Filter device and high-frequency front-end circuit incorporating the same

Abstract

The filter (100) of the present application has a main body (110) and filters (FLT1, FLT2) having different passbands. In the main body (110), an inductor of the filter (FLT1) is disposed in a region (RG1), and an inductor of the filter (FLT2) is disposed in a region (RG2). The inductor included in the filter (FLT1) is a longitudinal coil including a flat plate electrode provided to the main body and a via hole extending in a normal direction of the main body. In the filter (FLT2), the inductor disposed at a position facing the region (RG1) is a planar coil having a winding axis in the normal direction of the main body (110). When viewed from the normal direction of the main body (110), an imaginary line (CL1) drawn from the center of the extending direction of the flat plate electrode in the filter (FLT1) to a direction orthogonal to the extending direction does not cross the inductor of the filter (FLT2).

Description

Technical Field

[0001] This disclosure relates to filter devices and high-frequency front-end circuits incorporating the filter devices, and more specifically, to techniques for improving the pass-through characteristics in a duplexer comprising two LC filters. Background Technology

[0002] Japanese Patent Application Publication No. 2019-507972 (Patent Document 1) discloses a multiplexer comprising a high-frequency band filter and a low-frequency band filter constructed from LC circuits. In the multiplexer of Japanese Patent Application Publication No. 2019-507972 (Patent Document 1), the inductor of the high-frequency band filter is configured as a 2D spiral inductor on the surface of the substrate, and the inductor of the low-frequency band filter is configured as a 3D inductor in a layer inside the substrate.

[0003] In addition, Japanese Patent Application Publication No. 11-40920 (Patent Document 2) discloses a structure in which the inductors are arranged such that the magnetic flux generated by adjacent inductors is approximately orthogonal to each other in a composite component that integrates multiple inductors.

[0004] Patent Document 1: Japanese Patent Publication No. 2019-507972

[0005] Patent Document 2: Japanese Patent Application Publication No. 11-40920

[0006] However, in the structures disclosed in Japanese Patent Application Publication No. 2019-507972 (Patent Document 1) and Japanese Patent Application Publication No. 11-40920 (Patent Document 2), in the inductors included in the filters arranged adjacently, the magnetic flux passing through the hollow diameter of one inductor interferes with the other inductor, so the two inductors may be magnetically coupled to each other.

[0007] In filter devices (duplexers, multiplexers) that contain multiple LC filters, if the inductors of different filters are magnetically coupled to each other, a decrease in Q value and / or a deterioration in isolation will occur, raising concerns about a reduction in filter performance. Summary of the Invention

[0008] This disclosure was made to solve such a problem, and its purpose is to suppress the degradation of filter characteristics in a filter device consisting of multiple LC filters.

[0009] The filter device of the first aspect of this disclosure includes: a main body, a first filter having a first passband, and a second filter having a second passband different from the first passband. When viewed from the normal direction of the main body, an inductor included in the first filter is disposed in a first region, and an inductor included in the second filter is disposed in a second region, wherein the second region is adjacent to the first region. The first filter and the second filter each include at least one inductor. The inductor included in the first filter is a longitudinal coil comprising a planar electrode disposed on the main body and a through-hole extending in the normal direction of the main body. In the second filter, the inductor disposed at a position facing the first region is a planar coil with the normal direction of the main body as its winding axis. When viewed from the normal direction of the main body, an imaginary line drawn from the center of the extending direction of the planar electrode in the first filter in a direction orthogonal to that extending direction does not intersect the inductor included in the second filter.

[0010] The filter device of the second aspect of this disclosure includes: a main body, a first filter having a first passband, and a second filter having a second passband different from the first passband. The first filter and the second filter each include at least one inductor. Viewed from the normal direction of the main body, the inductor included in the first filter is disposed in a first region, and the inductor included in the second filter is disposed in a second region, wherein the second region is adjacent to the first region. The inductor included in the first filter is a longitudinal coil comprising a planar electrode disposed on the main body and a through-hole extending in the normal direction of the main body. In the second filter, the inductor disposed at a position facing the first region includes a longitudinal coil and a planar coil wound around the normal direction of the main body. The distance between the longitudinal coil of the second filter and the first region is greater than the distance between the planar coil and the first region. When viewed from the normal direction of the main body, (i) a first imaginary line drawn from the center of the extension direction of the plate electrode in the first filter to a direction orthogonal to the extension direction does not intersect the inductor included in the second filter, and (ii) a second imaginary line drawn from the center of the extension direction of the plate electrode in the second filter to a direction orthogonal to the extension direction does not intersect the inductor included in the first filter.

[0011] In the filter device disclosed herein, two filters (a first filter and a second filter) are arranged in adjacent regions within the main body. The inductor of the first filter is a longitudinal coil composed of a planar electrode and a via. In the second filter, the inductor arranged facing the first filter is a planar coil. Furthermore, an imaginary line drawn from the center of the extending direction of the planar electrode in the first filter in a direction orthogonal to that extending direction does not intersect with the inductor included in the second filter. By adopting such a structure, magnetic field generated by the inductor of one filter can be prevented from interfering with the inductor of the other filter, thus suppressing magnetic coupling between the inductors. Therefore, the degradation of filter characteristics can be suppressed. Attached Figure Description

[0012] Figure 1 This is a block diagram of a communication device having a high-frequency front-end circuit with a filter device according to embodiment 1.

[0013] Figure 2 This is the equivalent circuit diagram of the filter device in Implementation Method 1.

[0014] Figure 3 It means Figure 2 A three-dimensional view of the interior of the filter device.

[0015] Figure 4 It means Figure 2 An exploded perspective view of an example of a stacked structure of a filter device.

[0016] Figure 5 It is used for Figure 2 The diagram illustrates the configuration of the inductors in the filter device.

[0017] Figure 6 This is a diagram used to illustrate the configuration of the inductors in each filter of the filter device in Comparative Example 1.

[0018] Figure 7 This is a diagram used to illustrate the pass-through characteristics of the filter device in Embodiment 1 and Comparative Example 1.

[0019] Figure 8 This is a diagram used to illustrate the configuration of the inductors in each filter of the filter device in Comparative Example 2.

[0020] Figure 9 This is a diagram used to illustrate the pass-through characteristics of the filter devices in Embodiment 1 and Comparative Example 2.

[0021] Figure 10 This is a diagram used to explain the configuration of the inductors of each filter in the filter device of Embodiment 2.

[0022] Figure 11 This is a diagram used to explain the configuration of the inductors in each filter of the filter device in Embodiment 3. Detailed Implementation

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals and their descriptions will not be repeated.

[0024] [Implementation Method 1]

[0025] (Basic structure of a communication device)

[0026] Figure 1 This is a block diagram of a communication device 10 including a high-frequency front-end circuit 20, which applies the filter device 100 of the implementation embodiment. The high-frequency front-end circuit 20 divides the high-frequency signal received by the antenna device ANT into multiple predetermined frequency bands and transmits them to subsequent processing circuits. The high-frequency front-end circuit 20 can be used, for example, in mobile terminals such as mobile phones, smartphones, or tablet computers, and communication devices such as personal computers with communication functions.

[0027] Reference Figure 1 The communication device 10 includes a high-frequency front-end circuit 20 and an RF signal processing circuit (hereinafter also referred to as "RFIC") 30, wherein the high-frequency front-end circuit 20 includes a filter device 100. Figure 1 The high-frequency front-end circuit 20 shown is the front-end circuit of the receiving system. The high-frequency front-end circuit 20 includes a filter device 100 and amplifier circuits LNA1 and LNA2.

[0028] The filter device 100 is a duplexer comprising a filter FLT1 (first filter) and a filter FLT2 (second filter) with passbands of different frequency ranges. In the following description, the filter device 100 will be referred to as a "duplexer".

[0029] Filter FLT1 is connected between antenna terminal TA (which serves as a common terminal) and first terminal T1. Filter FLT1 is a low-pass filter that uses the low-frequency band (LB) as the passband and the high-frequency band (HB) as the non-passband. Filter FLT2 is connected between antenna terminal TA and second terminal T2. Filter FLT2 is a high-pass filter that uses the high-frequency band as the passband and the low-frequency band as the non-passband. Alternatively, filters FLT1 and FLT2 can also be bandpass filters.

[0030] Filters FLT1 and FLT2 allow only the high-frequency signals corresponding to the passbands of their respective filters from the high-frequency signals received by the antenna device ANT to pass through. This splits the received signal from the antenna device ANT into signals with multiple predetermined frequency bands.

[0031] Amplifier circuits LNA1 and LNA2 are so-called low-noise amplifiers. Amplifier circuits LNA1 and LNA2 amplify the high-frequency signals that have passed through the corresponding filters with low noise and then transmit them to RFIC30.

[0032] RFIC30 is an RF signal processing circuit that processes the high-frequency signals transmitted and received by the antenna device ANT. Specifically, RFIC30 processes the high-frequency signals input from the antenna device ANT via the receiving-side signal path of the high-frequency front-end circuit 20 through down-conversion and the like, and outputs the received signal generated by the signal processing to the baseband signal processing circuit (not shown).

[0033] In such Figure 1 When the high-frequency front-end circuit 20 is used as a receiving circuit, in the filter device 100, the antenna terminal TA becomes the input terminal IN, and the first terminal T1 and the second terminal T2 become the first output terminal OUT1 and the second output terminal OUT2, respectively. Alternatively, the high-frequency front-end circuit can also be used as a transmitting circuit. In this case, the first terminal T1 and the second terminal T2 of the filter device 100 become input terminals, and the antenna terminal TA becomes a common output terminal. In this case, a power amplifier is used as the amplifier included in the amplification circuit.

[0034] (Structure of the filter device)

[0035] Figure 2 It means Figure 1 A diagram of the equivalent circuit of an example of the filter device (duplexer) 100 in the diagram. Figure 1 As explained, filter FLT1 is connected between antenna terminal TA and first terminal T1. Additionally, filter FLT2 is connected between antenna terminal TA and second terminal T2.

[0036] Filter FLT1 includes inductors L11 and L12 and capacitor C12 forming a series arm circuit, and capacitor C11 forming a parallel arm circuit. Inductor L11 is connected to the antenna terminal TA, and inductor L12 is connected between inductor L11 and the first terminal T1. That is, inductors L11 and L12 are connected in series between the antenna terminal TA and the first terminal T1. Capacitor C11 is connected between the connection node between inductors L11 and L12 and the ground terminal GND. Capacitor C12 is connected in parallel with inductor L12. Filter FLT1, through these structures, serves as a low-pass filter that allows signals in frequency bands lower than a specified frequency to pass through.

[0037] Filter FLT2 includes inductors L21 and L24 and capacitors C21 and C25 forming a series arm circuit, and inductors L22 and L23 and capacitors C22 to C24 forming a parallel arm circuit. One end of inductor L21 is connected to the antenna terminal TA, and the other end is connected to one end of capacitor C21. Capacitor C25 is connected between the other end of capacitor C21 and the second terminal T2. Inductor L24 is connected in parallel with capacitor C25.

[0038] One end of capacitor C22 is connected to the connection node between inductor L21 and capacitor C21. The other end of capacitor C22 is connected to the ground terminal GND via inductor L22. One end of capacitor C23 is connected to the connection node between capacitor C21 and capacitor C25. The other end of capacitor C23 is connected to the ground terminal GND via inductor L22.

[0039] One end of inductor L23 is connected to the connection node between capacitors C21 and C25. The other end of inductor L23 is connected to the ground terminal GND via capacitor C24.

[0040] The filter FLT2 functions as a bandpass filter through an LC resonator consisting of a notch filter L21, an inductor L22 and capacitors C21 to C23, a resonator consisting of an inductor L23 and capacitor C24, and a resonator consisting of an inductor L24 and capacitor C25.

[0041] Furthermore, in the example of the filter device 100 of Embodiment 1, the passband of filter FLT1 is set in the vicinity of 0 to 960 MHz, and the passband of filter FLT2 is set in the vicinity of 1427 MHz to 2690 MHz. Therefore, in the filter device 100, filter FLT2 functions as a high-pass filter.

[0042] Next, use Figures 3-5 The internal structure of the filter device 100 is described in detail. Figure 3 It means Figure 2 A three-dimensional view of the interior of the filter device 100. Figure 4 This is an exploded perspective view showing an example of the stacked structure of the filter device 100. Additionally, Figure 5 This diagram illustrates the configuration of the inductors in the filter device 100, specifically, it shows how... Figure 4 Top view of dielectric layers LY2 to LY8 overlapping.

[0043] Reference Figure 3 and Figure 4 The filter device 100 includes a main body 110 formed by stacking multiple dielectric layers LY1 to LY17 along a predetermined direction to form a cuboid or approximately cuboid. In the main body 110, the direction in which the multiple dielectric layers LY1 to LY17 are stacked is designated as the stacking direction. Each dielectric layer of the main body 110 is formed, for example, of ceramics such as low-temperature co-fired ceramics (LTCC) or resin. Inside the main body 110, inductors and capacitors for constituting filters FLT1 and FLT2 are constructed through multiple electrodes disposed in each dielectric layer and multiple through-holes disposed between the dielectric layers. Furthermore, in... Figures 3-5 The dielectric of the main body 110 is omitted; only the wiring pattern, vias, and conductors of the terminals disposed therein are shown. In this specification, a "via" refers to a conductor formed in the dielectric layer for connecting electrodes disposed in different dielectric layers. Vias are formed, for example, by conductive paste, plating, and / or metal pins.

[0044] In the following explanation, the stacking direction of the main body 110 is referred to as the "Z-axis direction", the direction perpendicular to the Z-axis direction and along the long side of the main body 110 is referred to as the "X-axis direction", and the direction along the short side of the main body 110 is referred to as the "Y-axis direction". In addition, in the following, the positive direction of the Z-axis in each figure will be referred to as the top side, and the negative direction will be referred to as the bottom side.

[0045] On the first main surface 111 (dielectric layer LY1) of the main body 110, a directional mark DM for determining the orientation of the filter device 100 is disposed. On the second main surface 112 (dielectric layer LY17) of the main body 110, antenna terminals TA, first terminals T1, second terminals T2, and ground terminals GND are disposed as external terminals for connecting the filter device 100 to external devices. Each external terminal is a planar electrode, which is an LGA (Land Grid Array) terminal regularly arranged on the second main surface 112 of the main body 110. Figure 3 and Figure 4In the example shown, generally speaking, a low-frequency band filter FLT1 is arranged on the left side (negative direction of the X-axis) of the main body 110, and a high-frequency band filter FLT2 is arranged on the right side (positive direction of the X-axis).

[0046] The antenna terminal TA, located on the second main surface 112 (dielectric layer LY17), is connected to the branch point PB1 of filters FLT1 and FLT2 in the dielectric layer LY2 via vias VA1 and VA2 and a planar electrode PA1. The vias VA1 and VA2 are offset by the planar electrode PA1 located in the dielectric layer LY16.

[0047] First, the details of filter FLT1, which is a low-pass filter, will be explained. At the branch point PB1, a linear planar electrode PL1 extending in the negative X-axis direction from the branch point PB1 is connected. A via VL1 is connected to one end of the planar electrode PL1. The planar electrode PL1 is connected to one end of a strip-shaped planar electrode PL1A disposed in the dielectric layer LY8 via the via VL1. A via VL1A is connected to the other end of the planar electrode PL1A. The planar electrode PL1A is connected to one end of a linear planar electrode PL1B disposed in the dielectric layer LY2 via the via VL1A. The planar electrode PL1B extends in the X-axis direction in the dielectric layer LY2, and a via VL1B is connected to its other end. The planar electrode PL1B is connected to one end of a strip-shaped planar electrode PL1C disposed in the dielectric layer LY8 via the via VL1B.

[0048] A via VL1C is connected to the other end of the planar electrode PL1C. The planar electrode PL1C is connected to one end of the linear planar electrode PL1D disposed in the dielectric layer LY2 via the via VL1C. The planar electrode PL1D extends along the X-axis in the dielectric layer LY2, and a via VL1D is connected to its other end. The planar electrode PL1D is connected to one end of the strip-shaped planar electrode PL1E disposed in the dielectric layer LY8 via the via VL1D.

[0049] A via VL1E is connected to the other end of the planar electrode PL1E. The planar electrode PL1E is connected to one end of a linear planar electrode PL1F disposed in the dielectric layer LY2 via the via VL1E. The planar electrode PL1F extends along the X-axis in the dielectric layer LY2, and a via VL1F is connected to its other end. The planar electrode PL1F is connected to one end of a linear planar electrode P1 disposed in the dielectric layer LY8 via this via VL1F. The planar electrodes PA1, PL1-PL1F, and vias VA1, VA2, and VL1-VL1F constitute a [structure / structure]. Figure 2 Inductor L11 in the middle.

[0050] A planar electrode P1 extends along the Y-axis in the dielectric layer LY8, and its other end is connected to a via VL2. Planar electrode P1 is connected to one end of a linear planar electrode PL2 disposed in the dielectric layer LY2 via via VL2. Planar electrode PL2 extends along the X-axis in the dielectric layer LY2, and its other end is connected to a via VL2A. Planar electrode PL2 is connected to one end of a linear planar electrode PL2A disposed in the dielectric layer LY8 via via VL2A.

[0051] A via hole VL2B is connected to the other end of the planar electrode PL2A. The planar electrode PL2A is connected to one end of the linear planar electrode PL2B disposed in the dielectric layer LY2 via the via hole VL2B. The planar electrode PL2B extends along the X-axis in the dielectric layer LY2, and a via hole VL2C is connected to its other end. The planar electrode PL2B is connected to the capacitor electrode PC1 disposed in the dielectric layer LY16 and the capacitor electrode PC3 disposed in the dielectric layer LY14 via the via hole VL2C. Furthermore, the via hole VL2C is offset within the dielectric layer LY9. The capacitor electrode PC1 is connected to the first terminal T1 via the via hole V1. The planar electrodes PL2-PL2B, the via holes VL2-VL2C, V1, and the capacitor electrode PC1 constitute a... Figure 2 Inductor L12 in the middle.

[0052] When viewed from above in the stacking direction, capacitor electrodes PC1 and PC3 are each configured as a portion of the capacitor electrode PC2 disposed on the dielectric layer LY15. The combined capacitance formed by the capacitors PC1 and PC2, and the capacitors PC2 and PC3, constitutes a capacitor. Figure 2 Capacitor C12 in the middle.

[0053] Furthermore, a portion of the capacitor electrode PC2 has a shape that overlaps with the planar electrode PG disposed on the dielectric layer LY16 when the main body 110 is viewed from the stacking direction. The planar electrode PG is connected to the ground terminal GND through vias VG1 and VG2. Therefore, the capacitor electrode PC2 and the planar electrode PG constitute a [missing information - likely a specific structure or configuration]. Figure 2 Capacitor C11 in the middle.

[0054] Next, the details of filter FLT2, which serves as a high-pass filter, will be explained. Branch point PB1 is connected to one end of a strip-shaped planar electrode PL3 wound around the axis (Z-axis) of the stacking direction of the main body 110. A via VL3 is connected to the other end of the planar electrode PL3. The planar electrode PL3 is connected via the via VL3 to one end of a strip-shaped planar electrode PL3A disposed in the dielectric layer LY3.

[0055] Like plate electrode PL3, plate electrode PL3A is also an electrode wound around the Z-axis, with a via VL3A connected to its other end. Plate electrode PL3A is connected to one end of strip-shaped plate electrode PL3B disposed on dielectric layer LY4 via via VL3A. Plate electrode PL3B, like plate electrode PL3, is also an electrode wound around the Z-axis, with a via VL3B connected to its other end. Plate electrode PL3B is connected to one end of strip-shaped plate electrode PL3C disposed on dielectric layer LY6 via via VL3B.

[0056] The planar electrode PL3C has a roughly C-shaped form, with a via VL3C connected to its other end. The via VL3C connects to the capacitor electrode PC11 disposed on the dielectric layer LY10, and to the capacitor electrode PC10 disposed on the dielectric layer LY11. The planar electrodes PA1, PL3-PL3C, and the vias VA1, VA2, and VL3-VL3C constitute a [structure / structure]. Figure 2 Inductor L21 in the middle.

[0057] The capacitor electrode PC10 is configured such that, when viewed from above in the stacking direction, a portion of it overlaps with the capacitor electrode PC7 disposed on the dielectric layer LY12. The capacitor electrodes PC7 and PC10 together constitute a... Figure 2 Capacitor C22.

[0058] Capacitor electrode PC7 is connected to one end of a strip-shaped planar electrode PL4 disposed in dielectric layer LY6 via via VL4. Planar electrode PL4 has a roughly L-shaped form, and its other end is connected to via VL4A. Planar electrode PL4 is connected to one end of a strip-shaped planar electrode PL4A disposed in dielectric layer LY5 via via VL4A. Planar electrode PL4A is an electrode wound around the Z-axis, and its other end is connected to via via VL4B. Planar electrode PL4A is connected to one end of a strip-shaped planar electrode PL4B disposed in dielectric layer LY4 via via VL4B.

[0059] The planar electrode PL4B is also an electrode wound around the Z-axis, with a via VL4C connected to its other end. The planar electrode PL4B is connected via VL4C to one end of the strip-shaped planar electrode PL4C disposed in the dielectric layer LY3. The planar electrode PL4C is also an electrode wound around the Z-axis, with a via VL4D connected to its other end. The planar electrode PL4C is connected via VL4D to one end of the linear planar electrode PL4D disposed in the dielectric layer LY2.

[0060] The planar electrode PL4D extends along the Y-axis, and a via VL4E is connected to its other end. The via VL4E is offset within the dielectric layer LY7 and connects to the capacitor electrode PC5 disposed in the dielectric layer LY14 and the planar electrode PG disposed in the dielectric layer LY16. As described above, the planar electrode PG is connected to the ground terminal GND of the dielectric layer LY17. Therefore, the planar electrodes PG, PL4 to PL4D, and vias VG1, VG2, and VL4 to VL4E constitute a... Figure 2 Inductor L22 in the middle.

[0061] A portion of capacitor electrode PC5 is configured to overlap with capacitor electrode PC6 disposed on dielectric layer LY13 when the main body 110 is viewed from above in the stacking direction. Capacitor electrode PC5 and capacitor electrode PC6 constitute a... Figure 2 Capacitor C23 in the middle.

[0062] Capacitor electrode PC6 is connected to capacitor electrode PC9 disposed on dielectric layer LY11 via via VL5. Capacitor electrodes PC6 and PC9 are configured to partially overlap with capacitor electrodes PC7 and PC8 disposed on dielectric layer LY12 when the main body 110 is viewed from above in the stacking direction. The capacitor electrodes PC6, PC9, and PC7 constitute a... Figure 2 The capacitor C21 is located in the middle. Additionally, capacitor electrodes PC6, PC9, and PC8 constitute a... Figure 2 The capacitor in the middle is C25.

[0063] Capacitor electrode PC9 is connected to strip-shaped planar electrodes PL5 and PL6 at branch point PB2 in dielectric layer LY2 via via hole VL5A. Planar electrode PL5 has an approximate L-shape. A via hole VL5B is connected to the end of planar electrode PL5 opposite to branch point PB2. Planar electrode PL5 is connected to one end of strip-shaped planar electrode PL5A disposed in dielectric layer LY3 via via hole VL5B.

[0064] The planar electrode PL5A is an electrode wound around the Z-axis, with a via VL5C connected to its other end. The planar electrode PL5A is connected to one end of the strip-shaped planar electrode PL5B disposed on the dielectric layer LY4 via the via VL5C.

[0065] Like PL5A, the planar electrode PL5B is also a wound electrode around the Z-axis, with a via VL5D connected to its other end. PL5B is connected via VL5D to one end of the strip-shaped planar electrode PL5C disposed on the dielectric layer LY5. PL5C, like PL5A, is also a wound electrode around the Z-axis, with a via VL5E connected to its other end. PL5C is connected via VL5E to the capacitor electrode PC4 disposed on the dielectric layer LY15. The planar electrodes PL5-PL5C, the capacitor electrode PC9, and the vias VL5-VL5E constitute a complete system. Figure 2 Inductor L23 in the middle.

[0066] When viewed from above in the stacking direction, a portion of the capacitor electrode PC4 overlaps with the planar electrode PG disposed on the dielectric layer LY16. The capacitor electrode PC4 and the planar electrode PG together form a... Figure 2 Capacitor C24 in the middle.

[0067] The planar electrode PL6 is a straight electrode extending along the Y-axis from the branch point PB2 of the dielectric layer LY2. A via VL6 is connected to the end of the planar electrode PL6 opposite to the branch point PB2. The planar electrode PL6 is connected to one end of the strip-shaped planar electrode PL6A disposed in the dielectric layer LY7 via the via VL6. A via VL6A is connected to the other end of the planar electrode PL6A. The planar electrode PL6A is connected to one end of the planar electrode PL6B disposed in the dielectric layer LY2 via the via VL6A.

[0068] The planar electrode PL6B is a straight electrode extending along the Y-axis, with a via VL6B connected to its other end. The planar electrode PL6B is connected via VL6B to one end of the strip-shaped planar electrode PL6C disposed on the dielectric layer LY7. At the other end of the planar electrode PL6C, a via VL6C is connected. The planar electrode PL6C is connected via VL6C to the capacitor electrode PC8 disposed on the dielectric layer LY12 and the planar electrode PA2 disposed on the dielectric layer LY16. The planar electrode PA2 is connected via via V2 to the second terminal T2 disposed on the dielectric layer LY17. The planar electrodes PA2, PL6~PL6C, and vias VL6~VL6C constitute a... Figure 2 The inductor L24 in the middle.

[0069] As mentioned above, Figure 5 This is a top view showing the overlapping of dielectric layers LY2 to LY8 in the filter device 100. (Example) Figure 3 and Figure 4 As described above, the filter device 100 is located in the main body 110. Figure 5 On the left side (the negative direction of the X-axis), there is a low-pass filter, filter FLT1. Figure 5 A high-pass filter, FLT2, is located on the right side (positive direction of the X-axis). Inductors L11 and L12 of filter FLT1 are located in region RG1 (first region) of the main body 110. In addition, inductors L21 to L24 of filter FLT2 are located in region RG2 (second region) of the main body 110.

[0070] like Figure 3 and Figure 4 As explained, the inductors L11 and L12 of filter FLT1 are configured as longitudinal coils containing planar electrodes and vias. The winding axis of inductors L11 and L12 is in the Y-axis direction, and they are wound with more than two turns to ensure the desired inductance. Inductor L11 is wound counterclockwise (CCW) towards the positive Y-axis, and inductor L12 is wound clockwise (CW) towards the positive Y-axis. Therefore, a magnetic field is generated in the Y-axis direction through inductors L11 and L12.

[0071] From Figure 4 The connection state of inductors L11 and L12, as described above, dictates that when a signal is transmitted from antenna terminal TA to first terminal T1 via filter FLT1, the signal passes through inductor L11 in the direction of arrow AR1, and through inductor L12 in the direction of arrow AR2. Therefore, the directions of the magnetic field generated by inductor L11 and inductor L12 are opposite to each other. Consequently, magnetic coupling between the inductors can be suppressed within filter FLT1.

[0072] In filter FLT2, inductors L21, L22, and L23 are helical coils connected via vias to planar coils wound along the Z-axis direction of the body 110. Inductor L24 is a longitudinal coil wound along the X-axis direction. Therefore, inductors L21, L22, and L23 generate a magnetic field in the Z-axis direction, and inductor L24 generates a magnetic field in the X-axis direction. Inductors L21 and L23, positioned facing filter FLT1, are wound with two or more turns.

[0073] In the filter device 100 of Embodiment 1, when viewed from the stacking direction of the main body 110, the direction of the magnetic field generated by the filter FLT1 is orthogonal to the direction of the magnetic field generated by the filter FLT2, and the coils of the filters do not face each other on the object side. In other words, the imaginary line CL1 drawn in the filter FLT1 from the center of the extending direction of the plate electrode constituting the inductor to a direction orthogonal to the extending direction does not intersect the inductors L21 to L24 of the filter FLT2, and the angle between the direction (second direction) in which the imaginary line CL1 extends and the direction (first direction) from region RG1 to region RG2 is 90°.

[0074] With this structure, in the filter device 100, the magnetic field generated by filter FLT1 will not interfere with the magnetic field generated by inductors L21 and L23 of filter FLT2, which are positioned facing region RG1. Thus, magnetic coupling between the inductors of filter FLT1 and filter FLT2 can be suppressed.

[0075] (Through characteristics)

[0076] Next, the transmission characteristics of the filter device 100 of Embodiment 1 will be described using comparative examples. Figure 6 This diagram illustrates the arrangement of inductors in each filter of the filter device 100X in Comparative Example 1. In the filter device 100X, the inductors L11X and L12X included in the low-frequency band filter FLT1X contain planar coils wound along the Z-axis. The high-frequency band side is the same as that of filter FLT2 in Embodiment 1. In the case of the filter device 100X, the magnetic field generated by the inductors L11X and L12X of filter FLT1X interferes with the magnetic field generated by the inductors L21 and L23 of filter FLT2, which are arranged at a position facing region RG1, and the inductors may magnetically couple with each other.

[0077] Figure 7 This is a diagram used to illustrate the transmission characteristics of the filter device 100 of Embodiment 1 and the filter device 100X of Comparative Example 1. Figure 7 In the graph, frequency is shown on the horizontal axis and insertion loss is shown on the vertical axis. Figure 7 In the diagram, solid lines LN10 and LN20 represent the insertion losses of filters FLT1 and FLT2 in the filter device 100 of Embodiment 1, respectively. Additionally, dashed lines LN11 and LN21 represent the insertion losses of filters FLT1X and FLT2 in the filter device 100X of Comparative Example 1, respectively.

[0078] like Figure 7As shown, on the low-frequency side, the Q value of the inductor is improved by suppressing magnetic coupling, thereby improving the insertion loss of the filter device 100 of Embodiment 1 compared to the filter device 100X of Comparative Example 1. Furthermore, as... Figure 2 As shown in the equivalent circuit diagram, the inductor L11 on the low-frequency band side is a component that can also be directly seen from the filter FLT2 on the high-frequency band side. Therefore, for the high-frequency band side, the filter device 100 and filter device 100X have the same structure, but by improving the Q value of the inductor L11 on the low-frequency band side, the insertion loss of the filter FLT2 on the high-frequency band side is also improved in Embodiment 1 compared to the filter device 100X of Comparative Example 1.

[0079] in addition, Figure 8 This diagram illustrates the configuration of inductors in each filter of the filter device 100Y in Comparative Example 2, which has a different structure. In the filter device 100Y, the inductors L11Y and L12Y included in the low-frequency band filter FLT1Y are both longitudinal coils, just like those in the filter device 100 of Embodiment 1. However, the inductors L11Y and L12Y are configured with the X-axis direction as the winding axis. That is, the angle between the imaginary lines CL2 and CL2A drawn from the center of the extending direction of the plate electrode in the inductors L11Y and L12Y and the direction from region RG1 to region RG2 is 0°.

[0080] Therefore, the directions of the magnetic fields generated by inductors L11Y and L12Y are the directions of filter FLT2. Thus, the magnetic fields generated by inductors L11Y and L12Y of filter FLT1Y interfere with the magnetic fields generated by inductors L21 and L23 of filter FLT2, which are positioned facing region RG1. The inductors may be magnetically coupled to each other.

[0081] Figure 9 This is a diagram used to illustrate the transmission characteristics of the filter device 100 of Embodiment 1 and the filter device 100Y of Comparative Example 2. Figure 9 In the graph, frequency is shown on the horizontal axis and insertion loss is shown on the vertical axis. Figure 9 In the diagram, solid lines LN30 and LN40 represent the insertion losses of filters FLT1 and FLT2 in the filter device 100 of Embodiment 1, respectively. Dashed lines LN31 and LN41 represent the insertion losses of filters FLT1Y and FLT2 in the filter device 100Y of Comparative Example 2, respectively.

[0082] like Figure 9As shown, the insertion loss in the passbands of both the low-frequency and high-frequency sides is almost the same as that of filter device 100 and filter device 100Y. However, in filter device 100Y of Comparative Example 2, since the inductors are magnetically coupled to each other, the attenuation of the attenuation electrode near the passband (around 1.5 GHz) on the low-frequency side and the attenuation of the attenuation electrode near the passband (around 1.0 GHz) on the high-frequency side are reduced. In other words, in filter device 100 of Embodiment 1, the attenuation characteristics in the non-passband are improved compared to those of filter device 100Y of Comparative Example 2.

[0083] As described above, in a filter device (duplexer) having two filters with different passbands, the inductor of the low-frequency band filter is formed by using a vertical coil, and the inductor of the high-frequency band filter is formed by using a planar coil facing the low-frequency band filter. By configuring the low-frequency band inductor and the high-frequency band inductor to be non-magnetically coupled, the degradation of filter characteristics can be suppressed.

[0084] Furthermore, in the above description, the case in which the inductor on the low-frequency band side is configured as a vertical coil and the inductor on the high-frequency band side of the filter facing the low-frequency band side is configured as a planar coil was described. However, it is also possible to use a planar coil to configure the low-frequency band side and a vertical coil to configure the high-frequency band side.

[0085] Furthermore, the above description only addressed the case where the low-frequency band filter contains two inductors, but the low-frequency band filter can also contain three or more inductors.

[0086] In Embodiment 1, “filter FLT1” and “filter FLT2” correspond to “first LC filter” and “second LC filter” in this disclosure. In Embodiment 1, “inductor L11” and “inductor L12” correspond to “first inductor” and “second inductor” in this disclosure.

[0087] [Implementation Method 2]

[0088] In Embodiment 1, the case where the winding axis of the inductor included in the low-frequency band filter FLT1 is in the Y-axis direction, that is, the angle between the direction from filter FLT1 towards filter FLT2 (first direction) and the direction of the winding axis of the inductor of filter FLT1 (second direction) is 90°, is described. However, the angle between the first direction and the second direction may not necessarily be 90°.

[0089] Figure 10This diagram illustrates the arrangement of inductors in each filter of the filter device 100A according to Embodiment 2. The filter device 100A has a structure in which the low-frequency band side filter FLT1 from Embodiment 1 is replaced with filter FLT1A. Furthermore, the high-frequency band side filter FLT2 is the same as in filter device 100. In filter device 100A, elements that are not repeated in filter device 100 are described.

[0090] Reference Figure 10 The low-frequency filter FLT1A includes inductors L11A and L12A configured as vertical coils. Inductor L11A is arranged such that, when viewed from the stacking direction of the main body 110, the imaginary line CL3 drawn from the center of the extending direction of the planar electrode in a direction orthogonal to that extending direction is inclined in the Y-axis direction. More specifically, inductor L11A is configured such that the angle θ between the direction of the aforementioned imaginary line CL3 (i.e., the direction of the winding axis) and the direction from region RG1 towards region RG2 is 45° or more and 90° or less (45°≤θ≤90°). In this case, the imaginary line CL3 does not intersect with the inductors L21 to L24 included in filter FLT2. Furthermore, inductor L12A is configured such that the imaginary line CL3A is in the Y-axis direction.

[0091] In this configuration, where the winding axis of the inductor, configured as a vertical coil on the low-frequency side, is tilted, magnetic coupling between the low-frequency and high-frequency inductors can be suppressed by omitting the high-frequency inductor, which is configured as a planar coil, from the direction of the magnetic field formed by the inductor. Therefore, the degradation of filter characteristics in the duplexer can be suppressed.

[0092] [Implementation Method 3]

[0093] In Embodiments 1 and 2, the structure of all inductors in the region RG1 facing the low-frequency band side of the filter FLT2 on the high-frequency band side was described as planar coils. However, in Embodiment 3, the structure of the inductors in the filter on the high-frequency band side of the region RG1 facing the low-frequency band side, including vertical coils, was described.

[0094] Figure 11 This diagram illustrates the arrangement of inductors in each filter of the filter device 100B in Embodiment 3. The filter device 100B has a structure in which the high-frequency band side filter FLT2 in Embodiment 1 is replaced with filter FLT2B. Furthermore, the low-frequency band side filter FLT1 is the same as in filter device 100. In filter device 100B, elements that are not repeated in filter device 100 are described.

[0095] Reference Figure 11In the high-frequency band filter FLT2B, the inductors L23 and L24 of the filter FLT2 in filter device 100 are replaced with inductors L23B and L24B. Inductor L23B is a planar coil, adjacent to inductors L21 and L22 in the positive Y-axis direction, and arranged facing region RG1. Inductor L24B is a longitudinal coil composed of a planar electrode extending in the X-axis direction and a through-hole extending in the stacking direction of the body 110. The winding axis of inductor L24B is in the Y-axis direction. Inductor L24B is arranged adjacent to inductor L23B in the positive Y-axis direction. In other words, inductor L23B is arranged between inductors L21 and L24B.

[0096] The negative X-axis end of inductor L24B faces region RG1 of filter FLT1 on the low-frequency band side. However, the distance between inductor L24B and region RG1 is greater than the distance between inductor L21 and region RG1, and the distance between inductor L23B and region RG1. Furthermore, it is preferable that the distance between inductors L11 and L12 on the low-frequency band side and inductor L24B on the high-frequency band side is 50 μm or more.

[0097] In filter FLT1, the imaginary line CL1, drawn from the center of the extending direction of the planar electrodes constituting inductors L11 and L12 (which are vertical coils), in a direction orthogonal to that extending direction, does not intersect with inductors L21, L22, L23B, and L24B in filter FLT2B. Similarly, in filter FLT2B, the imaginary line CL4, drawn from the center of the extending direction of the planar electrodes constituting inductor L24B (which is a vertical coil), in a direction orthogonal to that extending direction, does not intersect with inductors L11 and L12.

[0098] By configuring the inductors L11 and L12 in filter FLT1 in such a way that the magnetic field generated by filter FLT1 does not interfere with the magnetic field generated by the inductors L21 and L23B of filter FLT2B, which are positioned facing region RG1. Furthermore, since the inductor L24B of filter FLT2B, which is a vertical coil, is positioned further away from region RG1 than the inductors L21 and L23B, interference between the magnetic field generated by inductor L24B and the magnetic field generated by the inductors L11 and L12 of filter FLT1 can be suppressed.

[0099] In this way, even if the inductor L24B, which is configured as a vertical coil, is located in the region RG1 facing the filter FLT1, by being located further away from the region RG1 than the inductors L21 and 23B of the planar coil, the magnetic coupling between the vertical coils can be suppressed, and the reduction of isolation between the filters FLT1 and FLT2B can be suppressed.

[0100] Furthermore, it is generally known that the inductance of a coil is proportional to the diameter of its air core and inversely proportional to its length. Therefore, to achieve the same inductance value, by increasing the air core diameter compared to the inductor L24 in Embodiment 1, as in inductor L24B, the overall wire length of the inductor can be shortened. Therefore, by reducing conductor losses in inductor L24B, the insertion loss of filter FLT2B can be reduced.

[0101] Therefore, by adopting a structure like the filter device 100B of Embodiment 3, the degradation of filter characteristics in the duplexer can be suppressed.

[0102] In addition, Figure 11 In the filter device 100B, the inductors L11 and L12 of filter FLT1 and the inductor L24B of filter FLT2B are described as longitudinal coils with the Y-axis as the winding axis. However, as long as the imaginary line drawn from the center of the extending direction of the plate electrode constituting the longitudinal coil to a direction orthogonal to that extending direction does not intersect with the inductor of another filter, these inductors L11, L12, and L24B can also be configured with the winding axis inclined from the Y-axis direction, as in the inductor L11A in the filter device 100A of embodiment 2.

[0103] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of this disclosure is defined not by the description of the above embodiments but by the claims, and is intended to include all modifications equivalent to or within the scope of the claims.

[0104] Explanation of reference numerals in the attached figures

[0105] 10…Communication device, 20…High-frequency front-end circuit, C11, C12, C21~C25…Capacitors, 100, 100A, 100B, 100X, 100Y…Filter device, 110…Main body, 111, 112…Main surface, ANT…Antenna device, CL1, CL2, CL2A, CL3, CL3A, CL4…Imaginary line, DM…Directional marker, FLT1, FLT1A, FLT1X, FLT1Y, FLT2, FLT2B…Filter, GND…Ground terminal, IN…Input terminal, L11, L11A, L11X, L11Y, L12, L12A, L12X, L12Y, L21~L24, L23B, L24B…Inductors, LNA1, LNA2…Amplifier circuit, LY1~LY17…Dielectric layer, OUT1, OUT2… Output terminals; P1, PA1, PA2, PG, PL1, PL1A~PL1F, PL2, PL2A, PL2B, PL3, PL3A~PL3C, PL4, PL4A~PL4D, PL5, PL5A~PL5C, PL6, PL6A~PL6C… Planar electrodes; PB1, PB2… Branch points; PC1~PC11… Capacitor electrodes; T1… First terminal; T2… Second terminal; TA… Antenna terminal; V1, V2, VA1, VA2, VG1, VG2, VL1, VL1A~VL1F, VL2, VL2A~VL2C, VL3, VL3A~VL3C, VL4, VL4A~VL4E, VL5, VL5A~VL5E, VL6, VL6A~VL6C… Through holes.

Claims

1. A filter device comprising: main body; A first filter having a first passband; and The second filter has a second passband that is different from the first passband described above. When viewed from the normal direction of the aforementioned main body, the inductor included in the first filter is disposed in the first region, and the inductor included in the second filter is disposed in the second region, wherein, The second region mentioned above is adjacent to the first region mentioned above. The first filter and the second filter mentioned above each include at least one inductor. The inductor included in the first filter is a longitudinal coil comprising a planar electrode and a via, wherein the planar electrode is disposed on the main body, and the via extends in the normal direction of the main body. In the second filter described above, the inductor positioned facing the first region is a planar coil with the normal direction of the main body as its winding axis. When viewed from the normal direction of the aforementioned main body, an imaginary line drawn from the center of the extending direction of the aforementioned planar electrode in the first filter to a direction orthogonal to that extending direction does not intersect with the inductor included in the aforementioned second filter. The aforementioned first filter includes a first inductor and a second inductor, wherein the first inductor and the second inductor are connected in series between the input terminal and the output terminal. The first inductor and the second inductor mentioned above are the aforementioned vertical coils.

2. The filter device according to claim 1, wherein, The angle between the first direction from the first region toward the second region and the second direction extending from the imaginary line is 45° or more and 90° or less.

3. The filter device according to claim 2, wherein, The first direction mentioned above is orthogonal to the second direction mentioned above.

4. The filter device according to any one of claims 1 to 3, wherein, The inductor included in the first filter has more than two turns.

5. The filter device according to claim 1, wherein, The direction of the magnetic field generated by the first inductor is different from the direction of the magnetic field generated by the second inductor.

6. The filter device according to claim 5, wherein, The direction of the magnetic field generated by the first inductor is opposite to the direction of the magnetic field generated by the second inductor.

7. The filter device according to any one of claims 1 to 3, wherein, The passband of the first filter is lower than that of the second filter.

8. A filter device comprising: main body; A first filter having a first passband; and The second filter has a second passband that is different from the first passband described above. The first filter and the second filter mentioned above each include at least one inductor. When viewed from the normal direction of the aforementioned main body, the inductor included in the first filter is disposed in the first region, and the inductor included in the second filter is disposed in the second region, wherein, The second region mentioned above is adjacent to the first region mentioned above. The inductor included in the first filter is a longitudinal coil comprising a planar electrode and a via, wherein the planar electrode is disposed on the main body, and the via extends in the normal direction of the main body. In the second filter described above, the inductor positioned facing the first region includes a longitudinal coil and a planar coil wound around the normal direction of the main body. The distance between the vertical coil of the second filter and the first region is greater than the distance between the planar coil and the first region. When viewed from the direction of the normal to the aforementioned main body, A first imaginary line drawn from the center of the extending direction of the planar electrode in the first filter to a direction orthogonal to that extending direction does not intersect the inductor included in the second filter. A second imaginary line drawn from the center of the extension direction of the planar electrode in the second filter to a direction orthogonal to that extension direction does not intersect the inductor included in the first filter.

9. A high-frequency front-end circuit comprising the filter device according to any one of claims 1 to 8.

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