filter circuit

Abstract

To realize a filter circuit that can reduce the number of elements in a filter circuit while increasing the amount of attenuation in a frequency range higher than the frequency of a signal to be filtered.SOLUTION: A filter circuit 1 includes a first port 2, a second port 3, a third port 4, a first filter 10 arranged between the first port 2 and the second port 3 in terms of the circuit configuration and including a plurality of resonators 11 to 14, a high-pass filter circuit 21 arranged between the first port 2 and the third port 4 in terms of the circuit configuration, a conductor 7 arranged between the first port 2 and the first filter 10 in terms of the circuit configuration, and forming an attenuation pole in a predetermined frequency range in the pass attenuation characteristics between the first port 2 and the third port 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a filter circuit including a band-pass filter circuit and a high-pass filter circuit.

Background Art

[0002] In small mobile communication devices, a configuration is widely used in which an antenna commonly used in a plurality of applications with different systems and operating frequency bands is provided, and a plurality of signals transmitted and received by this antenna are separated using a diplexer.

[0003] Generally, a diplexer that separates a first signal having a frequency within a first frequency band and a second signal having a frequency within a second frequency band higher than the first frequency band includes a common port, a first signal port, a second signal port, a first filter provided in a first signal path from the common port to the first signal port, and a second filter provided in a second signal path from the common port to the second signal port.

[0004] As the first filter, for example, a band-pass filter including a plurality of resonators configured to be electromagnetically coupled to each other is used. Hereinafter, such a band-pass filter is also referred to as a resonator-type band-pass filter. Patent Document 1 discloses a resonator-type band-pass filter.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In some cases, a signal splitter is required to have a high pass-through attenuation in the frequency range higher than the frequency of the signal filtered by the second filter. In this case, for example, a bandpass filter can be used as the second filter, which consists of a high-pass filter and a low-pass filter connected in series. In this bandpass filter, the low-pass filter can form an attenuation pole on the high-frequency side of the passband of the second filter (bandpass filter). This makes it possible to increase the pass-through attenuation in the frequency range higher than the frequency of the signal filtered by the second filter.

[0007] In recent years, the market has demanded miniaturization and space-saving for small mobile communication devices, and this has also led to a demand for miniaturization of the demultiplexers used in these devices. When a bandpass filter, which connects a high-pass filter and a low-pass filter in series, is used as the second filter, the number of elements in the bandpass filter increases, making it difficult to miniaturize the demultiplexer. Furthermore, if the number of frequency ranges where high pass-through attenuation is required increases, the number of attenuation poles that must be formed on the high-frequency side of the passband of the second filter (bandpass filter) also increases. In this case, there is a problem in that the number of elements in the low-pass filter increases.

[0008] The above problem applies not only to demultiplexers, but to all filter circuits that require a high pass-through attenuation in the frequency range higher than the frequency of the signal being filtered.

[0009] The present invention has been made in view of the above problems, and its objective is to provide a filter circuit that can reduce the number of elements in the filter circuit while increasing the pass-through attenuation in the frequency range higher than the frequency of the signal to be filtered. [Means for solving the problem]

[0010] The filter circuit of the present invention The first port and The second port, The third port and In terms of circuit configuration, a bandpass filter circuit including multiple resonators is provided between the first port and the second port, In terms of circuit configuration, a high-pass filter circuit is provided between the first port and the third port, In terms of the circuit configuration, a conductor provided between the first port and the bandpass filter circuit, which forms an attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port and the third port, It is equipped with. [Effects of the Invention]

[0011] In the filter circuit of the present invention, the conductor provided between the first port and the bandpass filter circuit forms an attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port and the third port. As a result, according to the present invention, it is possible to reduce the number of elements in the filter circuit while increasing the pass-through attenuation in the frequency range higher than the frequency of the signal to be filtered. [Brief explanation of the drawing]

[0012] [Figure 1] This is a circuit diagram showing the circuit configuration of a filter circuit according to one embodiment of the present invention. [Figure 2] This is a perspective view showing the appearance of a laminated filter circuit according to one embodiment of the present invention. [Figure 3] This is an explanatory diagram showing the pattern formation surface of the first to third dielectric layers in a laminate of a filter circuit according to one embodiment of the present invention. [Figure 4] This is an explanatory diagram showing the pattern formation surface of the fourth to sixth dielectric layers in a laminate of a filter circuit according to one embodiment of the present invention. [Figure 5] This is an explanatory diagram showing the pattern formation surface of the 7th to 17th dielectric layers in a laminate of a filter circuit according to one embodiment of the present invention. [Figure 6] This is an explanatory diagram showing the pattern formation surface of the 18th to 20th dielectric layers in a laminate of a filter circuit according to one embodiment of the present invention. [Figure 7] FIG. 21 is an explanatory diagram showing the pattern formation surfaces of the 21st and 22nd dielectric layers in the laminate of the filter circuit according to an embodiment of the present invention. [Figure 8] FIG. 22 is a perspective view showing the inside of the laminate of the filter circuit according to an embodiment of the present invention. [Figure 9] FIG. 23 is a plan view showing a part of the inside of the laminate of the filter circuit according to an embodiment of the present invention. [Figure 10] FIG. 24 is a characteristic diagram showing the pass attenuation characteristics of the models of the first and second embodiments. MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, referring to FIG. 1, an outline of the configuration of a filter circuit 1 according to an embodiment of the present invention will be described. The filter circuit 1 according to the present embodiment is a diplexer that separates a first signal having a frequency within a first passband and a second signal having a frequency within a second passband higher than the first passband. The filter circuit 1 includes a first filter 10 that selectively passes the first signal and a second filter 20 that selectively passes the second signal.

[0014] The filter circuit 1 further includes a first port 2, a second port 3, a third port 4, a signal path 5 connecting the first port 2 and the second port 3, and a signal path 6 connecting the first port 2 and the third port 4. The first filter 10 is provided between the first port 2 and the second port 3 in terms of circuit configuration. The second filter 20 is provided between the first port 2 and the third port 4 in terms of circuit configuration. In the present application, the expression "in terms of circuit configuration" is used to refer to the arrangement on the circuit diagram, not the arrangement in the physical configuration.

[0015] The signal path 5 is a path from the first port 2 via the first filter 10 to the second port 3. The signal path 6 is a path from the first port 2 via the second filter 20 to the third port 4. The first signal with a frequency within the first passband selectively passes through the signal path 5 provided with the first filter 10. The second signal with a frequency within the second passband selectively passes through the signal path 6 provided with the second filter 20. In this way, the filter circuit 1 separates the first signal and the second signal.

[0016] In this embodiment, the first filter 10 is a band-pass filter circuit including a plurality of resonators. The second filter 20 includes a high-pass filter circuit 21. In particular, in this embodiment, the second filter 20 further includes a low-pass filter circuit 22 provided between the high-pass filter circuit 21 and the third port 4. The high-pass filter circuit 21 and the low-pass filter circuit 22 constitute a band-pass filter.

[0017] Since the first and second filters 10 and 20 are components of the filter circuit 1, it can also be said that the filter circuit 1 includes a band-pass filter circuit, a high-pass filter circuit 21, and a low-pass filter circuit 22.

[0018] The filter circuit 1 further includes a conductor 7 provided between the first port 2 and the first filter 10 (band-pass filter circuit) in terms of circuit configuration. The conductor 7 is a connection conductor constituting a part of the signal path 5. The conductor 7 forms an attenuation pole in a predetermined frequency region in the pass attenuation characteristic between the first port 2 and the third port 4. In particular, in this embodiment, the predetermined frequency region is a frequency region higher than the frequency of the second signal filtered by the second filter 20 (a frequency region higher than the second passband). The conductor 7 causes impedance mismatch with respect to the high-pass filter circuit 21 of the second filter 20 between the first port 2 and the first filter 10 (band-pass filter circuit).

[0019] Next, with reference to Figure 1, the configurations of the first and second filters 10 and 20 will be described in detail. First, the first filter 10 will be described. The first filter 10 includes resonators 11, 12, 13, and 14, and capacitors C11, C12, C13, C14, C15, C16, C17, and C18.

[0020] The resonators 11 to 14 are arranged in this order from the first port 2 side in the circuit configuration. The resonators 11 to 14 are configured such that resonators 11 and 12 are adjacent to each other and electromagnetically coupled in the circuit configuration, resonators 12 and 13 are adjacent to each other and electromagnetically coupled in the circuit configuration, and resonators 13 and 14 are adjacent to each other and electromagnetically coupled in the circuit configuration. In this embodiment, each of the resonators 11 to 14 is a quarter-wavelength resonator.

[0021] Each of the resonators 11 to 14 has a first end and a second end. The first end of resonator 11 is electrically connected to the conductor 7. The first end of resonator 14 is connected to the second port 3. The second end of each of the resonators 11 to 14 is connected to ground.

[0022] Capacitor C11 is positioned between the first end of resonator 11 and ground in the circuit configuration. Capacitor C12 is positioned between the first end of resonator 12 and ground in the circuit configuration. Capacitor C13 is positioned between the first end of resonator 13 and ground in the circuit configuration. Capacitor C14 is positioned between the first end of resonator 14 and ground in the circuit configuration.

[0023] Resonator 11 and resonator 12 are capacitively coupled via capacitor C15. Resonator 13 and resonator 14 are capacitively coupled via capacitor C16.

[0024] One end of capacitor C17 is connected to the first end of resonator 11. One end of capacitor C18 is connected to the other end of capacitor C17. The other end of capacitor C18 is connected to the first end of resonator 14.

[0025] Next, the high-pass filter circuit 21 of the second filter 20 will be described. The high-pass filter circuit 21 includes inductors L21 and L22, and capacitors C21, C22, C23, C24, and C25.

[0026] One end of capacitor C21 is connected to the first port 2. Also, one end of capacitor C21 is electrically connected to conductor 7. One end of capacitor C22 is connected to the other end of capacitor C21. One end of capacitor C23 is connected to the other end of capacitor C22.

[0027] One end of inductor L21 is connected to the junction point between capacitors C21 and C22. One end of capacitor C24 is connected to the other end of inductor L21. The other end of capacitor C24 is connected to ground.

[0028] One end of capacitor C25 is connected to the junction point between capacitors C22 and C23. One end of inductor L22 is connected to the other end of capacitor C25. The other end of inductor L22 is connected to ground.

[0029] Next, the low-pass filter circuit 22 of the second filter 20 will be described. The low-pass filter circuit 22 includes an inductor L23 and capacitors C26 and C27. One end of the inductor L23 is connected to the other end of the capacitor C23 of the high-pass filter circuit 21. The other end of the inductor L23 is connected to the third port 4.

[0030] One end of capacitor C26 is connected to one end of inductor L23. The other end of capacitor C26 is connected to ground. Capacitor C27 is connected in parallel with inductor L23.

[0031] Next, with reference to Figure 2, the other components of the filter circuit 1 will be described. Figure 2 is a perspective view showing the appearance of the laminated structure of the filter circuit 1.

[0032] The filter circuit 1 further comprises a laminate 50 including a plurality of stacked dielectric layers and a plurality of conductors (a plurality of conductor layers and a plurality of through-holes). The laminate 50 integrates the first to third ports 2 to 4, the first filter 10 which is a bandpass filter circuit, the second filter 20 which includes a high-pass filter circuit 21 and a low-pass filter circuit 22, and the conductor 7.

[0033] The laminate 50 has a bottom surface 50A and an upper surface 50B located at both ends of the stacking direction T of the multiple dielectric layers, and four side surfaces 50C to 50F connecting the bottom surface 50A and the upper surface 50B. Side surfaces 50C and 50D face opposite each other, and side surfaces 50E and 50F also face opposite each other. Side surfaces 50C to 50F are perpendicular to the upper surface 50B and the bottom surface 50A.

[0034] Here, as shown in Figure 2, we define the X, Y, and Z directions. The X, Y, and Z directions are orthogonal to each other. In this embodiment, the direction parallel to the stacking direction T is defined as the Z direction. The direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction. Furthermore, the expression "when viewed from the stacking direction T" means viewing the object from a position away in the Z or -Z direction.

[0035] As shown in Figure 2, the bottom surface 50A is located at the -Z edge of the laminate 50. The top surface 50B is located at the Z edge of the laminate 50. The side surface 50C is located at the -X edge of the laminate 50. The side surface 50D is located at the X edge of the laminate 50. The side surface 50E is located at the -Y edge of the laminate 50. The side surface 50F is located at the Y edge of the laminate 50.

[0036] The planar shape of the laminate 50 when viewed from the stacking direction T, that is, the shape of the bottom surface 50A or the top surface 50B, is elongated in one direction. In this embodiment in particular, the planar shape of the laminate 50 when viewed from the stacking direction T is a rectangular shape that is elongated in the direction parallel to the X direction.

[0037] The filter circuit 1 further includes terminals 111, 112, 113, 114, 115, and 116 provided on the bottom surface 50A of the laminate 50. Terminals 111, 112, and 113 are arranged in this order in the X direction at a position closer to side surface 50E than to side surface 50F. Terminals 114, 115, and 116 are arranged in this order in the -X direction at a position closer to side surface 50F than to side surface 50E.

[0038] Terminal 112 is a signal terminal corresponding to the first port 2. Terminal 114 is a signal terminal corresponding to the third port 4. Terminal 116 is a signal terminal corresponding to the second port 3. Therefore, the first to third ports 2 to 4 are located on the bottom surface 50A of the laminate 50. Terminals 111, 113, and 115 are each connected to ground.

[0039] Next, with reference to Figures 3(a) to 7(b), an example of multiple dielectric layers and multiple conductors constituting the laminate 50 will be described. In this example, the laminate 50 has 22 stacked dielectric layers. Hereinafter, these 22 dielectric layers will be referred to as the 1st to 22nd dielectric layers, from bottom to top. The 1st to 22nd dielectric layers will also be denoted by reference numerals 51 to 72.

[0040] In Figures 3(a) to 6(c), multiple circles represent multiple through-holes. Multiple through-holes are formed in each of the dielectric layers 51 to 70. Each of the multiple through-holes is formed by filling the through-hole holes with conductive paste. Each of the multiple through-holes is connected to a conductive layer or other through-holes. In Figures 3(a) to 6(c), multiple specific through-holes among the multiple through-holes are labeled with reference numerals.

[0041] Figure 3(a) shows the pattern formation surface of the first dielectric layer 51. Terminals 111 to 116 are formed on the pattern formation surface of the dielectric layer 51. The through-hole denoted as 51T1 is connected to terminal 112. In the following description, the through-hole denoted as 51T1 will simply be referred to as through-hole 51T1. Through-holes with other designations will also be referred to in the same way as through-hole 51T1.

[0042] Figure 3(b) shows the pattern formation surface of the second dielectric layer 52. Conductor layers 521, 522, 523, and 524 are formed on the pattern formation surface of the dielectric layer 52. Conductor layer 521 has a first end and a second end. The through-hole 52T1 shown in Figure 3(b) is connected to the vicinity of the first end of the conductor layer 521. The through-hole 52T2 shown in Figure 3(b) is connected to the vicinity of the second end of the conductor layer 521. The through-hole 51T1 formed in the dielectric layer 51 is connected to the portion between the first and second ends of the conductor layer 521.

[0043] Figure 3(c) shows the pattern formation surface of the third dielectric layer 53. Conductor layers 531, 532, 533, and 534 are formed on the pattern formation surface of the dielectric layer 53. The through holes 53T1b, 53T2b, 53T3b, and 53T4b shown in Figure 3(c) are connected to the conductor layer 531.

[0044] Figure 4(a) shows the pattern formation surface of the fourth dielectric layer 54. Conductor layers 541, 542, and 543 are formed on the pattern formation surface of the dielectric layer 54.

[0045] The through-holes 54T1b, 54T2b, 54T3b, and 54T4b shown in Figure 4(a) are connected to the through-holes 53T1b, 53T2b, 53T3b, and 53T4b formed in the dielectric layer 53, respectively. The through-hole 54T4a shown in Figure 4(a) is connected to the conductor layer 541.

[0046] Figure 4(b) shows the pattern formation surface of the fifth dielectric layer 55. Conductor layers 551, 552, 553, and 554 are formed on the pattern formation surface of the dielectric layer 55.

[0047] The through-holes 55T1b, 55T2b, 55T3b, 55T4a, and 55T4b shown in Figure 4(b) are connected to 54T1b, 54T2b, 54T3b, 54T4a, and 54T4b formed in the dielectric layer 54, respectively. The through-holes 55T2a and 55T3a shown in Figure 4(b) are connected to the conductor layers 551 and 552, respectively.

[0048] Figure 4(c) shows the pattern formation surface of the sixth dielectric layer 56. Conductor layers 561, 562, 563, 564, 565, and 566 are formed on the pattern formation surface of the dielectric layer 56. Conductor layer 564 is connected to conductor layer 563. In Figure 4(c), the boundary between conductor layer 563 and conductor layer 564 is shown by a dotted line.

[0049] The through-holes 56T1a and 56T5b shown in Figure 4(c) are connected to the conductor layers 561 and 566, respectively. The through-holes 56T1b, 56T2a, 56T2b, 56T3a, 56T3b, 56T4a, and 56T4b shown in Figure 4(c) are connected to the dielectric layers 55 formed by 55T1b, 55T2a, 55T2b, 55T3a, 55T3b, 55T4a, and 55T4b, respectively.

[0050] Figure 5(a) shows the pattern formation surface of the seventh dielectric layer 57. A conductive layer 571 is formed on the pattern formation surface of the dielectric layer 57. The through holes 57T1a, 57T1b, 57T2a, 57T2b, 57T3a, 57T3b, 57T4a, 57T4b, and 57T5b shown in Figure 5(a) are connected to 56T1a, 56T1b, 56T2a, 56T2b, 56T3a, 56T3b, 56T4a, 56T4b, and 56T5b formed in the dielectric layer 56, respectively.

[0051] Figure 5(b) shows the pattern formation surface of the eighth dielectric layer 58. Conductor layers 581, 582, and 583 are formed on the pattern formation surface of the dielectric layer 58.

[0052] The through-holes 58T1a, 58T1b, 58T2a, 58T2b, 58T3a, 58T3b, 58T4a, 58T4b, and 58T5b shown in Figure 5(b) are connected to 57T1a, 57T1b, 57T2a, 57T2b, 57T3a, 57T3b, 57T4a, 57T4b, and 57T5b formed in the dielectric layer 57, respectively. The through-holes 58T5a, 58T6a, and 58T6b shown in Figure 5(b) are connected to the conductor layers 581, 582, and 583, respectively.

[0053] Figure 5(c) shows the pattern formation surfaces of the 9th to 17th dielectric layers 59-67. Through holes 59T1a, 59T1b, 59T2a, 59T2b, 59T3a, 59T3b, 59T4a, 59T4b, 59T5a, 59T5b, 59T6a, and 59T6b are formed in each of the dielectric layers 59-67. The through-holes 59T1a, 59T1b, 59T2a, 59T2b, 59T3a, 59T3b, 59T4a, 59T4b, 59T5a, 59T5b, 59T6a, and 59T6b formed in dielectric layer 59 are connected to the through-holes 58T1a, 58T1b, 58T2a, 58T2b, 58T3a, 58T3b, 58T4a, 58T4b, 58T5a, 58T5b, 58T6a, and 58T6b formed in dielectric layer 58, respectively. In addition, in dielectric layers 59 to 67, through-holes with the same sign that are adjacent to each other vertically are connected to each other.

[0054] Figure 6(a) shows the pattern formation surface of the 18th dielectric layer 68. A conductor layer 681 for the inductor is formed on the pattern formation surface of the dielectric layer 68.

[0055] The through-holes 68T1a, 68T1b, 68T2a, 68T2b, 68T3a, 68T3b, 68T4a, 68T4b, 68T5b, 68T6a, and 68T6b shown in Figure 6(a) are connected to the through-holes 59T1a, 59T1b, 59T2a, 59T2b, 59T3a, 59T3b, 59T4a, 59T4b, 59T5b, 59T6a, and 59T6b formed in the dielectric layer 67, respectively.

[0056] The conductor layer 681 has a first end and a second end. The through-hole 68T5a shown in Figure 6(a) and the through-hole 59T5a formed in the dielectric layer 67 are connected to the vicinity of the first end of the conductor layer 681. The through-hole 68T5c shown in Figure 6(a) is connected to the vicinity of the second end of the conductor layer 681.

[0057] Figure 6(b) shows the pattern formation surface of the 19th dielectric layer 69. A conductive layer 691 for the inductor is formed on the pattern formation surface of the dielectric layer 69.

[0058] The through-holes 69T1a, 69T1b, 69T2a, 69T2b, 69T3a, 69T3b, 69T4a, 69T4b, 69T5b, 69T6a, and 69T6b shown in Figure 6(b) are connected to the through-holes 68T1a, 68T1b, 68T2a, 68T2b, 68T3a, 68T3b, 68T4a, 68T4b, 68T5b, 68T6a, and 68T6b formed in the dielectric layer 68, respectively.

[0059] The conductor layer 691 has a first end and a second end. The through-hole 68T5a formed in the dielectric layer 68 is connected to the vicinity of the first end in the conductor layer 691. The through-hole 69T5c shown in Figure 6(b) and the through-hole 68T5c formed in the dielectric layer 68 are connected to the vicinity of the second end in the conductor layer 681.

[0060] Figure 6(c) shows the pattern formation surface of the 20th dielectric layer 70. Conductor layers 701, 702, 703, and 704 for resonators and conductor layers 705 and 706 for inductors are formed on the pattern formation surface of the dielectric layer 70. Each of the conductor layers 701 to 706 has a first end and a second end.

[0061] The through-hole 70T1a shown in Figure 6(c) and the through-hole 69T1a formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 701. The through-hole 70T1b shown in Figure 6(c) and the through-hole 69T1b formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 701.

[0062] The through-hole 70T2a shown in Figure 6(c) and the through-hole 69T2a formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 702. The through-hole 70T2b shown in Figure 6(c) and the through-hole 69T2b formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 702.

[0063] The through-hole 70T3a shown in Figure 6(c) and the through-hole 69T3a formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 703. The through-hole 70T3b shown in Figure 6(c) and the through-hole 69T3b formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 703.

[0064] The through-hole 70T4a shown in Figure 6(c) and the through-hole 69T4a formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 704. The through-hole 70T4b shown in Figure 6(c) and the through-hole 69T4b formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 704.

[0065] The through-hole 70T5b shown in Figure 6(c) and the through-hole 69T5b formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 705. The through-hole 70T5c shown in Figure 6(c) and the through-hole 69T5c formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 705.

[0066] The through-hole 70T6a shown in Figure 6(c) and the through-hole 69T6a formed in the dielectric layer 69 are connected to the vicinity of the first end of the conductor layer 706. The through-hole 70T6b shown in Figure 6(c) and the through-hole 69T6b formed in the dielectric layer 69 are connected to the vicinity of the second end of the conductor layer 706.

[0067] Figure 7(a) shows the pattern formation surface of the 21st dielectric layer 71. Conductor layers 711, 712, 713, and 714 for resonators and conductor layers 715 and 716 for inductors are formed on the pattern formation surface of the dielectric layer 71. Each of the conductor layers 711 to 716 has a first end and a second end.

[0068] The through-hole 70T1a formed in the dielectric layer 70 is connected to the vicinity of the first end of the conductor layer 711. The through-hole 70T1b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 711.

[0069] The through-hole 70T2a formed in the dielectric layer 70 is connected to the vicinity of the first end of the conductor layer 712. The through-hole 70T2b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 712.

[0070] The through-hole 70T3a formed in the dielectric layer 70 is connected to the vicinity of the first end of the conductor layer 713. The through-hole 70T3b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 713.

[0071] The through-hole 70T4a formed in the dielectric layer 70 is connected to the vicinity of the first end of the conductor layer 714. The through-hole 70T4b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 714.

[0072] The through-hole 70T5b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 715. The through-hole 70T5c formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 715.

[0073] The through-hole 70T6a formed in the dielectric layer 70 is connected to the vicinity of the first end of the conductor layer 716. The through-hole 70T6b formed in the dielectric layer 70 is connected to the vicinity of the second end of the conductor layer 716.

[0074] Figure 7(b) shows the pattern formation surface of the 22nd dielectric layer 72. A mark 721 is formed on the pattern formation surface of the dielectric layer 72.

[0075] The laminate 50 shown in Figure 2 is constructed by stacking dielectric layers 51 to 72, with the pattern-forming surface of the first dielectric layer 51 becoming the bottom surface 50A of the laminate 50, and the surface of the 22nd dielectric layer 72 opposite to the pattern-forming surface becoming the top surface 50B of the laminate 50.

[0076] Each of the multiple through-holes shown in Figures 3(a) to 6(c) is connected to a conductor layer or another through-hole that overlaps in the stacking direction T when the first to 21st dielectric layers 51 to 71 are stacked. Furthermore, among the multiple through-holes shown in Figures 3(a) to 6(c), those located within a terminal or a conductor layer are connected to that terminal or conductor layer.

[0077] Figure 8 shows the interior of the laminate 50, which is constructed by stacking dielectric layers 51 to 72 from the first to the 22nd layer. As shown in Figure 8, multiple conductor layers and multiple through-holes, as shown in Figures 3(a) to 7(a), are stacked inside the laminate 50. Note that mark 721 is omitted in Figure 8.

[0078] The following describes the correspondence between the circuit components of the filter circuit 1 shown in Figure 1 and the internal components of the laminate 50 shown in Figures 3(a) to 7(b). First, the components of the first filter 10 will be described. The resonator 11 is composed of conductive layers 701, 711, through-holes 56T1a, 57T1a, 58T1a, 59T1a, 68T1a, 69T1a, 70T1a, and through-holes 53T1b, 54T1b, 55T1b, 56T1b, 57T1b, 58T1b, 59T1b, 68T1b, 69T1b, 70T1b.

[0079] The resonator 12 is composed of conductor layers 702 and 712, through-holes 55T2a, 56T2a, 57T2a, 58T2a, 59T2a, 68T2a, 69T2a, and 70T2a, and through-holes 53T2b, 54T2b, 55T2b, 56T2b, 57T2b, 58T2b, 59T2b, 68T2b, 69T2b, and 70T2b.

[0080] The resonator 13 is composed of conductor layers 703 and 713, through-holes 55T3a, 56T3a, 57T3a, 58T3a, 59T3a, 68T3a, 69T3a, and 70T3a, and through-holes 53T3b, 54T3b, 55T3b, 56T3b, 57T3b, 58T3b, 59T3b, 68T3b, 69T3b, and 70T3b.

[0081] The resonator 14 is composed of conductor layers 704 and 714, through-holes 54T4a, 55T4a, 56T4a, 57T4a, 58T4a, 59T4a, 68T4a, 69T4a, and 70T4a, and through-holes 53T4b, 54T4b, 55T4b, 56T4b, 57T4b, 58T4b, 59T4b, 68T4b, 69T4b, and 70T4b.

[0082] Capacitor C11 is composed of conductive layers 521, 531 and dielectric layers 52 between these conductive layers. Capacitor C12 is composed of conductive layers 531, 551 and dielectric layers 53, 54 between these conductive layers. Capacitor C13 is composed of conductive layers 531, 552 and dielectric layers 53, 54 between these conductive layers. Capacitor C14 is composed of conductive layers 531, 541 and dielectric layers 53 between these conductive layers.

[0083] Capacitor C15 is composed of conductive layers 551, 561 and a dielectric layer 55 between these conductive layers. Capacitor C16 is composed of conductive layers 552, 562 and a dielectric layer 55 between these conductive layers. Capacitor C17 is composed of conductive layers 561, 571 and a dielectric layer 56 between these conductive layers. Capacitor C18 is composed of conductive layers 562, 571 and a dielectric layer 56 between these conductive layers.

[0084] Next, the components of the high-pass filter circuit 21 of the second filter 20 will be described. The inductor L21 is composed of conductor layers 681, 691, 705, 715, through-holes 58T5a, 59T5a, 68T5a, through-holes 56T5b, 57T5b, 58T5b, 59T5b, 68T5b, 69T5b, 70T5b, and through-holes 68T5c, 69T5c, 70T5c.

[0085] Inductor L22 is composed of conductor layers 706 and 716, through-holes 58T6a, 59T6a, 68T6a, 69T6a, and 70T6a, and through-holes 58T6b, 59T6b, 68T6b, 69T6b, and 70T6b.

[0086] Capacitor C21 is composed of conductive layers 553, 563 and a dielectric layer 55 between these conductive layers. Capacitor C22 is composed of conductive layers 554, 564 and a dielectric layer 55 between these conductive layers. Capacitor C23 is composed of conductive layers 543, 554 and a dielectric layer 54 between these conductive layers. Capacitor C24 is composed of conductive layers 532, 542 and a dielectric layer 53 between these conductive layers. Capacitor C25 is composed of conductive layers 554, 565 and a dielectric layer 55 between these conductive layers.

[0087] Next, the components of the low-pass filter circuit 22 of the second filter 20 will be described. The inductor L23 is made up of a conductor layer 522. The capacitor C26 is made up of conductor layers 533, 543 and a dielectric layer 53 between these conductor layers. The capacitor C27 is made up of conductor layers 534, 543 and a dielectric layer 53 between these conductor layers.

[0088] Next, the structural features of the filter circuit 1 according to this embodiment will be described with reference to Figures 1, 8, and 9. Figure 9 is a plan view showing a part of the interior of the laminate 50.

[0089] The resonator 11 includes two through-hole rows T1a and T1b, and a conductor layer 11a connecting the two through-hole rows T1a and T1b. The through-hole row T1a is formed by connecting through-holes 56T1a, 57T1a, 58T1a, 59T1a, 68T1a, and 69T1a in series. The through-hole row T1b is formed by connecting through-holes 53T1b, 54T1b, 55T1b, 56T1b, 57T1b, 58T1b, 59T1b, 68T1b, and 69T1b in series. The conductor layer 11a is formed by two conductor layers 701 and 711 connected to each other by through-holes 70T1a and 70T1b. The two through-hole rows T1a and T1b and the conductor layer 11a are connected in the order of through-hole row T1a, conductor layer 11a, and through-hole row T1b, so as to circle around an axis parallel to the Y direction.

[0090] The resonator 12 includes two through-hole rows T2a and T2b, and a conductor layer 12a connecting the two through-hole rows T2a and T2b. The through-hole row T2a is formed by connecting through-holes 55T2a, 56T2a, 57T2a, 58T2a, 59T2a, 68T2a, and 69T2a in series. The through-hole row T2b is formed by connecting through-holes 53T2b, 54T2b, 55T2b, 56T2b, 57T2b, 58T2b, 59T2b, 68T2b, and 69T2b in series. The conductor layer 12a is formed by two conductor layers 702 and 712 connected to each other by through-holes 70T2a and 70T2b. The two through-hole rows T2a and T2b and the conductor layer 12a are connected in the order of through-hole row T2a, conductor layer 12a, and through-hole row T2b, so as to circle around an axis parallel to the Y direction.

[0091] The resonator 13 includes two through-hole rows T3a and T3b, and a conductor layer 13a connecting the two through-hole rows T3a and T3b. The through-hole row T3a is formed by connecting through-holes 55T3a, 56T3a, 57T3a, 58T3a, 59T3a, 68T3a, and 69T3a in series. The through-hole row T3b is formed by connecting through-holes 53T3b, 54T3b, 55T3b, 56T3b, 57T3b, 58T3b, 59T3b, 68T3b, and 69T3b in series. The conductor layer 13a is formed by two conductor layers 703 and 713 connected to each other by through-holes 70T3a and 70T3b. The two through-hole rows T3a and T3b and the conductor layer 13a are connected in the order of through-hole row T3a, conductor layer 13a, and through-hole row T3b, so as to circle around an axis parallel to the Y direction.

[0092] The resonator 14 includes two through-hole rows T4a and T4b, and a conductor layer 14a connecting the two through-hole rows T4a and T4b. The through-hole row T4a is formed by connecting through-holes 54T4a, 55T4a, 56T4a, 57T4a, 58T4a, 59T4a, 68T4a, and 69T4a in series. The through-hole row T4b is formed by connecting through-holes 53T4b, 54T4b, 55T4b, 56T4b, 57T4b, 58T4b, 59T4b, 68T4b, and 69T4b in series. The conductor layer 14a is formed by two conductor layers 704 and 714 connected to each other by through-holes 70T4a and 70T4b. The two through-hole rows T4a and T4b and the conductor layer 14a are connected in the order of through-hole row T4a, conductor layer 14a, and through-hole row T4b, so as to circle around an axis parallel to the Y direction.

[0093] The inductor L21 includes two through-hole rows T5a and T5b, and a conductor layer L21a connecting the two through-hole rows T5a and T5b. The through-hole row T5a is formed by connecting through-holes 58T5a and 59T5a in series. The through-hole row T5b is formed by connecting through-holes 56T5b, 57T5b, 58T5b, 59T5b, 68T5b, and 69T5b in series. The conductor layer L21a is formed by four conductor layers 681, 691, 705, and 715 connected to each other by through-holes 68T5a, 68T5c, 69T5c, 70T5b, and 70T5c.

[0094] The inductor L22 includes two through-hole rows T6a and T6b, and a conductor layer L22a connecting the two through-hole rows T6a and T6b. The through-hole row T6a is formed by connecting through-holes 58T6a, 59T6a, 68T6a, and 69T6a in series. The through-hole row T6b is formed by connecting through-holes 58T6b, 59T6b, 68T6b, and 69T6b in series. The conductor layer L22a is formed by two conductor layers 706 and 716 connected to each other by through-holes 70T6a and 70T6b.

[0095] In terms of circuit configuration, the through-hole rows T1b, T2b, T3b, and T4b are provided between the conductor layers 11a, 12a, 13a, and 14a and the ground, respectively. The through-hole rows T1b, T2b, T3b, and T4b are aligned along the shorter side, i.e., the Y direction, of the planar shape of the laminate 50 when viewed from the stacking direction T.

[0096] The interior region of the laminate 50 can be divided into two regions by the through-hole rows T1b, T2b, T3b, and T4. In this embodiment, the region including the through-hole rows T1b, T2b, T3b, and T4, and located on the -X side of the through-hole rows T1b, T2b, T3b, and T4, is called the first region, and the region located on the X side of the through-hole rows T1b, T2b, T3b, and T4 is called the second region. The first and second regions are arranged in this order along the longitudinal direction, i.e., the X direction, of the planar shape of the laminate 50 when viewed from the stacking direction T.

[0097] The first region contains multiple elements that constitute the first filter 10. Specifically, the first region contains multiple conductive layers and multiple through-holes that constitute the resonators 11-14 and capacitors C11-C18 of the first filter 10.

[0098] The second region contains multiple elements that constitute the second filter 20. Specifically, the second region contains multiple conductive layers and multiple through-holes that constitute the inductors L21 to L23 and capacitors C21 to C27 of the second filter 20.

[0099] The conductor layer 521 constitutes at least a part of the conductor 7 shown in Figure 1. Specifically, the portion of the conductor layer 521 between the portion to which the through-hole 51T1 is connected and the portion to which the through-hole 52T1 (see Figure 3(b)) is connected constitutes at least a part of the conductor 7. The portion of the conductor layer 521 to which the through-hole 51T1 is connected corresponds to one end of the conductor 7 on the first port 2 side.

[0100] As described above, the resonator 11 has a first end and a second end. Specifically, the first end of the resonator 11 is the -Z-direction end of the through-hole 56T1a that constitutes the through-hole row T1a of the resonator 11. Specifically, the second end of the resonator 11 is the -Z-direction end of the through-hole 53T1b that constitutes the through-hole row T1b of the resonator 11. The first end of the resonator 11 is electrically connected to the conductor layer 521. The second end of the resonator 11 is electrically connected to ground.

[0101] In Figure 9, the symbol D1 represents the distance from the portion of the conductor layer 521 corresponding to the first port 2 side end of the conductor 7 (the portion to which the through-hole 51T1 is connected) to the first end of the resonator 11 (the -Z side end of the through-hole 56T1a), as viewed from the stacking direction T. The symbol D2 represents the distance from the portion of the conductor layer 521 corresponding to the first port 2 side end of the conductor 7 (the portion to which the through-hole 51T1 is connected) to the second end of the resonator 11 (the -Z side end of the through-hole 53T1b), as viewed from the stacking direction T. In this embodiment, distance D1 is greater than distance D2.

[0102] Next, the operation and effects of the filter circuit 1 according to this embodiment will be described. In this embodiment, the conductor 7 provided between the first port 2 and the first filter 10 (bandpass filter circuit) forms an attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port 2 and the third port 4. In addition, in this embodiment, the low-pass filter circuit 22 forms at least one attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port 2 and the third port 4. As a result, according to this embodiment, the number of elements in the filter circuit 1 can be reduced compared to the case where all attenuation poles are formed by the low-pass filter circuit 22, while increasing the pass-through attenuation amount in a predetermined frequency range.

[0103] The following describes the simulation results demonstrating that the conductor 7 can form an attenuation pole. The simulation used the model of the first embodiment and the model of the second embodiment. Each of the models of the first and second embodiments is a model of the filter circuit 1 equipped with the laminate 50 shown in Figures 2 and 8. In the model of the first embodiment, the width of the conductor layer 521, which constitutes at least a part of the conductor 7, was set to 100 μm. In the model of the second embodiment, the width of the conductor layer 521 was set to 140 μm. The simulation determined the pass-through attenuation characteristics between the first port 2 and the third port 4.

[0104] Figure 10 is a characteristic diagram showing the pass-through attenuation characteristics of the models of the first and second embodiments. In Figure 10, the horizontal axis represents frequency, and the vertical axis represents attenuation. In Figure 10, the curve denoted by reference numeral 81 shows the pass-through attenuation characteristics of the model of the first embodiment, and the curve denoted by reference numeral 82 shows the pass-through attenuation characteristics of the model of the first embodiment. In Figure 10, reference numerals 81a and 81c indicate the attenuation poles formed by the low-pass filter circuit 22 in the model of the first embodiment, and reference numeral 81b indicates the attenuation pole formed by the conductor 7 in the model of the first embodiment. In Figure 10, reference numerals 82a and 82c indicate the attenuation poles formed by the low-pass filter circuit 22 in the model of the second embodiment, and reference numeral 82b indicates the attenuation pole formed by the conductor 7 in the model of the second embodiment.

[0105] As can be seen from the simulation results, according to this embodiment, the conductor 7 can form an attenuation pole in a frequency range higher than the frequency of the second signal filtered by the second filter 20 (a frequency range higher than the second passband).

[0106] Furthermore, Figure 10 shows that the frequencies of the attenuation poles 81a and 81c formed by the low-pass filter circuit 22 in the first embodiment model are the same as or nearly the same as the frequencies of the attenuation poles 82a and 82c formed by the low-pass filter circuit 22 in the second embodiment model. Also, Figure 10 shows that the frequency of the attenuation pole 81b formed by the conductor 7 in the first embodiment model is different from the frequency of the attenuation pole 82b formed by the conductor 7 in the second embodiment model. The results of this simulation show that the frequency of the attenuation poles can be controlled by controlling the shape of the conductor layer 521, i.e., the shape of the conductor 7. In the simulation, the frequency of the attenuation poles is controlled by changing the width of the conductor layer 521. However, the frequency of the attenuation poles can be controlled not only by the width of the conductor layer 521, but also by the length of the conductor layer 521.

[0107] The following describes other effects of this embodiment. As mentioned above, in this embodiment, distance D1 is greater than distance D2. According to this embodiment, the space for arranging the conductor layer 521 can be increased compared to the case where distance D1 is smaller than distance D2. As a result, according to this embodiment, it becomes easier to control the shape of the conductor layer 521.

[0108] It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the second filter 20 may not include a low-pass filter circuit 22. Also, each of the inductors L21 and L22 of the high-pass filter circuit 21 of the second filter 20 may be composed of wound conductive layers.

[0109] As explained above, the filter circuit of the present invention is The first port and The second port, The third port and In terms of circuit configuration, a bandpass filter circuit including multiple resonators is provided between the first port and the second port, In terms of circuit configuration, a high-pass filter circuit is provided between the first port and the third port, In terms of the circuit configuration, a conductor provided between the first port and the bandpass filter circuit, which forms an attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port and the third port, It is equipped with.

[0110] In the filter circuit of the present invention, the conductor may cause an impedance mismatch with respect to the high-pass filter circuit between the first port and the band-pass filter circuit.

[0111] Furthermore, in the filter circuit of the present invention, the conductor may constitute part of the signal path from the first port through the bandpass filter circuit to the second port.

[0112] Furthermore, the filter circuit of the present invention may further include a low-pass filter circuit provided between the high-pass filter circuit and the third port in terms of circuit configuration. The high-pass filter circuit and the low-pass filter circuit may constitute a band-pass filter. A predetermined frequency range may exist on the high-frequency side of the passband of the band-pass filter in terms of pass-through attenuation characteristics.

[0113] Furthermore, in the filter circuit of the present invention, the high-pass filter circuit may include a capacitor electrically connected to a conductor.

[0114] Furthermore, the filter circuit of the present invention may further include a laminate for integrating a first port, a second port, a third port, a bandpass filter circuit, a high-pass filter circuit, and a conductor, and may comprise a laminate containing a plurality of laminated dielectric layers and a plurality of conductor layers. The plurality of conductor layers may include a specific conductor layer that includes one end of the conductor on the first port side and constitutes at least a part of the conductor. The plurality of resonators may include a specific resonator that is closest to the first port in the circuit configuration. The specific resonator may have a first end electrically connected to a specific conductor layer and a second end electrically connected to ground. When viewed from the lamination direction of the plurality of dielectric layers, the distance from the portion of the specific conductor layer corresponding to one end of the conductor to the first end may be greater than the distance from the portion of the specific conductor layer corresponding to one end of the conductor to the second end. Each of the plurality of resonators may include two through-hole rows and a conductor layer portion connecting the two through-hole rows. Each of the two through-hole rows may be formed by two or more through-holes connected in series. [Explanation of Symbols]

[0115] 1...Filter circuit, 2...First port, 3...Second port, 4...Third port, 5,6...Signal path, 7...Conductor, 10...First filter, 11~14...Resonator, 20...Second filter, 21...High-pass filter circuit, 22...Low-pass filter circuit, 50...Laminate, 50A...Bottom surface, 50B...Top surface, 50C~50F...Side surfaces, 51~72...Dielectric layer, C11~C18,C21~C27...Capacitors, L21~L23...Inductors.

Claims

1. The first port and The second port and The third port and In terms of circuit configuration, a bandpass filter circuit including a plurality of resonators is provided between the first port and the second port, In terms of circuit configuration, a high-pass filter circuit is provided between the first port and the third port, In terms of the circuit configuration, a conductor provided between the first port and the bandpass filter circuit, which forms an attenuation pole in a predetermined frequency range in the pass-through attenuation characteristics between the first port and the third port, A laminate for integrating the first port, the second port, the third port, the bandpass filter circuit, the highpass filter circuit, and the conductor, comprising a laminate including a plurality of laminated dielectric layers and a plurality of conductor layers, Equipped with, The plurality of conductor layers include a specific conductor layer that includes one end of the conductor on the first port side and constitutes at least a part of the conductor, The plurality of resonators include, in terms of circuit configuration, a specific resonator that is closest to the first port. The aforementioned specific resonator has a first end electrically connected to the aforementioned specific conductor layer and a second end electrically connected to ground. When viewed from the stacking direction of the plurality of dielectric layers, the distance from the portion corresponding to one end of the conductor in the particular conductive layer to the first end is greater than the distance from the portion corresponding to one end of the conductor in the particular conductive layer to the second end. Each of the plurality of resonators includes two rows of through-holes and a conductive layer connecting the two rows of through-holes. A filter circuit characterized in that each of the two through-hole rows is formed by two or more through-holes connected in series.

2. The filter circuit according to claim 1, characterized in that the conductor causes an impedance mismatch with respect to the high-pass filter circuit between the first port and the band-pass filter circuit.

3. The filter circuit according to claim 1, characterized in that the conductor constitutes part of the signal path from the first port through the bandpass filter circuit to the second port.

4. Furthermore, the filter circuit according to claim 1 is characterized in that, in terms of circuit configuration, it includes a low-pass filter circuit provided between the high-pass filter circuit and the third port.

5. The high-pass filter circuit and the low-pass filter circuit constitute a band-pass filter. The filter circuit according to claim 4, characterized in that the predetermined frequency range exists on the high-frequency side of the passband of the bandpass filter in the pass-through attenuation characteristics.

6. The filter circuit according to claim 1, characterized in that the high-pass filter circuit includes a capacitor electrically connected to the conductor.

Images