Filter device and high-frequency front-end circuit having the filter device

Abstract

The filter device (100) of the present invention includes: an input terminal (T1), an output terminal (T2), a main body (110), a common electrode (PC) disposed on the main body (110), a ground terminal (GND), and LC parallel resonators (RC1 to RC3) connected to the common electrode (PC) and the ground terminal (GND). Each resonator includes a capacitor, a first via, and a second via. One end of the first via is connected to the common electrode (PC), and the other end is connected to the ground terminal (GND) via the capacitor. One end of the second via is connected to the common electrode (PC), and the other end is not connected to the ground terminal (GND) via the capacitor. A second via is connected between the portions of the common electrode (PC) that allow connection of the first vias of two adjacent resonators.

Description

Technical Field

[0001] This disclosure relates to filter devices and high-frequency front-end circuits having the filter devices, and more particularly, to techniques for improving the characteristics of stacked LC filters. Background Technology

[0002] International Patent Publication No. 2019 / 097774 (Patent Document 1) discloses a stacked bandpass filter with four stages of LC parallel resonators arranged between the input and output terminals. In the bandpass filter of International Patent Publication No. 2019 / 097774 (Patent Document 1), two capacitors (a first capacitor and a second capacitor) are connected in series between the resonators connected to the input terminal and the resonator connected to the output terminal, and a third capacitor is formed between the connection node of these two capacitors and the ground point. With this structure, the frequency of the attenuation electrode on the lower frequency side of the passband remains almost unchanged, while the frequency of the attenuation electrode on the higher frequency side of the passband varies.

[0003] Patent Document 1: International Publication No. 2019 / 097774.

[0004] International Patent Publication No. 2019 / 097774 (Patent Document 1) describes an inductor in a bandpass filter comprising LC parallel resonators. The inductor is formed by two via conductors and a line conductor connecting these via conductors, all formed in the stacking direction of a multilayer dielectric substrate. The line conductors of each LC parallel resonator are arranged separately. In such a bandpass filter, adjusting the magnetic coupling between the resonators is generally achieved by changing the position (spaced) of the via conductors forming the inductors, or by changing the spacing between the resonators themselves.

[0005] However, changing the configuration of the via conductors may decrease the Q value due to the change in the inductor's core diameter. Furthermore, changing the spacing between specific resonators may affect the magnetic coupling with other resonators, potentially increasing losses.

[0006] Such bandpass filters are sometimes used in portable communication devices, such as mobile phones or smartphones. In such portable terminals, there is a demand for further miniaturization and thinning. However, miniaturizing the filter further restricts the freedom of the via conductor configuration, making it difficult to adjust the magnetic coupling between resonators. Summary of the Invention

[0007] This disclosure was made to solve such a problem, and its purpose is to adjust the magnetic coupling between resonators while suppressing the decrease in Q value in a multi-stage cascaded filter containing multiple LC parallel resonators.

[0008] The filter device disclosed herein includes: an input terminal, an output terminal, a main body, a common electrode disposed on the main body, a ground terminal, and first to third LC parallel resonators connected to the common electrode and the ground terminal. Each resonator includes a capacitor, a first via, and a second via. One end of the first via is connected to the common electrode, and the other end is connected to the ground terminal via the capacitor. One end of the second via is connected to the common electrode, and the other end is not connected to the ground terminal via the capacitor. A second via is connected between the portions of the common electrode that allow connection of the first vias of adjacent resonators.

[0009] In the filter device of this disclosure, multiple LC parallel resonators (first LC parallel resonator to third LC parallel resonator) that are magnetically coupled to each other are connected by a common electrode. By configuring it in this way, the arrangement of the vias of the inductors constituting each resonator is not limited, and the magnetic coupling between adjacent LC parallel resonators is adjusted by the shape of the common electrode. Therefore, in a multi-stage LC filter, it is possible to suppress the decrease in Q value and adjust the magnetic coupling between resonators. Attached Figure Description

[0010] 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.

[0011] Figure 2 This is the equivalent circuit diagram of the filter device in Implementation Method 1.

[0012] Figure 3 yes Figure 2 A perspective view of the filter device.

[0013] Figure 4 It means Figure 2 An exploded perspective view of an example of a stacked structure of a filter device.

[0014] Figure 5 yes Figure 2 A top view of the common electrode in the filter device.

[0015] Figure 6 This is a diagram illustrating the configuration of the resonator in the filter device of the comparative example.

[0016] Figure 7 It means Figure 2 The diagram shows the characteristics of the filter device.

[0017] Figure 8 This is a diagram used to illustrate the first example of magnetic coupling adjustment.

[0018] Figure 9 It means Figure 8The first example is a graph of the characteristics.

[0019] Figure 10 This is a diagram used to illustrate the second example of magnetic coupling adjustment.

[0020] Figure 11 It means Figure 8 The second example is a graph of the characteristics.

[0021] Figure 12 This is a top view of the common electrode in the filter device of Modified Example 1.

[0022] Figure 13 This is a top view of the common electrode in the filter device of Modified Example 2.

[0023] Figure 14 This is a top view of the common electrode in the filter device of Modified Example 3.

[0024] Figure 15 This is a top view of the common electrode in the filter device of Modified Example 4.

[0025] Figure 16 This is an exploded perspective view showing an example of the stacked structure of the filter device in Embodiment 2.

[0026] Figure 17 yes Figure 16 A top view of the common electrode in the filter device.

[0027] Figure 18 It means Figure 16 The diagram shows the characteristics of the filter device.

[0028] Figure 19 This is the equivalent circuit diagram of the filter device in Implementation Method 3.

[0029] Figure 20 It means Figure 19 An exploded three-dimensional view of the stacked structure of the filter device.

[0030] Figure 21 yes Figure 19 A top view of the common electrode in the filter device.

[0031] Figure 22 It means Figure 19 The diagram shows the characteristics of the filter device.

[0032] Figure 23 This is a top view of the common electrode in the filter device of Modified Example 5.

[0033] Figure 24 This is a top view of the common electrode in the filter device of Modified Example 6.

[0034] Figure 25 This is an exploded perspective view showing an example of the stacked structure of the filter device in Embodiment 4.

[0035] Figure 26 It means Figure 25 The diagram shows the characteristics of the filter device.

[0036] Figure 27 This diagram illustrates the effect of the presence or absence of a shared electrode and internal shielding on the external shielding. Detailed Implementation

[0037] 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 description will not be repeated.

[0038] [Implementation Method 1]

[0039] (Basic structure of a communication device)

[0040] Figure 1 This is a block diagram of a communication device 10 having a high-frequency front-end circuit 20 with the filter device of embodiment 1. The communication device 10 is, for example, a mobile phone base station.

[0041] Reference Figure 1 The communication device 10 includes: an antenna 12, a high-frequency front-end circuit 20, a mixer 30, a local oscillator 32, a D / A converter (DAC) 40, and an RF circuit 50. Furthermore, the high-frequency front-end circuit 20 includes bandpass filters 22 and 28, an amplifier 24, and an attenuator 26. Additionally, in... Figure 1 In this description, the high-frequency front-end circuit 20 includes a transmitting circuit that transmits high-frequency signals from the antenna 12, but the high-frequency front-end circuit 20 may also include a receiving circuit that receives high-frequency signals via the antenna 12.

[0042] The communication device 10 up-converts the transmit signal from the RF circuit 50 to a high-frequency signal and emits it from the antenna 12. The transmit signal output from the RF circuit 50, i.e., the modulated digital signal, is converted into an analog signal by the D / A converter 40. The mixer 30 mixes the transmit signal, converted from digital to analog by the D / A converter 40, with the oscillation signal from the local oscillator 32 and up-converts it to a high-frequency signal. The bandpass filter 28 removes unwanted waves generated by the up-conversion, extracting only the transmit signal of the desired frequency band. The attenuator 26 adjusts the strength of the transmit signal. The amplifier 24 amplifies the power of the transmit signal passing through the attenuator 26 to a specified level. The bandpass filter 22 removes unwanted waves generated during amplification and allows only the signal components of the frequency band determined by the communication standard to pass through. The transmit signal passing through the bandpass filter 22 is emitted from the antenna 12.

[0043] The bandpass filters 22 and 28 in the communication device 10 described above can be filter devices corresponding to those disclosed herein.

[0044] (Structure of the filter device)

[0045] Next, use Figures 2-5 The detailed structure of the filter device 100 of Embodiment 1 will be described.

[0046] Figure 2 This is the equivalent circuit diagram of filter device 100. (Refer to...) Figure 2 The filter device 100 includes an input terminal T1, an output terminal T2, and resonators RC1 to RC4. Each of the resonators RC1 to RC4 is an LC parallel resonator that connects an inductor and a capacitor in parallel.

[0047] The resonator RC1 includes inductors L1A and L1B connected in series, and capacitor C1 connected in parallel with inductors L1A and L1B. The connection node N1A of inductor L1A and capacitor C1 is connected to the input terminal T1 via capacitor C0. The connection node N1B of inductor L1B and capacitor C1 is connected to the ground terminal GND.

[0048] The resonator RC2 includes inductors L2A and L2B connected in series, and capacitor C2 connected in parallel with inductors L2A and L2B. The connection node N2A of inductor L2A and capacitor C2 is connected to the output terminal T2 via capacitor C5. The connection node N2B of inductor L2B and capacitor C2 is connected to the ground terminal GND.

[0049] The resonator RC3 includes inductors L3A and L3B connected in series, and capacitor C3 connected in parallel with inductors L3A and L3B. The connection node N3A of inductor L3A and capacitor C3 is connected to the connection node N1A of resonator RC1 via capacitor C13. The connection node N3B of inductor L3B and capacitor C3 is connected to the ground terminal GND.

[0050] The resonator RC4 includes inductors L4A and L4B connected in series, and capacitor C4 connected in parallel with inductors L4A and L4B. The connection node N4A of inductors L4A and capacitor C4 is connected to the connection node N2A of resonator RC2 via capacitor C24. The connection node N4B of inductors L4B and capacitor C4 is connected to the ground terminal GND.

[0051] Furthermore, the connection node N1A of resonator RC1 and the connection node N2A of resonator RC2 are connected via capacitor C12. Also, the connection nodes of the two inductors in each resonator are interconnected. This shared connection portion of the resonators is connected to... Figure 4 The common electrode PC is described later.

[0052] Each resonator is magnetically coupled to the others. Thus, the filter device 100 has a structure with four stages of resonators magnetically coupled to each other between the input terminal T1 and the output terminal T2. By adjusting the resonant frequency of each resonator, the filter device 100 functions as a bandpass filter that allows signals in the desired frequency band to pass through.

[0053] Furthermore, the capacitor C0 connected to the input terminal T1 and the capacitor C5 connected to the output terminal T2 are not required, and the resonators RC1 and RC2 can also be directly connected to the input terminal T1 and the output terminal T2 respectively.

[0054] Figure 3 This is a perspective view 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.

[0055] Reference Figure 3 as well as Figure 4 The filter device 100 includes a cuboid or approximately cuboid body 110 formed by stacking multiple dielectric layers LY1 to LY12 in a stacking direction. The dielectric layers LY1 to LY12 are formed, for example, of ceramics such as low-temperature co-fired ceramics (LTCC) or resin. Inside the body 110, multiple electrodes disposed in each dielectric layer and multiple vias disposed between the dielectric layers constitute an inductor and a capacitor for forming an LC resonant circuit. Furthermore, in this specification, "via" refers to a conductor disposed in a dielectric layer for connecting electrodes disposed in different dielectric layers. Vias are formed, for example, of conductive paste, plating, and / or metal pins.

[0056] Furthermore, in the following description, the stacking direction of the dielectric layers LY1 to LY12 in the main body 110 is defined as the "Z-axis direction", the direction perpendicular to the Z-axis direction and along the long side of the main body 110 is defined as the "X-axis direction", and the direction along the short side of the main body 110 is defined as the "Y-axis direction". In addition, in the following, the positive direction of the Z-axis in each figure is sometimes referred to as the upper side, and the negative direction is sometimes referred to as the lower side.

[0057] On the upper surface 111 (first layer LY1) of the main body 110, there is a directional mark DM for determining the orientation of the filter device 100. On the lower surface 112 (twelfth layer LY12) of the main body 110, there are external terminals (input terminal T1, output terminal T2, and ground terminal GND) for connecting the filter device 100 to external devices. Each of the input terminal T1, output terminal T2, and ground terminal GND is a flat electrode, which is an LGA (Land Grid Array) terminal regularly arranged on the lower surface 112 of the main body 110.

[0058] like Figure 2 As described above, the filter device 100 has four stages of LC parallel resonators. More specifically, it includes: a resonator RC1 configured to include vias V1A and V1B and a capacitor electrode P2; a resonator RC2 configured to include vias V2A and V2B and a capacitor electrode P8; a resonator RC3 configured to include vias V3A and V3B and a capacitor electrode P3; and a resonator RC4 configured to include vias V4A and V4B and a capacitor electrode P7.

[0059] The capacitor electrode P2 of resonator RC1 and the capacitor electrode P8 of resonator RC2 are located on the tenth layer LY10. Capacitor electrode P2 is opposite to the planar electrode P1 located on the eleventh layer LY11. The capacitor electrode P2 and the planar electrode P1 together constitute... Figure 2 The capacitor C0. The plate electrode P1 is connected to the input terminal T1 located on the twelfth layer LY12 through the through hole V0.

[0060] Capacitor electrode P8 is opposite to plate electrode P9 located on the eleventh layer LY11. The capacitor electrode P8 and plate electrode P9 together form a... Figure 2 The capacitor C5. The flat plate electrode P9 is connected to the output terminal T2 located on the twelfth layer LY12 through the through hole V5.

[0061] The capacitor electrode P2 of the resonator RC1 is connected to the common electrode PC located on the second layer LY2 via via V1A. Additionally, the common electrode PC is connected to the planar electrode PG1 located on the ninth layer LY9 via via V1B. The planar electrode PG1 is connected to the planar electrode PG2 located on the eleventh layer LY11 via vias VG1, VG2, and VG3. Furthermore, the planar electrode PG2 is connected to the ground terminal GND located on the twelfth layer LY12 via vias VG4 and VG5. A portion of the capacitor electrode P2 is also opposite the planar electrode PG1, and the capacitor electrode P2 and the planar electrode PG1 together constitute... Figure 2 Capacitor C1 is located within the capacitor. Furthermore, vias V1A and V1B are connected to... Figure 2The inductors L1A and L1B in the diagram correspond to the following respectively.

[0062] The capacitor electrode P8 of the resonator RC2 is connected to the common electrode PC disposed on the second layer LY2 via the via V2A. Additionally, the common electrode PC is connected to the planar electrode PG1 disposed on the ninth layer LY9 via the via V2B. A portion of the capacitor electrode P8 also faces the planar electrode PG1, forming a structure with the capacitor electrode P8 and the planar electrode PG1. Figure 2 Capacitor C2 is located within the capacitor. Furthermore, vias V2A and V2B are connected to... Figure 2 The inductors L2A and L2B in the diagram correspond to the following respectively.

[0063] The capacitor electrode P3 of resonator RC3 and the capacitor electrode P7 of resonator RC4 are disposed on the eighth layer LY8. Capacitor electrode P3 is connected to the common electrode PC disposed on the second layer LY2 via via V3A. Additionally, the common electrode PC is connected to the planar electrode PG1 disposed on the ninth layer LY9 via via V3B. Capacitor electrode P3 and planar electrode PG1 are opposite each other, forming a [structure / feature]. Figure 2 Capacitor C3. Furthermore, vias V3A and V3B are connected to... Figure 2 The inductors L3A and L3B in the diagram correspond to the following respectively.

[0064] Capacitor electrode P7 is connected to a common electrode PC disposed on the second layer LY2 via via V4A. Additionally, the common electrode PC is connected to a planar electrode PG1 disposed on the ninth layer LY9 via via V4B. Capacitor electrode P7 and planar electrode PG1 are opposite each other, forming a [structure / feature]. Figure 2 Capacitor C4. Furthermore, vias V4A and V4B are connected to... Figure 2 The inductors L4A and L4B in the diagram correspond to the following respectively.

[0065] The via V1A of resonator RC1 is also connected to the planar electrode P4 located on the seventh layer LY7. A portion of the planar electrode P4 is opposite to the capacitor electrode P3 of resonator RC3. The planar electrode P4 and the capacitor electrode P3 together form a... Figure 2 Capacitor C13 in the middle.

[0066] The via V2A of resonator RC2 is also connected to the planar electrode P6 located on the seventh layer LY7. A portion of the planar electrode P6 is opposite to the capacitor electrode P7 of resonator RC4. The planar electrode P6 and the capacitor electrode P7 together form a... Figure 2 The capacitor C24 in the middle.

[0067] Furthermore, a portion of plate electrode P4 and a portion of plate electrode P6 are opposite to plate electrode P5 disposed on the sixth layer LY6. Plate electrodes P4 to P6 constitute... Figure 2 Capacitor C12 in the middle.

[0068] In the following description, the vias V1A, V2A, V3A, and V4A in each resonator that are connected to the ground terminal GND via a capacitor are referred to as "first vias". In addition, the vias V1B, V2B, V3B, and V4B in each resonator that are not connected to the ground terminal GND via a capacitor are referred to as "second vias".

[0069] Figure 5 This is a top view of the common electrode PC in the filter device 100. The common electrode PC is composed of a strip-shaped wiring pattern having a first end E1 and a second end E2. Figure 5 In the common electrode PC, there is a zigzag shape that alternately connects wiring patterns PT1, PT3, PT5, PT7 along the short side (Y-axis) of the body 110 and wiring patterns PT2, PT4, PT6 along the long side (X-axis) of the body 110. The wiring patterns PT1 to PT7 have the same line width.

[0070] A via V1A for resonator RC1 is connected to the first end E1 of the common electrode PC (i.e., one end of wiring pattern PT1). A via V1B for resonator RC1 is connected to the other end of wiring pattern PT1 (i.e., one end of wiring pattern PT2). A via V3A for resonator RC3 is connected to the other end of wiring pattern PT2 (i.e., one end of wiring pattern PT3). A via V3B for resonator RC3 is connected to the other end of wiring pattern PT3 (i.e., one end of wiring pattern PT4).

[0071] At the other end of wiring pattern PT4 (i.e., at one end of wiring pattern PT5), the via V4B of resonator RC4 is connected. At the other end of wiring pattern PT5 (i.e., at one end of wiring pattern PT6), the via V4A of resonator RC3 is connected. At the other end of wiring pattern PT6 (i.e., at one end of wiring pattern PT7), the via V2B of resonator RC2 is connected. At the other end of wiring pattern PT7 (i.e., at the second end E2 of the common electrode PC), the via V2A of resonator RC2 is connected. For example... Figure 5 As shown, in the common electrode PC, in order to ensure the symmetry of the filter characteristics, each via is configured to be linearly symmetrical with respect to the imaginary line CL1.

[0072] Thus, along the common electrode PC, a through-hole V1B (second through-hole) of resonator RC1 is disposed between the through-hole V1A of resonator RC1 and the through-hole V3A (first through-hole) of resonator RC3. Additionally, along the common electrode PC, a through-hole V2B (second through-hole) of resonator RC2 is disposed between the through-hole V2A of resonator RC2 and the through-hole V4A (first through-hole) of resonator RC4. Furthermore, along the common electrode PC, a through-hole V3B of resonator RC3 and a through-hole V4B (second through-hole) of resonator RC4 are disposed between the through-hole V3A of resonator RC3 and the through-hole V4A (first through-hole) of resonator RC4.

[0073] In other words, along the path of the common electrode PC, a second via is connected between the portions where the first vias of two adjacent resonators are connected. Furthermore, adjacent vias V3B and V4B are connected to the ground terminal GND via planar electrodes PG1, PG2 and vias VG1, VG2, VG3, VG4, VG5. Therefore, these two vias... Figure 5 The via V34B, as shown by the dashed line, can be considered as a single via. Thus, a structure is formed in which the first and second vias are alternately arranged along the common electrode PC from the first end E1 toward the second end E2.

[0074] In this way, multiple LC parallel resonators are connected to a strip-shaped common electrode. A "first via" connected to the ground terminal GND via a capacitor and a "second via" not connected to the ground terminal GND via a capacitor are alternately arranged along the common electrode, so that adjacent resonators are inductively coupled to each other.

[0075] Here, as a multi-stage filter device composed of multiple LC parallel resonators, a structure is known in which the conductors constituting each resonator are arranged separately. For example, in International Publication No. 2019 / 097774 (Patent Document 1), such as Figure 6 As shown in the filter device 200, the vias of the inductors constituting each resonator are connected by individual wiring electrodes PD1 to PD4, which are independent of each resonator.

[0076] Generally, to improve the characteristics of a filter device, it is necessary to increase the Q value. In a filter device using a multi-stage LC parallel resonator as described above, the Q value is affected by the core diameter of the inductors in each resonator, i.e., the via spacing. Specifically, there is a trend that the larger the core diameter of the inductors in each resonator, the higher the Q value. Therefore, vias are arranged in the filter device to make the via spacing of each resonator as wide as possible.

[0077] On the other hand, to achieve the desired filter characteristics, it is sometimes necessary to adjust the strength of the magnetic coupling between the resonators. The strength of the magnetic coupling between resonators can be adjusted by the distance (spacing) between them. However, in multi-stage filter devices, the resonators are mutually coupled. Changing the distance between specific resonators may change the coupling state of other resonators, thus adjusting the distance between resonators can be accompanied by design difficulties. Therefore, for design simplicity, although the Q value may decrease, the method of adjusting the coupling state by changing the via spacing is generally used. However, further miniaturization of the filter device further restricts the freedom of via placement, potentially making it impossible to achieve the desired filter characteristics.

[0078] In the filter device 100 of Embodiment 1, as described above, the vias of the inductors configured to form a plurality of LC parallel resonators RC1 to RC4 are connected to a common electrode PC. "First vias" connected to the ground terminal GND via capacitors and "second vias" not connected to the ground terminal GND via capacitors are alternately arranged along the common electrode PC. In this way, adjacent resonators are connected to each other by the common electrode, and in particular, in resonators RC3 and RC4 located near the center of the main body 110, two or more second vias are arranged relative to one first via, thus reducing losses. Furthermore, by adjusting the shape of the common electrode (e.g., line width or line length), the coupling state between resonators can be changed. Therefore, in each resonator, vias can be arranged at positions where optimal Q values ​​can be achieved, thus suppressing the decrease in Q values ​​and adjusting the magnetic coupling between resonators.

[0079] Next, use Figures 7-11 An example of magnetic coupling adjustment based on the change in the shape of the common electrode in the filter device 100 of Embodiment 1 will be described.

[0080] Figure 7 It means having Figure 5 The insertion loss (solid line LN10) from input terminal T1 to output terminal T2 in the filter device 100 with a common electrode PC of the shape shown, and Figure 6 A diagram showing the insertion loss (dashed line LN11) in the filter device 200 of the comparative example. Furthermore, the lower part... Figure 7 (b) is the upper part. Figure 7 A magnified view of part of region RG1 in (a).

[0081] Reference Figure 7 In the filter device 100 of Embodiment 1, compared with the filter device 200 of the comparative example, the attenuation electrode in the non-passband, which is closer to the low-frequency side of the passband, moves towards the passband side. Therefore, as... Figure 7 As shown in (b), the passband expands towards the lower frequency side, and the steepness in the non-passband increases. Furthermore, in the filter device 100 of Embodiment 1, the attenuation of the attenuation electrode in the non-passband, which is higher than the passband, is greater than that of the filter device 200 of the comparative example. Thus, by configuring a structure in which each resonator is connected to a common electrode PC, it is possible to expand the passband and improve the steepness.

[0082] Prepare filter devices 100A and 100B having a common electrode PC with a different shape than the filter device 100 of Embodiment 1. Figure 8 This is a top view of the common electrode PC in filter device 100A. (Example) Figure 8 As shown, in the filter device 100A, the linewidth W1 of wiring patterns PT2 and PT6 in the common electrode PC is compared with... Figure 5 The common electrode PC of the filter device 100 shown is wide. That is, in the filter device 100A, the line widths of wiring patterns PT2 and PT6 in the common electrode PC are wider than the line widths of wiring patterns PT1, PT3, PT4, PT5, and PT7. Figure 9 It means having Figure 8 A diagram showing the insertion loss in a filter device 100A with a common electrode PC of the shape shown. Figure 10 This is a top view of the common electrode PC in filter device 100B. (Example) Figure 10 As shown, in the filter device 100B, the linewidth W2 of the wiring pattern PT4 in the common electrode PC is greater than that of the common electrode PC. Figure 5 The common electrode PC of the filter device 100 shown is wide. That is, in the filter device 100B, the line width of the wiring pattern PT4 in the common electrode PC is wider than the line width of the wiring patterns PT1 to PT3 and PT5 to PT7. Figure 11 It means having Figure 10 A diagram showing the insertion loss in a filter device 100B with a common electrode PC of the shape shown. Furthermore, in Figure 9 as well as Figure 11 In the middle, for comparison, LN10 is represented by a dashed line. Figure 5 Insertion loss in this case.

[0083] Reference Figure 9 When the linewidth W1 of the wiring patterns PT2 and PT6 of the common electrode PC is wider than the linewidth of wiring patterns PT1, PT3, PT4, PT5, and PT7, the frequency of the attenuator on the lower frequency side of the passband is the same as the linewidth of wiring patterns PT1 to PT7. Figure 5 Compared to the case where the shift is towards the passband side ( Figure 9(Solid line LN20 in the diagram). That is, the attenuation steepness on the low-frequency side of the passband is increased. This is because, due to the increased linewidth of the wiring patterns PT2 and PT6, the shortest distance between the furthest resonators, i.e., between resonator RC1 and resonator RC2, becomes shorter, and the sensitivity of the magnetic coupling between resonator RC1 and resonator RC2 increases. This means... Figure 2 In the equivalent circuit, the inductance values ​​of inductors L1A and L2A decrease, while the proportion of inductors L1B and L2B in the overall resonator increases.

[0084] Next, refer to Figure 11 When the linewidth W2 of the wiring pattern PT4 of the common electrode PC is wider than the linewidths of wiring patterns PT1-PT3 and PT5-PT7, the high-frequency side of the passband shifts towards the higher-frequency side, and the passband width increases. Figure 11 (Solid line LN30 in the diagram). This is because, due to the increased linewidth of the wiring pattern PT4, the shortest distance between resonators RC3 and RC4 becomes shorter, and the sensitivity of the magnetic coupling between resonators RC3 and RC4 increases. This means... Figure 2 In the equivalent circuit, the inductance values ​​of inductors L3A and L4A decrease, while the proportion of inductors L3B and L4B in the overall resonator increases.

[0085] As described above, in a filter device composed of multiple LC parallel resonators, if each resonator is connected by a common electrode, the magnetic coupling between the resonators can be adjusted to a coupling state corresponding to the desired filter characteristics by changing the shape of this common electrode. In this case, it is not necessary to change the configuration of the vias that constitute inductors in each resonator, thus suppressing the decrease in Q value.

[0086] [Variation Example]

[0087] The following variations illustrate cases where the number of stages of the LC parallel resonators included in the filter device is different, and cases where the via configuration of the resonators is different.

[0088] (Variation Example 1)

[0089] Figure 12 This is a top view of the common electrode PC1 in the filter device 100C of Modified Example 1. The filter device 100C is an example of a structure including three LC parallel resonators.

[0090] Reference Figure 12In the filter device 100C, within the main body 110, first vias V10A, V11A, and V12A of each resonator are arranged along one long side parallel to the X-axis, and second vias V10B and V11B are arranged along the other long side. The common electrode PC1 is configured in a generally W shape, such that vias V10A, V10B, V11A, and V11B lead to via V12A. That is, in the common electrode PC1, the first and second vias are arranged alternately in a zigzag pattern along a path from the first end to the second end.

[0091] Furthermore, in the filter device 100C, in order to make the vias symmetrical with respect to the imaginary line CL1, the second via of the resonator including via V11A is shared with via V10B and / or via V11B.

[0092] In this structure, the linewidth of the wiring pattern connecting vias V10A and V10B, and the wiring pattern connecting vias V10B and V11A, is adjusted in the direction of arrow AR11, thereby enabling adjustment of the magnetic coupling of the first and second stage resonators, as well as the magnetic coupling of the first and third stage resonators.

[0093] In addition, by adjusting the line width of the wiring patterns connecting vias V10B and V11A, and the wiring patterns connecting vias V11A and V11B, in the direction of arrow AR12, the magnetic coupling of the second and third stage resonators can be adjusted.

[0094] Furthermore, by adjusting the linewidth of the wiring patterns connecting vias V11A and V11B, and the wiring patterns connecting vias V11B and V12A, in the direction of arrow AR13, the magnetic coupling of the second and third stage resonators, as well as the magnetic coupling of the first and third stage resonators, can be adjusted.

[0095] As described above, when the filter device includes three LC parallel resonators, by connecting each resonator to a common electrode and changing the linewidth of the common electrode, the coupling state between the resonators can be adjusted without changing the position of the vias. Therefore, it is possible to suppress the decrease in Q value and adjust the coupling between the resonators.

[0096] (Variation Example 2)

[0097] Figure 13 This is a top view of the common electrode PC2 in the filter device 100D of Modified Example 2. The filter device 100D, like that of Embodiment 1, includes four LC parallel resonators, but the via configuration differs from that of the filter device 100.

[0098] Reference Figure 13 In the filter device 100D, similar to Modified Example 1, first through holes V20A to V23A are arranged along one long side of the main body 110, and second through holes V20B to V22B are arranged along the other long side. The common electrode PC2 is configured to reach through hole V23A from through hole V20A via through holes V20B, through holes V21A, through holes V21B, through holes V22A, and through holes V22B. That is, in the common electrode PC2, the first and second through holes are arranged alternately in a sawtooth pattern along the path from the first end to the second end.

[0099] Furthermore, in the filter device 100D, in order to configure the vias symmetrically with respect to the imaginary line CL1, the second via of any resonator is shared with the second via of the adjacent resonator.

[0100] In this structure, the linewidth of the wiring patterns connecting vias V20A and V20B, and the wiring patterns connecting vias V20B and V21A, is adjusted in the direction of arrow AR21, thereby enabling adjustment of the magnetic coupling of the first and second stage resonators, the magnetic coupling of the first and third stage resonators, and the magnetic coupling of the first and fourth stage resonators.

[0101] In addition, by adjusting the linewidth of the wiring patterns connecting vias V21A and V21B, and the wiring patterns connecting vias V21B and V22A, in the direction of arrow AR22, the magnetic coupling of the second and third stage resonators can be adjusted.

[0102] Furthermore, by adjusting the linewidth of the wiring patterns connecting vias V22A and V22B, and the wiring patterns connecting vias V22B and V23A, in the direction of arrow AR23, the magnetic coupling of the first and fourth stage resonators, the magnetic coupling of the second and fourth stage resonators, and the magnetic coupling of the third and fourth stage resonators can be adjusted.

[0103] As described above, even with different via configurations in the filter device, by connecting each resonator to a common electrode and changing the linewidth of the common electrode, the coupling state between the resonators can be adjusted without changing the via positions. Therefore, it is possible to suppress the decrease in Q value and adjust the coupling between the resonators.

[0104] (Variation Example 3)

[0105] Figure 14 This is a top view of the common electrode PC3 in the filter device 100E of Modified Example 3. The filter device 100E is an example of a structure including five LC parallel resonators.

[0106] Reference Figure 14 In the filter device 100E, a first through-hole V30A, a second through-hole V31B, a second through-hole V32B, and a first through-hole V34A are arranged along one long side of the main body 110, and a second through-hole V30B, first through-holes V31A to V33A, and a second through-hole V33B are arranged along the other long side. The common electrode PC3 is configured to reach through-hole V34A from through-hole V30A via through-holes V30B, V31A, V31B, V32A, V32B, V33A, and V33B.

[0107] In the filter device 100E, in order to configure the vias symmetrically with respect to the imaginary line CL1, the second via of any resonator is shared with the second via of the adjacent resonator. Furthermore, in a five-stage filter device, the vias can also be configured in a sawtooth shape, as in Modifications 1 and 2.

[0108] In this structure, the linewidth of the wiring patterns connecting vias V30A and V30B, and the wiring patterns connecting vias V30B and V31A, is adjusted in the direction of arrow AR31, thereby enabling adjustment of the magnetic coupling of the first and second stage resonators, the magnetic coupling of the first and third stage resonators, the magnetic coupling of the first and fourth stage resonators, and the magnetic coupling of the first and fifth stage resonators.

[0109] In addition, by adjusting the line width of the wiring patterns connecting vias V31A and V31B, and the wiring patterns connecting vias V31B and V32A, in the direction of arrow AR32, the magnetic coupling of the second and third stage resonators, as well as the magnetic coupling of the second and fourth stage resonators, can be adjusted.

[0110] In addition, by adjusting the line width of the wiring patterns connecting vias V32A and V32B, and the wiring patterns connecting vias V32B and V323, in the direction of arrow AR33, the magnetic coupling of the second and fourth stage resonators, as well as the magnetic coupling of the third and fourth stage resonators, can be adjusted.

[0111] Furthermore, by adjusting the linewidth of the wiring patterns connecting vias V33A and V33B, and the wiring patterns connecting vias V33B and V34A, in the direction of arrow AR34, the magnetic coupling of the first and fifth stage resonators, the magnetic coupling of the second and fifth stage resonators, the magnetic coupling of the third and fifth stage resonators, and the magnetic coupling of the fourth and fifth stage resonators can be adjusted.

[0112] As described above, when the filter device includes five LC parallel resonators, by connecting each resonator to a common electrode and changing the linewidth of the common electrode, the coupling state between the resonators can be adjusted without changing the position of the vias. Therefore, it is possible to suppress the decrease in Q value and adjust the coupling between the resonators.

[0113] (Variation Example 4)

[0114] Figure 15 This is a top view of the common electrode PC4 in the filter device 100F of Modified Example 4. Like Embodiment 1 and Modified Example 2, the filter device 100F includes four LC parallel resonators, but the configuration of the vias is further different. More specifically, in the filter device 100F, the vias are configured to be point-symmetric.

[0115] Reference Figure 15 In the filter device 100F, a first through-hole V40A, a second through-hole V41B, a first through-hole V42A, and a second through-hole V43B are arranged along one long side of the main body 110, and a second through-hole V40B, a first through-hole V41A, a second through-hole V42B, and a first through-hole V43A are arranged along the other long side. The common electrode PC4 is configured to reach through-hole V43A from through-hole V40A via through-holes V40B, V41A, V41B, V42B, V42A, and V43B. The through-holes in the common electrode PC4 are arranged to be point-symmetric with respect to point CP.

[0116] Thus, when the vias in the filter device are configured with point symmetry, connecting each resonator to a common electrode and adjusting the linewidth of the common electrode, etc., allows for adjustment of the coupling state between resonators without changing the via positions. Therefore, it is possible to suppress the decrease in Q value and adjust the coupling between resonators.

[0117] Furthermore, the features of this disclosure can also be applied to filter devices with six or more stages.

[0118] [Implementation Method 2]

[0119] In Implementation Method 1 Figure 8 as well as Figure 10 The method of adjusting magnetic coupling by adjusting the linewidth of the wiring pattern connecting the resonators is described in the paper.

[0120] In Embodiment 2, other adjustment examples regarding the magnetic coupling of resonators RC1 and RC2 connected to the input and output terminals will be described.

[0121] Figure 16This is an exploded perspective view showing an example of the stacked structure of the filter device 100G in Embodiment 2. Additionally, Figure 17 yes Figure 16 A top view of the common electrode PC1 in the filter device 100G.

[0122] Reference Figure 16 In the filter device 100G, it becomes the embodiment of implementation 1. Figure 4 The common electrode PC in the filter device 100 described herein is replaced with a common electrode PC1, and the vias V3B and V4B are, as described above. Figure 5 The description states that the structure was replaced with a via V34B, and a planar electrode P10 was added to the seventh layer LY7. In the filter device 100G, this is not repeatedly used... Figure 4 Explanation of recurring elements.

[0123] The planar electrode P10 has a roughly U-shaped shape and is located on the seventh layer LY7, positioned between planar electrodes P4 and P6. Planar electrode P10 is connected to via via V34B, and through via V34B, it is connected to the common electrode PC1 and the planar electrode PG1 (i.e., the ground terminal GND). Planar electrode P10 is capacitively coupled to planar electrode P5 located on the sixth layer LY6, and capacitor electrodes P3 and P7 located on the eighth layer LY8. Through planar electrode P10, the capacitors C1 to C4 in the resonator RC1 to RC4 are increased (…). Figure 2 ) capacitor.

[0124] Additionally, in the common electrode PC1 located in the second layer LY2, such as Figure 17 As shown, the connection positions of wiring pattern PT2 with wiring patterns PT1 and PT3, and the connection positions of wiring pattern PT6 with wiring patterns PT5 and PT7, are moved in the positive direction of the Y-axis. In other words, wiring pattern PT2 is connected between the portion of wiring pattern PT1 that connects to the through-hole V1A (first through-hole) of resonator RC1 and the portion that connects to the through-hole V1B (second through-hole), and between the portion of wiring pattern PT3 that connects to the through-hole V3A (first through-hole) of resonator RC3 and the portion that connects to the through-hole V34B (second through-hole). Furthermore, wiring pattern PT6 is connected between the portion of wiring pattern PT7 that connects to the through-hole V2A (first through-hole) of resonator RC2 and the portion that connects to the through-hole V2B (second through-hole), and between the portion of wiring pattern PT5 that connects to the through-hole V4A (first through-hole) of resonator RC4 and the portion that connects to the through-hole V34B (second through-hole).

[0125] The wiring pattern PT2 connecting resonators RC1 and RC3 is close to the open end side of resonator RC1 (i.e., the via V1A side), thereby shortening the shortest path distance from via V1A to via V34B, thus strengthening the magnetic coupling between resonators RC1 and RC3. Similarly, the wiring pattern PT6 connecting resonators RC2 and RC4 is close to the open end side of resonator RC4 (i.e., the via V2A side), thereby shortening the shortest path distance from via V2A to via V34B, thus strengthening the magnetic coupling between resonators RC2 and RC4. That is, by adjusting the distance LG1 from the end of wiring pattern PT1 on the via V1A side to wiring pattern PT2, and the distance LG1 from the end of wiring pattern PT7 on the via V2A side to wiring pattern PT6, the magnetic coupling between resonators RC1, RC2 and other resonators can be adjusted.

[0126] In addition, such as Figure 8 As explained, by adjusting the line width W1 of wiring patterns PT2 and PT6, the inductance values ​​of wiring patterns PT2 and PT6 can be adjusted. Additionally, as... Figure 10 As explained in the text, the inductance value of the wiring pattern PT4 can be adjusted by adjusting the line width W2 of the wiring pattern PT4 between the resonators RC3 and RC4.

[0127] like Figure 8 With the edges of wiring patterns PT2 and PT6 fixed to the negative Y-axis ends of wiring patterns PT1 and PT7, adjusting the linewidth W1 of wiring patterns PT2 and PT6 will result in the following: if the linewidth W1 is narrowed to increase the inductance, the distance LG1 becomes longer, thus weakening the magnetic coupling between the resonators. Conversely, if the linewidth W1 is widened to decrease the inductance, the distance LG1 becomes shorter, thus strengthening the magnetic coupling between the resonators. In other words, the inductance of the inductor connecting the resonators changes in tandem with the magnetic coupling between them. Therefore, for example, in a small filter device, if one wants to increase the inductance between the resonators and thus strengthen the magnetic coupling, this adjustment method may result in a situation where the desired filter characteristics cannot be achieved.

[0128] In the structure of Implementation Method 2, the inductance value between resonators is adjusted by the linewidth W1 of the wiring patterns PT2 and PT6, and the magnetic coupling between resonators is adjusted by the connection position (i.e., distance LG1) of the wiring patterns PT2 and PT6. This allows for independent adjustment of both the inductance value and the magnetic coupling between the resonators. Therefore, the design freedom is increased, and the desired filter characteristics are easily achieved.

[0129] Furthermore, increasing the inductance between resonators increases their impedance. Increasing the magnetic coupling between resonators RC1 and RC4 shifts the attenuation electrode near the passband towards the passband side. Additionally, increasing the magnetic coupling between resonators RC2 and RC3 widens the passband width.

[0130] Furthermore, in the above example, the adjustment of line width and connection position for both wiring patterns PT2 and PT6 was described, but it is also possible to adjust the line width and connection position for only one of wiring patterns PT2 and PT6.

[0131] Figure 18 This is a graph comparing the insertion loss when the connection positions (i.e., distance LG1) of the wiring patterns PT2 and PT6 are varied in the filter device 100G of Embodiment 2 and the filter device 100 of Embodiment 1, with the wiring patterns PT2 and PT6 having the same linewidth W1. Furthermore, the connection positions of the wiring patterns PT2 and PT6 in the filter device 100G are closer to the vias V1A and V2A than those in the filter device 100. Figure 18 In the diagram, the solid line LN40 represents the case of filter device 100G, and the dashed line LN41 represents the case of filter device 100.

[0132] like Figure 18 As shown, in filter device 100G, the magnetic coupling between resonators becomes stronger, resulting in the frequency generated by the attenuator being closer to the passband side compared to filter device 100. That is, the steepness of attenuation in the non-passband can be improved.

[0133] Furthermore, although not shown in the figure, the wiring pattern PT4 connecting resonators RC3 and RC4 can also have its line width W2 and connection position adjusted independently.

[0134] As described above, by independently adjusting the inductance value based on the linewidth of the wiring pattern connecting each resonator and adjusting the magnetic coupling between resonators based on the connection position of the wiring pattern, the design freedom can be increased and the desired filter characteristics can be achieved.

[0135] Furthermore, the “wiring pattern PT2” and “wiring pattern PT6” in Embodiment 2 correspond to the “first part” and “second part” in this disclosure, respectively.

[0136] [Implementation Method 3]

[0137] In Embodiment 3, the structure of a filter device that further improves the attenuation characteristics near the passband will be described.

[0138] Figure 19 This is an equivalent circuit diagram of the filter device 100H in Embodiment 3. The filter device 100H serves to remove... Figure 2 The equivalent circuit of the filter device 100 shown includes capacitors C0 and C5 at the input and output terminals. These capacitors share inductors L3B and L4B in resonators RC3 and RC4 as inductor L34B, thus coupling resonators RC3 and RC4 through capacitor C34. Figure 19 In the middle, without repetition with Figure 2 Explanation of recurring elements.

[0139] Figure 20 This is an exploded perspective view showing an example of the stacked structure of the filter device 100H in Embodiment 3. (Refer to...) Figure 20 In filter device 100H, similar to filter device 100, resonators RC1 to RC4 are configured within a main body 110 having multiple dielectric layers LY1 to LY12. Resonator RC1 is configured to include vias V51A and V51B and a capacitor electrode P12. Resonator RC2 is configured to include vias V52A and V52B and a capacitor electrode P19. Resonator RC3 is configured to include vias V53A and V534B and a capacitor electrode P13. Resonator RC4 is configured to include vias V54A and V534B and a capacitor electrode P18.

[0140] A directional mark DM for determining the direction of the filter device 100 is disposed on the upper surface 111 (first layer LY1) of the main body 110. In addition, external terminals (input terminal T1, output terminal T2, and ground terminal GND) for connecting to external devices are disposed on the lower surface 112 (twelfth layer LY12) of the main body 110.

[0141] Input terminal T1 is connected to the planar electrode P11 of the eleventh layer LY11 via via hole V50. A resonator RC1 is connected to the planar electrode P11 via via hole V51A. Via via hole V51A is connected to the common electrode PC11 located on the second layer LY2. Additionally, the common electrode PC11 is connected to the planar electrode PG11 located on the tenth layer LY10 via via hole V51B. The planar electrode PG11 is connected to the ground terminal GND located on the twelfth layer LY12 via via holes VG4 and VG5.

[0142] Via V51A connects to capacitor electrode P12 on layer LY9 (ninth layer) and to capacitor electrode P14 on layer LY7 (seventh layer). A portion of capacitor electrode P12 is opposite to the planar electrode PG11 on layer LY10 (tenth layer). Through capacitor electrode P12 and planar electrode PG11, a [structure / structure] is formed. Figure 19Capacitor C1 is located within the capacitor. Furthermore, vias V51A and V51B are connected to... Figure 19 The inductors L1A and L1B in the diagram correspond to the following respectively.

[0143] Output terminal T2 is connected to the planar electrode P20 of the eleventh layer LY11 via via V55. The planar electrode P20 is connected to the via V52A of the resonator RC2. Via V52A is connected to the common electrode PC11 of the second layer LY2. Additionally, the common electrode PC11 is connected to the planar electrode PG11 of the tenth layer LY10 via via V52B.

[0144] Via V52A connects to capacitor electrode P19 on layer LY9 (ninth layer) and to capacitor electrode P17 on layer LY7 (seventh layer). A portion of capacitor electrode P19 is opposite to the planar electrode PG11 on layer LY10 (tenth layer). The capacitor electrode P19 and the planar electrode PG11 together form... Figure 19 Capacitor C2 is located within the capacitor. Furthermore, vias V52A and V52B are connected to... Figure 19 The inductors L2A and L2B in the diagram correspond to the following respectively.

[0145] The capacitor electrode P14 located on the seventh layer LY7 is opposite to the capacitor electrode P13 of the resonator RC3 located on the eighth layer LY8. The capacitor electrodes P13 and P14 together form a... Figure 19 Capacitor C13 in the middle.

[0146] Capacitor electrode P13 is connected to the common electrode PC11 of the second layer LY2 via via V53A. Additionally, the common electrode PC11 is connected to the planar electrode PG11 of the tenth layer LY10 via via V534B. Capacitor electrode P13 and planar electrode PG11 are opposite each other, forming a [structure / structure]. Figure 19 Capacitor C3.

[0147] Through-hole V53A and Figure 19 The inductor L3A corresponds to this. Additionally, the via V534B is... Figure 19 The corresponding inductor is L34B.

[0148] The capacitor electrode P17 of the seventh layer LY7 is opposite to the capacitor electrode P18 of the resonator RC4 located on the eighth layer LY8. The capacitor electrodes P17 and P18 together form a... Figure 19 The capacitor C24 in the middle.

[0149] Capacitor electrode P18 is connected to the common electrode PC11 of the second layer LY2 via via V54A. Additionally, the common electrode PC11 is connected to the planar electrode PG11 of the tenth layer LY10 via via V534B, as described above. Capacitor electrode P18 and planar electrode PG11 are opposite each other, forming a [structure / feature]. Figure 19 Capacitor C4. Through-hole V54A and... Figure 19 The inductor L4A in the diagram corresponds to this.

[0150] A portion of capacitor electrode P14 and a portion of capacitor electrode P17 of the seventh layer LY7 are opposite to capacitor electrode P15 disposed on the sixth layer LY6. The capacitor electrodes P14, P15, and P17 constitute... Figure 19 Capacitor C12 in the middle.

[0151] Additionally, a capacitor electrode P16 is provided on the sixth layer LY6. Capacitor electrode P16 is partially opposite to capacitor electrodes P13 and P18 on the eighth layer LY8. The capacitor electrodes P13, P16, and P18 together form a... Figure 19 Capacitor C34 in the middle.

[0152] In Embodiment 3, the vias V51A, V52A, V53A, and V54A in each resonator that are connected to the ground terminal GND via a capacitor are referred to as "first vias". In addition, the vias V51B, V52B, and V534B in each resonator that are not connected to the ground terminal GND via a capacitor are referred to as "second vias".

[0153] Figure 21 This is a top view of the common electrode PC11 in the filter device 100H. The common electrode PC11 is composed of a strip-shaped wiring pattern having a first end E11 and a second end E12. Figure 21 As shown, the common electrode PC11 includes wiring patterns PT11, PT14, and PT16 extending along the short side (Y-axis) of the body 110, and wiring patterns PT12, PT13, and PT15 extending along the long side (X-axis) of the body 110. Wiring patterns PT12, PT13, and PT15 are connected in series between wiring pattern PT11 and wiring pattern PT16. Wiring pattern PT14 is connected to wiring pattern PT13. That is, the common electrode PC11 has a generally E-shaped form.

[0154] A via V51A for resonator RC1 is connected to the first end E11 of the common electrode PC11 (i.e., one end of wiring pattern PT11). A via V51B for resonator RC1 is connected to the other end of wiring pattern PT11. A via V52A for resonator RC2 is connected to the second end E12 of the common electrode PC11 (i.e., one end of wiring pattern PT16). A via V52B for resonator RC2 is connected to the other end of wiring pattern PT16.

[0155] In wiring pattern PT13, a via V53A for resonator RC3 is connected to the end of wiring pattern PT11. Additionally, in wiring pattern PT13, a via V54A for resonator RC4 is connected to the end of wiring pattern PT16.

[0156] Wiring pattern PT12 is connected between wiring pattern PT11 and wiring pattern PT13. Wiring pattern PT15 is connected between wiring pattern PT13 and wiring pattern PT16.

[0157] One end of wiring pattern PT14 is connected to a via V534B, which is shared by resonators RC3 and RC4. The other end of wiring pattern PT14 is connected to wiring pattern PT13.

[0158] In other words, in the common electrode PC11, from the first end E11 toward the second end E12, the through holes V51A, V51B, V53A, V54A, V52B, and V52A are sequentially connected to the common electrode PC11.

[0159] The common electrode PC11 has a roughly E-shaped design, with the portion connected to the via V53A of resonator RC3 and the portion connected to the via V54A of resonator RC4 adjacent to each other, thus... Figure 5 Compared to the zigzag-shaped common electrode PC of Embodiment 1, the shortest distance along the common electrode PC11 between the via V51A of resonator RC1 and the via V54A of resonator RC4 is shorter. That is, compared to the filter device 100 of Embodiment 1, the magnetic coupling between resonator RC1 and resonator RC4 is stronger.

[0160] Similarly, the shortest distance along the common electrode PC11 between the vias V52A and V53A of resonator RC2, and between the vias V51A and V52A of resonator RC2, also becomes shorter. Consequently, the magnetic coupling between resonators RC2 and RC3, and between resonators RC1 and RC2, becomes stronger.

[0161] Generally, in a filter device with four resonators, it is known that increasing the magnetic coupling between the first and third resonators, and between the second and fourth resonators, increases the attenuation at higher frequencies than the passband. Furthermore, it is known that increasing the magnetic coupling between the first and fourth resonators increases the attenuation at lower frequencies than the passband. Therefore, by setting the common electrode PC11 as... Figure 21 The shape shown can improve the attenuation characteristics near the passband.

[0162] Figure 22 It is used for explanation Figure 19 A graph showing the pass-through characteristics of the 100H filter device. Figure 22 In the diagram, the horizontal axis represents frequency, and the vertical axis represents insertion loss. Furthermore, in... Figure 22 The image shows the portion closer to the high-frequency side of the passband. Figure 22 The solid line LN50 in the figure represents the filter device 100H of Embodiment 3, and the dashed line LN51 represents the filter device 100 of Embodiment 1.

[0163] like Figure 22 As shown, compared to filter device 100 (dashed line LN51), filter device 100H (solid line LN50) has a larger insertion loss (attenuation) on the high-frequency side of the attenuator. Therefore, in filter device 100H, the attenuation characteristics can be further improved compared to the structure of embodiment 1.

[0164] Furthermore, by changing the distance LG11 between the ends of wiring patterns PT12 and PT15 in the positive Y-axis direction of the common electrode PC11 (one end of wiring patterns PT11, PT14, and PT16) to adjust the linewidth of wiring patterns PT12 and PT15, the shortest distance between vias remains unchanged, thus maintaining the degree of magnetic coupling and changing the inductance value between resonators. Conversely, by changing the distance LG12 between the ends of wiring patterns PT12 and PT15 in the negative Y-axis direction of the common electrode PC11 (the other end of wiring patterns PT11 and PT16) to adjust the linewidth of wiring patterns PT12 and PT15, the shortest distance between vias changes, thus changing the strength of magnetic coupling and adjusting the inductance value between resonators.

[0165] Furthermore, shortening the distance LG13 between vias V53A and V54A reduces the distances between resonators RC1 and RC4, RC2 and RC3, and RC3 and RC4, thus strengthening the magnetic coupling between these resonators. Conversely, increasing the distances between resonators RC1 and RC3, and between RC2 and RC4, weakens the magnetic coupling between these resonators, resulting in a change in the input / output impedance. This impedance change can be addressed, for example, by adjusting the capacitors between the resonators (…). Figure 19 The values ​​of capacitors C13 and C24 are used for matching.

[0166] (Variation Example 5)

[0167] Figure 23 This is a top view of the common electrode PC11A in the filter device 100H1 of Modified Example 5. In the filter device 100H1, the resonators RC3 and RC4 are each provided with a through hole connecting the common electrode PC11A and the plate electrode PG11.

[0168] More specifically, in the filter device 100H1, Figure 21 The wiring patterns PT13 and PT14 constitute a wiring pattern P134. The inductors in the resonators RC3 and RC4 are not shared as a single inductor. A via V53B is configured for via V53A, and a via V54B is configured for via V54A.

[0169] In a structure like filter device 100H1, compared to filter device 100H, the magnetic coupling between resonators RC3 and RC4 is weaker, thus increasing the attenuation near the attenuation pole in the passband, while the passband width is slightly narrower. For either filter device 100H or filter device 100H1, the desired attenuation characteristics and passband width should be appropriately selected.

[0170] (Variation Example 6)

[0171] Figure 24 This is a top view of the common electrode PC11B in the filter device 100H2 of Modified Example 6. The common electrode PC11B includes wiring patterns PT11, PT16, PT17, and PT18 extending along the short side (Y-axis) of the body 110, and wiring patterns PT12, PT13, and PT15 extending along the long side (X-axis) of the body 110. Wiring pattern PT12 is connected between wiring pattern PT11 and wiring pattern PT17. Wiring pattern PT13 is connected between wiring pattern PT17 and wiring pattern PT18. Wiring pattern PT15 is connected between wiring pattern PT18 and wiring pattern PT16.

[0172] In filter device 100H2, if with Figure 23 Compared to the filter device 100H1 in Modified Example 5, the positions of vias V53A and V53B in resonator RC3 are interchanged, and the positions of vias V54A and V54B in resonator RC4 are interchanged. Furthermore, in filter device 100H2, vias V51B in resonator RC1 and V53B in resonator RC3 are shared and removed, and vias V52B in resonator RC2 and V54B in resonator RC4 are shared and removed.

[0173] That is, at the negative Y-axis ends of wiring patterns PT11, PT16, PT17, and PT18, there are through holes V51A, V52A, V53A, and V54A respectively connected to the ground terminal GND via a capacitor, and at the positive Y-axis ends of wiring patterns PT17 and PT18, there are through holes V53B and V54B respectively connected without connecting to the ground terminal GND via a capacitor.

[0174] In this structure, the magnetic field lines generated by the coils of the closed loop formed by the wiring pattern and vias in each resonator are in the same direction. Therefore, compared with the structure of the filter device 100H1 in Modified Example 5, the magnetic coupling between resonators RC1 and RC3, and between resonators RC2 and RC4, is also stronger. As a result, the attenuation at higher frequencies than the passband can be increased.

[0175] Furthermore, the choice between resonators RC1 and RC3, and between resonators RC2 and RC4, can be made appropriately based on the overall size of the filter device, such as the filter device 100H2, by using a structure where the vias are configured in the same way. This is similar to the filter device 100H1.

[0176] Specifically, when the size of the filter device, especially its size in the Z-axis direction, is relatively large, the length of the vias increases, and the diameter of the hollow core of the coils in each resonator increases. Therefore, if the vias of the resonators are configured in the same way as in the filter device 100H2 of Modified Example 6, excessive magnetic coupling may occur. In such cases, it is preferable to adopt a structure in which the vias are arranged in opposite directions, as in the filter device 100H1 of Modified Example 5, to reduce magnetic coupling and thereby achieve the desired filter characteristics.

[0177] On the other hand, when the size of the filter device, especially its size in the Z-axis direction, is relatively small, the length of the via becomes shorter, and therefore the magnetic coupling between the resonators tends to weaken. Therefore, it is preferable to set the vias of the resonators in the same configuration, as in the filter device 100H2 of Modified Example 6, to strengthen the magnetic coupling and thereby achieve the desired filter characteristics.

[0178] Furthermore, in the filter device 100H2 of Modified Example 6, the coupling degree between each resonator can also be adjusted by adjusting the line width of the wiring patterns PT12, PT13, and PT15.

[0179] [Implementation Method 4]

[0180] In Embodiment 4, a structure for reducing the influence of external shielding on filter characteristics caused by the housing or other external shielding of a communication device disposed in a filter housing will be described.

[0181] In the filter devices disclosed in the above embodiments, a common electrode is disposed on the second layer LY2 at the uppermost side of the main body 110. This common electrode becomes the path for the current flowing in the resonator. Therefore, if there is an external shield on the upper surface of the filter device, capacitive coupling with the external shield will occur, which may become an important factor affecting the filter characteristics.

[0182] As a way to reduce the impact of the external shield, one consideration is to extend the distance between the filter device and the external shield. However, in this case, ensuring this separation distance may become a significant factor hindering the miniaturization of the main body of the communication device.

[0183] In the filter device of Embodiment 4, an internal shield connected to the ground terminal GND is disposed in the main body 110 on a layer above the common electrode. This suppresses variations in filter characteristics caused by the external shield.

[0184] Figure 25 This is an exploded perspective view showing an example of the stacked structure of the filter device 100I in Embodiment 4. (Refer to...) Figure 25 In filter device 100I, similar to filter device 100, resonators RC1 to RC4 are formed within the main body 110 having multiple dielectric layers LY1 to LY12. Furthermore, filter device 100I eliminates... Figure 19 The structure of capacitor C34 in the equivalent circuit of filter device 100H in Embodiment 3 is shown.

[0185] In the filter device 100I, resonator RC1 is configured to include vias V61A and V61B and capacitor electrode P21. Resonator RC2 is configured to include vias V62A and V62B and capacitor electrode P28. Resonator RC3 is configured to include vias V63A and V634B and capacitor electrode P22. Resonator RC4 is configured to include vias V64A and V634B and capacitor electrode P26.

[0186] A directional mark DM for determining the direction of the filter device 100 is disposed on the upper surface 111 (first layer LY1) of the main body 110. In addition, external terminals (input terminal T1, output terminal T2, and ground terminal GND) for connecting to external devices are disposed on the lower surface 112 (twelfth layer LY12) of the main body 110.

[0187] Input terminal T1 is connected to capacitor electrode P21 of layer 11 (LY11) via via hole V60. A portion of capacitor electrode P21 is opposite to plate electrode PG21 located on layer 10 (LY10). The capacitor electrode P21 and plate electrode PG21 together constitute... Figure 19 Capacitor C1 in the middle.

[0188] A via V61A for resonator RC1 is connected to capacitor electrode P21. Via V61A connects to common electrode PC21 on the third layer LY3 and common electrode PC22 on the fourth layer LY4. Common electrodes PC21 and PC22 are connected to plate electrode PG21 on the tenth layer LY10 via via V61B. Plate electrode PG21 is connected to the ground terminal GND on the twelfth layer LY12 via via VG4. Via VG4 also connects to plate electrode P27 on the eleventh layer LY11. Plate electrode P27 is connected to the ground terminal GND via vias VG4 and VG5.

[0189] Via V61A connects to capacitor electrode P23 on the eighth layer LY8. A portion of capacitor electrode P23 is opposite to capacitor electrode P22 on the ninth layer LY9. Capacitor electrodes P22 and P23 together form... Figure 19 Capacitor C13 is located within the capacitor. Furthermore, vias V61A and V61B are connected to... Figure 19 The inductors L1A and L1B in the diagram correspond to the following respectively.

[0190] Output terminal T2 is connected to capacitor electrode P28 on the eleventh layer LY11 via via V65. A portion of capacitor electrode P28 is opposite to plate electrode PG21 on the twelfth layer LY12. The capacitor electrode P28 and plate electrode PG21 together form a... Figure 19 Capacitor C2 in the middle.

[0191] A via V62A for resonator RC2 is connected to capacitor electrode P28. Via V62A is connected to common electrode PC21 on the third layer LY3 and common electrode PC23 on the fourth layer LY4. Additionally, common electrodes PC21 and PC23 are connected to the planar electrode PG21 on the tenth layer LY10 via via V62B.

[0192] Additionally, via V62A is connected to capacitor electrode P25 in the eighth layer LY8. A portion of capacitor electrode P25 is opposite to capacitor electrode P26 in the ninth layer LY9. Capacitor electrodes P25 and P26 together form a... Figure 19 Capacitor C24 is included. Furthermore, vias V62A and V62B are connected to... Figure 19 The inductors L2A and L2B in the diagram correspond to the following respectively.

[0193] The capacitor electrode P22 of the ninth layer LY9 is connected to the common electrode PC21 of the third layer LY3 and the common electrode PC22 of the fourth layer LY4 via via V63A. Additionally, the common electrode PC21 is connected to the planar electrode PG21 of the tenth layer LY10 via via V634B. Via via V63A and... Figure 19 The inductor L3A corresponds to this. Additionally, the via V634B is... Figure 19 The corresponding inductor is L34B.

[0194] The capacitor electrode P26 of the ninth layer LY9 is connected to the common electrode PC21 of the third layer LY3 and the common electrode PC23 of the fourth layer LY4 via via V64A. Additionally, the common electrode PC21 is connected to the planar electrode PG21 of the tenth layer LY10 via via V634B, as described above. Via via V64A and... Figure 19 The inductor L4A in the diagram corresponds to this.

[0195] Additionally, capacitor electrode P24 is also provided on the seventh layer LY7. Capacitor electrode P24 is partially opposite to capacitor electrodes P23 and P25 on the eighth layer LY8. The capacitor electrodes P23 to P25 together form a... Figure 19 Capacitor C12 in the middle.

[0196] In the filter device 100I of embodiment 4, a planar electrode PG22 is provided in the second layer LY2. The planar electrode PG22 at least covers the common electrode PC21 of the third layer LY3. In other words, when the main body 110 is viewed from the stacking direction (Z-axis direction), the planar electrode PG22 overlaps with the common electrode PC21.

[0197] The planar electrode PG22 is connected to the planar electrode PG21 (i.e., the ground terminal GND) via vias V61B, V62B, and V634B. The planar electrode PG22 functions as an internal shielding component for the common electrode PC21. Through the planar electrode PG22, coupling between the common electrode PC21 and the external shielding (not shown) capacitor outside the filter device is prevented. Furthermore, in Figure 25 In the example, the planar electrode PG22 is connected to the planar electrode PG21 (i.e., the ground terminal GND) through three vias V61B, V62B, and V634B. The large number of vias connecting the planar electrodes PG21 and PG22 makes the potential of the planar electrode PG22 more stable.

[0198] Furthermore, the common electrodes PC22 and PC23 in the fourth layer LY4 are configured to improve the Q value at the input and output terminals. By configuring the common electrodes PC22 and PC23, the insertion loss is improved.

[0199] Figure 26 It means Figure 25 A graph showing the pass-through characteristics of the filter device 100I. Figure 26 In the diagram, the horizontal axis represents frequency, and the vertical axis represents insertion loss and reflection loss. Figure 26 In the diagram, solid lines LN60 and LN70 represent the insertion loss and reflection loss of the filter device 100I in Embodiment 4, respectively, while dashed lines LN61 and LN71 represent the insertion loss and reflection loss without internal shielding, respectively.

[0200] Reference Figure 26 For the insertion loss within the passband, the values ​​are approximately the same for both the case with and without internal shielding. However, particularly for the lower frequency range beyond the passband, the insertion loss of the internally shielded filter device 100I increases, while its attenuation characteristics improve. Furthermore, the reflection loss within the passband is reduced in the filter device 100I compared to the case without internal shielding. Therefore, it can be seen that by incorporating internal shielding, the degradation of filter characteristics is suppressed.

[0201] Figure 27 This diagram illustrates the impact of the presence or absence of a common electrode and internal shielding on the filter characteristics of the external shield. Figure 27 In the above, the frequency at which the insertion loss in the passband with or without external shielding deteriorates and the attenuation on the high-frequency side becomes 20 dB (hereinafter referred to as the "attenuation point") is represented in cases 1 to 3.

[0202] Case 1 is as follows Figure 6As in the comparative example, there is no common electrode and each resonator is independent, and there is no internal shielding. In addition, case 2 is the case with a common electrode but no internal shielding, and case 3 is the case with a common electrode and internal shielding, as in the filter device 100I of embodiment 4.

[0203] Reference Figure 27 For the insertion loss in the passband, the reduction is about 0.30 dB without internal shielding (case 1, case 2), but in case 3 with internal shielding, the reduction is about 0.06 dB.

[0204] Furthermore, regarding the frequency of the attenuation point on the high-frequency side, in Case 1, with external shielding, the attenuation point frequency is more than 4 GHz lower than without external shielding. On the other hand, in Cases 2 and 3, the attenuation point frequency is 1 to 2 GHz higher. Thus, for the attenuation point, the difference caused by the presence or absence of internal shielding is almost invisible, and the variation in the attenuation point can be suppressed by using a common electrode.

[0205] Thus, in the filter device 100I of Embodiment 4, which has a shared electrode and internal shielding, the reduction in filter characteristics based on external shielding can be suppressed.

[0206] Furthermore, in embodiment 4, the common electrode PC21 can also be a rectangular flat plate electrode, or it can be the shape described in the above embodiments and variations. Additionally, in Figure 24 The example shown is an example where a flat plate electrode PG22 is arranged only on the upper surface side as an internal shield, but in addition, an internal shield can also be arranged on the side part of the body 110.

[0207] The embodiments disclosed herein should be considered illustrative in all respects and are not intended to limit the invention. The scope of this disclosure is defined not by the description of the embodiments above, but by the claims, and is intended to include all equivalents of the claims and all modifications within the scope.

[0208] Explanation of reference numerals in the attached figures

[0209] 10…communication device; 12…antenna; 20…high frequency front-end circuit; 22, 28…bandpass filter; 24…amplifier; 26…attenuator; 30…mixer; 32…local oscillator; 40…D / A converter; 50…RF circuit; 100, 100A~100I, 200…filter device; 110…main body; C0~C5, C12, C13, C24, C34…capacitors; DM…directivity marker; E 1. E2…end; GND…grounding terminal; L1A~L4A, L1B~L4B, L34B…inductors; LY1~LY12…dielectric layer; N1A~N4A, N1B~N4B…connection node; P1, P4~P6, P9~P11, P20, P27, PG1, PG2, PG11, PG21, PG22…plate electrode; P2, P3, P7, P8, P11~P19, P2 1~P26, P28… Capacitor electrodes; PC, PC1~PC4, PC11, PC21~PC23… Common electrodes; PD1~PD4… Wiring electrodes; PT1~PT7, PT11~PT16, PT134… Wiring patterns; RC1~RC4… Resonators; T1… Input terminals; T2… Output terminals; V0, V1A~V4A, V1B~V4B, V5, V10A~V12A, V1 0B, V11B, V23, V20A~V23A, V20B~V22B, V30A~V34A, V30B~V34B, V40A~V43A, V40B~V43B, V50, V51A~V54A, V51B~V54B, V534B, V55, V60, V61A~V64A, V61B, V62B, V634B, V65, VG1~VG5… Through holes.

Claims

1. A filter device comprising: Input terminals; Output terminals; main body; A common electrode is disposed on the main body; Grounding terminal; as well as The first LC parallel resonator, the second LC parallel resonator, and the third LC parallel resonator are respectively connected to the common electrode and the grounding terminal. The first LC parallel resonator, the second LC parallel resonator, and the third LC parallel resonator each include: Capacitor; A first through-hole, one end of which is connected to the common electrode, and the other end of which is connected to the ground terminal via the capacitor; and The second via has one end connected to the common electrode, and the other end connected to the ground terminal without passing through the capacitor. A second via is connected between the portions of the common electrode that connect the first vias of two adjacent LC parallel resonators.

2. The filter device according to claim 1, wherein, The common electrode is strip-shaped and includes a first end and a second end. The first through-hole of the first LC parallel resonator is connected to the first end and is electrically connected to the input terminal. The first through-hole of the second LC parallel resonator is connected to the second end and is electrically connected to the output terminal. The third LC parallel resonator is configured between the first LC parallel resonator and the second LC parallel resonator.

3. The filter device according to claim 2, wherein, It also includes a fourth LC parallel resonator arranged between the second LC parallel resonator and the third LC parallel resonator.

4. The filter device according to claim 3, wherein, The common electrode has a tortuous shape. Along the common electrode from the first end toward the second end, the first through-hole of the first LC parallel resonator, the second through-hole of the first LC parallel resonator, the first through-hole of the third LC parallel resonator, the second through-hole of the third LC parallel resonator, the second through-hole of the fourth LC parallel resonator, the first through-hole of the fourth LC parallel resonator, the second through-hole of the second LC parallel resonator, and the first through-hole of the second LC parallel resonator are sequentially connected to the common electrode. The width of the common electrode between the portion connected to the second via of the first LC parallel resonator and the portion connected to the first via of the third LC parallel resonator, and the width of the common electrode between the portion connected to the second via of the second LC parallel resonator and the portion connected to the first via of the fourth LC parallel resonator, is wider than the width of the other portions of the common electrode.

5. The filter device according to claim 3, wherein, The common electrode has a tortuous shape. Along the common electrode from the first end toward the second end, the first through-hole of the first LC parallel resonator, the second through-hole of the first LC parallel resonator, the first through-hole of the third LC parallel resonator, the second through-hole of the third LC parallel resonator, the second through-hole of the fourth LC parallel resonator, the first through-hole of the fourth LC parallel resonator, the second through-hole of the second LC parallel resonator, and the first through-hole of the second LC parallel resonator are sequentially connected to the common electrode. The width of the common electrode between the portion connected to the second via of the third LC parallel resonator and the portion connected to the second via of the fourth LC parallel resonator is wider than the width of the other portions of the common electrode.

6. The filter device according to claim 3, wherein, The common electrode includes a first portion between the portion for connecting the first LC parallel resonator and the portion for connecting the third LC parallel resonator. The first portion is connected between the portion for connecting the first through-hole of the first LC parallel resonator and the portion for connecting the second through-hole of the first LC parallel resonator, and between the portion for connecting the first through-hole of the third LC parallel resonator and the portion for connecting the second through-hole of the third LC parallel resonator.

7. The filter device according to claim 3, wherein, The common electrode includes a second portion between the portion for connecting the second LC parallel resonator and the portion for connecting the fourth LC parallel resonator. The second part is connected between the part connected to the first through hole of the second LC parallel resonator and the part connected to the second through hole of the second LC parallel resonator, and between the part connected to the first through hole of the fourth LC parallel resonator and the part connected to the second through hole of the fourth LC parallel resonator.

8. The filter device according to claim 6, wherein, The common electrode includes a second portion between the portion for connecting the second LC parallel resonator and the portion for connecting the fourth LC parallel resonator. The second part is connected between the part connected to the first through hole of the second LC parallel resonator and the part connected to the second through hole of the second LC parallel resonator, and between the part connected to the first through hole of the fourth LC parallel resonator and the part connected to the second through hole of the fourth LC parallel resonator.

9. The filter device according to any one of claims 3 to 8, wherein, It also has: A first capacitor connected between the first LC parallel resonator and the third LC parallel resonator; A second capacitor connected between the second LC parallel resonator and the fourth LC parallel resonator; as well as A third capacitor is connected between the first LC parallel resonator and the second LC parallel resonator.

10. The filter device according to claim 3, wherein, Along the common electrode from the first end toward the second end, the first through hole of the first LC parallel resonator, the second through hole of the first LC parallel resonator, the first through hole of the third LC parallel resonator, the first through hole of the fourth LC parallel resonator, the second through hole of the second LC parallel resonator, and the first through hole of the second LC parallel resonator are sequentially connected to the common electrode.

11. The filter device according to any one of claims 1 to 8, 10, wherein, It also includes a shielding component, which is disposed on the upper surface side closer to the main body than the common electrode and connected to the grounding terminal. When viewed from the top surface of the main body, the shielding component overlaps with the common electrode.

12. The filter device according to claim 9, wherein, It also includes a shielding component, which is disposed on the upper surface side closer to the main body than the common electrode and connected to the grounding terminal. When viewed from the top surface of the main body, the shielding component overlaps with the common electrode.

13. The filter device according to any one of claims 1 to 8, 10, and 12, wherein, The filter device is a bandpass filter that allows signals of a specific frequency band to pass through.

14. The filter device according to claim 9, wherein, The filter device is a bandpass filter that allows signals of a specific frequency band to pass through.

15. The filter device according to claim 11, wherein, The filter device is a bandpass filter that allows signals of a specific frequency band to pass through.

16. A high-frequency front-end circuit, The filter device comprises any one of claims 1 to 15.

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