conversion loss.

[0012] In a possible implementation of the first aspect, in any one of the first coil layer and the second coil layer, each two adjacent turns of the first winding are the first turn of the first winding and the second turn of the first winding, respectively. The turn of the second winding located between the first turn of the first winding and the second turn of the first winding is the middle turn of the second winding. The spacing between the middle turn of the second winding and the first turn of the first winding is smaller than the spacing between the middle turn of the second winding and the second turn of the first winding. In this way, the amount of magnetic coupling between the middle turn of the second winding and the first turn of the first winding is not significantly disturbed by the second turn of the first winding, improving the balance of the common mode filter.

[0013] In a possible implementation of the first aspect, the first coil layer and the second coil layer are disposed in and spaced apart by a dielectric layer. A conductive channel that coincides with the stacking direction passes through the dielectric layer. The first winding in the first coil layer is electrically connected to the first winding in the second coil layer through the conductive channel. The second winding in the first coil layer is electrically connected to the second winding in the second coil layer through the conductive channel. A portion of the second winding in the first coil layer close to the conductive channel intersects with a portion of the first winding in the second coil layer close to the conductive channel in a direction perpendicular to the stacking direction. In such a structure for connecting the first winding and the second winding, the conductive channel can pass along the stacking direction, provided that the sum of the lengths of the first windings in all coil layers and the sum of the lengths of the second windings in all coil layers are essentially equal, which facilitates processing and manufacturing.

[0014] In a possible implementation of the first aspect, the first winding and the second winding each have a connection end extending outside the spiral. The connection end is configured to connect to an input terminal or an output terminal, and the line width of the connection end is larger than the line width of the winding of the spiral. By increasing the line width of the connection end, the characteristic impedance of the input / output wiring is improved and the return loss of the common mode filter is reduced.

[0015] In a possible implementation of the first aspect, the common mode filter further includes a substrate, the second coil layer being disposed on a surface of the substrate and the first coil layer being located on the second coil layer, and an inlet terminal and an outlet terminal, both disposed on a side of the first coil layer away from the second coil layer.

[0016] In a possible implementation of the first embodiment, the substrate is made of a non-magnetic material. In this way, the common mode filter may be manufactured using a semiconductor process, the winding line width can be designed more flexibly, impedance control can be easily implemented, the dielectric material loss is low, and the two-wire common mode filter can have a high application bandwidth.

[0017] In a possible implementation of the first aspect, the common mode filter further includes a third coil layer and a fourth coil layer. The first coil layer, the second coil layer, the third coil layer and the fourth coil layer are stacked in sequence. In the third coil layer and the fourth coil layer, one turn of the second winding is present between each two adjacent turns of the first winding. In the third coil layer, the first winding and the second winding are arranged so as to surround from the outer turn to the inner turn, and the second winding is located on the outer turn with respect to the first winding. In the fourth coil layer, the first winding and the second winding are arranged so as to surround from the inner turn to the outer turn. The surrounding direction of the first winding and the second winding in the third coil layer is the same as the surrounding direction of the first winding and the second winding in the fourth coil layer. In this way, a two-wire common-mode filter can be formed that has extremely low high frequency insertion loss, a large common-mode suppression bandwidth, and extremely low mode conversion loss.

[0018] In a possible implementation of the first aspect, the common mode filter further includes a first substrate and a second substrate. At least one of the first substrate and the second substrate is made of a magnetic material. The first substrate and the second substrate are disposed opposite to each other, and a coil layer is disposed between the first substrate and the second substrate. At least one of the first substrate and the second substrate is made of a magnetic material, so that the common mode filter can meet low-frequency interference application scenarios without affecting balance.

[0019] According to a second aspect, the application provides a common mode filter. The common mode filter includes a first winding, a second winding, and a third winding. A part of the first winding and a part of the second winding are formed in a two-wire coil layer by rotating around the same axis. Another part of the first winding and another part of the second winding are formed in another two-wire coil layer by rotating around another same axis. In any two-wire coil layer, one turn of the second winding exists between each two adjacent turns of the first winding. A part of the third winding is formed in a single-wire coil layer, and another part of the third winding is formed in another other single-wire coil layer. Between the single-wire coil layer and the two-wire coil layer adjacent to the single-wire coil layer, the third winding, the first winding, and the second winding are alternately arranged in a direction perpendicular to the stacking direction, forming a plurality of independent triangular coupling structures. Any turn of the first winding or any turn of the second winding belongs to an independent triangular coupling structure.

[0020] According to the common mode filter provided in this application, the first winding and the second winding in each two-wire coil layer rotate around the same axis, and two adjacent turns of the first winding are spaced apart by one turn of the second winding. Thus, in any two-wire coil layer, the first winding and the second winding are spaced apart along the radial direction of the spiral. arrangement As a result, the common-mode coupling inductance between the first winding and the second winding is strengthened, and the balance of the common-mode magnetic coupling between the first winding and the second winding is improved.

[0021] Additionally, the third winding, the first winding, and the second winding are alternately arranged in a direction perpendicular to the lamination direction. arrangement In this way, the first winding, the second winding and the third winding have matched impedances and matched coupling inductances, so that the differential mode insertion losses formed by the three windings are matched and the return loss of the entire common mode filter is small.

[0022] In a possible implementation of the second aspect, in any two-wire coil layer, each two adjacent turns of the first winding are the first turn of the first winding and the second turn of the first winding, respectively. The turn of the second winding located between the first turn of the first winding and the second turn of the first winding is the middle turn of the second winding. The spacing between the middle turn of the second winding and the first turn of the first winding is S1. The spacing between the middle turn of the second winding and the second turn of the first winding is S2, where S1 is smaller than S2. The third winding, the middle turn of the second winding, and the first turn of the first winding form independent triangular coupling structures. In this way, adjacent triangular coupling structures can be horizontally spaced apart from each other in the orthogonal direction to the stacking direction, thereby reducing the characteristic impedance variation and distributed capacitance, and improving the insertion loss Sdd21, return loss Sdd11, and balance performance Scd21.

[0023] In a possible implementation of the second aspect, the interval between two adjacent triangular bonded structures in the stacking direction is d1, and the interval between the two-wire coil layer and the single-wire coil layer adjacent to each other in each triangular bonded structure is d2, and d2 is greater than d1. In this way, the two adjacent triangular bonded structures are spaced apart and separated from each other in the stacking direction. Similarly, the characteristic impedance variation and distributed capacitance are reduced, and the insertion loss Sdd21, the return loss Sdd11, and the balance performance Scd21 are improved.

[0024] In a possible implementation of the second aspect, the bi-wire coil layer and the mono-wire coil layer are disposed in and spaced apart by a dielectric layer. A first conductive channel, a second conductive channel, and a third conductive channel, which are aligned with the stacking direction, pass through the dielectric layer. The first windings in two adjacent bi-wire coil layers are electrically connected through the first conductive channel. The second windings in two adjacent bi-wire coil layers are electrically connected through the second conductive channel. The third windings in two adjacent mono-wire coil layers are electrically connected through the third conductive channel. In a direction perpendicular to the stacking direction, the first conductive channel, the second conductive channel, and the third conductive channel are staggered to form a triangular coupling structure. By forming a triangular coupling structure using the first conductive channel, the second conductive channel, and the third conductive channel, the balance of the common mode filter can be further improved.

[0025] In a possible implementation of the second aspect, one of the two adjacent two-wire coil layers is a first two-wire coil layer, and the other is a second two-wire coil layer. In the first coil layer, the first winding and the second winding are arranged to surround the winding of the inner turn from the outer turn, and the second winding is located on the outer turn with respect to the first winding. In the second coil layer, the first winding and the second winding are arranged to surround the winding of the inner turn from the inner turn to the outer turn, and the second winding is located on the inner turn with respect to the first winding. The surrounding direction of the first winding and the second winding in the second coil layer is the same as the surrounding direction of the first winding and the second winding in the first coil layer. Therefore, the sum of the lengths of the first windings in all two-wire coil layers is essentially equal to the sum of the lengths of the second windings in all two-wire coil layers. This eliminates the latency difference of signal transmission in the first winding and the second winding, and does not cause conversion from a differential mode signal to a common mode signal, thereby reducing the mode conversion loss of the common mode filter, reducing the high-frequency insertion loss, and widening the common mode suppression bandwidth.

[0026] In a possible implementation of the second aspect, a portion of the second winding in the first bi-wire coil layer near the second conductive channel crosses a portion of the first winding in the second bi-wire coil layer near the first conductive channel in a direction perpendicular to the stacking direction. In such a structure connecting the first winding and the second winding, the conductive channel can pass along the stacking direction, providing that the sum of the lengths of the first windings in all bi-wire coil layers and the sum of the lengths of the second windings in all bi-wire coil layers are essentially equal, which makes processing and manufacturing easier.

[0027] In a possible implementation of the second embodiment, there are two single-wire coil layers, a first single-wire coil layer and a second single-wire coil layer, and there are two two-wire coil layers, the first two-wire coil layer and the second two-wire coil layer. The three-wire common mode filter thus formed has a four-layer structure. Compared with a conventional three-wire common mode filter having more than six layers, the three-wire common mode filter reduces the number of winding layers and implements a miniaturization of the entire three-wire common mode filter.

[0028] In a possible implementation of the second aspect, a first monofilament coil layer, a first bifilar coil layer, a second bifilar coil layer, and a second monofilament coil layer are stacked in sequence.

[0029] In a possible implementation of the second aspect, a first monofilament coil layer, a first bifilar coil layer, a second monofilament coil layer, and a second bifilar coil layer are stacked in sequence.

[0030] In a possible implementation of the second aspect, a first bi-wire coil layer, a first mono-wire coil layer, a second mono-wire coil layer, and a second bi-wire coil layer are stacked in sequence.

[0031] In a possible implementation of the second aspect, a first bi-wire coil layer, a first mono-wire coil layer, a second bi-wire coil layer, and a second mono-wire coil layer are stacked in sequence.

[0032] In a possible implementation of the second aspect, the first bi-wire coil layer, the second bi-wire coil layer, the first mono-wire coil layer, and the second mono-wire coil layer each have a connection end extending outside the spiral. The connection end is configured to connect to an inlet terminal or an outlet terminal, and the line width of the connection end is larger than the line width of the winding of the spiral. Increasing the line width of the connection end improves the characteristic impedance of the input / output wiring and reduces the return loss of the common mode filter.

[0033] In a possible implementation of the second aspect, the common mode filter further includes a substrate having a first surface and a second surface facing each other, the substrate having a conductive channel passing from the first surface to the second surface, a first monofilament coil layer and a first bifilament coil layer disposed on the first surface, a second monofilament coil layer and a second bifilament coil layer disposed on the second surface, and an inlet terminal and an outlet terminal disposed on the surface of the first monofilament coil layer and the first bifilament coil layer away from the substrate, respectively, the first monofilament coil layer and the first bifilament coil layer disposed on the first surface of the substrate, and the second monofilament coil layer and the second bifilament coil layer disposed on the second surface of the substrate. In this manner, the substrate can be used to separate and space a plurality of triangular coupling structures from each other in the stacking direction.

[0034] In a possible implementation of the second embodiment, the substrate is made of a non-magnetic material. In this way, the common mode filter may be manufactured using semiconductor processes, the winding line width can be designed more flexibly, impedance control can be easily implemented, the dielectric material loss is low, and the two-wire common mode filter can have a high application bandwidth.

[0035] In a possible implementation of the second aspect, the common mode filter further includes a first substrate and a second substrate. At least one of the first substrate and the second substrate is made of a magnetic material. The first substrate and the second substrate are disposed opposite to each other, and a bi-wire coil layer and a mono-wire coil layer are disposed between the first substrate and the second substrate, respectively. At least one of the first substrate and the second substrate is made of a magnetic material, so that the common mode filter can meet low-frequency interference application scenarios without affecting balance.

[0036] According to a third aspect, the present application further provides a terminal device including a printed circuit board and a common mode filter according to any one of the implementations of the first aspect. The common mode filter is electrically connected to the printed circuit board.

[0037] The terminal device provided in this embodiment of the application includes the common mode filter in the first embodiment. Therefore, the terminal device provided in this embodiment of the application and the common mode filter in the above-mentioned technical solution can solve the same technical problem and achieve the same expected effect. [Brief description of the drawings]

[0038] [Figure 1] FIG. 2 is a schematic diagram showing a part of the configuration of a terminal device according to one embodiment of the present invention.

[0039] [Diagram 2] FIG. 2 is a cross-sectional view of a two-wire common mode filter according to an embodiment of the present application.

[0040] [Diagram 3] FIG. 2 is a schematic diagram of the wiring of two adjacent coil layers of a two-wire common mode filter according to an embodiment of the present application.

[0041] [Figure 4]FIG. 2 is a three-dimensional schematic diagram of a connection relationship between two adjacent coil layers according to an embodiment of the present application.

[0042] [Diagram 5] FIG. 2 is a two-dimensional schematic diagram illustrating the connection relationship between two adjacent coil layers according to an embodiment of the present application.

[0043] [Figure 6] FIG. 13 is a cross-sectional view of another two-wire common mode filter according to an embodiment of the present application.

[0044] [Figure 7] 7 is a schematic diagram of the wiring of each coil layer in FIG. 6.

[0045] [Figure 8] FIG. 7 is a top view of FIG. 6.

[0046] [Figure 9] 9 is a cross-sectional view taken along line AA in FIG. 8.

[0047] [Figure 10] FIG. 13 is a cross-sectional view of yet another two-wire common mode filter according to an embodiment of the present application.

[0048] [Figure 11] FIG. 13 is a cross-sectional view of yet another two-wire common mode filter according to an embodiment of the present application.

[0049] [Figure 12] FIG. 13 is a cross-sectional view of yet another two-wire common mode filter in accordance with an embodiment of the present application.

[0050] [Figure 13(a)] FIG. 13 is a curve diagram of the differential mode insertion loss Sdd21 of FIG.

[0051] [Figure 13(b)] FIG. 13 is a curve diagram of the common mode insertion loss Scc21 in FIG. 12.

[0052] [Figure 13(c)] FIG. 13 is a curve diagram of mode conversion loss Scd21 in FIG.

[0053] [Figure 13(d)] FIG. 13 is a curve diagram of the return loss Sdd11 of FIG.

[0054] [Figure 14] 1A-1C are schematic diagrams of corresponding structures after completion of each step in a method for manufacturing a two-wire common mode filter according to an embodiment of the present application.

[0055] [Figure 15] FIG. 13 is a cross-sectional view of a further two-wire common mode filter according to an embodiment of the present application.

[0056] [Figure 16(a)] FIG. 16 is a curve diagram comparing the differential mode insertion loss Sdd21 of FIG. 15 with the prior art.

[0057] [Figure 16(b)] FIG. 15 is a curve diagram comparing the common mode insertion loss Scc21 with the conventional technique.

[0058] [Figure 16(c)] FIG. 16 is a curve diagram comparing the mode conversion loss Scd21 in FIG. 15 with the prior art.

[0059] [Figure 16(d)] FIG. 16 is a curve diagram comparing the return loss Sdd11 of FIG. 15 with the prior art.

[0060] [Figure 17] 1A-1C are schematic diagrams of corresponding structures after completion of each step in a method for manufacturing a two-wire common mode filter according to an embodiment of the present application.

[0061] [Figure 18] FIG. 2 is a cross-sectional view of a three-wire common mode filter according to an embodiment of the present application.

[0062] [Figure 19] FIG. 2 is a schematic diagram of the wiring of each coil layer of a three-wire common mode filter according to an embodiment of the present application.

[0063] [Figure 20] FIG. 2 is a schematic diagram of the wiring of each coil layer of a three-wire common mode filter according to an embodiment of the present application.

[0064] [Figure 21] FIG. 2 is a two-dimensional schematic diagram of the connection relationship between adjacent coil layers according to one embodiment of the present application.

[0065] [Figure 22] FIG. 13 is a cross-sectional view of another three-wire common mode filter according to an embodiment of the present application.

[0066] [Figure 23] FIG. 13 is a cross-sectional view of yet another three-wire common mode filter in accordance with an embodiment of the present application.

[0067] [Figure 24] FIG. 13 is a cross-sectional view of yet another three-wire common mode filter in accordance with an embodiment of the present application.

[0068] [Diagram 25] FIG. 13 is a cross-sectional view of yet another three-wire common mode filter in accordance with an embodiment of the present application.

[0069] [Figure 26] FIG. 1 is a partial cross-sectional view of a three-wire common mode filter in the prior art.

[0070] [Figure 27]FIG. 2 is a schematic diagram of a structure of a triangular coupling structure in a three-wire common mode filter according to an embodiment of the present application.

[0071] [Figure 28] FIG. 13 is a cross-sectional view of a further three-wire common mode filter according to an embodiment of the present application.

[0072] [Figure 29] FIG. 13 is a cross-sectional view of yet a further three-wire common mode filter in accordance with an embodiment of the present application.

[0073] [Diagram 30] FIG. 2 is a three-dimensional view of another three-wire common mode filter according to an embodiment of the present application.

[0074] [Figure 31(a)] FIG. 30 is a curve diagram comparing the differential mode insertion loss Sdd21 of FIG. 29 with the prior art.

[0075] [Figure 31(b)] FIG. 30 is a curve diagram comparing the common mode insertion loss Scc21 of FIG. 29 with the prior art.

[0076] [Figure 31(c)] FIG. 30 is a curve diagram comparing the mode conversion loss Scd21 in FIG. 29 with the prior art.

[0077] [Figure 31(d)] FIG. 30 is a curve diagram comparing the return loss Sdd11 of FIG. 29 with the prior art.

[0078] [Diagram 32] 1A-1C are schematic diagrams of corresponding structures after each step in a method for manufacturing a three-wire common mode filter according to an embodiment of the present application is completed.

[0079] [Diagram 33]FIG. 13 is a three-dimensional view of yet another three-wire common mode filter according to an embodiment of the present application.

[0080] [Diagram 34] FIG. 13 is a cross-sectional view of yet a further three-wire common mode filter in accordance with an embodiment of the present application.

[0081] [Diagram 35] 1A to 1C are schematic diagrams illustrating corresponding configurations after each step in a method for manufacturing a three-wire common mode filter according to an embodiment of the present application is completed.

[0082] Reference numbers: 01-PCB, 02-electrical connection structure, 03-common mode filter, 1-first winding, 101-first turn of first winding, 102-second turn of first winding, 2-second winding, 201-first turn of second winding, 202-second turn of second winding, 3-third winding, 4-dielectric layer, 5-conductive channel, 51-first conductive channel, 52-second conductive channel, 53-third conductive channel, 6-connection end, 7-inlet terminal, 71-first inlet terminal, 72-second inlet terminal inlet terminal, 73 - third inlet terminal, 8 - outlet terminal, 81 - first outlet terminal, 82 - second outlet terminal, 83 - third outlet terminal, 9 - substrate, 91 - first substrate, 92 - second substrate, 10 - support plate, 11 - triangular bond structure, 111 - first triangular bond structure, 112 - second triangular bond structure, 113 - third triangular bond structure, L1 - first coil layer, L2 - second coil layer, L3 - third coil layer, L4 - fourth coil layer, L21 - first bi-wire coil layer, L22 - second bi-wire coil layer, L31 - first solid wire coil layer, L32 - second solid wire coil layer DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] In order to facilitate understanding of the technical solution, the following describes technical terms in this application.

[0084] The differential mode insertion loss S-parameter is an important parameter in signal transmission. Sij denotes the energy injected at port j and measured at port i. The differential mode insertion loss parameter, also called the Sdd21 parameter, represents the ratio of the energy of the differential mode signal output from port 2 to the energy of the differential mode signal input from port 1. An Sdd21 value close to 0 dB is preferable.

[0085] The common mode insertion loss S-parameter, also known as the Scc21 parameter, represents the ratio of the common mode noise energy from port 2 to the common mode noise energy from port 1. The smaller the Scc21 value, the stronger the common mode noise suppression capability, and the wider the frequency band, the larger the suppression bandwidth.

[0086] The mode conversion loss S-parameter, also known as the Scd21 parameter, describes how much of the differential mode signal energy input from port 1 is converted to common mode noise energy output from port 2. A smaller Scd21 indicates a better balanced filter and smaller mode loss.

[0087] The return loss S-parameter, also known as the Sdd11 parameter, represents how much of the energy of the differential mode signal input from port 1 is reflected back to port 1. An Sdd11 value less than is preferred.

[0088] Hereinafter, the technical solutions in the embodiments of this application will be described in detail with reference to the accompanying drawings.

[0089] One embodiment of the present application provides a terminal device, the terminal device being a mobile phone. 、 Tablet computers (pads), intelligent wearable products (such as smart watches or smart bands), virtual reality ( V R) devices, augmented reality ( AIn the embodiment of this application, the specific form of the terminal device is not particularly limited.

[0090] These terminal devices generally include a camera module, a display module, etc., and also include an antenna. In order to suppress interference caused by the antenna signal on the signal transmitted from the processor to the camera module or the display module, the terminal device further includes a common mode filter. The common mode filter is configured to suppress common mode noise and transmit the differential data signal.

[0091] 5th generation mobile communication technology ( 5 With the development of 5G, the antennas in these terminal devices also cover the 5G frequency band. In this case, the performance of the common mode filter needs to be further optimized. For example, it is required that the mode conversion loss is extremely small, the common mode suppression bandwidth is larger, and the high frequency insertion loss is extremely small. In the 5G high frequency and high speed application scenario of these terminal devices, the current of the antenna coupled to the high speed interface will be superimposed on the high speed signal through mode conversion, and the current of the camera and display will be greatly reduced. Module This can prevent display distortion and stripes from occurring.

[0092] FIG. 1 is a diagram showing a part of the structure of the terminal device. P The PCB01 includes a common mode filter 03 and a common mode circuit board 01. The common mode filter 03 is integrated on the PCB01 and electrically connected to the PCB01 via an electrical connection structure 02. For example, a differential signal line is disposed on the PCB01, and the common mode filter 03 is electrically connected to the differential signal line via the electrical connection structure 02.

[0093] In terminal devices, the D-PHY and C-PHY protocols are usually used as data transmission standards. In the D-PHY protocol standard, signals are transmitted over two differential lines. In the C-PHY protocol standard, different levels are transmitted over three wires on the transmitting side, and a differential output is provided on the receiving side.

[0094] In other words, in the D-PHY protocol standard, a two-wire common mode filter is used, i.e. there are two windings, and in the C-PHY protocol standard, a three-wire common mode filter is used, i.e. there are three windings.

[0095] Therefore, this application provides two common mode filters, namely, a two-wire common mode filter and a three-wire common mode filter. The two-wire common mode filter and the three-wire common mode filter will be described in detail below.

[0096] The configuration of the two-wire common mode filter will be described in detail below.

[0097] 2 and 3 are diagrams of the structure of a two-wire common mode filter. The common mode filter includes a first winding 1 and a second winding 2. A part of the first winding 1 and a part of the second winding 2 are formed in a first coil layer L1 by rotating them around the same axis (axis P1 shown in FIG. 3). Another part of the first winding 1 and another part of the second winding 2 are formed in a second coil layer L2 laminated with the first coil layer L1 by rotating them around another same axis (axis P2 shown in FIG. 3). The first coil layer L1 and the second coil layer L2 are laminated along the P direction in FIG. 2, and the first coil layer L1 and the second coil layer L2 are spaced apart by a dielectric layer 4.

[0098] To implement the electrical connection between two adjacent coil layers, a conductive channel 5 passes through the dielectric layer 4, which is electrically connected to the windings having the same name in the first coil layer and in the second coil layer. In other words, the first winding in the first coil layer is electrically connected with the first winding in the second coil layer through a conductive channel, and the second winding in the first coil layer is also electrically connected with the second winding in the second coil layer through a conductive channel.

[0099] Figure 3 shows the wiring structure of the first coil layer L1 and the second coil layer L2 of Figure 2. In the first coil layer L1 and the second coil layer L2, one turn of the second winding 2 is present between two adjacent turns of the first winding 1.

[0100] The first winding 1 in the first coil layer L1 is electrically connected to the first winding 1 in the second coil layer L2 (by the dashed line W1 in FIG. 3), and the second winding 2 in the first coil layer L1 is electrically connected to the second winding 2 in the second coil layer L2 (by the dashed line W2 in FIG. 3).

[0101] In this way, in either the first coil layer L1 or the second coil layer L2, the first winding 1 and the second winding 2 are arranged so as to be spaced apart from each other along the radial direction of the spiral (direction D shown in FIG. 3). arrangement Therefore, in each coil layer, the common mode coupling inductance between the first winding 1 and the second winding 2 can be strengthened, and the common mode suppression can be improved. When a differential signal passes through each coil layer, the magnetic fluxes generated by reversing the differential mode current in the first winding and the second winding cancel each other out, thereby reducing the transmission loss of the differential signal and improving the quality of the differential signal.

[0102] The difference between the wiring in the first coil layer L1 and the wiring in the second coil layer L2 is as follows, see FIG. 3. In the first coil layer L1, from the inner turn to the outer turn, the first winding 1 is located on the inner turn with respect to the second winding 2, i.e., the first winding 1 is located on the inner turn closer to the axis P1. However, in the first coil layer L2, from the inner turn to the outer turn, the second winding 2 is located on the inner turn with respect to the first winding 1, i.e., the second winding 2 is located on the inner turn closer to the axis P2.

[0103] In this way, when the number of turns in the first coil layer L1 is the same as the number of turns in the second coil layer L2, the sum of the lengths of the first winding 1 in the two coil layers is essentially equal to the sum of the lengths of the second winding 2. After the differential signals are transmitted through the first coil layer L1 and the second coil layer L2, the latency difference of the signal transmission is eliminated and the conversion between the differential mode signal and the common mode signal is reduced, thereby reducing Scd21 and improving the balance of the common mode filter.

[0104] As shown in Figure 3, the first and second windings in two adjacent coil layers need to be electrically connected separately through conductive channels. The wiring structure shown in Figure 3 is as follows: In the first coil layer L1, the first winding 1 and the second winding 2 are arranged in a counterclockwise direction from the outer turn to the inner turn. To In the first coil layer L2, the first winding 1 and the second winding 2 are also arranged in a counterclockwise direction from the inner turn to the outer turn. To 4 is a diagram of a connection structure of the first winding 1 and the second winding 2 between the first coil layer L1 and the second coil layer L2 shown in FIG.

[0105] Refer to FIG. 4. A first conductive channel 51 passing through a dielectric layer is electrically connected to a first winding 1 in two adjacent coil layers, and a second conductive channel 52 passing through a dielectric layer is electrically connected to a second winding 2 in two adjacent coil layers. Additionally, a portion of the second winding 2 in the first coil layer L1 close to the second conductive channel 52 crosses a portion of the first winding 1 in the second coil layer L2 close to the first conductive channel 51 in a direction perpendicular to the stacking direction (direction Q shown in FIG. 5). When the windings are electrically connected through an interlayer cross structure, as shown in FIG. 4, both the first conductive channel 51 and the second conductive channel 52 pass in a direction parallel to the stacking direction.

[0106] 6 is a cross-sectional view of another two-wire common mode filter having four coil layers, i.e., a first coil layer L1, a second coil layer L2, a third coil layer L3, and a fourth coil layer L4. The first coil layer L1, the second coil layer L2, the third coil layer L3, and the fourth coil layer L4 are stacked in sequence along a stacking direction P.

[0107] 6 is only one embodiment of a two-wire common mode filter, and alternatively, more coil layers may be included. In conclusion, in a two-wire common mode filter, there are N coil layers, where N is an even number equal to or greater than 2.

[0108] Fig. 7 shows the wiring structure of each coil layer in Fig. 6. The winding method of the first coil layer L1 and the second coil layer L2 is the same as that shown in Fig. 3, the winding method of the third coil layer L3 is the same as that of the first coil layer L1, and the winding method of the fourth coil layer L4 is the same as that of the second coil layer L2.

[0109] Additionally, the first winding 1 in the first coil layer L1 is electrically connected to the first winding 1 in the second coil layer L2 (as shown by the dashed line in FIG. 3), and the second winding 2 in the first coil layer L1 is electrically connected to the second winding 2 in the second coil layer L2 (as shown by the dashed line in FIG. 7), implementing the electrical connection between the first coil layer L1 and the second coil layer L2.

[0110] The first winding 1 in the second coil layer L2 is electrically connected to the first winding 1 in the third coil layer L3 (as shown by the dashed line in FIG. 7), and the second winding 2 in the second coil layer L2 is electrically connected to the second winding 2 in the third coil layer L3 (as shown by the dashed line in FIG. 7), implementing an electrical connection between the second coil layer L2 and the third coil layer L3.

[0111] The first winding 1 in the third coil layer L3 is electrically connected to the first winding 1 in the fourth coil layer L4 (as shown by the dashed line in FIG. 7), and the second winding 2 in the third coil layer L3 is electrically connected to the second winding 2 in the fourth coil layer L4 (as shown by the dashed line in FIG. 7), implementing an electrical connection between the third coil layer L3 and the fourth coil layer L4.

[0112] In Fig. 7, even between two adjacent coil layers, the first winding connection and the second winding connection are electrically connected via the structure shown in Fig. 4 and Fig. 5. The specific connection structure will not be described in detail here.

[0113] In the two-wire common mode filter shown in FIG. 7, the first winding 1 and the second winding 2 are both arranged to surround the spiral in the radial direction, so that the first winding 1 and the second winding 2 are arranged at intervals to enhance the common mode magnetic field coupling between the first winding and the second winding in each coil layer, improve the common mode inductance, and improve the common mode suppression.

[0114] Additionally, the first winding and the second winding are crossed and exchanged between two adjacent coil layers. For example, in the first coil layer L1, the first winding 1 is on the inside and the second winding 1 is on the outside, in the second coil layer L2, the first winding 1 is on the outside and the second winding 1 is on the inside, in the third coil layer L3, the first winding 1 is on the inside and the second winding 1 is on the outside, and in the fourth coil layer L4, the first winding 1 is on the outside and the second winding 1 is on the inside. This can greatly reduce the mode conversion loss of the signal and basically achieve zero latency difference.

[0115] It should be noted that in FIG. 7, the elliptical spiral structure formed in each coil layer is only one embodiment, and alternatively, a rectangular spiral, a circular spiral, etc. may be used.

[0116] Fig. 8 is a diagram of the structure of the first coil layer L1, the second coil layer L2, the third coil layer L3, and the fourth coil layer L4 projected onto a plane perpendicular to the stacking direction P in Fig. 7. Fig. 9 is a cross-sectional view taken along line AA in Fig. 8. In Fig. 9, the first winding 1 and the second winding 2 between each two adjacent coil layers are disposed facing each other in the perpendicular direction Q to the stacking direction P.

[0117] In FIG. 9, there is a large distributed capacitance between two adjacent coil layers. In order to reduce the distributed capacitance, reduce the loss, increase the common mode suppression bandwidth, and further improve the balance, this application further provides a two-wire common mode filter. As shown in FIG. 10, in the two-wire common mode filter, the first winding 1 and the second winding 2 are staggered in the orthogonal direction Q of the lamination direction P. It should also be understood that by staggering the adjacent coil layers, the parasitic distributed capacitance between the two layers can be greatly reduced, and the common mode suppression bandwidth and mode conversion performance of the common mode filter can be further improved.

[0118] Refer to FIG. 8. When there are multiple coil layers, the first winding and the second winding each have a connection end that extends outside the spiral. The connection end 6 is configured to connect to an inlet terminal or an outlet terminal. Since the upper coil layer and the lower coil layer have different windings, as shown in FIG. 7, in the first coil layer L1, the first winding 1 and the second winding 2 are arranged to surround each other in a clockwise direction from the inner turn to the outer turn. In the second coil layer L2, the first winding and the second winding are arranged to surround each other in a clockwise direction from the inner turn to the outer turn. In this way, the connection end 6 connected to the first winding 1 and the connection end 6 connected to the second winding 2 extend in opposite directions, and are not spiral windings. The first winding and the second winding are arranged to surround each other in parallel around the axis. In this way, there is a high impedance between the two connection ends 6. Refer to FIG. 8. In order to reduce the impedance, mitigate the sudden impedance change due to non-coupling, and reduce the return loss, the connection end may be widened, ie the line width of the connection end 6 is larger than the line width of the winding of the spiral.

[0119] Refer to FIG. 11. In order to further improve the balance of the two-wire common mode filter, in any coil layer, each two adjacent turns of the first winding are the first turn 101 of the first winding and the second turn 102 of the first winding, respectively. The turn of the second winding located between the first turn 101 of the first winding and the second turn 102 of the first winding is the middle turn 201 of the second winding. The interval S1 between the middle turn 201 of the second winding and the first turn 101 of the first winding is smaller than the interval S2 between the middle turn 201 of the second winding and the second turn 102 of the first winding. In this way, the middle turn 201 of the second winding and the first turn 101 of the first winding form an independent coupling structure T1. The middle turn 202 of the second winding and the second turn 102 of the first winding form another independent coupling structure T2. The magnetic coupling impact between the coupling structure T1 and the coupling structure T2 is small, which further improves the mode conversion performance and balance.

[0120] 12 shows a two-wire common mode filter having a substrate 9. The common mode filter includes a substrate 9. A plurality of coil layers are disposed on the same surface of the substrate 9 and stacked along a stacking direction P. In this manner, the inlet terminal 7 and the outlet terminal 8 are disposed on the surface of the plurality of coil layers away from the substrate 9.

[0121] The inlet terminal 7 includes a first inlet terminal electrically connected to the first winding 1 and a second inlet terminal electrically connected to the second winding.

[0122] The outlet terminal 8 includes a first outlet terminal electrically connected to the first winding 1 and a second outlet terminal electrically connected to the second winding.

[0123] In general, the first inlet terminal and the second inlet terminal are electrically connected to the first winding and the second winding corresponding to the coil layer located at the top through a conductive channel. The first outlet terminal and the second outlet terminal are electrically connected to the first winding and the second winding corresponding to the coil layer located at the bottom through another conductive channel. For example, as shown in FIG. 12, the first coil layer L1, the second coil layer L2, the third coil layer L3, and the fourth coil layer L4 are sequentially stacked along the direction toward the substrate 9. In this way, the first inlet terminal and the second inlet terminal are electrically connected to the first winding and the second winding corresponding to the first coil layer L1 through a conductive channel, and the first outlet terminal and the second outlet terminal are electrically connected to the first winding and the second winding corresponding to the fourth coil layer L4 through another conductive channel.

[0124] In the structure shown in FIG. 12, the substrate 9 may be made of a magnetic material, or may be made of a non-magnetic material such as silicon, glass, resin, ceramic, or ferrite.

[0125] 13(a) to 13(d) show performance simulations of a two-wire common mode filter when the substrate 9 in the structure of FIG. 12 is a non-magnetic substrate.

[0126] Figure 13(a) shows the curve of the differential mode insertion loss Sdd21 of the common mode filter. From this curve, we can see that when the differential mode insertion loss Sdd21 of the two-wire common mode filter is larger than -4dB, the corresponding bandwidth reaches 20GHz.

[0127] Figure 13(b) shows the curve of the common mode insertion loss Scc21 of the common mode filter. From this curve, we can see that when the Scc21 of the two-wire common mode filter is smaller than -15dB, the corresponding common mode suppression bandwidth is 1.5GHz~6GHz, which is larger than 5GHz in total.

[0128] Figure 13(c) is the curve diagram of the mode conversion loss Scd21 of the common mode filter. From this curve, we can see that the Scd21 of the two-wire common mode filter is less than -40 dB within 8 GHz. This can effectively suppress the noise in the 5G interference frequency band and minimize the impact on signal transmission.

[0129] Figure 13d shows the curve of the return loss Sdd11 of the common mode filter. From this curve, we can see that the return loss Sdd11 is smaller than -20dB within 8GHz.

[0130] When the substrate 9 is made of a non-magnetic material such as silicon, glass, etc., the two-wire common mode filter may be manufactured using a conventional semiconductor process. Hereinafter, a method for manufacturing the two-wire common mode filter using a semiconductor process will be described in detail.

[0131] As shown in Figure 14, the method for manufacturing a common mode filter includes the following steps:

[0132] As shown in (a) and (b) of FIG. 14, a dielectric layer 4 is formed on the surface of a substrate 9 made of a non-magnetic material.

[0133] As shown in FIG. 14(c), the dielectric layer 4 is patterned to form a pattern layer on the substrate 9.

[0134] As shown in (d) of Fig. 14, a first winding and a second winding are disposed on a substrate on which a pattern layer is formed, and the first winding and the second winding are rotated around the same axis to form a spiral first coil layer L1. In the first coil layer L1, from the inner turn to the outer turn, the first winding is located at the inner turn with respect to the second winding.

[0135] Additionally, when forming the first coil layer L1, the first winding and the second winding are arranged in a counterclockwise direction from the outside to the inside.

[0136] As shown in FIG. 14(e), another dielectric layer 4 is formed above the first coil layer L1, and a conductive channel 5 is formed in this another dielectric layer 4.

[0137] As shown in FIG. 14(f), the second coil layer L2, the third coil layer L3, and the fourth coil layer L4 are formed in sequence by the methods shown in FIGS. 14(b), (c), and (d).

[0138] In the second coil layer L2, from inner turn to outer turn, the second winding is located on the inner turn relative to the first winding.

[0139] In the third coil layer L3, from inner turn to outer turn, the first winding is located at the inner turn relative to the second winding.

[0140] In the fourth coil layer L4, from inner turn to outer turn, the second winding is located on the inner turn relative to the first winding.

[0141] When forming the second coil layer L2, the first winding and the second winding are disposed so as to surround each other counterclockwise from the inside to the outside.

[0142] When forming the first coil layer L3, the first winding and the second winding are disposed so as to surround each other counterclockwise from the outside to the inside.

[0143] When the fourth coil layer L4 is formed, the first winding and the second winding are disposed so as to surround it counterclockwise from the inside to the outside.

[0144] 14(g), an inlet terminal 7 and an outlet terminal 8 are formed. The inlet terminal 7 is electrically connected to the first winding and the second winding in the fourth coil layer L4, and the outlet terminal 8 is electrically connected to the first winding and the second winding in the first coil layer L1.

[0145] When using semiconductor processes to manufacture common mode filters, the line width of the windings can be designed more flexibly, impedance control can be easily implemented, the dielectric material loss is lower, and the two-wire common mode filter can have a higher application bandwidth.

[0146] FIG. 15 shows another two-wire common mode filter having a substrate. The common mode filter includes a first substrate 91 and a second substrate 92. The first substrate 91 and the second substrate 92 are disposed opposite to each other, and a plurality of coil layers are stacked between the first substrate 91 and the second substrate 92 along the stacking direction P. An inlet terminal 7 and an outlet terminal 8 are located on both sides of the common mode filter. Additionally, the inlet terminal 7 is electrically connected to the first winding and the second winding in the fourth coil layer L4, and the outlet terminal 8 is electrically connected to the first winding and the second winding in the first coil layer L1.

[0147] In the two-wire common mode filter shown in Fig. 15, the first substrate 91 and the second substrate 92 are each made of a non-magnetic material. Alternatively, one of the first substrate 91 and the second substrate 92 is made of a non-magnetic material. Alternatively, the first substrate 91 and the second substrate 92 are each made of a magnetic material.

[0148] As shown in FIG. 15, when the first substrate 91 and the second substrate 92 are each made of a non-magnetic material, or when the substrate 9 in the two-wire common mode filter manufactured in FIG. 14 is also made of a non-magnetic material, and the differential mode insertion loss Sdd21 of the common mode filter is 3 dB, the corresponding bandwidth reaches 20 GHz. Therefore, the excellent high-frequency performance of the common mode filter makes it a suitable common mode filter for ultra-high-speed application scenarios, for example, all 5G ultra-high-speed scenarios that use two-wire differential interface standards and have a transmission speed of 16 Gbps or higher. Specific products include cameras, 、 Including mobile phone liquid crystal display (LCD), PAD LCD, PC LCD, and high definition multimedia interface (HDMI).

[0149] To meet some low-frequency application scenarios, at least one of the first substrate 91 and the second substrate 92 in Fig. 15 may be made of a magnetic material, which can enhance the magnetic field coupling between the windings without changing the balance, improve the common mode inductance, and reduce the common mode suppression frequency.

[0150] 16(a) to 16(d) are performance simulations of a two-wire common-mode filter when at least one of the two substrates in the structure of FIG. 15 is a magnetic substrate.

[0151] As shown in Figure 16(a), the black solid line is the curve of the differential mode insertion loss Sdd21 of the common mode filter, and the dashed line is the curve of the differential mode insertion loss Sdd21 in the prior art. From the two curves, it can be seen that the differential mode insertion loss Sdd21 of the two-wire common mode filter is obviously reduced.

[0152] As shown in FIG. 16(a), the black solid line is the curve of the common mode insertion loss Scc21 of the common mode filter, and the dashed line is the curve of the common mode insertion loss Scc21 in the prior art. From the two curves, it can be seen that the center frequency of Scc21 has moved to about 2GHz, and when Scc21 is smaller than -15 dB, the corresponding common mode suppression bandwidth may cover 900MHz to 5GHz. Therefore, the performance of the common mode filter meets the 5G communication frequency band and the Global System for Mobile Communications (GSM) standard, and satisfies the 5G high-speed high-frequency scenario with a transmission speed of less than 10Gbps.

[0153] As shown in Figure 16c, the black solid line is the curve of the mode conversion loss Sdd21 of the common mode filter, and the dashed line is the curve of the mode conversion loss Scd21 in the prior art. From the two curves, it can be seen that the mode conversion loss of the common mode filter is obviously more preferable than that of the prior art.

[0154] As shown in Figure 16d, the black solid line is the curve of the return loss Sdd11 of the common mode filter, and the dashed line is the curve of the return loss Sdd11 in the prior art. The return loss of the common mode filter is more favorable than that of the prior art.

[0155] The structure shown in Figure 15 may be fabricated using a magnetic device thin film process. Below, a method for fabricating a two-wire common mode filter using a magnetic device thin film process is described in detail.

[0156] As shown in Figure 17, the method for manufacturing a common mode filter includes the following steps.

[0157] As shown in FIGS. 17(a) and (b), a dielectric layer 4 is formed on the surface of a support plate 10.

[0158] 17(c), the first winding and the second winding are set on the dielectric layer 4, so that the first winding and the second winding are disposed on the dielectric layer 4 to form a spiral first coil layer L1 in which the first winding and the second winding rotate around the same axis. In the first coil layer L1, from the inner turn to the outer turn, the first winding is located at the inner turn with respect to the second winding.

[0159] Additionally, when forming the first coil layer L1, the first winding and the second winding are arranged in a counterclockwise direction from the outside to the inside.

[0160] As shown in FIG. 17(d), another dielectric layer 4 is formed above the first coil layer L1, and a conductive channel 5 is formed in this another dielectric layer 4.

[0161] As shown in FIG. 17(e), the second coil layer L2, the third coil layer L3, and the fourth coil layer L4 are formed in sequence by the methods shown in FIGS. 17(b), (c), and (d).

[0162] In the second coil layer L2, from inner turn to outer turn, the second winding is located on the inner turn relative to the first winding.

[0163] In the third coil layer L3, from inner turn to outer turn, the first winding is located at the inner turn relative to the second winding.

[0164] In the fourth coil layer L4, from inner turn to outer turn, the second winding is located on the inner turn relative to the first winding.

[0165] When forming the second coil layer L2, the first winding and the second winding are disposed so as to surround each other counterclockwise from the inside to the outside.

[0166] When forming the first coil layer L3, the first winding and the second winding are disposed so as to surround the first coil layer L3 in a counterclockwise direction from the outside to the inside.

[0167] When the fourth coil layer L4 is formed, the first winding and the second winding are disposed so as to surround it counterclockwise from the inside to the outside.

[0168] As shown in FIG. 17(f), the support plate 10 is removed.

[0169] As shown in FIG. 17(g), a first substrate 91 and a second substrate 92 are disposed, so that four coil layers are loaded between the first substrate 91 and the second substrate 92.

[0170] As shown in FIG. 17(h), an entrance terminal 7 and an exit terminal 8 are disposed on the side surfaces including the first substrate 91, the second substrate 92, and the four coil layers.

[0171] Additionally, when manufacturing a two-wire common mode filter according to FIG. 17, after forming the multiple coil layers and before arranging the inlet terminals and the outlet terminals, the method further includes cutting the common mode filter along a direction parallel to the stacking direction, and then arranging the inlet terminals and the outlet terminals.

[0172] Above, a method for manufacturing a two-wire common mode filter having four coil layers is provided. If there are more coil layers, the two-wire common mode filter may be manufactured by analogy according to the above-mentioned method, and the details will not be described again here.

[0173] The configuration of the three-wire common mode filter will be described in detail below.

[0174] Fig. 18 is a cross-sectional view of a three-wire common mode filter, and Fig. 19 shows the wiring structure of each coil layer in Fig. 18. The common mode filter includes a two-wire coil layer and a single-wire coil layer.

[0175] 18, the bi-wire coil layer in the three-wire common mode filter provided in this application includes two layers, namely, a first bi-wire coil layer L21 and a second bi-wire coil layer L22, and the mono-wire coil layer includes two layers, namely, a first mono-wire coil layer L31 and a second mono-wire coil layer L32.

[0176] In this way, since the two-wire coil layer includes the first winding and the second winding, the formed three-wire common mode filter has four coil layers. The number of wiring layers is reduced compared to the conventional six coil layers, thereby reducing the thickness of the entire three-wire common mode filter in the lamination direction and realizing the miniaturization of the three-wire common mode filter.

[0177] Indeed, in some implementations there may be more than two bi-wire coil layers, and there may be more than two mono-wire coil layers.

[0178] Refer to Fig. 19. A part of the first winding 1 and a part of the second winding 2 are formed in a first coil layer by rotating them around the same axis. Another part of the first winding 1 and another part of the second winding 2 are formed in another two-wire coil layer by rotating them around another same axis. A part of the third winding 3 is formed in a solid-wire coil layer, and another part of the third winding is formed in another solid-wire coil layer.

[0179] The first winding 1 in the first biwire coil layer L21 is electrically connected to the first winding 1 in the second biwire coil layer L22 (as shown by the dashed line in FIG. 19), and the second winding 2 in the first biwire coil layer L21 is electrically connected to the second winding 2 in the second biwire coil layer L22 (as shown by the dashed line in FIG. 19), implementing the electrical connection between the first biwire coil layer L21 and the second biwire coil layer L22.

[0180] The third winding 3 in the first solid-wire coil layer L31 is electrically connected to the third winding 3 in the second solid-wire coil layer L32 (as shown by the dashed line in FIG. 19), implementing an electrical connection between the first solid-wire coil layer L31 and the second solid-wire coil layer L32.

[0181] Furthermore, as shown in FIG. 19, in the first biwire coil layer L21 and the second biwire coil layer L22, one turn of the second winding 2 is present between each two adjacent turns of the first winding 1.

[0182] FIG. 20 shows another wiring structure of each coil layer of FIG. 18. The difference between FIG. 20 and FIG. 19 is that in the first two-wire coil layer L21 of FIG. 19, the first winding and the second winding are arranged so as to surround from the outer turn to the inner turn, and the second winding is located on the outer turn with respect to the first winding. In the second two-wire coil layer L22, the first winding and the second winding are arranged so as to surround from the inner turn to the outer turn, and the second winding is located on the inner turn with respect to the first winding. In the first two-wire coil layer L21 shown in FIG. 20, the first winding and the second winding are arranged so as to surround from the outer turn to the inner turn, and the second winding is located on the outer turn with respect to the first winding. In the second bifilar coil layer L22, the first winding and the second winding are arranged circumferentially from inner turn to outer turn, with the second winding still located on the inner turn relative to the first winding.

[0183] 19 compared with the structure shown in Fig. 20, when the number of turns in the first two-wire coil layer L21 is the same as the number of turns in the second two-wire coil layer L22, the sum of the lengths of the first windings 1 in the two two-wire coil layers is essentially equal to the sum of the lengths of the second windings 2. After the differential signals are transmitted through the first two-wire coil layer L21 and the second two-wire coil layer L22, the latency difference of the signal transmission is eliminated and no conversion from the differential mode signal to the common mode signal occurs, thereby reducing Scd21 and improving the balance of the common mode filter.

[0184] 4 and 5 may be configured to connect the first winding and the second winding when the first two-wire coil layer L21 and the second two-wire coil layer L22 are routed as shown in Fig. 19. Specifically, a portion of the first two-wire coil layer L21 close to the conductive channel of the second winding 2 intersects with a portion of the second two-wire coil layer L22 close to the conductive channel of the first winding 1 in a plane perpendicular to the stacking direction.

[0185] When routing the first two-wire coil layer L21 and the second two-wire coil layer L22 as shown in Fig. 20, the first winding and the second winding are not exchanged between the two two-wire coil layers, so the interlayer cross structure shown in Fig. 4 and Fig. 5 does not need to be electrically connected with the windings. The connection structure shown in Fig. 21 may be used. Specifically, the portion close to the conductive channel of the second winding 2 in the first two-wire coil layer L21 does not intersect with the portion close to the conductive channel of the first winding 1 in the second two-wire coil layer L22 in the orthogonal plane to the stacking direction.

[0186] It should be noted that in Figures 19 and 20, the approximately rectangular spiral structure formed in each coil layer is only one embodiment, and alternatively, a rectangular spiral, a circular spiral, etc. may be used.

[0187] See Fig. 19 and Fig. 20. The first winding and the second winding each have a connection end 6 extending outside the spiral, and the third winding also has a connection end 6 extending outside the spiral. The connection end 6 is configured to connect to an inlet terminal or an outlet terminal. See Fig. 19, the connection ends 6 are spaced apart from each other in the first bi-wire coil layer L21 and the second bi-wire coil layer L2. The difference between the spiral winding is that the first winding and the second winding are arranged to surround the axis in parallel. Thus, there is a high impedance between the two connection ends. See Fig. 19. In order to reduce the impedance, mitigate the sudden impedance change due to non-coupling, and reduce the return loss, the connection end may be widened, i.e., the line width of the connection end 6 is larger than the line width of the spiral winding. Similarly, the width of the connection ends in the first mono-wire coil layer L31 and the second mono-wire coil layer L32 may also be larger than the line width.

[0188] The two bi-wire coil layers and the two mono-wire coil layers have multiple stacking methods.

[0189] 22 shows a stacking method, in which a first single-wire coil layer L31, a first biwire coil layer L21, a second biwire coil layer L22, and a second single-wire coil layer L32 are stacked in this order.

[0190] 23 shows another lamination method, in which a first single-wire coil layer L31, a first biwire coil layer L21, a second single-wire coil layer L32, and a second biwire coil layer L22 are laminated in this order.

[0191] 24 shows another lamination method, in which a first biwire coil layer L21, a first solid wire coil layer L31, a second solid wire coil layer L32, and a second biwire coil layer L22 are laminated in this order.

[0192] 25 shows another lamination method, in which a first biwire coil layer L21, a first monowire coil layer L31, a second biwire coil layer L22, and a second monowire coil layer L32 are laminated in this order.

[0193] As shown in Figures 22 to 25, the third winding 3, the first winding 1, and the second winding 2 are alternately arranged in a direction perpendicular to the stacking direction between adjacent two-wire coil layers and adjacent single-wire coil layers, forming a plurality of independent triangular combination structures 11, and any turn of the first winding 1 or any turn of the second winding 2 also belongs to an independent triangular combination structure 11.

[0194] It should be noted that any turn of the first winding or any turn of the second winding also belongs to an independent triangular coupling structure 11. For example, as shown in FIG. 25, the first turn 101 of the first winding belongs only to the second triangular coupling structure 112.

[0195] 26 is a cross-sectional view of a three-wire common mode filter in the prior art. As can be seen from FIG. 26, the first turn 101 of the first winding belongs to a first triangular connection structure 111 and a second triangular connection structure 112.

[0196] Compared with the conventional three-wire common mode filter shown in Fig. 26, the three-wire common mode filter provided in this embodiment of this application in Fig. 25 forms multiple triangular coupling structures independent of each other. In this way, the impedance and coupling inductance of the three wires can be basically matched and not influenced by the three wires of another triangular coupling structure, which can ensure that the signal mode conversion loss is reduced and the balance is improved. In addition, the three-wire common mode filter with four-layer wiring structure has smaller parasitic capacitance and larger suppression bandwidth.

[0197] 27 shows a triangular coupling structure according to this application. In a specific implementation, the spacing 1a between the third winding 3 and the first winding 1, the spacing 1b between the third winding 3 and the second winding 2, and the spacing 1c between the second winding 2 and the first winding 1 are set so that the three windings have equal impedance and equal coupling. Inductance As long as the above is implemented, it does not necessarily form an equilateral triangle.

[0198] As shown in Figures 22 and 24, the first two-wire coil layer L21 and the second two-wire coil layer L22 are arranged symmetrically with respect to the mid-plane M, and the first single-wire coil layer L31 and the second single-wire coil layer L32 are also arranged symmetrically with respect to the mid-plane M.

[0199] As shown in Figures 23 and 25, the first two-wire coil layer L21 and the second two-wire coil layer L22 are arranged asymmetrically with respect to the mid-plane M, and the first single-wire coil layer L31 and the second single-wire coil layer L32 are also arranged asymmetrically with respect to the mid-plane M.

[0200] The balance can be further improved by arranging the first two-wire coil layer L21, the first single-wire coil layer L31, the second two-wire coil layer L22, and the second single-wire coil layer L32 symmetrically with respect to the mid-plane M shown in Figures 22 and 24.

[0201] It should be noted that the intermediate plane M here is a plane perpendicular to the stacking direction P, as shown in FIG. 22, and the distance X1 between the intermediate plane M and the first surface of the common mode filter is equal to or close to the distance X2 between the intermediate plane M and the second surface of the common mode filter.

[0202] Generally, a first conductive channel 51, a second conductive channel 52 and a third conductive channel 53 pass through the dielectric layer 4, as shown in FIG.

[0203] The first winding in the first bi-wire coil layer L21 is electrically connected to the first winding in the second bi-wire coil layer through a conductive channel 51.

[0204] The second winding in the first bi-wire coil layer L21 is electrically connected to the second winding in the second coil layer through a conductive channel 52.

[0205] The third winding in the first solid-wire coil layer L31 is electrically connected to the third winding in the second solid-wire coil layer L32 via a third conductive channel 53.

[0206] Refer to Fig. 28. In order to further improve the balance, in the perpendicular direction Q to the stacking direction P, the first conductive channel 51, the second conductive channel 52, and the third conductive channel 53 are not located on the same straight line, but as shown in Fig. 28, the first conductive channel 51, the second conductive channel 52, and the third conductive channel 53 are arranged alternately to form a triangular bonding structure 11.

[0207] In order to further improve the balance of the three-wire common mode filter, two adjacent triangular coupling structures are separated and spaced apart from each other in the direction crossing the stacking direction. Referring to FIG. 28, in any two-wire coil layer, each two adjacent turns of the first winding are the first winding first turn 101 and the first winding second turn 102, respectively. The turn of the second winding located between the first winding first turn 101 and the first winding second turn 102 is the second winding middle turn 2. The interval S1 between the second winding middle turn 2 and the first winding first turn 101 is smaller than the interval S2 between the second winding middle turn 2 and the first winding second turn 102. The third winding 3, the second winding middle turn 2, and the first winding first turn 101 form independent triangular coupling structures. In this way, the first triangular coupling structure 111 and the second triangular coupling structure 112 are spaced apart in a direction perpendicular to the lamination direction (also called the horizontal direction), thereby reducing the characteristic impedance variation and distributed capacitance, and improving the insertion loss Sdd21, the return loss Sdd11, and the balance performance Scd21. In the design of S2 and S1, both the balance performance requirement and the overall length requirement of the common mode filter (the size along the Q direction in FIG. 28) need to be considered in the design of S2 and the design of S1.

[0208] Refer to FIG. 28. Additionally, in the stacking direction, the interval between two adjacent triangular coupling structures is d1, and in each triangular coupling structure, the interval between the two-wire coil layer and the single-wire coil layer adjacent to each other is d2, and d2 is greater than d1. In this way, the two adjacent triangular coupling structures are spaced and separated from each other in the stacking direction, which reduces the characteristic impedance variation and distributed capacitance, and improves the insertion loss Sdd21, the return loss Sdd11, and the balance performance Scd21. However, separating and separating the two adjacent triangular coupling structures from each other reduces the common mode inductance and weakens the low-frequency interference suppression ability. Therefore, in the design of d1 and d2, it is necessary to consider both the balance performance requirement and the height requirement for the entire common mode filter in the design of d1 and the design of d2.

[0209] For example, as shown in Fig. 25, the interval d1 between two adjacent triangular bonded structures in this specification is the interval between the first monowire coil layer L31 and the second biwire coil layer L22 between the adjacent second triangular bonded structure 112 and the third triangular bonded structure 113, since the first monowire coil layer L31 is adjacent to the second biwire coil layer L22 between the adjacent second triangular bonded structure 112 and the third triangular bonded structure 113. In another example, as shown in Fig. 28, the first biwire coil layer L21 is adjacent to the second biwire coil layer L22 between the adjacent second triangular bonded structure 112 and the third triangular bonded structure 113, since the first biwire coil layer L21 is adjacent to the second biwire coil layer L22 between the adjacent second triangular bonded structure 112 and the third triangular bonded structure 113, the interval d1 between the adjacent second triangular bonded structure 112 and the third triangular bonded structure 113 is the interval between the first biwire coil layer L21 and the second biwire coil layer L22.

[0210] 29 and 30 show a three-wire common mode filter having a substrate. The three-wire common mode filter includes a first substrate 91 and a second substrate 92. The first substrate 91 and the second substrate 92 are disposed opposite each other, and a plurality of coil layers are stacked between the first substrate 91 and the second substrate 92 along the stacking direction P. An inlet terminal 7 and an outlet terminal 8 are located on both sides of the common mode filter.

[0211] The inlet terminal 7 includes a first inlet terminal 71, a second inlet terminal 72, and a third inlet terminal 73. The first inlet terminal 71 is electrically connected to the first winding in the first bi-wire coil layer, the second inlet terminal 72 is electrically connected to the second winding in the first bi-wire coil layer, and the third inlet terminal 73 is electrically connected to the third winding in the first mono-wire coil layer.

[0212] The outlet terminal 8 includes a first outlet terminal 81, a second outlet terminal 82, and a third outlet terminal 83. The first outlet terminal 81 is electrically connected to the first winding in the second two-wire coil layer, the second outlet terminal 82 is electrically connected to the second winding in the second two-wire coil layer, and the third outlet terminal 83 is electrically connected to the third winding in the second single-wire coil layer.

[0213] FIG. 28 and FIG. 30 In the three-wire common mode filter shown in FIG. 1, the first substrate 91 and the second substrate 92 are each made of a non-magnetic material. Alternatively, one of the first substrate 91 and the second substrate 92 is made of a non-magnetic material. Alternatively, the first substrate 91 and the second substrate 92 are each made of a magnetic material.

[0214] When at least one of the first substrate 91 and the second substrate 92 is a magnetic material, the common-mode magnetic field coupling between the windings is strengthened, the common-mode inductance is improved, and the common-mode suppression frequency is mainly about 3.3 GHz, which meets the main frequency band of 5G RF interference and is suitable for the application scenario of the camera C-PHY high-speed interface in current 5G mobile phones.

[0215] 31a to 31d are performance simulations of a two-wire common mode filter when at least one of the two substrates in the structures of FIGS. 29 and 30 is a magnetic substrate.

[0216] As shown in Figure 16(a), the black solid line is the curve of the differential mode insertion loss Sdd21 of the three-wire common mode filter, and the dashed line is the curve of the differential mode insertion loss Sdd21 in the conventional technology. From the two curves, it can be seen that the differential mode insertion loss Sdd21 of the three-wire common mode filter is obviously reduced.

[0217] As shown in Figure 16(a), the solid black line is the curve for the common mode insertion loss Scc21 of the three-wire common mode filter, and the dashed line is the curve for the common mode insertion loss Scc21 in the conventional technology. These two curves show that the three-wire common mode filter has a small parasitic capacitance and a large suppression bandwidth.

[0218] As shown in Figure 31c, the black solid line is the curve of the mode conversion loss Sdd21 of the common mode filter, and the dashed line is the curve of the mode conversion loss Scd21 in the prior art. From these two curves, it can be seen that the three-wire common mode filter reduces the mode conversion loss of the signal.

[0219] As shown in Figure 31d, the black solid line is the curve of the return loss Sdd11 of the common mode filter, and the dashed line is the curve of the return loss Sdd11 in the prior art. The insertion loss difference of the three-wire common mode filter is smaller, and the impedance matching of the three wires is higher.

[0220] The structures shown in Figures 29 and 30 may be fabricated using a magnetic device thin film process. A method for fabricating a common mode filter using a magnetic device thin film process will now be described in detail.

[0221] As shown in Figure 32, the method for manufacturing a three-wire common mode filter includes the following steps:

[0222] As shown in (a) and (b) of FIG. 32, a dielectric layer 4 is formed on the surface of a support plate 10.

[0223] As shown in FIG. 32(c), a third winding is disposed on the dielectric layer 4, and the third winding rotates around an axis to form a spiral first monofilament coil layer L31.

[0224] When the first single-wire coil layer L31 is formed, the third winding is disposed so as to surround it counterclockwise from the outside to the inside.

[0225] As shown in FIG. 32(d), another dielectric layer 4 is formed above the first single-wire coil layer L31, and a conductive channel 5 is formed in this another dielectric layer 4.

[0226] Using the methods shown in (b), (c), and (d) of Figures 32, a first two-wire coil layer L21, a second two-wire coil layer L22, and a second single-wire coil layer L32 are formed in sequence as shown in (e) of Figure 32.

[0227] In the first bifilar coil layer L21, from the inner turn to the outer turn, the second winding is located at the inner turn relative to the first winding.

[0228] In the second bifilar coil layer L22, from inner turn to outer turn, the first winding is located at the inner turn relative to the second winding.

[0229] When forming the first two-wire coil layer L21, the first winding and the second winding are disposed so as to surround each other counterclockwise from the outside to the inside.

[0230] When forming the second two-wire coil layer L22, the first winding and the second winding are disposed in a counterclockwise surrounding manner from the inside to the outside.

[0231] When forming the second single-wire coil layer L32, the third winding is disposed so as to surround it counterclockwise from the inside to the outside.

[0232] As shown in FIG. 32(f), the support plate 10 is removed.

[0233] As shown in FIG. 32(g), a first substrate 91 and a second substrate 92 are disposed, so that four coil layers are loaded between the first substrate 91 and the second substrate 92.

[0234] As shown in FIG. 32(h), an inlet terminal 7 and an outlet terminal 8 are disposed.

[0235] 33 and 34 show another three-wire common mode filter having a substrate. The three-wire common mode filter has a substrate 9. The substrate 9 has a first surface and a second surface facing each other. A first biwire coil layer 21 and a first monowire coil layer 31 are disposed on the first surface, and a second biwire coil layer 22 and a second monowire coil layer 32 are disposed on the second surface. In this way, the substrate 9 can be used to separate and separate the triangular bonded structures that are aligned in the stacking direction.

[0236] In the structures of Figures 33 and 34, conductive channels pass through the substrate 9 to implement electrical connections between the first bi-wire coil layer 21 and the second bi-wire coil layer 22, and also to implement electrical connections between the first mono-wire coil layer 31 and the second mono-wire coil layer 32.

[0237] The substrates of FIGS. 33 and 34 may be made of a magnetic material or a non-magnetic material, such as ferrite, resin, ceramic, silicon, glass, etc. When the substrate is made of silicon, the conductive channel formed in the substrate is called a through silicon via ( T When a substrate is made from glass, the conductive channel formed in the substrate is called a through-glass via ( T GV).

[0238] When the substrate of the three-wire common mode filter of Figures 33 and 34 is not made of magnetic material, the height is not reduced, so that the separation distance between the upper coil layer and the lower coil layer is further increased. Therefore, the three-wire common mode filter has excellent high-frequency performance, and the common mode suppression resonance frequency is above 8GHz, so that it is more suitable for future millimeter wave band communication and C-PHY ultra-high speed rate application scenarios.

[0239] When the substrate 9 in the structure of Figures 33 and 34 is a non-magnetic substrate, the three-wire common mode filter may be manufactured using a conventional semiconductor process. A method for manufacturing a three-wire common mode filter using a semiconductor process will be described in detail below.

[0240] As shown in Figure 35, the method for manufacturing a three-wire common mode filter includes the following steps:

[0241] As shown in FIG. 35(a), a conductive channel 5 is formed in a substrate 9 made of a non-magnetic material, passing from a first surface A1 to a second surface A2.

[0242] As shown in FIG. 35(b), a dielectric layer 4 is formed on the first surface A1.

[0243] As shown in FIG. 35(c), the dielectric layer 4 is patterned to form a pattern layer on the substrate 9.

[0244] As shown in FIG. 35(d), a third winding is disposed on the substrate on which the pattern layer is formed, and the third winding rotates around an axis to form a spiral first monofilament coil layer L31.

[0245] When the first single-wire coil layer L31 is formed, the third winding is disposed so as to surround it counterclockwise from the outside to the inside.

[0246] As shown in FIG. 35(e), another dielectric layer 4 is formed above the first monofilament coil layer L31, and a conductive channel 5 is formed in this another dielectric layer 4.

[0247] The first two-wire coil layer L21 is formed as shown in FIG. 35(f) by combining (b), (c), and (d) of FIG.

[0248] In the first bifilar coil layer L21, from the inner turn to the outer turn, the second winding is located at the inner turn relative to the first winding.

[0249] When forming the first two-wire coil layer L21, the first winding and the second winding are disposed so as to surround each other counterclockwise from the outside to the inside.

[0250] As shown in FIG. 35(g), the substrate 9 on which the first bilinear coil layer L21 and the first monolinear coil layer L31 are formed is disposed upside down so that the second surface A2 of the substrate faces upward.

[0251] As shown in FIG. 35(h), a dielectric layer 4 is formed on the first surface A2.

[0252] As shown in FIG. 35(i), the dielectric layer 4 is patterned to form a pattern layer on the substrate 9.

[0253] As shown in (j) of Figure 35, a first winding and a second winding are disposed on a substrate on which a pattern layer is formed, and the first winding and the second winding rotate around the same axis to form a spiral second biwire coil layer L22.

[0254] In the second bifilar coil layer L22, from inner turn to outer turn, the first winding is located at the inner turn relative to the second winding.

[0255] When forming the second two-wire coil layer L22, the first winding and the second winding are disposed in a counterclockwise surrounding manner from the inside to the outside.

[0256] As shown in Fig. 35(k), another dielectric layer 4 is formed above the second bi-wire coil layer L22, and a conductive channel 5 is formed in this another dielectric layer 4. The dielectric layer 4 is patterned to form a pattern layer on the substrate 9. A third winding is disposed in the pattern layer to form the second mono-wire coil layer L32.

[0257] When forming the second single-wire coil layer L32, the third winding is disposed so as to surround it counterclockwise from the inside to the outside.

[0258] As shown in FIG. 35(l), an inlet terminal 7 and an outlet terminal 8 are disposed.

[0259] In the description of this specification, the particular features, structures, materials, or characteristics described may be combined in any one or more of the embodiments or examples as suitable.

[0260] The above description is merely a specific implementation of this application, but is not intended to limit the scope of protection of this application. Any modifications or replacements that can be easily understood by those skilled in the art within the technical scope disclosed in this application shall be included in the scope of protection of this application. Therefore, the scope of protection of this application shall be subject to the scope of protection of the claims.

Claims

1. A common mode filter comprising: A first winding; a second winding; a portion of the first winding and a portion of the second winding are formed by rotating around a same axis in a first coil layer, and another portion of the first winding and another portion of the second winding are formed by rotating around another same axis in a second coil layer stacked with the first coil layer, and one turn of the second winding is present between each two adjacent turns of the first winding in the first coil layer and the second coil layer; In the first coil layer, the first winding and the second winding are disposed so as to surround each other from an outer turn to an inner turn, and the second winding is located on the outer turn with respect to the first winding, In the second coil layer, the first winding and the second winding are disposed so as to surround each other from an inner turn to an outer turn, and the second winding is located in the inner turn with respect to the first winding, a surrounding direction of the first winding and the second winding in the second coil layer is the same as a surrounding direction of the first winding and the second winding in the first coil layer.

2. 2. The common mode filter according to claim 1, wherein the first winding and the second winding are alternately arranged in a direction perpendicular to a stacking direction of the first coil layer and the second coil layer.

3. 3. The common mode filter according to claim 1, wherein in either the first coil layer or the second coil layer, each two adjacent turns of the first winding are a first turn of the first winding and a second turn of the first winding, respectively, a turn of the second winding located between the first turn of the first winding and the second turn of the first winding is an intermediate turn of the second winding, and a distance between the intermediate turn of the second winding and the first turn of the first winding is smaller than a distance between the intermediate turn of the second winding and the second turn of the first winding.

4. the first coil layer and the second coil layer are disposed within a dielectric layer and spaced apart by the dielectric layer, a conductive channel along the stacking direction passes through the dielectric layer, the first winding in the first coil layer is electrically connected to the first winding in the second coil layer via the conductive channel, and the second winding in the first coil layer is electrically connected to the second winding in the second coil layer via the conductive channel; 3. The common mode filter according to claim 2, wherein a portion of the second winding in the first coil layer close to the conductive channel intersects with a portion of the first winding in the second coil layer close to the conductive channel in a direction perpendicular to the stacking direction.

5. 5. A common mode filter as claimed in any one of claims 1 to 4, wherein the first winding and the second winding each have a connection end extending outside the spiral, the connection end being configured to connect to an inlet terminal or an outlet terminal, and the line width of the connection end being greater than the line width of the spiral winding.

6. The common mode filter further comprises: a substrate, the second coil layer being disposed on a surface of the substrate, and the first coil layer being located on the second coil layer; 6. The common mode filter of claim 5, including the inlet terminal and the outlet terminal both disposed on a side of the first coil layer remote from the second coil layer.

7. A common mode filter comprising: A first winding; a second winding, a portion of the first winding and a portion of the second winding being formed by rotating about a same axis in a two-wire coil layer, and another portion of the first winding and another portion of the second winding being formed by rotating about another same axis in another two-wire coil layer, and in any one of the two-wire coil layers, one turn of the second winding is present between every two adjacent turns of the first winding; a third winding, a portion of the third winding being formed on a single-wire coil layer and another portion of the third winding being formed on another single-wire coil layer; a common mode filter in which, between the single-wire coil layer and a two-wire coil layer adjacent to the single-wire coil layer, the third winding, the first winding, and the second winding are alternately arranged in a direction perpendicular to the stacking direction to form a plurality of mutually independent triangular coupling structures, and any turn of the first winding or any turn of the second winding also belongs to an independent triangular coupling structure.

8. In any of the two-wire coil layers, each two adjacent turns of the first winding are a first turn of the first winding and a second turn of the first winding, a turn of the second winding located between the first turn of the first winding and the second turn of the first winding is an intermediate turn of the second winding, a spacing between the intermediate turn of the second winding and the first turn of the first winding is S1, a spacing between the intermediate turn of the second winding and the second turn of the first winding is S2, and S1 is smaller than S2; 8. The common mode filter of claim 7, wherein the third winding, the middle turn of the second winding, and the first turn of the first winding form an independent triangular coupling structure.

9. 9. The common mode filter according to claim 7, wherein in the stacking direction, a distance between two adjacent triangular coupled structures is d1, and in each triangular coupled structure, a distance between the adjacent two-wire coil layers and the adjacent single-wire coil layers is d2, and d2 is greater than d1.

10. the bi-wire coil layer and the mono-wire coil layer are disposed within a dielectric layer and spaced apart by the dielectric layer, a first conductive channel, a second conductive channel, and a third conductive channel aligned with the stacking direction pass through the dielectric layer, a first winding in two adjacent bi-wire coil layers is electrically connected via the first conductive channel, a second winding in two adjacent bi-wire coil layers is electrically connected via the second conductive channel, and a third winding in two adjacent bi-wire coil layers is electrically connected via the third conductive channel; A common mode filter as described in any one of claims 7 to 9, wherein in the perpendicular direction to the stacking direction, the first conductive channel, the second conductive channel, and the third conductive channel are alternately arranged to form a triangular coupling structure.

11. one of the two adjacent bi-wire coil layers is a first bi-wire coil layer and the other is a second bi-wire coil layer; In the first bi-wire coil layer, the first winding and the second winding are disposed so as to surround the first winding from an outer turn to an inner turn, and the second winding is located on the outer turn with respect to the first winding, 11. The common mode filter according to claim 10, wherein in the second two-wire coil layer, the first winding and the second winding are arranged so as to surround each other from an inner turn to an outer turn, the second winding is located on the inner turn with respect to the first winding, and a surrounding direction of the first winding and the second winding in the second two-wire coil layer is the same as a surrounding direction of the first winding and the second winding in the first two-wire coil layer.

12. 12. The common mode filter according to claim 11, wherein a portion of the second winding in the first biwire coil layer close to the second conductive channel intersects a portion of the first winding in the second biwire coil layer close to the first conductive channel in a direction perpendicular to the stacking direction.

13. 13. A common mode filter as claimed in any one of claims 11 to 12, wherein there are two single-wire coil layers, a first single-wire coil layer and a second single-wire coil layer, and there are two two-wire coil layers, the first two-wire coil layer and the second two-wire coil layer.

14. The common mode filter comprises: a substrate having a first surface and a second surface opposed to one another, the substrate having a conductive channel passing from the first surface to the second surface; the first monofilament coil layer and the first bifilar coil layer are disposed on the first surface, and the second monofilament coil layer and the second bifilar coil layer are disposed on the second surface; 14. The common mode filter of claim 13, further comprising an inlet terminal and an outlet terminal disposed on a surface of the first single-wire coil layer and the first bi-wire coil layer, respectively, remote from the substrate.

15. A terminal device, comprising: A printed circuit board; A common mode filter according to any one of claims 1 to 14, The common mode filter is electrically connected to the printed circuit board.

Images