High-frequency filter and common mode noise filter

Abstract

This high-frequency filter includes a first input / output terminal, a second input / output terminal, and a plurality of filter circuits connected in series between the first input / output terminal and the second input / output terminal. In this high-frequency filter, a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and a filter circuit electrode constituting each of the plurality of filter circuits are formed on a substrate. The plurality of filter circuits have the same circuit configuration. In a first direction of the substrate, the plurality of filter circuit electrodes are arranged side by side between the first pad electrode and the second pad electrode. Adjacent filter circuit electrodes among the plurality of filter circuit electrodes have a line-symmetric shape with respect to a first virtual reference line which passes through an intermediate position between the adjacent filter circuit electrodes and which extends in a second direction orthogonal to the first direction.

Description

High-frequency filter, common-mode noise filter

[0001] This invention relates to the structure of a high-frequency filter and a common-mode noise filter.

[0002] The common-mode noise filter of Non-Patent Document 1 is formed on a semiconductor substrate. In the common-mode noise filter of Non-Patent Document 1, a first pad group for external connection is formed at one end in the first direction of the semiconductor substrate. The common-mode noise filter of Non-Patent Document 1 includes a second pad group for external connection at the other end in the first direction of the semiconductor substrate.

[0003] Between the first pad group and the second pad group in the first direction of the semiconductor substrate, a circuit pattern (filter circuit pattern) that realizes the function of the filter is formed.

[0004] The filter circuit pattern is determined by the number of stages of the filter. For example, if the filter has two stages, the same-shaped circuit pattern is repeated twice and connected to each other. At this time, the circuit pattern constituting each stage of the filter is formed by an electrode pattern formed in a plurality of layers of the semiconductor substrate and via electrodes connecting the electrode patterns of each layer.And the circuit pattern constituting each stage of the filter has the same shape in plan view.

[0005] An Ultra-Compact Common Mode Bandstop Filter With Modified-T Circuits in Integrated Passive Device (IPD) Process

[0006] However, in the conventional configuration as shown in Non-Patent Document 1, there is a problem that the number of via electrodes increases. When the number of via electrodes increases, the resistance value as a filter circuit increases, and the filter characteristics deteriorate.

[0007] Therefore, an object of the present invention is to suppress an increase in the resistance value of the filter circuit and suppress deterioration of the filter characteristics.

[0008] A high-frequency filter according to one embodiment of this invention comprises a first input / output terminal, a second input / output terminal, and a plurality of filter circuits connected in series between the first input / output terminal and the second input / output terminal. The high-frequency filter is formed on a substrate with a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and filter circuit electrodes each constituting the plurality of filter circuits.

[0009] Multiple filter circuits share the same circuit configuration. In the first direction of the substrate, the multiple filter circuit electrodes are arranged side by side between the first pad electrode and the second pad electrode. Adjacent filter circuit electrodes in the multiple filter circuit electrodes are symmetrical with respect to a first virtual reference line that passes through the midpoint between adjacent filter circuit electrodes and extends in a second direction perpendicular to the first direction.

[0010] In this configuration, adjacent filter circuit electrodes have a symmetrical shape, allowing them to be connected on the same layer of the substrate. Furthermore, the shape of this connection pattern is simplified and shortened.

[0011] Furthermore, the electrode pattern in the direction from the first pad electrode to the second pad electrode is approximately the same as the electrode pattern in the direction from the second pad electrode to the first pad electrode. This ensures symmetry in the circuit pattern of the filter circuit.

[0012] According to this invention, the increase in the resistance value of the filter circuit can be suppressed, thereby preventing deterioration of the filter characteristics.

[0013] Figure 1 is a circuit diagram of a common-mode noise filter according to the first embodiment of the present invention. Figure 2 is a plan view of the common-mode noise filter according to the first embodiment of the present invention. Figure 3 is an enlarged plan view of the filter circuit according to the first embodiment of the present invention. Figure 4 is a partial cross-sectional view of the filter circuit according to the first embodiment of the present invention. Figure 5(A) is a plan view of the electrode pattern of the first electrode layer of the filter circuit, and Figure 5(B) is a plan view of the electrode pattern of the second electrode layer of the filter circuit. Figure 6 is an enlarged plan view of a high-frequency filter according to the second embodiment of the present invention. Figure 7 is an enlarged plan view of a high-frequency filter according to the third embodiment of the present invention. Figure 8 is an enlarged plan view of a high-frequency filter according to the fourth embodiment of the present invention.

[0014] [First Embodiment] A high-frequency filter and a common-mode noise filter according to the first embodiment of the present invention will be described with reference to the figures.

[0015] (Circuit Configuration) Figure 1 is a circuit diagram of a common-mode noise filter according to the first embodiment of the present invention. As shown in Figure 1, the common-mode noise filter 10 comprises a first common-mode noise filter 21, a second common-mode noise filter 22, and a third common-mode noise filter 23. The common-mode noise filter 10 comprises a first input / output terminal P1, a second input / output terminal P2, a third input / output terminal P3, a fourth input / output terminal P4, and a reference potential connection terminal PGND.

[0016] The first input / output terminal P1 and the second input / output terminal P2 are input / output terminals for the first differential signal. The third input / output terminal P3 and the fourth input / output terminal P4 are input / output terminals for the second differential signal (the signal paired with the first differential signal). The first input / output terminal P1 and the third input / output terminal P3 constitute the input / output terminals for one end of the pair of differential signals in the common-mode noise filter 10. The second input / output terminal P2 and the fourth input / output terminal P4 constitute the input / output terminals for the other end of the pair of differential signals in the common-mode noise filter 10.

[0017] The first input / output terminal P1 and the third input / output terminal P3 are connected to the first common-mode noise filter 21. The first common-mode noise filter 21 is connected to the second common-mode noise filter 22. The second common-mode noise filter 22 is connected to the third common-mode noise filter 23. The third common-mode noise filter 23 is connected to the second input / output terminal P2 and the fourth input / output terminal P4. In addition, the first common-mode noise filter 21, the second common-mode noise filter 22, and the third common-mode noise filter 23 are connected to the reference potential connection terminal PGND through the inductor 300. The reference potential connection terminal PGND is connected to a reference potential (for example, ground potential).

[0018] Thus, the first common-mode noise filter 21, the second common-mode noise filter 22, and the third common-mode noise filter 23 are connected in series between the input / output terminal pair of the first input / output terminal P1 and the third input / output terminal P3 and the input / output terminal pair of the second input / output terminal P2 and the fourth input / output terminal P4. As a result, the common-mode noise filter 10 constitutes a three-stage common-mode noise filter.

[0019] (Circuit of the first common-mode noise filter 21) The first common-mode noise filter 21 comprises a first T-type filter circuit 21T1 and a second T-type filter circuit 21T2.

[0020] The first T-type filter circuit 21T1 includes an inductor 311, an inductor 312, a capacitor 313, and a shunt capacitor 317. Inductors 311 and 312 are connected in series. Inductors 311 and 312 are magnetically coupled in the forward direction. Inductors 311 and 312 correspond to the "first inductor" and the "second inductor," respectively.

[0021] The series circuit of inductors 311 and 312 and the capacitor 313 are connected in parallel. Capacitor 313 corresponds to a "parallel capacitor".

[0022] One terminal of the shunt capacitor 317 is connected to the intermediate node where inductors 311 and 312 are connected. The terminal of inductor 311 opposite to the connection end with inductor 312 is connected to the first input / output terminal P1.

[0023] The second T-type filter circuit 21T2 includes an inductor 314, an inductor 315, a capacitor 316, and a shunt capacitor 318. Inductors 314 and 315 are connected in series. Inductors 314 and 315 are magnetically coupled in the forward direction. Inductors 314 and 315 correspond to the "first inductor" and "second inductor," respectively.

[0024] The series circuit of inductors 314 and 315 and the capacitor 316 are connected in parallel. Capacitor 316 corresponds to a "parallel capacitor".

[0025] One terminal of the shunt capacitor 318 is connected to the intermediate node where inductors 314 and 315 are connected. The terminal of inductor 314 opposite to the connection end with inductor 315 is connected to the third input / output terminal P3.

[0026] The other terminal of shunt capacitor 317 and the other terminal of shunt capacitor 318 are connected, and this connection point is connected to the reference potential connection terminal PGND through inductor 300.

[0027] The inductances of inductors 311, 312, 314, and 315 are the same. The capacitances of capacitors 313 and 316 are the same. The capacitances of shunt capacitors 317 and 318 are the same.

[0028] (Circuit of the second common-mode noise filter 22) The second common-mode noise filter 22 includes a third T-type filter circuit 22T1 and a fourth T-type filter circuit 22T2.

[0029] The third T-type filter circuit 22T1 includes inductors 321 and 322, a capacitor 323, and a shunt capacitor 327. Inductors 321 and 322 are connected in series. Inductors 321 and 322 are magnetically coupled in the forward direction. Inductors 321 and 322 correspond to the "first inductor" and "second inductor," respectively.

[0030] The series circuit of inductors 321 and 322 is connected in parallel to the capacitor 323. Capacitor 323 corresponds to a "parallel capacitor".

[0031] One terminal of the shunt capacitor 327 is connected to the intermediate node where inductors 321 and 322 are connected. The terminal of inductor 321 opposite to the terminal connected to inductor 322 is connected to inductor 312 of the first T-type filter circuit 21T1.

[0032] The fourth T-type filter circuit 22T2 comprises inductors 324 and 325, a capacitor 326, and a shunt capacitor 328. Inductors 324 and 325 are connected in series. Inductors 324 and 325 are magnetically coupled in the forward direction. Inductors 324 and 325 correspond to the "first inductor" and "second inductor," respectively.

[0033] The series circuit of inductors 324 and 325 is connected in parallel to the capacitor 326. Capacitor 326 corresponds to a "parallel capacitor".

[0034] One terminal of the shunt capacitor 328 is connected to the intermediate node where inductors 324 and 325 are connected. The terminal of inductor 324 opposite to the terminal connected to inductor 325 is connected to inductor 315 of the second T-type filter circuit 21T2.

[0035] The other terminal of shunt capacitor 327 and the other terminal of shunt capacitor 328 are connected, and this connection point is connected to the reference potential connection terminal PGND through inductor 300.

[0036] The inductances of inductors 321, 322, 324, and 325 are the same. The inductances of inductors 321, 322, 324, and 325 are the same as the inductances of inductors 311, 312, 314, and 315. The capacitances of capacitors 323 and 326 are the same. The capacitances of capacitors 323 and 326 are the same as the capacitances of capacitors 313 and 316. The capacitances of shunt capacitors 327 and 328 are the same. The capacitances of shunt capacitors 327 and 328 are the same as the capacitances of shunt capacitors 317 and 318.

[0037] (Circuit of the third common-mode noise filter 23) The third common-mode noise filter 23 includes a fifth-type T filter circuit 23T1 and a sixth-type T filter circuit 23T2.

[0038] The fifth T-type filter circuit 23T1 comprises an inductor 331, an inductor 332, a capacitor 333, and a shunt capacitor 337. Inductors 331 and 332 are connected in series. Inductors 331 and 332 are magnetically coupled in the forward direction. Inductors 331 and 332 correspond to the "first inductor" and the "second inductor," respectively.

[0039] The series circuit of inductors 331 and 332 is connected in parallel to the capacitor 333. Capacitor 333 corresponds to a "parallel capacitor".

[0040] One terminal of the shunt capacitor 337 is connected to an intermediate node where the inductor 331 and the inductor 332 are connected. The terminal of the inductor 331 opposite to the connection end with the inductor 332 is connected to the inductor 322 of the third T-type filter circuit 22T1. The terminal of the inductor 332 opposite to the connection end with the inductor 331 is connected to the second input / output terminal P2.

[0041] The sixth T-type filter circuit 23T2 includes an inductor 334, an inductor 335, a capacitor 336, and a shunt capacitor 338. The inductor 334 and the inductor 335 are connected in series. The inductor 334 and the inductor 335 are magnetically coupled in the forward direction. The inductor 334 and the inductor 335 respectively correspond to the "first inductor" and the "second inductor".

[0042] The series circuit of the inductor 334 and the inductor 335 and the capacitor 336 are connected in parallel. The capacitor 336 corresponds to the "parallel capacitor".

[0043] One terminal of the shunt capacitor 338 is connected to an intermediate node where the inductor 334 and the inductor 335 are connected. The terminal of the inductor 334 opposite to the connection end with the inductor 335 is connected to the inductor 325 of the fourth T-type filter circuit 22T2. The terminal of the inductor 335 opposite to the connection end with the inductor 334 is connected to the fourth input / output terminal P4.

[0044] The other terminal of the shunt capacitor 337 and the other terminal of the shunt capacitor 338 are connected, and this connection point is connected to the reference potential connection terminal PGND through the inductor 300.

[0045] The inductances of inductors 331, 332, 334, and 335 are the same. The inductances of inductors 331, 332, 334, and 335 are the same as the inductances of inductors 311, 312, 314, and 315. The capacitances of capacitors 333 and 336 are the same. The capacitances of capacitors 333 and 336 are the same as the capacitances of capacitors 313 and 316. The capacitances of shunt capacitors 337 and 338 are the same. The capacitances of shunt capacitors 337 and 338 are the same as the capacitances of shunt capacitors 317 and 318.

[0046] With this configuration, the common-mode noise filter 10 receives the first differential signal of the pair of differential signals from the first input / output terminal P1, transmits it through the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1, and outputs it from the second input / output terminal P2. Furthermore, the common-mode noise filter 10 receives the second differential signal of the pair of differential signals from the third input / output terminal P3, transmits it through the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2, and outputs it from the fourth input / output terminal P4. Thus, the common-mode noise filter 10 suppresses common-mode noise superimposed on the pair of differential signals with the above circuit configuration.

[0047] Alternatively, the common-mode noise filter 10 inputs the first differential signal among a pair of differential signals from the second input / output terminal P2, transmits it through the fifth T-type filter circuit 23T1, the third T-type filter circuit 22T1, and the first T-type filter circuit 21T1, and outputs it from the first input / output terminal P1. Further, the common-mode noise filter 10 inputs the second differential signal among a pair of differential signals from the fourth input / output terminal P4, transmits it through the sixth T-type filter circuit 23T2, the fourth T-type filter circuit 22T2, and the second T-type filter circuit 21T2, and outputs it from the third input / output terminal P3. Then, the common-mode noise filter 10 suppresses the common-mode noise superimposed on the pair of differential signals by the above circuit configuration.

[0048] (Structure) FIG. 2 is a plan view of the common-mode noise filter according to the first embodiment of the present invention. FIG. 3 is an enlarged plan view of the filter circuit according to the first embodiment of the present invention. FIG. 4 is a partial cross-sectional view of the filter circuit according to the first embodiment of the present invention. FIG. 4 is a view seen from the A-A cross section shown in FIG. 3. FIG. (A) is a plan view of the electrode pattern of the first electrode layer of the filter circuit, and FIG. (B) is a plan view of the electrode pattern of the second electrode layer of the filter circuit. The Y-axis direction in each figure corresponds to the "first direction", and the X-axis direction corresponds to the "second direction".

[0049] (Substrate Structure) As shown in FIGS. 2, 3, 4, 5(A), and 5(B), the common-mode noise filter 10 includes a substrate 90. The substrate 90 includes a base material (not shown) and a plurality of insulator layers 900, 901, 902. Note that the substrate 90 may further include an insulator layer according to the circuit configuration of the common-mode noise filter 10.

[0050] The substrate is, for example, a semiconductor substrate, and is composed of an undoped semiconductor. The substrate is not limited to a semiconductor substrate, but may be an insulating material such as a glass substrate. The multiple insulating layers 900, 901, and 902 are formed on the surface side of the substrate via a highly insulating layer such as SiN, and are composed of a material having a predetermined dielectric constant. The multiple insulating layers 900, 901, and 902 are arranged in the order of insulating layer 900, insulating layer 901, and insulating layer 902, starting from the surface side of the substrate 90 and moving towards the substrate at the bottom of the substrate 90.

[0051] The interface (contact surface) between the insulating layer 900 and the insulating layer 901 is used as the first conductive layer. The interface between the insulating layer 901 and the insulating layer 902 is used as the second conductive layer.

[0052] (Pad electrode group) The common-mode noise filter 10 comprises a first pad electrode PDP1, a second pad electrode PDP2, a third pad electrode PDP3, a fourth pad electrode PDP4, and a ground pad electrode PDG.

[0053] The first pad electrode PDP1 constitutes the first input / output terminal P1. The second pad electrode PDP2 constitutes the second input / output terminal P2. The third pad electrode PDP3 constitutes the third input / output terminal P3. The fourth pad electrode PDP4 constitutes the fourth input / output terminal P4. The ground pad electrode PDG constitutes the reference potential connection terminal PGND.

[0054] The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG are approximately square when viewed in plan (viewed in the direction of stacking of the multiple insulating layers of the substrate 90). The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG have the minimum area required for soldering when mounting the common-mode noise filter 10 to another circuit board or the like.

[0055] The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG are formed in the first conductive layer and are exposed to the outside of the substrate 90 over a predetermined area through an opening formed in the insulating layer 91.

[0056] The first pad electrode PDP1 and the second pad electrode PDP2 are arranged at a predetermined distance from each other along the first direction (Y-axis direction in Figure 2) of the substrate 90. The first pad electrode PDP1 and the second pad electrode PDP2 are arranged on a line parallel to the Y-axis.

[0057] The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned at a predetermined distance from each other along the first direction (Y-axis direction in Figure 2) of the substrate 90. The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned on a line parallel to the Y-axis.

[0058] The first pad electrode PDP1 and the third pad electrode PDP3 are positioned at a predetermined distance from each other along the second direction (the X-axis direction in Figure 2) of the substrate 90. The first pad electrode PDP1 and the third pad electrode PDP3 are positioned on a line parallel to the X-axis.

[0059] The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned at a predetermined distance from each other along the second direction (the X-axis direction in Figure 2) of the substrate 90. The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned on a line parallel to the X-axis.

[0060] The ground pad electrode PDG is positioned so as to include the center point of a rectangle formed by the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4 as its four corners. In this case, it is preferable that the center point of the ground pad electrode PDG coincides with the center point of the rectangle.

[0061] As a result, the first pad electrode PDP1 and the second pad electrode PDP2 are positioned symmetrically with respect to the X-axis reference line AxeX0 (second virtual reference line) which passes through the center point of the ground pad electrode PDG. The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned symmetrically with respect to the X-axis reference line AxeX0.

[0062] The first pad electrode PDP1 and the third pad electrode PDP3 are positioned symmetrically with respect to the Y-axis reference line AxeY, which passes through the center point of the ground pad electrode PDG. The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0063] (Filter circuit electrode group) The common-mode noise filter 10 comprises a plurality of inductor electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, and Pt335. Each of the plurality of inductor electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, and Pt335 constitutes each of the plurality of inductors 311, 312, 314, 315, 321, 322, 324, 325, 331, 332, 334, and 335, respectively.

[0064] The common-mode noise filter 10 comprises a plurality of capacitor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, and Pt336. Each of the plurality of capacitor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, and Pt336 constitutes each of the plurality of capacitors 313, 316, 323, 326, 333, and 336.

[0065] Multiple inductor electrodes Pt311, Pt312 and a capacitor electrode Pt313 constitute the filter circuit electrodes of the first T-type filter circuit 21T1. Multiple inductor electrodes Pt321, Pt322 and a capacitor electrode Pt323 constitute the filter circuit electrodes of the third T-type filter circuit 22T1. Multiple inductor electrodes Pt331, Pt332 and a capacitor electrode Pt333 constitute the filter circuit electrodes of the fifth T-type filter circuit 23T1.

[0066] The filter circuit electrodes of the first T-type filter circuit 21T1, the filter circuit electrodes of the third T-type filter circuit 22T1, and the filter circuit electrodes of the fifth T-type filter circuit 23T1 are positioned between the first pad electrode PDP1 and the second pad electrode PDP2. The filter circuit electrodes of the first T-type filter circuit 21T1, the filter circuit electrodes of the third T-type filter circuit 22T1, and the filter circuit electrodes of the fifth T-type filter circuit 23T1 are arranged in line along the Y-axis. More specifically, they are arranged in the order of the filter circuit electrodes of the first T-type filter circuit 21T1, the filter circuit electrodes of the third T-type filter circuit 22T1, and the filter circuit electrodes of the fifth T-type filter circuit 23T1, moving from the first pad electrode PDP1 toward the second pad electrode PDP2.

[0067] The filter circuit electrodes of the first T-type filter circuit 21T1 and the filter circuit electrodes of the third T-type filter circuit 22T1 are symmetrical with respect to the X-axis reference line AxeX12 (see Figure 3, first virtual reference line), which passes through the midpoint between these adjacent filter circuit electrodes, is perpendicular to the Y-axis direction, and extends in the X-axis direction.

[0068] The filter circuit electrodes of the third T-type filter circuit 22T1 and the filter circuit electrodes of the fifth T-type filter circuit 23T1 are symmetrical with respect to the X-axis reference line AxeX23 (see Figure 3, first virtual reference line), which passes through the midpoint between these adjacent filter circuit electrodes, is perpendicular to the Y-axis direction, and extends in the X-axis direction.

[0069] The filter circuit electrodes of the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1 are symmetrical with respect to the X-axis reference line AxeX0.

[0070] Multiple inductor electrodes Pt314, Pt315 and a capacitor electrode Pt316 constitute the filter circuit electrodes of the second T-type filter circuit 21T2. Multiple inductor electrodes Pt324, Pt325 and a capacitor electrode Pt326 constitute the filter circuit electrodes of the fourth T-type filter circuit 22T2. Multiple inductor electrodes Pt334, Pt335 and a capacitor electrode Pt336 constitute the filter circuit electrodes of the sixth T-type filter circuit 23T2.

[0071] The filter circuit electrodes of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 are positioned between the third pad electrode PDP3 and the fourth pad electrode PDP4. The filter circuit electrodes of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 are arranged in line along the Y-axis. More specifically, they are arranged in the order of the filter circuit electrodes of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2, moving from the third pad electrode PDP3 toward the fourth pad electrode PDP4.

[0072] The filter circuit electrodes of the second T-type filter circuit 21T2 and the filter circuit electrodes of the fourth T-type filter circuit 22T2 are symmetrical with respect to the X-axis reference line AxeX12 (see Figure 3, first virtual reference line).

[0073] The filter circuit electrodes of the fourth T-type filter circuit 22T2 and the filter circuit electrodes of the sixth T-type filter circuit 23T2 are symmetrical with respect to the X-axis reference line AxeX23 (see Figure 3, first virtual reference line).

[0074] The filter circuit electrodes of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 are symmetrical with respect to the X-axis reference line AxeX0.

[0075] (Filter circuit electrodes of the first T-type filter circuit 21T1: See Figures 2, 3, 4, 5(A), and 5(B)) The filter circuit electrodes of the first T-type filter circuit 21T1 are composed of an inductor electrode Pt311, an inductor electrode Pt312, and a capacitor electrode Pt313. The capacitor electrode Pt313 includes a counter electrode Pt3131 and a counter electrode Pt3132.

[0076] The inductor electrode Pt311 is formed in the second electrode layer. The inductor electrode Pt311 is a wound, strip-shaped electrode pattern. The inductor electrode Pt311 has a first end E1 (311) and a second end E2 (311). The inductor electrode Pt311 is formed counterclockwise from the first end E1 (311) toward the second end E2 (311).

[0077] The second end E2 (311) is connected to the first pad electrode PDP1 of the first electrode layer through the wiring electrode Pt301 and the via conductor VIA01 formed in the insulating layer 901. The second end E2 (311) is also connected to the counter electrode Pt3131 (second electrode layer) of the capacitor electrode Pt313. The counter electrode Pt3131 is positioned in the inner opening OP311 of the wound inductor electrode Pt311.

[0078] The first end E1 (311) is connected to the first end E1 (312) of the inductor electrode Pt312 formed in the first electrode layer through a via conductor VIA31 formed in the insulating layer 901. The first end E1 (311) of the inductor electrode Pt311 is also connected to the filter side electrode Pt317 (formed in the second electrode layer) of the shunt capacitor 317 through a wiring electrode Pt391.

[0079] The inductor electrode Pt312 is formed in the first electrode layer. The inductor electrode Pt312 is a wound, strip-shaped electrode pattern. The inductor electrode Pt312 has a first end E1 (312) and a second end E2 (312). The inductor electrode Pt312 is formed clockwise from the first end E1 (312) to the second end E2 (312).

[0080] The first end E1 (312) is connected to the first end E1 (311) of the inductor electrode Pt311 formed in the second electrode layer via the via conductor VIA31.

[0081] The second end E2 (312) is connected to the counter electrode Pt3132 (first electrode layer) of the capacitor electrode Pt313. The counter electrode Pt3132 is positioned in the inner opening OP312 of the wound inductor electrode Pt312. The second end E2 (312) is connected to the wiring electrode Pt302 that extends toward the second pad electrode PDP2.

[0082] Inductor electrodes Pt312 and Pt311 overlap when viewed from above. As a result, inductors 311 and 312 are forward coupled.

[0083] Furthermore, the counter electrode Pt3131 and the counter electrode Pt3132 overlap when viewed from above.

[0084] This completes the formation of capacitor 313.

[0085] This configuration forms a series circuit of inductor 311 and inductor 312 and a parallel circuit of capacitor 313, that is, a first T-type filter circuit 21T1.

[0086] Furthermore, openings OP311 and OP312 overlap, forming opening OP31 of the first T-type filter circuit 21T1.

[0087] (Filter circuit electrodes of the third T-type filter circuit 22T1: See Figures 2, 3, 4, 5(A), and 5(B)) The filter circuit electrodes of the third T-type filter circuit 22T1 are composed of an inductor electrode Pt321, an inductor electrode Pt322, and a capacitor electrode Pt323. The capacitor electrode Pt323 includes a counter electrode Pt3231 and a counter electrode Pt3232.

[0088] The inductor electrode Pt321 is formed in the first electrode layer. The inductor electrode Pt321 is a wound, strip-shaped electrode pattern. The inductor electrode Pt321 has a first end E1 (321) and a second end E2 (321). The inductor electrode Pt321 is formed counterclockwise from the first end E1 (321) toward the second end E2 (321).

[0089] The inductor electrode Pt321 has a shape that is symmetrical to the inductor electrode Pt312 with respect to the X-axis reference line AxeX12.

[0090] The second end E2 (321) is connected to the second end E2 (312) of the inductor electrode Pt312 through the wiring electrode Pt302. The second end E2 (321) of the inductor electrode Pt321 is connected to the counter electrode Pt3231 (first electrode layer) of the capacitor electrode Pt323. The counter electrode Pt3231 is positioned in the inner opening OP321 of the wound inductor electrode Pt321.

[0091] The counter electrode Pt3231 of the capacitor electrode Pt323 has a shape that is symmetrical to the counter electrode Pt3132 of the capacitor electrode Pt313 with respect to the X-axis reference line AxeX12.

[0092] The first end E1 (321) is connected to the first end E1 (322) of the inductor electrode Pt322 formed in the second electrode layer through a via conductor VIA32 formed in the insulating layer 901.

[0093] The inductor electrode Pt322 is formed in the second electrode layer. The inductor electrode Pt322 is a wound, strip-shaped electrode pattern. The inductor electrode Pt322 has a first end E1 (322) and a second end E2 (322). The inductor electrode Pt322 is formed clockwise from the first end E1 (322) to the second end E2 (322).

[0094] The first end E1 (322) is connected to the first end E1 (321) of the inductor electrode Pt321 formed in the first electrode layer via the via conductor VIA32.

[0095] The second end E2 (322) is connected to the counter electrode Pt3232 (second electrode layer) of the capacitor electrode Pt323. The counter electrode Pt3232 is positioned in the inner opening OP322 of the wound inductor electrode Pt322. The second end E2 (322) is connected to the wiring electrode Pt303 that extends toward the second pad electrode PDP2. In addition, the first end E1 (322) of the inductor electrode Pt322 is connected to the filter side electrode Pt327 (formed in the second electrode layer) of the shunt capacitor 327 through the wiring electrode Pt392.

[0096] Inductor electrodes Pt321 and Pt322 overlap when viewed from above. As a result, inductors 321 and 322 are forward coupled.

[0097] Furthermore, the counter electrode Pt3231 and the counter electrode Pt3232 overlap when viewed from above.

[0098] This completes the formation of capacitor 323.

[0099] This configuration forms a series circuit of inductor 321 and inductor 322 and a parallel circuit of capacitor 323, that is, a third T-type filter circuit 22T1.

[0100] Furthermore, openings OP321 and OP322 overlap, forming opening OP32 of the third T-type filter circuit 22T1.

[0101] (Filter circuit electrodes of the fifth T-type filter circuit 23T1: See Figures 2, 3, 4, 5(A), and 5(B)) The filter circuit electrodes of the fifth T-type filter circuit 23T1 are composed of an inductor electrode Pt331, an inductor electrode Pt332, and a capacitor electrode Pt333. The capacitor electrode Pt333 includes a counter electrode Pt3331 and a counter electrode Pt3332.

[0102] The inductor electrode Pt331 is formed in the second electrode layer. The inductor electrode Pt331 is a wound, strip-shaped electrode pattern. The inductor electrode Pt331 has a first end E1 (331) and a second end E2 (331). The inductor electrode Pt331 is formed counterclockwise from the first end E1 (331) toward the second end E2 (331).

[0103] The second end E2 (331) is connected to the second end E2 (322) of the inductor electrode Pt322 through the wiring electrode Pt303. The second end E2 (331) of the inductor electrode Pt331 is connected to the counter electrode Pt3331 (second electrode layer) of the capacitor electrode Pt333. The counter electrode Pt3331 is positioned in the inner opening OP331 of the wound inductor electrode Pt331.

[0104] The first end E1 (331) is connected to the first end E1 (332) of the inductor electrode Pt332 formed in the first electrode layer through a via conductor VIA33 formed in the insulating layer 901. The first end E1 (331) of the inductor electrode Pt331 is connected to the filter side electrode Pt337 (formed in the second electrode layer) of the shunt capacitor 337 through a wiring electrode Pt393.

[0105] The inductor electrode Pt332 is formed in the first electrode layer. The inductor electrode Pt332 is a wound, strip-shaped electrode pattern. The inductor electrode Pt332 has a first end E1 (332) and a second end E2 (332). The inductor electrode Pt332 is formed clockwise from the first end E1 (332) to the second end E2 (332).

[0106] The first end E1 (332) is connected to the first end E1 (331) of the inductor electrode Pt331 formed in the second electrode layer via the via conductor VIA33.

[0107] The second end E2 (332) is connected to the counter electrode Pt3332 (first electrode layer) of the capacitor electrode Pt333. The counter electrode Pt3332 is positioned in the inner opening OP332 of the wound inductor electrode Pt332. The second end E2 (332) is connected to the second pad electrode PDP2 through the wiring electrode Pt304 (first electrode layer).

[0108] Inductor electrodes Pt332 and Pt331 overlap when viewed from above. As a result, inductors 331 and 332 are forward coupled.

[0109] Furthermore, the counter electrode Pt3331 and the counter electrode Pt3332 overlap when viewed from above.

[0110] This completes the formation of capacitor 333.

[0111] Furthermore, this configuration forms a series circuit of inductor 331 and inductor 332 and a parallel circuit of capacitor 333, that is, a fifth T-type filter circuit 23T1.

[0112] Furthermore, openings OP331 and OP332 overlap to form opening OP33 of the fifth T-type filter circuit 23T1.

[0113] With this electrode pattern, the filter circuit electrodes of the first T-type filter circuit 21T1 and the filter circuit electrodes of the third T-type filter circuit 22T1 can be made symmetrical with respect to the X-axis reference line AxeX12. Furthermore, the filter circuit electrodes of the third T-type filter circuit 22T1 and the filter circuit electrodes of the fifth T-type filter circuit 23T1 can be made symmetrical with respect to the X-axis reference line AxeX23.

[0114] Furthermore, the circuit pattern consisting of the filter circuit electrodes of the first T-type filter circuit 21T1, the filter circuit electrodes of the third T-type filter circuit 22T1, and the filter circuit electrodes of the fifth T-type filter circuit 23T1 can achieve a shape that is symmetrical with respect to the X-axis reference line AxeX0.

[0115] With this configuration, the filter circuit electrodes of the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1 each contain only one via conductor. Therefore, the resistance values ​​of the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1 can be kept low.

[0116] Furthermore, the filter circuit electrodes of the first T-type filter circuit 21T1 and the filter circuit electrodes of the third T-type filter circuit 22T1 are connected on the same layer, without using via conductors. In addition, the filter circuit electrodes of the third T-type filter circuit 22T1 and the filter circuit electrodes of the fifth T-type filter circuit 23T1 are connected on the same layer, without using via conductors. Therefore, the resistance value of the wiring electrodes connecting the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1 to each other can be kept low.

[0117] Furthermore, the electrode pattern in the direction from the first pad electrode PDP1 (first input / output terminal) to the second pad electrode PDP2 (second input / output terminal) and the electrode pattern in the direction from the second pad electrode PDP2 (second input / output terminal) to the first pad electrode PDP1 (first input / output terminal) are approximately the same. This achieves symmetry in the circuit pattern of the filter circuit.

[0118] Therefore, a high-frequency filter configured using a series circuit of the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1 can suppress an increase in resistance. Thus, this high-frequency filter can suppress transmission loss and prevent deterioration of filter characteristics.

[0119] Furthermore, in the first T-type filter circuit 21T1, the capacitor electrode Pt313 is positioned inside the wound inductor electrodes Pt311 and Pt312. This allows the first T-type filter circuit 21T1 to be made compact (space-saving) and prevents the wiring electrodes from becoming undesirably long.

[0120] In the third T-type filter circuit 22T1, the capacitor electrode Pt323 is positioned inside the wound inductor electrodes Pt321 and Pt322. This allows the third T-type filter circuit 22T1 to be made compact (space-saving) and prevents the wiring electrodes from becoming undesirably long.

[0121] In the fifth T-type filter circuit 23T1, the capacitor electrode Pt333 is positioned inside the wound inductor electrodes Pt331 and Pt332. This allows the fifth T-type filter circuit 23T1 to be made compact (space-saving) and prevents the wiring electrodes from becoming unnecessarily long.

[0122] (Filter circuit electrodes of the second T-type filter circuit 21T2: See Figure 2) The filter circuit electrodes of the second T-type filter circuit 21T2 consist of an inductor electrode Pt314, an inductor electrode Pt315, and a capacitor electrode Pt316.

[0123] The inductor electrode Pt314 has a shape that is symmetrical to the inductor electrode Pt311 with respect to the Y-axis reference line AxeY. The inductor electrode Pt315 has a shape that is symmetrical to the inductor electrode Pt312 with respect to the Y-axis reference line AxeY. The capacitor electrode Pt316 has a shape that is symmetrical to the capacitor electrode Pt313 with respect to the Y-axis reference line AxeY.

[0124] (Filter circuit electrodes of the fourth T-type filter circuit 22T2: See Figure 2) The filter circuit electrodes of the fourth T-type filter circuit 22T2 consist of an inductor electrode Pt324, an inductor electrode Pt325, and a capacitor electrode Pt326.

[0125] The inductor electrode Pt324 has a shape that is symmetrical to the inductor electrode Pt321 with respect to the Y-axis reference line AxeY. The inductor electrode Pt325 has a shape that is symmetrical to the inductor electrode Pt322 with respect to the Y-axis reference line AxeY. The capacitor electrode Pt326 has a shape that is symmetrical to the capacitor electrode Pt323 with respect to the Y-axis reference line AxeY.

[0126] (Filter circuit electrodes of the 6th T-type filter circuit 23T2: See Figure 2) The filter circuit electrodes of the 6th T-type filter circuit 23T2 consist of an inductor electrode Pt334, an inductor electrode Pt335, and a capacitor electrode Pt336.

[0127] The inductor electrode Pt334 has a shape that is symmetrical to the inductor electrode Pt331 with respect to the Y-axis reference line AxeY. The inductor electrode Pt335 has a shape that is symmetrical to the inductor electrode Pt332 with respect to the Y-axis reference line AxeY. The capacitor electrode Pt336 has a shape that is symmetrical to the capacitor electrode Pt333 with respect to the Y-axis reference line AxeY.

[0128] With this configuration, the filter circuit electrodes of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 each contain only one via conductor. Therefore, the resistance values ​​of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 can be kept low.

[0129] Furthermore, the filter circuit electrodes of the second T-type filter circuit 21T2 and the filter circuit electrodes of the fourth T-type filter circuit 22T2 are connected on the same layer, without using via conductors. In addition, the filter circuit electrodes of the fourth T-type filter circuit 22T2 and the filter circuit electrodes of the sixth T-type filter circuit 23T2 are connected on the same layer, without using via conductors. Therefore, the resistance value of the wiring electrodes connecting the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 to each other can be kept low.

[0130] Furthermore, the electrode pattern in the direction from the third pad electrode PDP3 (third input / output terminal) to the fourth pad electrode PDP4 (fourth input / output terminal) is approximately the same as the electrode pattern in the direction from the fourth pad electrode PDP4 (fourth input / output terminal) to the third pad electrode PDP3 (third input / output terminal). This achieves symmetry in the circuit pattern of the filter circuit.

[0131] Therefore, a high-frequency filter configured using a series circuit of the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2 can suppress the increase in resistance, suppress transmission loss, and suppress deterioration of filter characteristics.

[0132] Furthermore, in the second T-type filter circuit 21T2, the capacitor electrode Pt316 is positioned inside the wound inductor electrodes Pt314 and Pt315. This allows the second T-type filter circuit 21T2 to be made compact (space-saving) and prevents the wiring electrodes from becoming undesirably long.

[0133] In the fourth T-type filter circuit 22T2, the capacitor electrode Pt326 is positioned inside the wound inductor electrodes Pt324 and Pt325. This allows the fourth T-type filter circuit 22T2 to be made compact (space-saving) and prevents the wiring electrodes from becoming undesirably long.

[0134] In the sixth-type T filter circuit 23T2, the capacitor electrode Pt336 is positioned inside the wound-type inductor electrodes Pt334 and Pt335. This allows the sixth-type T filter circuit 23T2 to be made compact (space-saving) and prevents the wiring electrodes from becoming undesirably long.

[0135] Furthermore, the filter circuit electrodes of the first T-type filter circuit 21T1, the second T-type filter circuit 21T2, the third T-type filter circuit 22T1, the fourth T-type filter circuit 22T2, the fifth T-type filter circuit 23T1, and the sixth T-type filter circuit 23T2 are symmetric with respect to the X-axis reference line AxeX0 and the Y-axis reference line AxeY. As a result, the common-mode noise filter 10 can achieve superior filtering characteristics.

[0136] (Electrode patterns on the reference potential side from each filter circuit: see Figure 2) The common-mode noise filter 10 comprises filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, Pt338 of a plurality of shunt capacitor electrodes, and reference potential connection electrodes PtCG1, PtCG2 of the shunt capacitor electrodes.

[0137] Multiple filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, and Pt338 are each rectangular in shape with a predetermined area and are formed in the second electrode layer.

[0138] The reference potential connection electrode PtCG1 is formed in the first electrode layer. The reference potential connection electrode PtCG2 is formed in the electrode layer closer to the substrate than the second electrode layer.

[0139] Reference potential connection electrodes PtCG1 and PtCG2 overlap with multiple filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, and Pt338 in a plan view.

[0140] The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt317 overlap and face each other constitutes a shunt capacitor 317. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt318 overlap and face each other constitutes a shunt capacitor 318. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt327 overlap and face each other constitutes a shunt capacitor 327. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt328 overlap and face each other constitutes a shunt capacitor 328. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt337 overlap and face each other constitutes a shunt capacitor 337. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter side electrode Pt338 overlap and face each other constitutes a shunt capacitor 338.

[0141] Multiple filter-side electrodes Pt317, Pt327, and Pt337 are arranged in the Y-axis direction between the first pad electrode PDP1 and the second pad electrode PDP2. In the Y-axis direction, the multiple filter-side electrodes Pt317, Pt327, and Pt337 are arranged in the order of filter-side electrode Pt317, filter-side electrode Pt327, and filter-side electrode Pt337, from the first pad electrode PDP1 side toward the second pad electrode PDP2 side. As a result, the multiple shunt capacitors 317, 327, and 337 are arranged in the Y-axis direction between the first pad electrode PDP1 and the second pad electrode PDP2.

[0142] The Y-axis centers of the arrangement of filter-side electrodes Pt317, Pt327, and Pt337 are approximately positioned on the X-axis reference line AxeX0, and are arranged symmetrically with respect to the X-axis reference line AxeX0.

[0143] The filter-side electrode Pt317 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt311, Pt312 and capacitor electrode Pt313 in the X-axis direction. The filter-side electrode Pt327 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt321, Pt322 and capacitor electrode Pt323 in the X-axis direction. The filter-side electrode Pt337 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt331, Pt332 and capacitor electrode Pt333 in the X-axis direction.

[0144] Multiple filter-side electrodes Pt318, Pt328, and Pt338 are arranged in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4. In the Y-axis direction, the multiple filter-side electrodes Pt318, Pt328, and Pt338 are arranged in the order of filter-side electrode Pt318, filter-side electrode Pt328, and filter-side electrode Pt338, from the third pad electrode PDP3 side toward the fourth pad electrode PDP4 side. As a result, the multiple shunt capacitors 318, 328, and 338 are arranged in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4.

[0145] The Y-axis centers of the arrangement of filter-side electrodes Pt318, Pt328, and Pt338 are approximately positioned on the X-axis reference line AxeX0, and are arranged symmetrically with respect to the X-axis reference line AxeX0.

[0146] The filter-side electrode Pt318 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt314, Pt315 and capacitor electrode Pt316 in the X-axis direction. The filter-side electrode Pt328 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt324, Pt325 and capacitor electrode Pt326 in the X-axis direction. The filter-side electrode Pt338 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt334, Pt335 and capacitor electrode Pt336 in the X-axis direction.

[0147] With this configuration, the electrode patterns for connecting the multiple shunt capacitors 317, 318, 327, 328, 337, and 338 to the reference potential are approximately symmetrical with respect to the X-axis reference line AxeX0 and the Y-axis reference line AxeY. Therefore, the common-mode noise filter 10 can achieve superior filtering characteristics.

[0148] Furthermore, the inductor 300 is composed of a second electrode layer and a linear, wound inductor electrode Pt300 formed on the electrode layer closer to the substrate than the second electrode layer. Preferably, the inductor electrode Pt300 is positioned on the Y-axis reference line AxeY.

[0149] Furthermore, it is preferable that the inductor electrode Pt300 is positioned between the second pad electrode PDP2 and the fourth pad electrode PDP4. Additionally, as shown in Figure 2, it is preferable that the inductor electrode Pt300 overlaps the Y-axis reference line AxeY and is connected to the reference potential connection electrode PtCG2 and the ground pad electrode PDG by wiring electrodes extending in the Y-axis direction.

[0150] This allows the common-mode noise filter 10 to achieve even better filtering characteristics.

[0151] [Second Embodiment] A high-frequency filter and a common-mode noise filter according to a second embodiment of the present invention will be described with reference to the figures. Figure 6 is an enlarged plan view of the high-frequency filter according to the second embodiment of the present invention.

[0152] The high-frequency filter of the common-mode noise filter 10A in the second embodiment has a different number of filter stages compared to the high-frequency filter of the common-mode noise filter 10 in the first embodiment. The other configurations of the high-frequency filter of the common-mode noise filter 10A are the same as those of the high-frequency filter of the common-mode noise filter 10, and the explanation of the similar parts will be omitted.

[0153] The high-frequency filter of the common-mode noise filter 10A is composed of a two-stage filter circuit. Specifically, as shown in Figure 6, the high-frequency filter is composed of a series circuit of the third T-type filter circuit 22T1 and the fifth T-type filter circuit 23T1 shown in the first embodiment.

[0154] The inductor electrode Pt321 of the filter circuit electrode of the third T-type filter circuit 22T1 is connected to the first pad electrode PDP1 through the wiring electrode Pt302A of the same layer.

[0155] Thus, if the number of filter circuits connected in series is even, via conductors do not need to be used for the connection between the first pad electrode PDP1 and the second pad electrode PDP2.

[0156] As a result, the high-frequency filter of the common-mode noise filter 10A can further suppress the increase in resistance, further suppress transmission loss, and further suppress deterioration of filter characteristics.

[0157] [Third Embodiment] A high-frequency filter and a common-mode noise filter according to a third embodiment of the present invention will be described with reference to the figures. Figure 7 is an enlarged plan view of the high-frequency filter according to the third embodiment of the present invention.

[0158] The high-frequency filter of the common-mode noise filter 10B according to the third embodiment has a different number of filter stages compared to the high-frequency filter of the common-mode noise filter 10A according to the second embodiment. The other configurations of the high-frequency filter of the common-mode noise filter 10B are the same as those of the high-frequency filter of the common-mode noise filter 10A, and the explanation of the similar parts will be omitted.

[0159] The high-frequency filter of the common-mode noise filter 10B is composed of a four-stage filter circuit. Specifically, as shown in Figure 7, the high-frequency filter is composed of the third T-type filter circuit 22T1 and the fifth T-type filter circuit 23T1 shown in the first embodiment, and the seventh T-type filter circuit 24T1 and the eighth T-type filter circuit 25T1.

[0160] The seventh T-type filter circuit 24T1 comprises an inductor electrode Pt341, an inductor electrode Pt342, a capacitor electrode Pt343, and a via conductor VIA34. The inductor electrodes Pt341 and Pt342 are wound and form an opening OP34. The seventh T-type filter circuit 24T1 is connected to a wiring electrode Pt394 and to a shunt capacitor corresponding to the seventh T-type filter circuit 24T1.

[0161] The seventh T-type filter circuit 24T1 has the same configuration as the third T-type filter circuit 22T1.

[0162] The inductor electrode Pt341 is connected to the inductor electrode Pt332 of the fifth T-type filter circuit 23T1 through the wiring electrode Pt302 of the same layer.

[0163] The 8th T-type filter circuit 25T1 comprises an inductor electrode Pt351, an inductor electrode Pt352, a capacitor electrode Pt353, and a via conductor VIA35. The inductor electrodes Pt351 and Pt352 are wound and form an opening OP35. The 8th T-type filter circuit 25T1 is connected to a wiring electrode Pt395 and to a shunt capacitor corresponding to the 8th T-type filter circuit 25T1.

[0164] The 8th T-type filter circuit 25T1 has the same configuration as the 5th T-type filter circuit 23T1.

[0165] The inductor electrode Pt351 is connected to the inductor electrode Pt342 of the 7th T-type filter circuit 24T1 via the wiring electrode Pt305 of the same layer.

[0166] The inductor electrode Pt352 is connected to the second pad electrode PDP2 through the wiring electrode Pt306 in the same layer.

[0167] Thus, if the number of filter circuits connected in series is even, via conductors do not need to be used for the connection between the first pad electrode PDP1 and the second pad electrode PDP2.

[0168] As a result, the high-frequency filter of the common-mode noise filter 10B can further suppress the increase in resistance, further suppress transmission loss, and further suppress deterioration of filter characteristics.

[0169] [Fourth Embodiment] A high-frequency filter and a common-mode noise filter according to the fourth embodiment of the present invention will be described with reference to the figures. Figure 8 is an enlarged plan view of the high-frequency filter according to the fourth embodiment of the present invention.

[0170] The high-frequency filter of the common-mode noise filter 10C according to the fourth embodiment has a different number of filter stages compared to the high-frequency filter of the common-mode noise filter 10 according to the first embodiment. The other configurations of the high-frequency filter of the common-mode noise filter 10C are the same as those of the high-frequency filter of the common-mode noise filter 10, and the explanation of the similar parts will be omitted.

[0171] The high-frequency filter of the common-mode noise filter 10C is composed of a single-stage filter circuit. Specifically, as shown in Figure 8, the high-frequency filter is composed solely of the first T-type filter circuit 21T1 shown in the first embodiment.

[0172] The filter circuit electrodes of the first T-type filter circuit 21T1 are symmetrical in a plan view with respect to the X-axis reference line AxeX1 (third virtual reference line) passing through the via conductor VIA31.

[0173] The inductor electrode Pt312 is connected to the second pad electrode PDP2 through the wiring electrode Pt302 in the same layer.

[0174] Thus, even with a single-stage filter circuit, the number of via conductors included in the filter circuit can be reduced, and the line symmetry allows the high-frequency filter of the common-mode noise filter 10C to suppress an increase in resistance, suppress transmission loss, and suppress deterioration of filter characteristics.

[0175] <1> A high-frequency filter comprising: a first input / output terminal; a second input / output terminal; and a plurality of filter circuits connected in series between the first input / output terminal and the second input / output terminal, wherein a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and filter circuit electrodes constituting each of the plurality of filter circuits are formed on a substrate, wherein the plurality of filter circuits have the same circuit configuration, the plurality of filter circuit electrodes are arranged side by side between the first pad electrode and the second pad electrode in a first direction of the substrate, and adjacent filter circuit electrodes in the plurality of filter circuit electrodes are symmetrical with respect to a first virtual reference line that passes through the intermediate position of the adjacent filter circuit electrodes and extends in a second direction perpendicular to the first direction.

[0176] <2> The high-frequency filter according to <1>, wherein the plurality of filter circuit electrodes have a shape that is symmetrical with respect to a second virtual reference line that passes through the center in the first direction in the formation region of the plurality of filter circuit electrodes and extends in the second direction.

[0177] <3> The high-frequency filter according to <1> or <2>, wherein the filter circuit comprises a first series circuit of a first inductor and a second inductor connected in series with each other and magnetically coupled to each other, and a parallel capacitor connected in parallel with the first series circuit.

[0178] <4> The high-frequency filter according to <3>, wherein the first inductor and the second inductor are configured in a wound type, and the parallel capacitor is arranged in the central opening of the wound type.

[0179] <5> The high-frequency filter according to <3> or <4>, wherein the substrate comprises a plurality of insulating layers, the plurality of insulating layers comprising a first insulating layer, a second insulating layer, in order from the surface side of the substrate toward the base material, the first counter electrodes of the first inductor and the parallel capacitor formed in the first insulating layer, and the second counter electrodes of the second inductor and the parallel capacitor formed in the second insulating layer.

[0180] <6> The high-frequency filter according to <4>, wherein the first inductor in adjacent filter circuit electrodes has a shape symmetric with respect to the first virtual reference line, and the second inductor in adjacent filter circuit electrodes has a shape symmetric with respect to the first virtual reference line.

[0181] <7> The high-frequency filter according to <5> or <6>, wherein the first counter electrode in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line, and the second counter electrode in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line.

[0182] <8> The high-frequency filter according to any one of <1> to <7>, wherein the number of the plurality of filter circuit electrodes is even.

[0183] <9> The high-frequency filter according to any one of <1> to <7>, wherein the number of the plurality of filter circuit electrodes is an odd number of three or more.

[0184] <10> A high-frequency filter comprising: a first input / output terminal; a second input / output terminal; and a filter circuit connected in series between the first input / output terminal and the second input / output terminal, wherein a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and a filter circuit electrode constituting the filter circuit are formed on a substrate, wherein in a first direction of the substrate, the filter circuit electrode is arranged between the first pad electrode and the second pad electrode, and the filter circuit electrode has a shape that is symmetrical with respect to a third virtual reference line extending in a second direction perpendicular to the first direction in the formation region of the plurality of filter circuit electrodes when viewed from above.

[0185] <11> A common-mode noise filter comprising: a first high-frequency filter and a second high-frequency filter having the configuration of any one of <1> to <10>; a third input / output terminal; a fourth input / output terminal; a ground connection terminal; and a ground connection circuit connecting the first high-frequency filter and the second high-frequency filter to the ground connection terminal, wherein the first high-frequency filter is connected between the first input / output terminal and the second input / output terminal in the first direction; the second high-frequency filter is connected between the third input / output terminal and the fourth input / output terminal in the first direction; the first input / output terminal and the third input / output terminal are aligned in the second direction; the second input / output terminal and the fourth input / output terminal are aligned in the second direction; the first high-frequency filter and the second high-frequency filter are aligned in the second direction; the ground connection circuit is positioned between the first high-frequency filter and the second high-frequency filter in the second direction; the first input / output terminal and the second input / output terminal are used as input / output terminals for a first differential signal; and the third input / output terminal and the fourth input / output terminal are used as input / output terminals for a second differential signal.

[0186] 10, 10A, 10B, 10C: Common-mode noise filters 21: First common-mode noise filter 21T1: First T-type filter circuit 21T2: Second T-type filter circuit 22: Second common-mode noise filter 22T1: Third T-type filter circuit 22T2: Fourth T-type filter circuit 23: Third common-mode noise filter 23T1: Fifth T-type filter circuit 23T2: Sixth T-type filter circuit 24T1: Seventh T-type filter circuit 25T1: Eighth T-type filter circuit 90: Substrate 91: Insulator layer 300, 311, 312, 314, 315, 321, 322, 324, 325, 331, 332, 334, 335: Inductors 313, 316, 323, 326, 333, 336: Capacitors 317, 318, 327, 328, 337, 338: Shunt capacitors 900, 901, 902: Insulator layers AxeX0, AxeX1, AxeX12, AxeX23: X-axis reference line AxeY: Y-axis reference line E1: First end E2: Second end OP31, OP311, OP312, OP32, OP321, OP322, OP33, OP331, OP332, OP34, OP35: Openings P1: First input / output terminal P2: Second input / output terminal P3: Third input / output terminal P4: Fourth input / output terminal PDG: Ground pad electrode PDP1: First pad electrode PDP2: Second pad electrode PDP3: Third pad electrode PDP4: Fourth pad electrode PGND: Reference potential connection terminal Pt300: Inductor electrode Pt301, Pt302, Pt302A, Pt303, Pt304, Pt305, Pt306, Pt391, Pt392, Pt393, Pt394, Pt395: Wiring electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, Pt335, Pt341, Pt342, Pt351, Pt352: Inductor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, Pt336, Pt343, Pt353: Capacitor electrode Pt3131, Pt3132, Pt3231, Pt3232, Pt3331, Pt3332: Opposing electrodes Pt317, Pt318, Pt327, Pt328, Pt337, Pt338: Filter-side electrodes PtCG1, PtCG2: Reference potential connection electrodesVIA01, VIA31, VIA32, VIA33, VIA34, VIA35: Via conductors

Claims

1. A high-frequency filter comprising: a first input / output terminal; a second input / output terminal; and a plurality of filter circuits connected in series between the first input / output terminal and the second input / output terminal, wherein a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and filter circuit electrodes constituting each of the plurality of filter circuits are formed on a substrate, wherein the plurality of filter circuits have the same circuit configuration, the plurality of filter circuit electrodes are arranged side by side between the first pad electrode and the second pad electrode in a first direction of the substrate, and adjacent filter circuit electrodes in the plurality of filter circuit electrodes are symmetrical with respect to a first virtual reference line that passes through the intermediate position of the adjacent filter circuit electrodes and extends in a second direction perpendicular to the first direction.

2. The high-frequency filter according to claim 1, wherein the plurality of filter circuit electrodes have a shape that is symmetrical with respect to a second virtual reference line that passes through the center in the first direction in the formation region of the plurality of filter circuit electrodes and extends in the second direction.

3. The high-frequency filter according to claim 1 or claim 2, comprising: a first series circuit of a first inductor and a second inductor connected in series with respect to each other and magnetically coupled to each other; and a parallel capacitor connected in parallel with respect to the first series circuit.

4. The high-frequency filter according to claim 3, wherein the first inductor and the second inductor are configured in a wound type, and the parallel capacitor is arranged in the central opening of the wound type.

5. The high-frequency filter according to claim 3 or claim 4, wherein the substrate comprises a plurality of insulating layers, the plurality of insulating layers comprising a first insulating layer, a second insulating layer, in order from the surface side of the substrate toward the base material, the first counter electrodes of the first inductor and the parallel capacitor formed in the first insulating layer, and the second counter electrodes of the second inductor and the parallel capacitor formed in the second insulating layer.

6. The high-frequency filter according to claim 4, wherein the first inductor in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line, and the second inductor in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line.

7. The high-frequency filter according to claim 5 or claim 6, wherein the first counter electrode in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line, and the second counter electrode in the adjacent filter circuit electrodes has a shape symmetrical with respect to the first virtual reference line.

8. The high-frequency filter according to any one of claims 1 to 7, wherein the number of the plurality of filter circuit electrodes is even.

9. The high-frequency filter according to any one of claims 1 to 7, wherein the number of the plurality of filter circuit electrodes is an odd number of three or more.

10. A high-frequency filter comprising: a first input / output terminal; a second input / output terminal; and a filter circuit connected in series between the first input / output terminal and the second input / output terminal, wherein a first pad electrode constituting the first input / output terminal, a second pad electrode constituting the second input / output terminal, and a filter circuit electrode constituting the filter circuit are formed on a substrate, wherein in a first direction of the substrate, the filter circuit electrode is positioned between the first pad electrode and the second pad electrode, and the filter circuit electrode has a shape that is symmetrical with respect to a third virtual reference line extending in a second direction perpendicular to the first direction in the formation region of the plurality of filter circuit electrodes when viewed from above.

11. A common-mode noise filter comprising: a first high-frequency filter and a second high-frequency filter having the configuration of a high-frequency filter according to any one of claims 1 to 10; a third input / output terminal; a fourth input / output terminal; a ground connection terminal; and a ground connection circuit connecting the first high-frequency filter and the second high-frequency filter to the ground connection terminal, wherein the first high-frequency filter is connected between the first input / output terminal and the second input / output terminal in the first direction; the second high-frequency filter is connected between the third input / output terminal and the fourth input / output terminal in the first direction; the first input / output terminal and the third input / output terminal are aligned in the second direction; the second input / output terminal and the fourth input / output terminal are aligned in the second direction; the first high-frequency filter and the second high-frequency filter are aligned in the second direction; the ground connection circuit is positioned between the first high-frequency filter and the second high-frequency filter in the second direction; the first input / output terminal and the second input / output terminal are input / output terminals for a first differential signal; and the third input / output terminal and the fourth input / output terminal are input / output terminals for a second differential signal.

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