JP2011071793A - Filter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device having steep attenuation characteristics and a great attenuation amount at the outside of a passband and suitable for a UWB (Ultra Wide Band). <P>SOLUTION: The filter device comprises: a first grounding electrode 2a and a second grounding electrode 2b which are disposed opposite to each other with a laminated body 1 interposed between them, the laminated body 1 being formed by laminating dielectric layers 1a; three or more resonator electrodes 3a-3d which are arrayed laterally so as to be electromagnetically connected to each other, one end of each being a short circuit end and the other end being an open end; a coupling electrode 4 which are arranged with the dielectric layer 1a interposed between the resonator electrodes 3a to 3d and the coupling electrode 4, one end and the other end of the coupling electrode being opposite respectively to the short circuit ends of the resonator electrodes 3a, 3d of the first stage and the last stage and being electrically connected to the opposite short circuit ends; and an input-terminal electrode 5 and an output-terminal electrode 6 electrically connected respectively to the resonator electrodes 3a, 3d of the first and last stages. The filter device further includes capacitive electrodes 8 which electromagnetically connect the coupling electrode 4 with at least one of the input-terminal electrode 5 and the output-terminal electrode 6. The filter device has the steep attenuation characteristics and the great attenuation amount at a high frequency side of the passband. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a filter device used in, for example, a wireless communication device such as a mobile phone, a wireless LAN (Local Area Network), a UWB (Ultra Wide Band), and other various communication devices.

  In recent years, wireless communication devices have been used in various applications such as mobile phones and wireless LANs, and the frequencies used in each wireless communication device are close to each other. In order to selectively pass only signals in the desired frequency band, and to prevent unwanted signals from being mixed in the signal band close to the low frequency side and high frequency side of the pass band so that high quality communication can be performed. A filter device having band pass characteristics having attenuation poles in the low frequency side and high frequency side attenuation bands of the pass frequency band is mounted.

  Along with the increase in information transmission capacity, wireless communication devices have secured the information transmission capacity by expanding the use bandwidth by increasing the frequency and bandwidth in the usable frequency band. Therefore, a filter device having a wide pass band and having an attenuation pole in the vicinity of the pass band (having a steep attenuation characteristic) has been demanded.

  For example, UWB, which is attracting attention as a new communication means, realizes large-capacity data transfer using a wide frequency band at a short distance of about 10 m. For example, according to the provisions of the US FCC (Federal Communication Commission) It is planned to use a very wide frequency band of 3.1 to 10.6 GHz. And in Japan, avoiding 5.15 GHz to 5.25 GHz used in wireless LAN IEEE802.11.a, using a low band using about 3.4 GHz to 4.8 GHz and a band about 7.25 GHz to 10.25 GHz. Standards divided into high bands are being drafted. For this reason, a low-band filter uses a wide band of about 3.4 GHz to 4.8 GHz (passes a signal of a frequency in this band), whereas in 5.15 GHz, which is only 0.35 GHz apart. A very steep attenuation characteristic that attenuates is required.

  In response to the demand for a bandpass filter having an attenuation pole near both sides of the passband in such a wide band, a coupling electrode 4 for electrically connecting the short-circuit ends of a plurality of resonance electrodes 3a to 3d as shown in FIG. Has been proposed. In this filter device, since the coupling electrode 4 is provided, not only capacitive coupling but also inductive coupling can be generated between the plurality of resonance electrodes 3a to 3d. Thereby, a signal in a frequency band in the vicinity of a predetermined pass band can be sharply attenuated (see Patent Document 1).

JP 2008-118615 A

  However, in recent years, it has been demanded that signals in a frequency band excluding a predetermined pass band be attenuated more greatly. In the conventional filter device, a signal in a frequency band near the pass band can be sharply attenuated by the coupling electrode. However, the coupling electrode causes λ / 2 resonance. When this λ / 2 resonance occurs, the attenuation characteristic jumps up. For example, in the case of a dual band filter device having both a low band and a high band, the λ / Due to the two resonances, the attenuation may not be steep or the resonance may occur outside the pass band of the high band filter, or noise due to the resonance may be generated in the pass band. There was a point.

  The present invention has been devised in view of the above problems, and its purpose is to attenuate signals in a frequency band excluding a predetermined pass band more greatly by reducing harmonic components due to λ / 2 resonance. For example, it is providing the filter apparatus which can be used suitably also for a UWB use.

The filter device of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a first ground electrode and a second ground electrode arranged so as to face each other with the laminated body interposed therebetween, and the laminated body. Three or more resonator electrodes that are aligned side by side in a plan view so as to be electromagnetically coupled to each other, one end of which is a short-circuited end and the other end is an open end, and the resonator electrodes in the stacked body, Is disposed on the second ground electrode side with the dielectric layer interposed therebetween, and one end is opposed to the short-circuited end of the first-stage resonator electrode and electrically connected to the opposed short-circuited end of the resonator electrode A coupled electrode electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode at the other end and connected to the short-circuited end of the opposed resonator electrode, and along the first-stage resonator electrode The first shape with the dielectric layer in between An input terminal electrode that is disposed on the first ground electrode side so as to face the resonator electrode of the first stage and is electromagnetically coupled to the first stage resonator electrode, and a shape along the last stage resonator electrode, A filter device comprising an output terminal electrode disposed on the first ground electrode side so as to face the final-stage resonator electrode across a dielectric layer and coupled to the final-stage resonator electrode and electromagnetic field There,
A capacitive electrode that electromagnetically couples the coupling electrode to at least one of the input terminal electrode and the output terminal electrode, the capacitive electrode facing the input terminal electrode with the dielectric layer in between The first ground electrode disposed on the first ground electrode side and connected to one end of the coupling electrode, and the first ground electrode so as to face the output terminal electrode through the dielectric layer And at least one of those connected to the other end of the coupling electrode.

  Further, the filter device of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a first ground electrode and a second ground electrode disposed so as to face each other with the laminated body interposed therebetween, Three or more resonator electrodes arranged side by side in a plan view so as to be electromagnetically coupled to each other in the stacked body, each having one end short-circuited and the other end open-ended, and the resonator in the stacked body The dielectric layer is sandwiched between the electrodes and disposed on the second ground electrode side, and one end thereof is electrically connected to the short-circuited end of the resonator electrode opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode of the final stage and the other end of the first electrode With the dielectric layer in between An input terminal electrode disposed on the first ground electrode side so as to face the first stage resonator electrode and electromagnetically coupled to the first stage resonator electrode, and a shape along the last stage resonator electrode A filter comprising an output terminal electrode disposed on the first ground electrode side so as to face the final stage resonator electrode across the dielectric layer and electromagnetically coupled to the final stage resonator electrode A capacitive electrode for electromagnetically coupling the coupling electrode to at least one of the input terminal electrode and the output terminal electrode, the capacitive electrode being connected to one end of the coupling electrode and the dielectric Arranged on the second ground electrode side so as to face each other through the body layer and connected to the input terminal electrode, and opposed to the other end of the coupling electrode through the dielectric layer To make the second Is characterized in that while being placed on the ground electrode side is at least one of those is connected to the output terminal electrode.

  Further, the filter device of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a first ground electrode and a second ground electrode disposed so as to face each other with the laminated body interposed therebetween, Three or more resonator electrodes arranged side by side in a plan view so as to be electromagnetically coupled to each other in the stacked body, each having one end short-circuited and the other end open-ended, and the resonator in the stacked body The dielectric layer is sandwiched between the electrodes and disposed on the second ground electrode side, and one end thereof is electrically connected to the short-circuited end of the resonator electrode opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode of the final stage and the other end of the first electrode With the dielectric layer in between An input terminal electrode disposed on the first ground electrode side so as to face the first stage resonator electrode and electromagnetically coupled to the first stage resonator electrode, and a shape along the last stage resonator electrode A filter comprising an output terminal electrode disposed on the first ground electrode side so as to face the final stage resonator electrode across the dielectric layer and electromagnetically coupled to the final stage resonator electrode The apparatus includes a capacitive electrode that electromagnetically couples the coupling electrode and at least one of the input terminal electrode and the output terminal electrode, and the capacitive electrodes face each other through the dielectric layer A first capacitor electrode and a second capacitor electrode, wherein the first capacitor electrode is connected to one end of the coupling electrode and the second capacitor electrode is connected to the input terminal electrode. And said first It is characterized in that the capacitive electrodes is at least one of which the second capacitor electrode is connected to the other end of the coupling electrode is connected to the output terminal electrode.

  Further, the filter device of the present invention is characterized in that, in the above configuration, when the resonator electrode is viewed in plan, an internal ground electrode is formed so as to surround the plurality of resonator electrodes. .

  Further, the filter device according to the present invention is configured such that, in each of the above configurations, the second ground electrode is opposed to the second ground electrode with the dielectric layer interposed between the second ground electrode and the resonator electrode, It has a plurality of shortened capacitance electrodes respectively electrically connected to the open ends of the resonator electrodes.

  In the filter device of the present invention, in the above configuration, when the resonator electrode is viewed in plan, an internal ground electrode is formed so as to surround the plurality of resonator electrodes, and a part of the shortened capacitance electrode is The dielectric layer is disposed so as to face the internal ground electrode.

  According to the filter device of the present invention, the capacitor electrode includes the capacitive electrode that electromagnetically couples the coupling electrode and at least one of the input terminal electrode and the output terminal electrode, and the capacitive electrode is interposed between the input terminal electrode and the dielectric layer. Arranged on the first ground electrode side so as to face each other and connected to one end of the coupling electrode, and on the first ground electrode side so as to face the output terminal electrode via the dielectric layer Since it is at least one of those arranged and connected to the other end of the coupling electrode, the coupling electrode and at least one of the input terminal electrode and the output terminal electrode are capacitively coupled via the capacitive electrode. Since the electromagnetic field coupling is strengthened, the phase of the signal passing through the coupling electrode can be changed. As a result, the λ / 2 resonance caused by the coupling electrode can be reduced, and a filter device in which jumping of the attenuation characteristic is suppressed in a frequency band excluding a predetermined pass band can be obtained.

  According to the filter device of the present invention, the capacitive electrode includes the capacitive electrode that electromagnetically couples the coupling electrode and at least one of the input terminal electrode and the output terminal electrode, and the capacitive electrode includes one end of the coupling electrode and the dielectric layer. The second ground electrode is disposed on the second ground electrode side so as to be opposed to each other and connected to the input terminal electrode, and the other end of the coupling electrode is opposed to the second dielectric layer via the dielectric layer. Since it is at least one of those arranged on the ground electrode side and connected to the output terminal electrode, the coupling electrode and at least one of the input terminal electrode and the output terminal electrode are capacitively coupled via the capacitive electrode. Thus, the electromagnetic field coupling is strengthened, so that the phase of the signal passing through the coupling electrode can be changed. As a result, the λ / 2 resonance caused by the coupling electrode can be reduced, and a filter device in which jumping of the attenuation characteristic is suppressed in a frequency band excluding a predetermined pass band can be obtained.

  According to the filter device of the present invention, the capacitive electrode that electromagnetically couples the coupling electrode to at least one of the input terminal electrode and the output terminal electrode is provided, and the capacitive electrodes face each other through the dielectric layer. A first capacitor electrode and a second capacitor electrode, wherein the first capacitor electrode is connected to one end of the coupling electrode and the second capacitor electrode is connected to the input terminal electrode; and The capacitor electrode is connected to the other end of the coupling electrode and the second capacitor electrode is at least one of those connected to the output terminal electrode, so that the coupling electrode, the input terminal electrode, and the output terminal electrode Since electromagnetic coupling is strengthened by capacitive coupling with at least one through the first capacitive electrode and the second capacitive electrode, the phase of the signal passing through the coupled electrode can be changed. As a result, the λ / 2 resonance caused by the coupling electrode can be reduced, and a filter device in which jumping of the attenuation characteristic is suppressed in a frequency band excluding a predetermined pass band can be obtained.

  According to the filter device of the present invention, in the above configuration, when the resonator electrode is viewed in plan, when the internal ground electrode is formed so as to surround the plurality of resonator electrodes, By encircling the periphery of the resonator electrode, leakage of electromagnetic waves generated from the resonator electrode to the periphery can be reduced. This effect is particularly useful for preventing adverse effects on other regions of the module substrate when the filter device of the present invention is formed in a partial region of the module substrate.

  According to the filter device of the present invention, in each of the above-described configurations, the second ground electrode is opposed to the second ground electrode with the dielectric layer interposed between the second ground electrode and the resonator electrode, and a plurality of resonator electrodes are provided. When there are a plurality of shortened capacitor electrodes that are electrically connected to the open ends, the distance between the shortened capacitor electrode and the second ground electrode is shorter than the distance between the resonator electrode and the second ground electrode. As a result, the coupling between the resonator electrode and the second ground electrode becomes stronger and the capacitive coupling of the resonator electrode is strengthened, so that the length of each resonator electrode can be shortened, and a smaller filter An apparatus can be provided.

  According to the filter device of the present invention, in the above configuration, when the resonator electrode is viewed in plan, the internal ground electrode is formed so as to surround the plurality of resonator electrodes, and a part of the shortened capacitance electrode is dielectric. When arranged so as to face the internal ground electrode across the body layer, the internal ground electrode is formed between the same dielectric layers as the dielectric layer on which the resonator electrode is formed, and the capacitor electrode is connected to the internal ground electrode. Since the wiring length of the through conductor and the like for electrical connection between the resonator electrode and the shortened capacitor electrode can be shortened by facing the electrodes so as to be coupled with each other, unnecessary inductance due to this wiring can be reduced, and the distance between the electrodes can be reduced. It is possible to obtain a filter device having excellent filter characteristics free from secondary resonance due to the inductance of the wiring.

It is a disassembled perspective view which shows typically an example of embodiment of the filter apparatus of this invention. It is a disassembled perspective view which shows typically the other example of embodiment of the filter apparatus of this invention. It is a disassembled perspective view which shows typically the other example of embodiment of the filter apparatus of this invention. It is a disassembled perspective view which shows typically the other example of embodiment of the filter apparatus of this invention. It is sectional drawing which shows the principal part of the cross section in the AA line of the filter apparatus shown in FIG. It is a figure which shows the simulation result of the transmission characteristic of the filter apparatus of this invention. It is a disassembled perspective view which shows the conventional filter apparatus.

  The filter device of the present invention will be described in detail below. 1 to 5, 1a is a dielectric layer, 1 is a laminate formed by laminating a dielectric layer 1a, 2a is a first ground electrode, 2b is a second ground electrode, 2c is an internal ground electrode, 3a -3d is a resonator electrode, 3a is a first-stage resonator electrode, 3d is a final-stage resonator electrode, 4 is a coupling electrode, 5 is an input terminal electrode, 5a is an external input terminal electrode, 6 is an output terminal electrode, and 6a is An external output terminal electrode, 7 is a shortened capacitor electrode, 8 is a capacitor electrode, 8a is a first capacitor electrode, and 8b is a second capacitor electrode. 1 to 4, broken lines indicate dielectric layers 1a for electrically connecting conductor layers (for example, first-stage resonator electrode 3a and input terminal electrode 5) located above and below dielectric layer 1a. It shows that there is a through conductor that penetrates.

  In the example shown in FIG. 1, the laminated body 1 is configured by laminating five dielectric layers 1a, and the four resonator electrodes 3a to 3d are arranged so that the short-circuited ends and the open ends are alternately switched. The example arranged in the so-called interdigital type is shown. The number of the dielectric layers 1a can be appropriately changed depending on the thickness of the dielectric layer 1a, the relative dielectric constant, and the like. Since the four resonator electrodes 3a to 3d are arranged in an interdigital manner in the coupling electrode 4, one end faces the short-circuited end of the first-stage resonator electrode 3a and the other end is the last-stage resonator electrode 3d. In order to face the short-circuited end portion, a crank type like the example shown in FIG. 1 is formed. Even if the same four resonator electrodes 3a to 3d are arranged in the so-called comb line type in which the directions of the short-circuited end and the open end are the same, the coupling electrode 4 has a U-shaped (C-shaped). ) Similarly, even when the arrangement of the resonator electrodes is the same interdigital type, the coupling electrode 4 is U-shaped (C-shaped) even when the number is an odd number such as five. Thus, the shape of the coupling electrode 4 is a shape corresponding to the arrangement and number of resonator electrodes.

  The resonator electrodes 3a to 3d are arranged side by side between the dielectric layers 1a and 1a of the multilayer body 1, and are electromagnetically coupled (edge coupled) to each other. The smaller distance between the adjacent resonator electrodes 3a, 3b, 3b, 3c, 3c, 3d is preferable because strong coupling can be obtained and the pass band can be easily widened. In order to satisfactorily form at equal intervals without short-circuiting each other, for example, the thickness is set to about 0.05 to 0.5 mm. In order to be arranged side by side and to be electromagnetically coupled to each other, the resonator electrodes 3a to 3d are preferably in the form of a strip.

  The resonator electrodes 3a to 3d may be aligned side by side in a plan view so as to be electromagnetically coupled to each other in the multilayer body 1. Normally, for example, as shown in FIG. 1, four resonator electrodes 3a to 3d are arranged between one dielectric layer 1a and 1a, but the resonator electrodes 3a and 3c are arranged as one dielectric layer 1a and 1a. The resonator electrodes 3b and 3d may be disposed between the other dielectric layers 1a and 1a with one dielectric layer 1a interposed therebetween. However, this arrangement is preferable because there is no short circuit between adjacent resonator electrodes, and the formation thereof is facilitated. However, the number of dielectric layers 1a is increased and the thickness of the filter device is increased.

  1 to 4, when the resonator electrodes 3a to 3d are arranged in an interdigital manner, the coupling between the resonator electrodes 3a to 3d is the addition of the coupling by the magnetic field and the coupling by the electric field. As a result, stronger coupling occurs between the resonator electrodes 3a to 3d, so that the frequency interval between the resonance frequencies in the respective resonance modes can be realized by a filter using a conventional quarter wavelength resonator. Thus, the filter device can be adjusted beyond the band that has been, and can have a wide passband. Further, the coupling between the resonator electrodes 3a to 3d arranged in the interdigital type is a strong magnetic field coupling, and it is not necessary to reduce the pattern width of the resonator electrodes 3a to 3d to increase the magnetic field. By increasing the pattern width of 3d, the electrical resistance of the resonator electrodes 3a to 3d can be reduced, and the Q value (quality factor) indicating the sharpness of the sharp resonance of the resonator can be increased. As a result, a filter device having a wide passband and a steep attenuation characteristic, for example, suitable for a bandpass filter for UWB applications can be obtained.

  Further, when the resonator electrodes 3a to 3d are arranged in the comb line type, since the coupling between the resonator electrodes 3a to 3d is weaker than that of the interdigital type, a narrow band and a steep characteristic can be obtained. Since the pattern width of each of the resonator electrodes 3a to 3d can be reduced, the size of the resonator electrodes 3a to 3d can be further reduced. Therefore, the filter device is suitable for a relatively small wireless device such as a mobile phone or a wireless LAN.

  In the example shown in FIGS. 1 to 4, four resonator electrodes 3a to 3d are provided. However, five or more resonator electrodes may be provided as long as the loss does not increase. In UWB low-band applications, four resonator electrodes are preferred from the balance of loss and attenuation characteristics.

  The resonator electrodes 3a to 3d include a first ground electrode 2a and a second ground electrode 2b (hereinafter referred to as the first ground electrode 2a and the second ground electrode 2b, respectively) positioned vertically. And a stripline resonator, and the short-circuit ends are connected to the upper and lower ground electrodes 2a and 2b and connected to the ground potential to function as a quarter-wave resonator. As shown in FIGS. 1 to 4, the connection between the resonator electrodes 3a to 3d and the upper and lower ground electrodes 2a and 2b is performed between the short-circuited ends of the resonator electrodes 3a to 3d between the layers where the resonator electrodes 3a to 3d are formed. A conductor layer is provided for connection between the conductor layer and a through conductor (not shown), or the conductor layer is extended to the end of the dielectric layer 1a so that the end face of the dielectric layer 1a ( What is necessary is just to connect by the end surface conductor (not shown) formed in the side surface of the laminated body 1. When a conductor layer for connecting the short-circuit ends of the resonator electrodes 3a to 3d is not provided, each of the resonator electrodes 3a to 3d may be connected to the ground electrodes 2a and 2b by a through conductor, The short-circuit ends of the electrodes 3a to 3d may be extended to the end of the dielectric layer 1a and connected to the ground electrodes 2a and 2b by end surface conductors formed on the end surface of the dielectric layer 1a (side surface of the multilayer body 1). When connected by an end face conductor, the end face conductor can function as a shield layer that reduces leakage of electromagnetic waves generated from the resonator electrodes 3a to 3d to the surroundings. It is preferable to arrange the electrode conductors 3a to 3d in a double or more manner around the electrodes 3a to 3d and arrange the through conductors as far as possible as viewed from the side surface, because the function of the shield becomes more remarkable. When the conductor layer for connecting the short-circuited ends of the resonator electrodes 3a to 3d is provided as in the example shown in FIGS. 1 to 4, the short-circuited ends of the resonator electrodes 3a to 3d are connected to the ground electrodes 2a and 2b. Since it becomes easy to do, it is preferable.

   Further, as in the example shown in FIGS. 1 to 4, the filter device of the present invention has a plurality of resonator electrodes in a plan view between the dielectric layers 1 a in which the resonator electrodes 3 a to 3 d are formed. An internal ground electrode 2c is preferably formed so as to surround 3a to 3d. By doing so, the internal ground electrode 2c surrounds the periphery of the resonator electrodes 3a to 3d, thereby reducing leakage of electromagnetic waves generated from the resonator electrodes 3a to 3d to the periphery. This effect is particularly useful in preventing adverse effects on other regions of the module substrate when the filter device is formed in a partial region of the module substrate. The internal ground electrode 2c is an annular one composed of a conductor layer for connecting the short-circuit ends of the resonator electrodes 3a to 3d described above and a conductor layer formed on both sides of the array of the resonator electrodes 3a to 3d. is there. If the connection between the ground electrodes 2a and 2b and the resonator electrodes 3a to 3d is performed also at the portions located on both sides of the array of the resonator electrodes 3a to 3d of the internal ground electrode 2c, electromagnetic waves generated from the resonator electrodes 3a to 3d are generated. Leakage to the surroundings can be more effectively reduced.

  The distance between the internal ground electrode 2c and the resonator electrodes 3a and 3d affects the magnetic field generated by the resonator electrodes 3a and 3d so that the Q value of the filter is lowered and the loss of the passband is not increased. The distance between the resonator electrodes 3a and 3d and the ground electrodes 2a and 2b is preferably larger than the distance between the resonator electrodes 3a and 3d and the ground electrodes 2a and 2b.

  The coupling electrode 4 is provided to strengthen the coupling between the first-stage resonator electrode 3a and the last-stage resonator electrode 3d, which are weakly coupled. For example, in the example shown in FIG. When the coupling between the electrode 3b and the third-stage resonator electrode 3c increases, the filter in the pass band such as the center frequency of the basic filter formed by the resonator electrodes 3a to 3d and the ground electrodes 2a and 2b deviates. The characteristic changes, and the design of the attenuation characteristic by adding the coupling electrode 4 becomes complicated. Further, when the line width of the pattern connecting the portion facing the first-stage resonator electrode 3a and the portion facing the last-stage resonator electrode 3d in the coupling electrode 4 is large, the coupling electrode 4 itself becomes a ground electrode. Since it functions, it affects the magnetic field generated by the resonator electrodes 3a to 3d, thereby lowering the Q value of the filter and increasing the loss of the passband. Therefore, the portion connecting the portion facing the first-stage resonator electrode 3a and the portion facing the last-stage resonator electrode 3d has an area facing the second-stage and third-stage resonator electrodes 3b and 3c. In order to make the coupling as small as possible, it is preferable to provide a pattern with a small width so as to be orthogonal to the second and third stage resonator electrodes 3b and 3c. Further, in order to reduce the coupling by increasing the distance to the portion facing the first-stage resonator electrode 3a and the last-stage resonator electrode 3d, this perpendicular portion is further provided with one or more dielectric layers 1a. It may be formed at a sandwiched position and connected to a portion facing the first-stage resonator electrode 3a and a portion facing the last-stage resonator electrode 3d by a through conductor.

  Depending on the number of dielectric layers 1a between the coupling electrode 4 and the resonator electrodes 3a and 3d, the distance between the coupling electrode 4 and the resonator electrodes 3a and 3d can be changed, or the pattern width and length of the coupling electrode 4 can be changed. The electromagnetic field between the coupling electrode 4 and the resonator electrodes 3a and 3d is changed by changing the area where the coupling electrode 4 and the resonator electrodes 3a and 3d overlap depending on the pattern shape and the position in plan view. The degree of coupling can be adjusted, and the frequency at which the attenuation pole occurs can be set arbitrarily. Sufficient coupling is obtained between the resonator electrodes 3a and 3d, and the resonator electrodes 3b and 3c other than the first-stage resonator electrode 3a and the final-stage resonator electrode 3d due to a positional shift when the filter device is manufactured The portion of the coupling electrode 4 that faces the first-stage resonator electrode 3a and the portion that faces the last-stage resonator electrode 3d have the shape of the resonator electrodes 3a and 3d. It is preferable that the shape is a band shape that is narrower than the resonator electrodes 3a and 3d.

  The filter device of the present invention is provided with a capacitive electrode 8 that electromagnetically couples the coupling electrode 4 and at least one of the input terminal electrode 5 and the output terminal electrode 6 as in the examples shown in FIGS. . When such a capacitive electrode 8 is provided, the coupling electrode 4 and at least one of the input terminal electrode 5 and the output terminal electrode 6 are capacitively coupled through the capacitive electrode 8 so that electromagnetic field coupling is strengthened. The phase of the signal passing through can be changed. Thereby, the λ / 2 resonance due to the coupling electrode 4 can be reduced, and a filter device in which the jump of the attenuation characteristic is suppressed in the frequency band excluding the predetermined pass band can be obtained.

  In the example shown in FIGS. 1 and 4, the capacitor electrode 8 is disposed on the first ground electrode 2 a side so as to face the input terminal electrode 5 with the dielectric layer 1 a interposed therebetween, and at one end of the coupling electrode 4. There are two types, one connected and the other connected to the other end of the coupling electrode 4 and arranged on the first ground electrode 2a side so as to face the output terminal electrode 6 through the dielectric layer 1a. Is formed.

  In the example shown in FIG. 2, the capacitor electrode 8 is disposed on the second ground electrode 2 b side so as to face one end of the coupling electrode 4 via the dielectric layer 1 a and is connected to the input terminal electrode 5. Are disposed on the second ground electrode 2b side so as to face the other end portion of the coupling electrode 4 through the dielectric layer 1a and connected to the output terminal electrode 6. ing.

  In the example shown in FIG. 3, the capacitor electrode 8 includes a first capacitor electrode 8 a and a second capacitor electrode 8 b that are opposed to each other with the dielectric layer 1 a interposed therebetween. The first capacitor electrode 8 a is the coupling electrode 4. The second capacitor electrode 8b is connected to the input terminal electrode 5 while being connected to one end, the first capacitor electrode 8a is connected to the other end of the coupling electrode 4, and the second capacitor electrode 8b is The output terminal electrode 6 is connected.

  When the capacitive electrode 8 is arranged as in the examples shown in FIGS. 1, 2 and 4, the dielectric between the capacitive electrode 8 and the coupling electrode 4, the input terminal electrode 5 or the output coupling electrode 6 opposed to the capacitive electrode 8 is used. The amount of bonding can be adjusted by the thickness of the body layer 1a. In the example shown in FIG. 3, the thickness of the dielectric layer 1a between the first capacitor electrode 8a and the second capacitor electrode 8b is equal to the dielectric layer 1a between the coupling electrode 4 and the resonator electrodes 3a to 3d. Or the thickness of the dielectric layer 1a between the input terminal electrode 5 and the output coupling electrode 6 dielectric layer 1a and the resonator electrodes 3a to 3d, but without increasing the number of dielectric layers 1a. The capacitor electrode 8a and the second capacitor electrode 8b can be opposed to each other, and the amount of coupling may be adjusted by the area of the first capacitor electrode 8a and the second capacitor electrode 8b. Further, the first capacitor electrode 8a or the second capacitor electrode 8b may be formed between the dielectric layers 1a and 1a on which the resonator electrodes 3a to 3d are formed. Since the positions of the first capacitor electrode 8a and the second capacitor electrode 8b in the stacking direction of the dielectric layer 1a are not limited to the positions shown in FIG. 3, the first capacitor electrode 8a and the second capacitor electrode 8b The amount of coupling can also be adjusted by the thickness of the dielectric layer 1a between the capacitor electrode 8b.

  The larger the area of the capacitive electrode 8, the stronger the coupling between the coupling electrode 4 and the input terminal electrode 5 or the output terminal electrode 6, but the coupling electrode 4, the first-stage resonator electrode 3a, and the last-stage resonator electrode 3d Coupling, the coupling between the input terminal electrode 5 and the first stage resonator electrode 3a, and the coupling between the output terminal electrode 6 and the last stage resonator electrode 3d are weakened, and the attenuation characteristics on both sides of the pass band of the filter characteristics are reduced. Since deterioration (steepness is impaired) and reflection characteristics in the passband are deteriorated, the coupling may be set so as not to be greatly impaired.

  As long as the shape of the capacitive electrode 8 is such that the coupling electrode 4 and the input terminal electrode 5 or the output terminal electrode 6 can be coupled with a predetermined coupling amount, as in the example shown in FIGS. The shape is not limited to a rectangular shape, and may be a square shape such as a square shape, a polygonal shape higher than that, a circular shape, an elliptical shape, or an oval shape. In the case where the capacitive electrode 8 is arranged as in the examples shown in FIGS. 1, 2, and 4, in order to suppress unnecessary coupling with the resonator electrodes 3a to 3d, the coupling electrode 4 opposed to the capacitive electrode 8 is provided. A shape along the input terminal electrode 5 and the output terminal electrode 6 and having a width smaller than these is preferable. When the first capacitor electrode 8a and the second capacitor electrode 8b are arranged as in the example shown in FIG. 3, in order to suppress unnecessary coupling with the resonator electrodes 3a and 3d and the internal ground electrode 2c, the resonator It is preferable to have an elongated shape having a width smaller than the distance between the electrodes 3a, 3d and the internal ground electrode 2c.

  If at least one of the capacitive electrode 8 is one that couples the coupling electrode 4 and the input terminal electrode 5 and one that couples the coupling electrode 4 and the output terminal electrode 6, the above-described effects can be obtained. However, it is preferable to provide both of them as in the examples shown in FIGS. In this way, since the coupling amount between the coupling electrode 4 and the input terminal electrode 5 or the output terminal electrode 6 is adjusted at two locations, the size and arrangement of the capacitive electrode 8, the thickness of the dielectric layer 1a, etc. , Design freedom increases. For example, if the coupling electrode 4 and the input terminal electrode 5 or the output terminal electrode 6 are coupled to each other by the capacitive electrode 8 at two locations, the respective capacitive electrodes 8 can be made small. It becomes easy to suppress unnecessary coupling with the electrodes 3a to 3d and the like. In addition, by combining the coupling electrode 4 with both the input terminal electrode 5 and the output terminal electrode 6, impedance matching at the center frequency of the pass band in the filter characteristics is facilitated.

  When the capacitive electrode 8 overlaps the second-stage resonator electrode 3b or the third-stage resonator electrode 3c in plan view, the resonator electrodes 3b and 3c are connected to the first-stage resonator electrode 3a via the capacitive electrode 8. 1 and the final stage resonator electrode 3d is coupled to affect the filter characteristics. Therefore, in the case of the example shown in FIG. 1, FIG. 2 and FIG. The shape and arrangement are preferably such that they do not protrude from the input terminal electrode 5 and the output terminal electrode 6 toward the second-stage resonator electrode 3b or the third-stage resonator electrode 3c in plan view. For the same reason, the portion connecting the capacitor electrode 8 to the coupling electrode 4, the input terminal electrode 5, and the output terminal electrode 6 should not overlap the second-stage resonator electrode 3 b or the third-stage resonator electrode 3 c. The connection between the capacitive electrode 8 and the coupling electrode 4, the input terminal electrode 5 and the output terminal electrode 6 is preferably led out to the outside of the resonator electrodes 3a to 3d arranged side by side.

  For the same reason, the first capacitor electrode 8a and the second capacitor electrode 8b are arranged so as not to overlap the second-stage resonator electrode 3b or the third-stage resonator electrode 3c in plan view. As shown in FIG. 3, the first capacitor electrode 8a and the second capacitor electrode 8b are arranged so as to face each other outside the resonator electrodes 3a to 3d arranged side by side in a plan view. It is preferable to do this.

  In the example shown in FIGS. 1 to 4, one capacitive electrode 8 is provided on each of the input terminal electrode 5 and one end of the coupling electrode 4, and the output terminal electrode 6 and the other end of the coupling electrode 4. A plurality of 8 may be provided.

  Further, in the filter device of the present invention, in the above-described configuration, as shown in the example shown in FIG. 4, the second ground electrode is sandwiched between the second ground electrode 2b and the resonator electrodes 3a to 3d. It is preferable to have a plurality of shortened capacitance electrodes 7 facing the electrode 2b and electrically connected to the open ends of the plurality of resonator devices 3a to 3d, respectively. As a result, the distance between the shortened capacitance electrode 7 and the second ground electrode 2b is shorter than the distance between the resonator electrodes 3a to 3d and the second ground electrode 2b, thereby the resonator electrodes 3a to 3d and the second ground electrode 2b. Since the coupling between the electrodes 2b becomes stronger and the C coupling between the resonator electrodes 3a to 3d and the second ground electrode 2b is strengthened, the length of each of the resonator electrodes 3a to 3d can be shortened. And a more compact filter device can be provided.

  Further, the filter device of the present invention is arranged so that a part of the shortened capacitance electrode 7 faces the internal ground electrode 2c with the dielectric layer 1a interposed therebetween as in the example shown in FIGS. It is preferable that The internal ground electrode 2c is formed between the same dielectric layers 1a and 1a as the dielectric layers 1a and 1a on which the resonator electrodes 3a to 3d are formed, and couples the shortened capacitance electrode 7 to the internal ground electrode 2c. In this case, compared with the case where the shortened capacitor electrode 7 is opposed so as to be coupled only with the second ground electrode 2b (in the case of the shortened capacitor electrode 7a shown by the broken line in FIG. 5), the resonator electrode Since the wiring length of a through conductor or the like for electrical connection between 3a to 3d and the shortened capacitance electrode 7 can be shortened, unnecessary inductance due to this wiring can be reduced, and there is no secondary resonance due to the inductance. It can be set as the filter apparatus which has the outstanding filter characteristic. Further, even when the wiring lengths of through conductors and the like for electrical connection between the resonator electrodes 3a to 3d and the shortened capacitor electrode 7 are the same, the electrostatic capacitance between the shortened capacitor electrode 7 and the internal ground electrode 2c is the same. Since the capacitance between the open ends of the resonator electrodes 3a to 3d and the ground potential is further increased and the length of the resonator electrodes 3a to 3d can be shortened, a more compact bandpass A filter device as a filter can be obtained.

  The shortened capacitance electrode 7 and the resonator electrodes 3a to 3d are electrically connected by a through conductor. When the shortened capacitor electrode 7 and the resonator electrodes 3a to 3d overlap in plan view, the coupling between the resonator electrodes 3a to 3d and the ground electrodes 2a and 2b is reduced by an amount corresponding to the overlapped area. When the shortened capacitor electrode 7 connected to the resonator electrode 3a and the other resonator electrodes 3b to 3d overlap in plan view, the coupling amount between the first resonator electrode 3a and the other resonator electrodes 3b to 3d changes. Therefore, as in the example shown in FIG. 4, the shortened capacitor electrode 7 is formed in an elongated shape such as a rectangle or an ellipse, and the open ends of the resonator electrodes 3 a to 3 d are connected to one end of the shortened capacitor electrode 7. The other end of the shortened capacitance electrode 7 may be oriented in the direction of extending the open ends of the resonator electrodes 3a to 3d.

  In the example shown in FIG. 4, the shortened capacitance electrode 7 is provided one below each of the resonator electrodes 3 a to 3 d with the dielectric layer 1 a interposed therebetween, but above and below the resonator electrodes 3 a to 3 d. One may be provided above each of the resonator electrodes 3a to 3d, or one may be provided above or below the resonator electrodes 3a to 3d.

  The input terminal electrode 5 and the output terminal electrode 6 are connected to the resonator electrodes 3a and 3d with the dielectric layer 1a interposed therebetween so as to be electromagnetically coupled to the resonator electrodes 3a and 3d, respectively, as in the examples shown in FIGS. Are arranged to face each other. In this case, as in the example shown in FIGS. 1 to 4, the input terminal electrode 5 has a shape along the first-stage resonator electrode 3a and is opposed to the first-stage resonator electrode 3a with the dielectric layer 1a interposed therebetween. The first stage resonator electrode 3a is arranged so as to be electromagnetically coupled to the outside and is formed on the outer surface of the laminate 1 on the open end side of the first stage resonator electrode 3a. It is connected to the input terminal electrode 5a. The output terminal electrode 6 has a shape along the final-stage resonator electrode 3d, and is disposed so as to face the final-stage resonator 3d of the resonator electrode 3 with the dielectric layer 1a interposed therebetween. In addition to being electromagnetically coupled to 3d, it is connected to an external output terminal electrode 6a that is formed on the outer surface of the laminate 1 on the open end side of the resonator electrode 3d at the final stage and is connected to an external circuit. With such a configuration, the coupling by the magnetic field and the coupling by the electric field are added between the input terminal electrode 5 and the first stage resonator electrode 3a and between the output terminal electrode 6 and the last stage resonator electrode 3d. Since strong coupling occurs, insertion loss at frequencies located between the resonance frequencies of the respective resonance modes, even in a pass band wider than that which can be realized by a filter using a conventional quarter wavelength resonator. It is possible to provide a filter device having a flat and low-loss pass characteristic over the entire wide passband without significantly increasing the. As a result, the filter device has a wide pass band and has a steep attenuation characteristic, which is suitable for a bandpass filter for UWB applications, for example.

  The connection between the input terminal electrode 5 and the external input terminal electrode 5a and the connection between the output terminal electrode 6 and the external output terminal electrode 6a are penetrating through the dielectric layer 1a as in the examples shown in FIGS. What is necessary is just to do with a conductor. Further, the input terminal electrode 5, the external input terminal electrode 5a, the output terminal electrode 6 and the external output terminal electrode 6a can be extended to the ends of the dielectric layer 1a and connected by end face conductors. When the connection between the resonator electrodes 3a to 3d and the ground electrodes 2a and 2b is performed by an end face conductor, the end face conductor can be formed simultaneously with other electrodes by printing a conductor paste or the like, which is convenient in manufacturing.

  Planar arrangement of the coupling electrode 4, the input terminal electrode 5, the output terminal electrode 6, and the shortening capacitor electrode 7 with respect to the resonator electrodes 3a to 3d and their distances (the thickness or number of layers of the dielectric layer 1a interposed therebetween) ) Is not particularly limited, and may be set so as to adjust the coupling between each electrode and the resonator electrodes 3a to 3d so as to obtain a desired attenuation characteristic.

As the dielectric layer 1a, for example, alumina, mullite, aluminum nitride, BaO—TiO ₂ series, CaO—TiO ₂ series, MgO—TiO ₂ series, ceramic materials such as glass ceramics, or tetrafluoroethylene resin (polytetra Fluoroethylene: PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin: ETFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluteroalkyl vinyl ether) Fluorine resin such as copolymer resin (PFA), glass epoxy resin, organic resin material such as polyimide is used. The shape and dimensions (thickness, width, length) of the dielectric layer 1a made of these materials are set according to the frequency used, the application, and the like. In the case of a ceramic material, low-temperature fired ceramics that can be fired simultaneously with a conductor material made of a low-resistance metal such as Au, Ag, or Cu that can transmit a higher frequency signal is preferable.

  The first ground electrode 2a, the second ground electrode 2b, the internal ground electrode 2c, the resonator electrodes 3a to 3d, the coupling electrode 4, the input terminal electrode 5, the output terminal electrode 6, the shortened capacitor electrode 7 and the capacitor electrode 8 are When the dielectric layer 1a is made of a ceramic material, the dielectric layer 1a is formed of a metallized layer containing a metal such as W, Mo, Mo—Mn, Au, Ag, or Cu as a main component. When the dielectric layer 1a is made of a resin material, a metal layer formed by a thick film printing method, various thin film forming methods, a plating method or a foil transfer method, or a plating layer on such a metal layer is formed. A formed layer, for example, a Cu layer, a Cr—Cu alloy layer or a Cr—Cu alloy layer coated with a Ni plating layer and an Au plating layer, and a TaN layer coated with a Ni—Cr alloy layer and an Au plating layer. Examples thereof include those deposited, those obtained by depositing a Pt layer and an Au plating layer on a Ti layer, and those obtained by depositing a Pt layer and an Au plating layer on a Ni—Cr alloy layer. The thickness and width are set according to the frequency and application of the transmitted high-frequency signal.

  Dielectric layer 1a, first ground electrode 2a, second ground electrode 2b, internal ground electrode 2c, resonator electrodes 3a to 3d, coupling electrode 4, input terminal electrode 5, output terminal electrode 6, shortened capacitance electrode 7 and A known method may be used to form the capacitor electrode 8. For example, if the dielectric layer 1a is made of glass ceramics, first prepare green sheets of glass ceramics to be the dielectric layers 1a, and print a conductor paste such as Ag in a predetermined shape on the green sheets by screen printing. The first ground electrode 2a, the second ground electrode 2b, the internal ground electrode 2c, the resonator electrodes 3a to 3d, the coupling electrode 4, the input terminal electrode 5, the output terminal electrode 6, the shortening capacitive electrode 7 and the capacitive electrode are applied. 8 electrode patterns are formed. Next, a green body with these electrode patterns formed thereon is stacked and pressure-bonded, for example, to produce a laminate, and this laminate is formed by firing at 850 to 1000 ° C. Thereafter, a plating film such as Ni plating or Au plating is formed on the conductor layer exposed on the outer surface. If the dielectric layer 1a is made of an organic resin material, for example, a first ground electrode 2a, a second ground electrode 2b, an internal ground electrode 2c, resonator electrodes 3a to 3d, and a coupling electrode 4 are formed on an organic resin sheet. , The input terminal electrode 5, the output terminal electrode 6, the shortened capacitor electrode 7, and the Cu foil processed into each electrode pattern shape of the capacitor electrode 8 are transferred, and the organic resin sheet on which the Cu foil is transferred is laminated and bonded with an adhesive. To form.

  The connection conductor that connects the ground electrodes 2a, 2b and the short-circuit ends of the resonator electrodes 3a to 3d is formed on the end surface of the through conductor or the dielectric layer 1a formed in the dielectric layer 1a located therebetween. By forming it in the form of the end face conductor, the degree of freedom in designing the filter device formed inside the laminated dielectric layers 1a is improved, and a more compact and high-performance filter device can be obtained.

  In the case where the dielectric layer 1a is made of ceramics such as glass ceramics, the through conductors or side conductors that serve as such connection conductors are, for example, the first ground electrode 2a and the second ground conductor in the manufacturing method described above. Before forming the electrode patterns of the ground electrode 2b, the internal ground electrode 2c, the resonator electrodes 3a to 3d, the coupling electrode 4, the input terminal electrode 5, the output terminal electrode 6, the shortened capacitor electrode 7 and the capacitor electrode 8, a green sheet is formed. Can be formed by filling a similar conductor paste into a through-hole previously formed by die processing or laser processing by a printing method or the like, and the end face conductors are electrodes of the resonator electrodes 3a to 3d, for example. After forming the green sheet laminate with the short-circuited end of the pattern exposed on the end face, the same conductor paste is printed on the side of the green sheet laminate It can be formed. In addition, the end face conductor is formed so that a through hole having a width about the width of the resonator electrodes 3a to 3d is formed in the green sheet, and the short-circuit end of the electrode pattern of the resonator electrodes 3a to 3d is in contact with the through hole. Thereafter, the conductive paste can be printed on the inner surface of the through hole before or after the green sheet is laminated, or can be formed by filling the through hole and cutting at the portion of the through hole. Similarly, when the dielectric layer 1a is made of a resin material, an organic resin sheet is used instead of the green sheet, and a through conductor is formed in the through hole by printing or plating a conductor paste, or a side conductor is formed by a thin film method or the like. May be formed. In order to expose the short-circuit ends of the electrode patterns of the resonator electrodes 3a to 3d on the side surfaces of the laminate, the short-circuit ends of the electrode patterns of the resonator electrodes 3a to 3d are located at the end of the green sheet (or organic resin sheet). Or after laminating green sheets (organic resin sheets) on which the electrode patterns of the resonator electrodes 3a to 3d are formed, the short-circuit ends of the electrode patterns of the resonator electrodes 3a to 3d are laminated so as to be exposed on the side surfaces. Just cut your body.

Specifically, a filter device as a band-pass filter having a center frequency of 3.9 GHz as used in the UWB low-band standard has the form shown in FIG. 4, for example, as the dielectric layer 1a. Glass ceramics having a relative dielectric constant of 9.4 are used, and the first ground electrode 2a, the second ground electrode 2b, the internal ground electrode 2c, the resonator electrodes 3a to 3d, the coupling electrode 4, the input terminal electrode 5, and the output terminal electrode 6 , By using Ag metallization for the shortened capacitor electrode 7, the capacitor electrode 8, and the through conductor. Glass ceramics having a relative dielectric constant of 9.4 include, for example, 50% by mass of crystallized glass mainly composed of PbO, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , ZnO and an alkaline earth metal oxide as glass components. And what consists of 50 mass% of alumina as a filler component may be used.

  At this time, the thickness of the dielectric layer 1a is 325 μm, 75 μm, 75 μm, 75 μm, and 350 μm in order from the top. The ground electrodes 2a and 2b have dimensions of 3.35 mm × 5.0 mm, and the internal ground electrode 2c has an outer dimension of 3.35 mm × 5.0 mm and an inner dimension (opening dimension) of 2.945 mm × 3.5 mm. In this opening, resonator electrodes 3a, 3b, 3c, and 3d with dimensions of 0.4 mm x 3.35 mm are arranged side by side at intervals of 0.155 mm, 0.135 mm, and 0.155 mm in order, and each short-circuited end is connected to the internal ground electrode 2c. Thus, the gap between each open end and the internal ground electrode 2c is 0.15 mm, and the gap between the resonator electrodes 3a and 3d and the internal ground electrode 2c is 0.45 mm. The internal ground electrode 2c and the ground electrodes 2a and 2b on the upper and lower surfaces of the laminate 1 are connected by through conductors having a diameter of 0.1 mm arranged on the outer periphery. The input terminal electrode 5 is 0.3 mm × 3.35 mm so as to overlap with the open end side of the first stage resonator electrode 3 a in a range of 0.3 mm × 3.35 mm in plan view, and an external input of 0.2 mm × 0.2 mm The terminal electrode 5a is connected with a through conductor having a diameter of 0.1 mm. Similarly, the output terminal electrode 6 of 0.3 mm × 3.35 mm is arranged so as to overlap 0.3 mm × 3.35 mm in plan view with the open end side of the final-stage resonator electrode 3 d, and has an external output of 0.2 mm × 0.2 mm. The terminal electrode 6a is connected with a through conductor having a diameter of 0.1 mm. The coupling electrode 4 has a crank shape in which two 0.1 mm × 2.0 mm facing portions are connected by a 1.545 mm × 0.1 mm connecting portion, and the two facing portions are the first-stage resonator electrode 3a and the final-stage resonator electrode, respectively. It is arranged so as to overlap with the 3d short-circuit end side in a range of 0.1 mm × 1.8 mm in plan view, and is connected to the internal ground electrode 2c by a through conductor having a diameter of 0.1 mm at the center of the portion overlapping with the internal ground electrode 2c. The shortened capacitance electrode 7 is a convex shape in which two rectangles of 0.2 mm × 0.4 mm and 0.4 mm × 0.6 mm are connected, and overlaps with the internal ground electrode 2c within a range of 0.4 mm × 0.6 mm, and the resonator electrodes 3a to 3d are opened. It arrange | positions so that it may overlap with the edge part in the range of 0.2 mm x 0.25 mm by planar view, and it connects by the through-conductor of diameter 0.1mm in the center of the overlapping part. Capacitance electrodes 8 and 8 have a distance of 0.175 mm from the short-circuit end side of first-stage resonator electrode 3a and last-stage resonator electrode 3d so as to face input terminal electrode 5 and output terminal electrode 6, respectively. The rectangular electrodes having a length of 0.15 mm and a width of 0.15 mm are arranged in the center of the width of the resonator electrodes 3a and 3d, and the first-stage resonator electrode 3a and the final-stage resonator electrode 3a are arranged from the capacitive electrodes 8 and 8, respectively. It is drawn out by a rectangular conductor having a length of 0.325 mm and a width of 0.1 mm toward the outside of the resonator electrode 3 d (opposite to the resonator electrodes 3 b and 3 c). In FIG. 2, the distance from the short-circuited ends of the first-stage resonator electrode 3a and the final-stage resonator electrode 3d is 0.2 mm, and the outside of the first-stage resonator electrode 3a and the final-stage resonator electrode 3d (resonator (Opposite side of electrodes 2b and 2c) Headed width is 0.35mm length pull in rectangular conductor of 0.1 mm, connecting between them the through conductors of diameter 0.1 mm.

  The filter characteristic of the filter device of the present invention in such an example is as shown by a solid characteristic curve in the diagram of FIG. Further, the filter characteristics obtained in the filter device (comparative example) not having the capacitor electrode 8 with respect to the filter properties of the filter device of the present invention in such an example are as shown by the broken characteristic curve in FIG. It will be a thing. In the diagram shown in the figure, the vertical axis represents insertion loss (unit: dB), and the horizontal axis represents frequency (unit: GHz).

  From the filter characteristics shown in FIG. 6, it can be seen that the filter characteristics of the filter device of the present invention have an attenuation characteristic with a large attenuation amount on the high frequency side than the pass band.

  From the above, the filter device of the present invention has the capacitive electrode 8 that electromagnetically couples the coupling electrode 4 and at least one of the input terminal electrode 5 and the output terminal electrode 6. 5 and at least one of the output terminal electrodes 6 are capacitively coupled through the capacitive electrode 8, so that electromagnetic field coupling is strengthened, so that the phase of the signal passing through the coupling electrode 4 can be changed. / 2 resonance can be reduced, and a filter device in which the jump of the attenuation characteristic is suppressed in a frequency band excluding a predetermined pass band can be obtained.

  The conventional filter device has a structure that does not have the shortened capacitance electrode 7 as compared with the comparative example. In such a conventional filter device, in order to have an attenuation pole at the same frequency as the filter device of the present invention (and the filter device of the comparative example), the resonator electrodes 3a to 3d must be lengthened. In addition to the increase in the size of the filter device, there is a jump in the attenuation characteristic on the higher frequency side than the attenuation pole, and the filter characteristic is not sufficiently attenuated in the attenuation band relative to the band used in the wireless LAN. End up.

DESCRIPTION OF SYMBOLS 1 ... Laminated body 1a ... Dielectric layer 2a ... 1st ground electrode 2b ... 2nd ground electrode 2c ... Internal ground electrode 3a, 3b, 3c, 3d ... Resonator Electrode 3a ... First stage resonator electrode 3d ... Last stage resonator electrode 4 ... Coupling electrode 5 ... Input terminal electrode 5a ... External input terminal electrode 6 ... Output terminal electrode 6a ..External output terminal electrode 7 ... shortened capacitor electrode 8 ... capacitor electrode 8a ... first capacitor electrode 8b ... second capacitor electrode

Claims (6)

A laminate in which a plurality of dielectric layers are laminated;
A first ground electrode and a second ground electrode arranged to face each other with the laminate interposed therebetween;
Three or more resonator electrodes that are aligned side by side in a plan view so as to be electromagnetically coupled to each other in the laminate, each having one end short-circuited and the other end open-ended,
The resonance is disposed on the second ground electrode side with the dielectric layer interposed between the resonator electrode and the resonator electrode in the stacked body, and one end of the resonator is opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode and electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode at the final stage,
The first-stage resonator electrode and the electromagnetic field are disposed on the first ground electrode side so as to face the first-stage resonator electrode with the dielectric layer interposed therebetween, in a shape along the first-stage resonator electrode. An input terminal electrode to be coupled;
The final-stage resonator electrode is arranged on the first ground electrode side so as to face the final-stage resonator electrode with the dielectric layer interposed therebetween in a shape along the final-stage resonator electrode. And an output terminal electrode to be electromagnetically coupled,
A capacitive electrode that electromagnetically couples the coupling electrode to at least one of the input terminal electrode and the output terminal electrode, the capacitive electrode facing the input terminal electrode with the dielectric layer in between The first ground electrode disposed on the first ground electrode side and connected to one end of the coupling electrode, and the first ground electrode so as to face the output terminal electrode through the dielectric layer And at least one of those connected to the other end of the coupling electrode. A laminate in which a plurality of dielectric layers are laminated;
A first ground electrode and a second ground electrode arranged to face each other with the laminate interposed therebetween;
Three or more resonator electrodes that are aligned side by side in a plan view so as to be electromagnetically coupled to each other in the laminate, each having one end short-circuited and the other end open-ended,
The resonance is disposed on the second ground electrode side with the dielectric layer interposed between the resonator electrode and the resonator electrode in the stacked body, and one end of the resonator is opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode and electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode at the final stage,
The first-stage resonator electrode and the electromagnetic field are disposed on the first ground electrode side so as to face the first-stage resonator electrode with the dielectric layer interposed therebetween, in a shape along the first-stage resonator electrode. An input terminal electrode to be coupled;
The final-stage resonator electrode is arranged on the first ground electrode side so as to face the final-stage resonator electrode with the dielectric layer interposed therebetween in a shape along the final-stage resonator electrode. And an output terminal electrode to be electromagnetically coupled,
A capacitive electrode that electromagnetically couples the coupling electrode to at least one of the input terminal electrode and the output terminal electrode, the capacitive electrode passing through one end of the coupling electrode and the dielectric layer Arranged on the second ground electrode side to face each other and connected to the input terminal electrode, and the other end of the coupling electrode to face the other through the dielectric layer 2. The filter device, wherein the filter device is at least one of those arranged on the ground electrode side and connected to the output terminal electrode. A laminate in which a plurality of dielectric layers are laminated;
A first ground electrode and a second ground electrode arranged to face each other with the laminate interposed therebetween;
Three or more resonator electrodes that are aligned side by side in a plan view so as to be electromagnetically coupled to each other in the laminate, each having one end short-circuited and the other end open-ended,
The resonance is disposed on the second ground electrode side with the dielectric layer interposed between the resonator electrode and the resonator electrode in the stacked body, and one end of the resonator is opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode and electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode at the final stage,
The first-stage resonator electrode and the electromagnetic field are disposed on the first ground electrode side so as to face the first-stage resonator electrode with the dielectric layer interposed therebetween, in a shape along the first-stage resonator electrode. An input terminal electrode to be coupled;
The final-stage resonator electrode is arranged on the first ground electrode side so as to face the final-stage resonator electrode with the dielectric layer interposed therebetween in a shape along the final-stage resonator electrode. And an output terminal electrode to be electromagnetically coupled,
A capacitive electrode that electromagnetically couples the coupling electrode and at least one of the input terminal electrode and the output terminal electrode, wherein the capacitive electrode is a first capacitor facing each other with the dielectric layer therebetween; An electrode and a second capacitor electrode, wherein the first capacitor electrode is connected to one end of the coupling electrode and the second capacitor electrode is connected to the input terminal electrode; and A filter device, wherein one capacitor electrode is connected to the other end of the coupling electrode, and the second capacitor electrode is at least one of those connected to the output terminal electrode. The filter device according to any one of claims 1 to 3, wherein an internal ground electrode is formed so as to surround the plurality of resonator electrodes when the resonator electrodes are viewed in plan. The dielectric layer is sandwiched between the second ground electrode and the resonator electrode so as to face the second ground electrode and electrically connected to the open ends of the plurality of resonator electrodes. 5. The filter device according to claim 1, further comprising a plurality of shortened capacitance electrodes. When the resonator electrode is viewed in plan, an internal ground electrode is formed so as to surround a plurality of the resonator electrodes, and a part of the shortened capacitor electrode is sandwiched between the internal ground electrode and the dielectric layer. 6. The filter device according to claim 5, wherein the filter device is disposed so as to face each other.

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