JP2006262349A - Resonance circuit, filter circuit, multilayer substrate and circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonance circuit capable of obtaining high attenuation near a passband frequency, filter circuit using the same, multilayer substrate and circuit module. <P>SOLUTION: The resonance circuit is constituted of a first capacitor 101 of which one terminal is connected to ground terminals 106, 107; a first inductor 103 of which one terminal is connected to another terminal of the first capacitor 101; a second capacitor 102 of which one terminal is connected to another terminal of the first inductor 103 and of which another terminal is connected to the ground terminals 106, 107; and a third capacitor 301 connected in parallel to the first inductor 103. In said resonance circuit 300, the passband frequency is set neat a low-frequency side attenuation pole and a wide passband width is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resonance circuit capable of obtaining a high attenuation near the passband, a filter circuit using the resonance circuit, a multilayer substrate, and a circuit module.

  In recent years, a filter circuit used in a 2.4 GHz band wireless device is required to have a high attenuation characteristic at a frequency in the vicinity of a pass band (for example, a frequency of a mobile phone). Moreover, it is necessary to block high frequency components used in other systems, for example, frequency components of 10 GHz to 12 GHz. Therefore, it is required to produce an LC filter satisfying these cutoff characteristics in a limited volume of an LTCC (Low Temperature Co-fired Ceramics) substrate.

  Conventionally, as an LC resonance circuit constituting this type of LC filter, for example, described in ““ Design of communication filter circuit and its application ”, Yoshihiro Konishi, Electronic General Publishing, P30 to P31” (Non-patent Document 1). What is being known.

  This Non-Patent Document 1 describes, for example, a one-stage LC resonance circuit shown in FIGS. 17 and 18. The LC resonance circuit 100 shown in FIG. 17 includes a capacitor 101 having one end grounded and the other end connected to the input / output terminals 104 and 105 and one end of the inductor 103, and one end grounded and the other end to the other end of the inductor 103. And a ground terminal 106, 107 on both input and output sides.

  Here, for example, the capacitance X of the capacitor 101 is set to 3.2 pF, the capacitance V of the capacitor 102 is set to 2 pF, the inductance B of the inductor 103 is set to 3.5 nH, and the passband frequency of this circuit is set to about 2.4 GHz. Can be used.

  An LC resonance circuit 200 shown in FIG. 18 has an inductor 203 having one end connected to the input / output terminals 204 and 205, a capacitor 201 connected in parallel to the inductor 203, one end connected to the other end of the inductor, and the other end The capacitor 202 is connected to a ground terminal, and ground terminals 206 and 207 on both input and output sides.

Here, for example, the capacitance V of the capacitor 202 is set to 0.8 pF, the capacitance H of the capacitor 201 is set to 1.2 pF, the inductance B of the inductor 203 is set to 3.5 nH, and the passband frequency of this circuit is set to about 2.4 GHz. It can be set and used.
“Design and application of communication filter circuits”, Yoshihiro Konishi, Electronic General Publishing, P30-P31.

  As described above, the conventional LC resonance circuit includes the resonance circuit 100 shown in FIG. 17 and the resonance circuit 200 shown in FIG. Such a generally known resonance circuit can be used to provide an attenuation pole at a frequency near the passband.

  For example, the resonant circuit 100 can change the passband frequency to a lower frequency while fixing the frequency of the attenuation pole by increasing the capacitance of the capacitor 101 directly connected to GND (ground).

  However, in order to move the passband frequency to the vicinity of the frequency of the attenuation pole, it is necessary to increase the capacitance X of the capacitor 101, which causes a problem that the passband width becomes extremely narrow. Further, at a high frequency, the conventional resonant circuit 100 is a circuit that cannot be realized by a multilayer inductor.

  On the other hand, the conventional resonant circuit 200 can set the passband frequency in the vicinity of the attenuation pole by increasing the capacitance H of the capacitor 201. However, the resonance circuit 200 has an extremely narrow bandwidth of the attenuation pole. In addition, there is a problem that high frequency components are not sufficiently attenuated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a resonant circuit capable of obtaining a high attenuation near the passband frequency, a filter circuit using the same, a multilayer substrate, and a circuit module. Is to provide.

  To achieve the above object, the present invention provides a first capacitor having one end connected to a ground terminal, a first inductor having one end connected to the other end of the first capacitor, and one end connected to the one end of the first inductor. And a second capacitor having one end connected to the other end of the first inductor and the other end connected to the ground terminal, and connected in parallel to the first inductor. A resonant circuit provided with a third capacitor is proposed.

  According to the resonance circuit of the present invention, the passband frequency is set in the vicinity of the attenuation pole on the low frequency side, and has a wide passband width.

  The present invention also proposes a resonance circuit in which a second inductor is connected in series between one end of the first inductor and the other end of the first capacitor.

  According to the present invention, it has the characteristics of the above-described resonance circuit and also exhibits high attenuation characteristics in a high frequency band.

  Furthermore, the present invention proposes a filter circuit in which an input terminal and an output terminal are connected to one end of the first inductor via a capacitor.

  The present invention also proposes a multilayer substrate in which the above-described filter circuit is configured on a plurality of substrates, and a circuit module in which active components and / or passive components are arranged on the multilayer substrate.

  The resonance circuit according to the present invention can realize a filter circuit having a passband frequency that can be set in the vicinity of the attenuation pole on the low frequency side and a wide passband width.

  Furthermore, the resonance circuit according to the present invention has the characteristics of the resonance circuit by adding a second inductor to the resonance circuit, and can realize a high attenuation characteristic in a high frequency band.

  In addition, the filter circuit and the multilayer substrate of the present invention can set the passband frequency in the vicinity of the attenuation pole on the low frequency side and have a wide passband width.

  Furthermore, the filter circuit and the multilayer substrate of the present invention have the above-mentioned characteristics by adding a second inductor to the filter circuit and the multilayer substrate, and realize high attenuation characteristics in a high frequency band. Can do.

  Furthermore, the circuit module according to the present invention has the above-described characteristics because the active component / passive component is disposed on the multilayer substrate, and can realize small and excellent electrical characteristics.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a first resonance circuit in one embodiment of the present invention, and FIG. 2 is a diagram showing a second resonance circuit in one embodiment of the present invention.

  In FIG. 1, reference numeral 300 denotes a first resonance circuit, and the same components as those in the conventional example shown in FIG. That is, the first resonance circuit 300 has one end grounded and the other end connected to the input / output terminals 104 and 105 and one end of the inductor 103, and one end grounded and the other end connected to the other end of the inductor 103. And the capacitor 301 connected in parallel to the inductor 103, and ground terminals 106 and 107 on both input and output sides.

  Here, for example, the capacitance X of the capacitor 101 is set to 1.2 pF, the capacitance V of the capacitor 102 is set to 1.5 pF, the capacitance H of the capacitor 301 is set to 0.5 pF, and the inductance B of the inductor 103 is set to 3.5 nH. Is set to about 2.4 GHz.

  The capacitor 101 corresponds to the first capacitor in the present invention, the capacitor 102 corresponds to the second capacitor, the inductor 103 corresponds to the first inductor, and the capacitor 301 corresponds to the third capacitor.

  In FIG. 2, reference numeral 400 denotes a second resonance circuit, which is provided with an inductor 401 with respect to the first resonance circuit 300 shown in FIG. The inductor 401 is connected in series between one end of the inductor 103 and the other end of the capacitor 101. Here, the inductance A of the inductor 401 is set to 0.5 nH, and the passband frequency of the circuit is set to about 2.4 GHz. The inductor 401 corresponds to the second inductor in the present invention.

  When the first resonant circuit 300 shown in FIG. 1 is configured as a filter circuit, the capacitance X of the capacitor 101 is smaller than that of the conventional resonant circuit 100 shown in FIG. .4 GHz) can be set in the vicinity of the frequency of the attenuation pole, and the pass bandwidth is not extremely narrowed. In addition, the second resonance circuit 400 shown in FIG. 2 adds an inductor 401 having a very small inductance to the first resonance circuit 300, thereby forming an arbitrary attenuation at a high frequency. A pole can be provided, and a desired frequency attenuation characteristic can be realized.

The first resonant circuit 300 according to the present embodiment, determines the passband frequency f _c by the following equation (1), (2) the frequency f _N of the attenuation pole is determined by the formula.

On the other hand, the conventional resonant circuit 100 shown in FIG. 17, determines the passband frequency f _c by the following equation (3), (4) frequency f _N of the attenuation pole is determined by the formula.

  Therefore, the reason why the first resonant circuit 300 according to the present embodiment has an attenuation pole at the same frequency as the conventional resonant circuit 100 shown in FIG. 17 is that H + V in the formula (2) is equal to V in the formula (4). Is the case. At this time, obviously, formula (1) <formula (3) is established. This is because the first resonant circuit 300 of this embodiment can set the passband frequency in the vicinity of the attenuation pole by adding a capacitor 101 having a smaller capacity to the conventional resonant circuit 100. It shows what you can do. Further, since the capacitance X of the capacitor 101 is small, the pass bandwidth is not extremely narrowed.

  FIG. 3 shows a comparison of the frequency characteristics when the X of the first resonant circuit 300 of the present embodiment and the resonant circuit 100 of the conventional example have the same capacitance, and the frequency characteristics of the first resonant circuit 300 of the present embodiment ( The solid line in the figure shows that the passband frequency is closer to the attenuation pole (2.05 GHz) on the lower frequency side than the frequency characteristic of the resonance circuit 100 of the conventional example (broken line in the figure). . Thereby, it can be seen that the frequency of the attenuation pole and the passband frequency can be set even if X is reduced.

  Next, a filter circuit using the above-described resonance circuit and a multilayer substrate in which this filter circuit is formed of an LTCC substrate will be described.

  FIG. 4 is a circuit diagram showing the filter circuit 500. This filter circuit 500 uses the above-described first resonance circuit 300. As shown in the figure, a capacitor 501 is provided between the input terminal 104 and one end of the inductor 103, and one end of the inductor 103 is connected. A capacitor 502 is provided between the output terminal 105 and the output terminal 105.

  Further, as shown in FIG. 5, a high attenuation characteristic can be obtained by increasing the number of resonant circuits and connecting them in parallel via a capacitor. The filter circuit 500 shown in FIG. 5 is configured by connecting two resonant circuits 310 and 320 in parallel.

  That is, one resonance circuit 310 includes a capacitor 101A having one end grounded and the other end connected to one end of the inductor 103A, and a capacitor 102A having one end grounded and the other end connected to the other end of the inductor 103A. And a capacitor 301A connected in parallel to the inductor 103A.

  The other resonance circuit 320 includes a capacitor 101B having one end grounded and the other end connected to one end of the inductor 103B, and a capacitor 102B having one end grounded and the other end connected to the other end of the inductor 103B. And a capacitor 301B connected in parallel to the inductor 103B.

  Further, a capacitor 511 is connected between one end of the inductor 103A of one resonance circuit 310 and the input terminal 104, and a capacitor 513 is connected between one end of the inductor 103B of the other resonance circuit 320 and the output terminal 105, A capacitor 512 is connected between one end of the inductor 103A and one end of the inductor 103B.

  In the filter circuit 500 described above, if the resonance frequencies of the two resonance circuits 310 and 320 are set equal, the attenuation in the cutoff frequency band can be increased, and if the resonance frequencies of the two resonance circuits 310 and 320 are set to different frequencies, Filter circuits having different cutoff frequency bands can be configured.

  Next, a multilayer substrate using the filter circuit 500 will be described.

  FIG. 6 is a perspective view showing a configuration of a multilayer substrate 520 formed by forming the filter circuit 500 on the LTCC substrate. As shown in the figure, the multilayer substrate 520 has a LTCC substrate 521 which is a rectangular parallelepiped and is provided with ground conductors 522 and 523 on the upper and lower surfaces, and a conductor constituting a capacitor and an inductor is disposed therein. Yes.

  In the LTCC substrate 521, a flat conductor 533 connected to the ground conductor 523 by a via conductor 532 and a flat common that is arranged so as to face the flat conductor 533 in parallel with a gap therebetween. A capacitor 101A is constituted by the conductor 534, and the capacitor 511 is constituted by a plate-like common conductor 534 and a plate-like conductor 553 arranged so as to face the plate-like common conductor 534 at a distance from each other in parallel. It is configured. The other end of the strip-shaped conductor 531 having one end connected to the flat-plate conductor 553 is exposed to the outside of the substrate as an input terminal 104 from an opening provided on the bottom surface of the substrate 521.

  Further, one end of the strip-shaped conductor 535 having one loop connected to the flat common conductor 534 is connected to one end of the loop-shaped conductor 537 having a loop via the via conductor 536. . The strip conductors 535 and 537 and the via conductor 536 form an inductor 103A. The strip conductors 535 and 537 are arranged so as to face each other with a predetermined interval in the vertical direction, and a capacitor 301A is formed by the facing portion of the strip conductors 535 and 537.

  A flat conductor 538 is connected to the other end of the strip conductor 537. Further, the flat conductor 538 is opposed to the ground conductor 539 disposed at a predetermined interval in the upward direction, thereby forming the capacitor 102A. The ground conductor 539 is connected to the upper and lower ground conductors 522 and 523 by a plurality of via conductors 552.

  A resonance circuit 310 is formed by each of the above plate-like conductors and strip-like conductors. In addition, the conductors constituting the resonance circuit 320 are arranged side by side with respect to the conductors constituting the resonance circuit 310.

  That is, the flat conductor 543 connected to the ground conductor 523 by the via conductors 542a and 542b, and the flat common conductor disposed so as to face the flat conductor 543 at a distance from each other in parallel. 547 constitutes a capacitor 101B, and a capacitor 513 is constituted by a plate-like common conductor 547 and a plate-like conductor 546 arranged so as to face the plate-like common conductor 547 at a distance from each other in parallel. ing. The flat conductor 546 is connected to one end of the strip conductor 541 via the via conductor 545, and the other end of the strip conductor 541 is exposed to the outside of the substrate as an output terminal 105 from an opening provided on the bottom surface of the substrate 521. is doing.

  Also, the other end of the loop-shaped conductor 548 having one end connected to the flat common conductor 547 and the loop-shaped conductor 548 is connected to one end of the loop-shaped conductor 550 having a loop shape via the via conductor 549. . The strip conductors 548 and 550 and the via conductor 549 form an inductor 103B. The strip conductors 548 and 550 are arranged to face each other with a predetermined interval in the vertical direction, and a capacitor 301B is formed by the facing portion of the strip conductors 548 and 550.

  A plate-like conductor 551 is connected to the other end of the strip-like conductor 550, and the plate-like conductor 551 is opposed to the ground conductor 539 arranged at a predetermined interval in the upward direction, whereby the capacitor 102B is Is formed.

  The flat common conductor 534 constituting the resonance circuit 310 and the flat common conductor 547 constituting the resonance circuit 320 are opposed to the flat common conductors 534 and 547 in parallel at a predetermined interval. Thus, a flat connection conductor 540 is provided, and the flat connection conductor 540, the flat common conductor 534, and the flat common conductor 547 form a capacitor 512.

  Further, the ground conductors 522 and 523 on the upper and lower surfaces are conductively connected by a plurality of via conductors 552.

  As described above, the filter circuit 500 is formed on the LTCC substrate, and the capacitors 301A and 301B are made of the parasitic capacitances of the multilayer inductors 103A and 103B, thereby realizing miniaturization. Further, the capacitors 511, 512, and 513 use a laminated structure, and are opposed to the flat plate-like conductors that are parallel to the flat plate-like common conductors 534 and 547, respectively, below the flat plate-like common conductor 534 and the flat plate-like common conductor 547. The size of the multilayer substrate 520 can be reduced by arranging 553, 546 and providing a flat connecting conductor 540 across the flat common conductor 534 and the second flat common conductor 547. is doing.

  Next, a description will be given of another embodiment of the filter circuit using the above-described resonance circuit and a multilayer substrate in which the filter circuit is formed on the LTCC substrate.

  FIG. 7 is a circuit diagram showing the filter circuit 600. This filter circuit 600 uses the above-described second resonance circuit 400. As shown in the figure, a capacitor 501 is provided between the input terminal 104 and one end of the inductor 103. A capacitor 502 is provided between one end and the output terminal 105.

  Thus, by using the second resonance circuit 400 described above, an arbitrary attenuation pole can be provided at a high frequency by the action of the inductor 401, and a high attenuation characteristic can be realized at a desired frequency.

  Next, a multilayer substrate using the filter circuit 600 will be described.

  FIG. 8 is a perspective view showing a configuration of a multilayer substrate 610 formed by forming the filter circuit 600 on the LTCC substrate. FIG. 9 is an end view for explaining the structure of the present embodiment taken along the line AA of FIG. As shown in the figure, the multilayer substrate 610 includes a LTCC substrate 611 having a rectangular parallelepiped shape and provided with ground conductors 612 and 613 on the upper and lower surfaces, and a conductor constituting a capacitor and an inductor is disposed therein. .

  In the LTCC substrate 611, the flat conductor 616 connected to the ground conductor 613 by the via conductor 615 and the flat conductor disposed so as to face the flat conductor 616 at a distance from each other in parallel. The body 617 constitutes the capacitor 101.

  Further, the inductor 401 is configured by a strip-shaped conductor 618 having one end connected to the flat-plate conductor 617.

  A flat common conductor 619 is connected to the other end of the belt-like conductor 618, and is arranged so as to face the flat common conductor 619 and the flat common conductor 619 in parallel with an interval in the vertical direction. Capacitors 501 and 502 are constituted by the planar conductors 626 and 627, respectively. The other end of the strip conductor 614 having one end connected to the flat conductor 626 is exposed to the outside of the substrate as an input terminal 104 from an opening provided on the bottom surface of the substrate 611. The other end of the strip-shaped conductor 628 whose one end is connected to the flat-plate conductor 627 is exposed to the outside of the substrate as an output terminal 105 from an opening provided on the bottom surface of the substrate 611.

  The other end of the strip-shaped conductor 620 having one end connected to the flat common conductor 619 and having a loop shape is connected to one end of the loop-shaped conductor 622 having a loop shape via the via conductor 621. . The strip conductors 620 and 622 and the via conductor 621 form an inductor 103. The strip conductors 620 and 622 are arranged so as to face each other with a predetermined interval in the vertical direction, and a capacitor 301 is formed by the facing portions of the strip conductors 620 and 622.

  A flat conductor 623 is connected to the other end of the strip conductor 622. Further, the flat conductor 623 faces the ground conductor 624 disposed at a predetermined interval in the upward direction, whereby the capacitor 102 is formed. The ground conductor 624 is connected to the upper and lower ground conductors 612 and 613 by a plurality of via conductors 625.

  A filter circuit 400 is formed by each of the above plate-like conductors and strip-like conductors.

  FIG. 10 is an end view showing a modified example of the multilayer substrate using the filter circuit 400. As shown by the multilayer substrate 610 ′ of the present modified example, the ground electrode 613 and the installation electrode 613 are spaced from each other. The capacitor 101 ′ is constituted by the flat-plate conductors 617 ′ opposed in parallel to each other, and the via conductor 618 ′ whose one end is connected to the flat-plate conductor 617 ′ and the other end is connected to the flat-plate common conductor 619 ′. Thus, the inductor 401 ′ having a small inductance may be configured.

  As described above, the filter circuit 600 is formed on the LTCC substrate 611, and the capacitor 301 is made of the parasitic capacitance of the multilayer inductor 103, thereby realizing downsizing. Furthermore, the capacitors 501 and 502 use a laminated structure and have a structure in which opposing flat plate conductors 626 and 627 that are parallel to the flat plate common conductor 619 are arranged in the vertical direction of the flat plate common conductor 619, respectively. Thus, the multilayer substrate 610 can be downsized. Further, the inductor 401 having a very small inductance is not made of an inductor pattern formed by windings, but is made of a transmission line made of a strip-shaped conductor, a via conductor, or the like, thereby realizing a reduction in size.

  The frequency characteristics of this multilayer substrate 610 are shown in FIG. In the figure, the horizontal axis represents frequency (GHz) and the vertical axis represents transmission gain (dB). As described above, the multilayer substrate 610 constituted by the filter circuit 600 using the second resonance circuit 400 has two attenuation poles of about 2.05 GHz and about 10.3 GHz, and the passband frequency is set to the lower frequency side. In the vicinity of the attenuation pole (2.05 GHz) and has a wide passband width.

  Next, an embodiment of a filter circuit using two of the above-described second resonance circuits 400 and a multilayer substrate in which this filter circuit is formed on an LTCC substrate will be described.

  FIG. 12 is a circuit diagram showing the filter circuit 650. This filter circuit 650 uses two of the second resonance circuits 400 described above. As shown in the figure, by connecting two resonance circuits 410 and 420 in parallel via a capacitor 652, a high attenuation characteristic is obtained. It is done.

  One resonant circuit 410 includes a capacitor 101A having one end grounded and the other end connected to one end of the inductor 401A, an inductor 103A having one end connected to the other end of the inductor 401A, and one end grounded and the other. The capacitor 102A has one end connected to the other end of the inductor 103A and the capacitor 301A connected in parallel to the inductor 103A.

  The other resonant circuit 420 includes a capacitor 101B having one end grounded and the other end connected to one end of the inductor 401B, an inductor 103B having one end connected to the other end of the inductor 401B, and one end grounded and the other. The capacitor 102B has one end connected to the other end of the inductor 103B, and the capacitor 301B connected in parallel to the inductor 103B.

  Furthermore, a capacitor 651 is connected between one end of the inductor 103A of one resonance circuit 410 and the input terminal 104, and a capacitor 653 is connected between one end of the inductor 103B of the other resonance circuit 420 and the output terminal 105, A capacitor 652 is connected between one end of the inductor 103A and one end of the inductor 103B.

  In the filter circuit 650, when the resonance frequencies of the two resonance circuits 410 and 420 are set to be equal, the attenuation in the cutoff frequency band can be increased, and when the resonance frequencies of the two resonance circuits 410 and 420 are set to different frequencies, Filter circuits having different cutoff frequency bands can be configured.

  Next, a multilayer substrate using the filter circuit 650 will be described.

  13 is a perspective view showing a configuration of a multilayer substrate 700 in which a filter circuit 650 is formed on an LTCC substrate, FIG. 14 is an internal configuration diagram viewed from the side, and FIG. 15 is an internal configuration diagram viewed from the front. As shown in the figure, the multilayer substrate 700 has an LTCC substrate 711 having a rectangular parallelepiped shape and provided with ground conductors 712 and 713 on the upper and lower surfaces, and a conductor constituting a capacitor and an inductor is disposed therein. .

  In the LTCC substrate 711, a flat conductor 715 connected to the ground conductor 713 by a via conductor 714 and a flat conductor disposed so as to face the flat conductor 715 at a distance from each other in parallel. The body 716 constitutes the capacitor 101A.

  Further, the inductor 401A is constituted by a strip-like conductor 717 having one end connected to the flat conductor 716.

  A flat plate-like common conductor 718 is connected to the other end of the strip-like conductor 717, and the flat plate-like common conductor 718 is arranged so as to face the flat plate-like common conductor 718 at a distance from each other in parallel. A capacitor 651 is constituted by the conductor 719. The other end of the conductor 720, one end of which is connected to the flat conductor 719, is exposed outside the substrate from an opening 751 provided on the bottom surface of the substrate 711 as the input terminal 104.

  In addition, the other end of the strip-shaped conductor 721 having a loop shape with one end connected to the flat conductor 718 is connected to one end of the loop-shaped conductor 723 having a loop shape via the via conductor 722. The strip conductors 721 and 723 and the via conductor 722 form an inductor 103A. The strip conductors 721 and 723 are arranged so as to face each other with a predetermined interval in the vertical direction, and a capacitor 301A is formed by the facing portion of the strip conductors 721 and 723.

  A flat conductor 724 is connected to the other end of the strip conductor 723. Further, the flat conductor 724 faces the ground conductor 725 disposed at a predetermined interval in the upward direction, thereby forming the capacitor 102A. The ground conductor 725 is connected to the upper and lower ground conductors 712 and 713 by a plurality of via conductors 742.

  A resonance circuit 410 is formed by each of the above plate-like conductors and strip-like conductors. In addition, a conductor constituting the resonance circuit 420 is arranged in a lateral direction with respect to the conductor constituting the resonance circuit 410.

  That is, the flat conductor 732 connected to the ground conductor 713 by the via conductors 731a and 731b, and the flat conductor 733 disposed so as to face the flat conductor 732 with a space therebetween. Thus, the capacitor 101B is configured.

  Further, the inductor 401B is configured by a strip-shaped conductor 734 having one end connected to the flat-plate conductor 733.

  A flat plate-like common conductor 737 is connected to the other end of the strip-like conductor 734, and the flat plate-like common conductor 737 and the flat plate arranged so as to face the plate-like common conductor 737 with a space therebetween in parallel. A capacitor 653 is constituted by the conductor 735. The other end of the conductor 736 whose one end is connected to the flat conductor 735 is exposed to the outside of the substrate from an opening 752 provided on the bottom surface of the substrate 711 as the output terminal 105.

  Further, the other end of the loop-shaped conductor 738 having one end connected to the flat-plate conductor 737 is connected to one end of the loop-shaped conductor 740 having a loop shape via the via conductor 739. These strip-like conductors 738 and 740 and via conductor 739 form an inductor 103B. Further, these band-shaped conductors 738 and 740 are arranged so as to face each other with a predetermined interval in the vertical direction, and a capacitor 301B is formed by the facing portion of the band-shaped conductors 738 and 740.

  A flat conductor 741 is connected to the other end of the strip conductor 740. Further, the flat conductor 741 is opposed to the ground conductor 725 arranged at a predetermined interval in the upward direction, thereby forming the capacitor 102B.

  Further, the flat common conductor 718 constituting the resonance circuit 410 and the flat common conductor 737 constituting the resonance circuit 420 are opposed in parallel to the flat common conductors 718 and 737 with a predetermined interval therebetween. In this manner, a flat connecting conductor 726 is provided, and the flat connecting conductor 726 and the flat common conductors 718 and 737 form a capacitor 652.

  Further, the ground conductors 712 and 713 on the upper and lower surfaces are conductively connected by a plurality of via conductors 742.

  As described above, the filter circuit 650 is formed on the LTCC substrate 711, and the capacitors 301A and 301B are made of the parasitic capacitances of the multilayer inductors 103A and 103B, thereby realizing miniaturization. Further, the capacitors 651, 652, and 653 use a laminated structure, and dispose the opposing flat plate conductors 719 and 735 parallel to the flat plate common conductors 718 and 737 under the flat plate common conductors 718 and 737, respectively. By adopting a structure in which the flat connecting conductors 726 are arranged so as to straddle the flat common conductors 718 and 737, the multilayer substrate 700 can be reduced in size. Further, the small inductance inductors 401A and 401B are not made of an inductor pattern formed by windings, but are made of a transmission line made of a strip-shaped conductor, a via conductor, or the like, thereby realizing a reduction in size.

  FIG. 16 is a diagram showing frequency characteristics of the multilayer substrate 700 described above. In the figure, the horizontal axis represents frequency (GHz) and the vertical axis represents transmission gain (dB). Thus, the multilayer substrate 700 is a filter having an attenuation pole that has a pass band in the 2.4 GHz band and exhibits high attenuation in 1.5 to 1.9 GHz and 10.5 to 11.5 GHz.

  The above-described embodiment is a specific example of the present invention, and the present invention is not limited only to the configuration of the above-described embodiment.

The circuit diagram which shows the 1st resonance circuit in one Embodiment of this invention The circuit diagram which shows the 2nd resonance circuit in one embodiment of the present invention The figure which shows the frequency characteristic of the 1st resonance circuit in one Embodiment of this invention, and the frequency characteristic of a prior art example The circuit diagram showing the filter circuit using the 1st resonance circuit in one embodiment of the present invention. The circuit diagram which shows the filter circuit using two 1st resonance circuits in one Embodiment of this invention The perspective view which shows the structure of the multilayer board | substrate using two 1st resonance circuits in one Embodiment of this invention. The circuit diagram which shows the filter circuit using the 2nd resonant circuit in one Embodiment of this invention The perspective view which shows the structure of the multilayer substrate using the 2nd resonance circuit in one Embodiment of this invention. The end view which shows the structure of the multilayer substrate using the 2nd resonance circuit in one Embodiment of this invention The end view which shows the modification of the multilayer substrate using the 2nd resonance circuit in one Embodiment of this invention The figure which shows the frequency characteristic of the multilayer substrate using the 2nd resonance circuit in one Embodiment of this invention The circuit diagram which shows the filter circuit using two 2nd resonance circuits in one Embodiment of this invention The perspective view which shows the structure of the multilayer substrate using two 2nd resonant circuits in one Embodiment of this invention. The side view which shows the structure of the multilayer substrate using two 2nd resonance circuits in one Embodiment of this invention The front view which shows the structure of the multilayer board | substrate using two 2nd resonant circuits in one Embodiment of this invention. The figure which shows the frequency characteristic of the multilayer board | substrate using two 2nd resonant circuits in one Embodiment of this invention. Circuit diagram showing conventional resonant circuit Circuit diagram showing conventional resonant circuit

Explanation of symbols

101101a, 101B, 102,102A, 102B, 301,301A, 301B, 501,502,511,512,513,651,652,653 ... Capacitor, 103,401,401A, 401B ... Inductor, 104 ... Input terminal, 105 ... Output terminal, 106,107 ... Ground terminal, 300 ... First resonant circuit, 400,410,420 ... Second resonant circuit, 500, 600, 650, filter circuit, 520, 610, 700, multilayer substrate, 521, 611, 711, LTCC substrate.

Claims (12)

A first capacitor having one end connected to the ground terminal; a first inductor having one end connected to the other end of the first capacitor; an input terminal and an output terminal connected to one end of the first inductor; In a resonant circuit comprising a second capacitor having one end connected to the other end of one inductor and the other end connected to a ground terminal,
A resonance circuit comprising a third capacitor connected in parallel to the first inductor. The resonance circuit according to claim 1, wherein a second inductor is connected in series between one end of the first inductor and the other end of the first capacitor. A first capacitor having one end connected to the ground terminal, a first inductor having one end connected to the other end of the first capacitor, and an input terminal and an output terminal connected to one end of the first inductor via the capacitor And a resonance circuit comprising a second capacitor having one end connected to the other end of the first inductor and the other end connected to a ground terminal, and a third capacitor connected in parallel to the first inductor. A filter circuit characterized by comprising: The filter circuit according to claim 3, wherein a second inductor is connected in series between one end of the first inductor and the other end of the first capacitor. 5. The filter circuit according to claim 3, wherein two or more of the resonance circuits are provided, and each of the resonance circuits is connected in parallel via a capacitor. A first capacitor having one end connected to a ground terminal and the other end connected to a common conductor, a first inductor having one end connected to the common conductor, and an input connected to the common conductor via a capacitor A filter comprising: a terminal and an output terminal; a second capacitor having one end connected to the other end of the first inductor and the other end connected to a ground terminal; and a third capacitor connected in parallel to the first inductor A multi-layer substrate, wherein a circuit is formed on a substrate having a plurality of layers, and the third capacitor is formed by a conductor facing portion of the first inductor formed in a laminated structure on the substrate. A second inductor provided in series between the common conductor and the other end of the first capacitor;
The multilayer substrate according to claim 6, wherein the second inductor is formed by a transmission line that connects the common conductor and a conductor constituting the first capacitor. A second inductor provided in series between the common conductor and the other end of the first capacitor;
The multilayer substrate according to claim 6, wherein the second inductor is formed of a via conductor for interlayer connection that connects the common conductor and a conductor constituting the first capacitor. 7. The multilayer according to claim 6, wherein the second inductor is formed by a conductor connecting the conductor forming the common conductor and the conductor forming the first capacitor. substrate. The first inductor is formed of a multilayer inductor having at least two strip-shaped conductors formed in at least two different layers and connected to each other by via conductors for interlayer connection and arranged to face each other,
10. The structure according to claim 6, wherein the third capacitor has a structure formed by a stray capacitance generated between the opposing portions of the two strip-shaped conductors constituting the first inductor. A multilayer substrate according to any one of the above.   The multilayer substrate according to any one of claims 6 to 10, wherein two or more of the resonance circuits are connected in parallel via a capacitor. An active component and / or a passive component is disposed on the multilayer substrate.

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