JP4986882B2 - Filter device - Google Patents

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. In addition, a filter device in which a plurality of dielectrics and electrodes are stacked is employed in response to a demand for miniaturization and thinning of wireless communication devices.

As a conventional filter device, as shown in an exploded perspective view in FIG. 11, a plurality of dielectric sheets 11a are laminated, bonded, and sintered and integrated into a dielectric chip 11, and a short-circuit end and an open end are provided. A plurality of resonator inner conductors 13 and inner insertion output electrodes 15b and 16b, which are arranged in an interdigital manner, are alternately embedded, and the resonator outer conductor 12a and external input / output electrodes are formed on the outer surface of the dielectric chip 11. In the strip line type multilayer dielectric filter provided with 15a and 16a, the inter-resonator conductors 13a and 13d are interdigital type in which the short-circuited end and the open end are alternated, and adjacent resonator inner conductors 13a A known example is one in which a short-circuit end connection pattern 17 that connects the resonator outer conductors 12a and 12a near the short-circuit end 13d is embedded (see, for example, Patent Document 1). According to this, by changing the position of the layer that forms the short-circuited end connection pattern 17 and the pattern shape such as the pattern width, an attenuation pole can be set at an arbitrary frequency near the passband and a steep attenuation characteristic can be obtained. It can be done.
JP 11-88009 A

  In recent years, UWB, which has been attracting attention as a new communication means, realizes large-capacity data transfer using a wide frequency band over 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. In Japan, avoiding the 5.15 GHz to 5.25 GHz used in the wireless LAN IEEE802.11.a, a low band using a band of about 3.4 GHz to 4.8 GHz, a band of about 6.3 GHz to 9.0 GHz, A standard divided into a high band using a band of about 7.25 GHz to 10.25 GHz has been proposed. For this reason, a high-band filter is required to have an attenuation characteristic in which a wide band of about 7.25 GHz to 10.25 GHz is used and an attenuation is sufficiently ensured in the stop band. In Europe, a high-band standard using a band of about 6.3 GHz to 9.0 GHz has been drafted.

  However, in the conventional filter device, there is a problem that if a pole that sharply attenuates to the higher frequency side than the pass band is formed, an attenuation characteristic with unnecessary jumping further to the higher frequency side than the attenuation pole is obtained. .

  The present invention has been devised in view of the above-mentioned problems, and its purpose is to be used for, for example, UWB, which has an excellent attenuation characteristic without unnecessary jumping at a higher frequency side than the passband. It is providing the filter apparatus which can be performed.

The filter device according to the present invention includes a stacked body in which a plurality of dielectric layers are stacked, a ground electrode disposed so as to face the stacked body, and a side-by-side so as to be electromagnetically coupled in the stacked body. A plurality of resonator electrodes, one end of which is a short-circuited end and the other end is an open end, and are formed in a layer different from the dielectric layer in which the resonator electrode is disposed in the stacked body. Input coupling having an electric signal input point where an electric signal is input from an external circuit to the open end side of the first-stage resonator electrode in a plan view while facing and electromagnetically coupling in a shape along the resonator electrode The electrode is formed in a layer different from the dielectric layer in which the resonator electrode is disposed in the stacked body, and is opposed to the electromagnetic field in a shape along the resonator electrode in the final stage, and in plan view. so And an output coupling electrode having an electrical signal output point electrical signal to an external circuit to the open end of the resonator electrodes of the last stage are output, together with the provided immediately above the end of the input coupling electrode, the input coupling An input terminal electrode electrically connected to the electrode; an output terminal electrode provided directly above the end of the output coupling electrode; and electrically connected to the output coupling electrode; and the input coupling in the stack. It is electrically connected to at least one of the electrode and the output coupling electrode, and is not directly connected to the input terminal electrode and the output terminal electrode, but is electromagnetically coupled to the electrode connected to the ground potential. And an auxiliary coupling electrode.

  The filter device according to the present invention further includes an internal ground electrode formed so as to surround the plurality of resonator electrodes in a plan view between the dielectric layers where the resonator electrodes are arranged. It is a feature.

  In the filter device of the present invention, the auxiliary coupling electrode connected to the input coupling electrode is connected to the first-stage resonator electrode and the output coupling electrode with the dielectric layer interposed therebetween in each of the above configurations. The auxiliary coupling electrode is disposed so as to be opposed to the final-stage resonator electrode across the dielectric layer so as to be electromagnetically coupled to each other.

  The filter device of the present invention is characterized in that, in each of the above-described configurations, the auxiliary coupling electrode is opposed to the internal ground electrode.

  The filter device according to the present invention may be configured such that, in each of the above configurations, one end faces the short-circuited end of the first-stage resonator electrode across the dielectric layer, and the other end sandwiches the dielectric layer. It has a coupling electrode that is disposed opposite to the short-circuited end of the resonator electrode and is electrically connected to the short-circuited end of the resonator electrode that is opposed to the one end and the other end of the resonator electrode. is there.

  In the filter device of the present invention, in each of the above configurations, the ground electrode is opposed to the ground electrode with the dielectric layer between the ground electrode and the resonator electrode, and the open ends of the plurality of resonator electrodes And a plurality of capacitive electrodes electrically connected to each other.

  Further, the filter device of the present invention is characterized in that, in the above configuration, a part of the capacitive electrode is disposed so as to be electromagnetically coupled to face the internal ground electrode across the dielectric layer. Is.

  In the filter device of the present invention, in each of the above-described configurations, the capacitor electrode connected to the first-stage resonator electrode across the dielectric layer is electromagnetically coupled to be connected to the input coupling electrode. The input coupling reinforcing electrode or the output coupling reinforcing electrode connected to the output coupling electrode by being electromagnetically coupled to the capacitive electrode connected to the resonator electrode at the final stage across the dielectric layer It is characterized by providing.

According to the filter device of the present invention, an electromagnetic signal is coupled to face each other in a shape along the first-stage resonator electrode, and an electric signal is input from an external circuit to the open end side of the first-stage resonator electrode in plan view. The input coupling electrode having an electrical signal input point is opposed to the electromagnetic coupling in a shape along the final-stage resonator electrode, and an electrical signal is sent to an external circuit on the open end side of the final-stage resonator electrode in plan view. Are provided with an output coupling electrode having an electrical signal output point from which the input coupling electrode and the first-stage resonator electrode are coupled, and the coupling between the output coupling electrode and the last-stage resonator electrode is a dielectric layer. Since it is coupled to the broadside via an interdigital type, the coupling by the magnetic field and the coupling by the electric field can be added to achieve a stronger electromagnetic coupling, which is realized by a filter using a conventional quarter wavelength resonator. OK It is possible to obtain a filter device having a flat and low-loss pass characteristic over the entire wide passband, in which the insertion loss does not increase greatly even in a wide passband far exceeding the range. it can. In addition, the input terminal electrode is provided directly above the end of the input coupling electrode, is electrically connected to the input coupling electrode, and is provided directly above the end of the output coupling electrode. The connected output terminal electrode is electrically connected to at least one of the input coupling electrode and the output coupling electrode, and is not directly connected to the input terminal electrode and the output terminal electrode. Since the auxiliary coupling electrode that opposes the electromagnetic field coupling is provided, the input coupling electrode and the output coupling are adjusted by adjusting the C coupling between the input coupling electrode and the output coupling electrode and the electrode connected to the ground potential by the auxiliary coupling electrode. Since the equivalent electrical length of the electrode can be adjusted, the attenuation pole of the λ / 2 resonance by the input coupling electrode or the output coupling electrode can be shifted to a desired frequency. By the shifted a lambda / 2 resonant attenuation pole may be a filter device having excellent damping properties to remove further unwanted jump occurs in the high-frequency side of the attenuation pole of the high-frequency side of the passband.

  According to the filter device of the present invention, when the internal ground electrode formed so as to surround the plurality of resonator electrodes in a plan view is provided between the dielectric layers where the resonator electrodes are arranged, the internal ground electrode resonates. By surrounding 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 in preventing adverse effects on other areas of the module substrate when the filter device of the present invention is formed in a partial area of the module substrate.

  Further, according to the filter device of the present invention, the auxiliary coupling electrode connected to the input coupling electrode has the first resonator electrode sandwiched between the dielectric layers, and the auxiliary coupling electrode connected to the output coupling electrode has the dielectric layer interposed therebetween. When arranged so as to be electromagnetically coupled to the resonator electrode at the final stage across the input, the C coupling between the input coupling electrode or the output coupling electrode and the resonator electrode constituting the resonator may be strengthened. Therefore, it is possible to provide a filter device that has a flatter pass characteristic over a wide passband with reduced reflection.

  Further, according to the filter device of the present invention, one end is opposed to the short-circuited end of the first-stage resonator electrode with the dielectric layer interposed therebetween, and the other end is short-circuited end of the final-stage resonator electrode with the dielectric layer interposed therebetween. The first-stage resonator electrode and the final-stage resonance are weakly coupled when the coupling electrode is disposed opposite to each other and electrically connected to the short-circuited ends of the resonator electrodes whose one end and the other end are opposed to each other. Since the coupling between the filter electrode and the filter electrode can be strengthened, an attenuation pole can be formed at a frequency closer to the filter pass band (lower or higher passband side), resulting in steeper attenuation characteristics. Can be provided.

  Further, according to the filter device of the present invention, when the auxiliary coupling electrode is arranged so as to face the internal ground electrode, the auxiliary coupling electrode can be arranged in the same layer as the input coupling electrode and the output coupling electrode. As a result, there is no need to form a through conductor that penetrates the dielectric layer in order to make electrical connection between the auxiliary coupling electrode, the input coupling electrode, and the output coupling electrode. An electrode can be formed, and a filter device with small variation in attenuation characteristics can be obtained.

  According to the filter device of the present invention, the ground electrode is opposed to the ground electrode with the dielectric layer interposed between the ground electrode and the resonator electrode, and electrically connected to the open ends of the plurality of resonator electrodes. When there are a plurality of capacitive electrodes, the distance between the capacitive electrode and the ground electrode is shorter than the distance between the resonator electrode and the ground electrode, which increases the coupling between the resonator electrode and the ground electrode. Therefore, the length of each resonator electrode can be shortened, and a smaller filter device can be provided.

  Further, according to the filter device of the present invention, when a part of the capacitance electrode is disposed so as to be electromagnetically coupled to the internal ground electrode across the dielectric layer, the internal ground electrode is the resonator electrode. It is formed between the same dielectric layers as the formed dielectric layers, and the wiring lengths of through conductors etc. that make electrical connection between the resonator electrode and the capacitive electrode when the capacitive electrode is opposed so as to be coupled with the internal ground electrode Therefore, it is possible to reduce unnecessary inductance due to this wiring, and it is possible to provide a filter device having excellent filter characteristics free from secondary resonance due to the wiring inductance between the electrodes.

  In addition, according to the filter device of the present invention, the input coupling reinforcing electrode connected to the input coupling electrode is electromagnetically coupled opposite to the capacitor electrode connected to the first-stage resonator electrode across the dielectric layer, and When the dielectric layer is sandwiched between the capacitive electrode connected to the final-stage resonator electrode and electromagnetically coupled opposite to the capacitive electrode and connected to the output-coupled electrode, it is connected to the first-stage resonator electrode. The electromagnetic coupling between the capacitive electrode formed and the input coupling reinforcing electrode connected to the input coupling electrode is added to the electromagnetic coupling between the first-stage resonator electrode and the input coupling electrode. The electromagnetic coupling between the capacitive electrode connected to the resonator electrode and the output coupling reinforcing electrode connected to the output coupling electrode is added to the electromagnetic coupling between the final-stage resonator electrode and the output coupling electrode. Between the input coupling electrode and the first-stage resonator electrode. EM coupling, and the coupling between the output coupling electrode and the final-stage resonator electrode is further strengthened, and the increase in insertion loss is further reduced even with a very wide pass bandwidth. It is possible to obtain a filter device that has a flatter and lower-loss pass characteristic over the entire band. This effect is that when the capacitor electrode is formed and the resonator electrode is shortened, the area where the input coupling electrode and the first stage resonator electrode overlap, and the area where the output coupling electrode and the last stage resonator electrode overlap, are reduced. Since the electromagnetic coupling between them becomes small, it is particularly useful in such a case, and a small and high-performance filter device can be obtained.

  Examples of embodiments of the filter device of the present invention will be described in detail below. 1 to 5, 7, and 8 are exploded perspective views showing examples of embodiments of the filter device of the present invention. 6 is a cross-sectional view showing a part of a cross section taken along line AA of the filter device of FIG. 1-8, 1a is a dielectric layer, 1 is a laminate formed by laminating a dielectric layer 1a, 2a is a ground electrode, 2b is an internal ground electrode, 3a to 3d are resonator electrodes, and 3a is a first stage resonance. 3c is the final stage resonator electrode, 4 is the input coupling electrode, 4a is the input terminal electrode, 4b is the input coupling reinforcing electrode, 5 is the output coupling electrode, 5a is the output terminal electrode, 5b is the output coupling reinforcing electrode, 6 is an auxiliary coupling electrode, 7 is a coupling electrode, and 8 is a capacitive electrode. The broken line indicates that there is a through conductor that penetrates the dielectric layer 1a for electrically connecting the conductor layers (for example, the resonator 3a and the input coupling electrode 4) located above and below the dielectric layer 1a. .

  In the example shown in FIGS. 1 to 3, the filter device of the present invention is such that an electric signal input from an external circuit to an input terminal electrode 4 a formed on the outer surface of the laminate 1 is input from an electric signal input point to an input coupling electrode. 4 is transmitted to the first-stage resonator electrode 3a electromagnetically coupled to the input coupling electrode 4 and further to the final-stage resonator electrode 3c by electromagnetic coupling, and is electromagnetically coupled to the final-stage resonator electrode 3c. The output coupling electrode 5 is transmitted to the output terminal electrode 5a to function as a filter.

  The filter device of the present invention includes a laminate 1 in which a plurality of dielectric layers 1 a are laminated, ground electrodes 2 a and 2 a arranged so as to face each other with the laminate 1 interposed therebetween, and electromagnetic waves in the laminate 1. Dielectrics in which a plurality of resonator electrodes 3a to 3c are arranged side by side so as to be coupled to each other, one end is a short-circuited end and the other end is an open end, and the resonator electrodes 3a to 3c are disposed in the laminate 1 Formed between layers different from between the body layers 1a and 1a, and opposingly electromagnetically coupled in a shape along the first-stage resonator electrode 3a, and an external circuit on the open end side of the first-stage resonator electrode 3a in plan view The input coupling electrode 4 having an electric signal input point to which an electric signal from the input signal is input and the dielectric layers 1a and 1a in which the resonator electrodes 3a to 3c are arranged in the laminate are formed between different layers, and the final stage Along the resonator electrode 3c of An output coupling electrode 5 having an electric signal output point at which an electric signal is output to an external circuit on the open end side of the final-stage resonator electrode 3c in a plan view, and the laminated body 1 And an auxiliary coupling electrode 6 that is electrically connected to at least one of the input coupling electrode 4 and the output coupling electrode 5 and electromagnetically couples to the electrode connected to the ground potential. Is.

  According to the filter device of the present invention, because of such a configuration, the coupling between the input coupling electrode 4 and the first-stage resonator electrode 3a and the coupling between the output coupling electrode 5 and the last-stage resonator electrode 3c are as follows. Since it is coupled to the broad side via the dielectric layer 1a in an interdigital manner, the coupling by the magnetic field and the coupling by the electric field can be added to achieve stronger electromagnetic coupling, and a conventional quarter wavelength resonator is used. A filter that has a flat and low-loss pass characteristic over the entire wide passband, with no significant increase in insertion loss, even in a wide passband that far exceeds the range that could be achieved with a special filter. A device can be obtained. Further, when the attenuation pole of λ / 2 resonance by the input coupling electrode 4 or the output coupling electrode 5 is located on the higher frequency side than the frequency at which unnecessary jump occurs, the auxiliary coupling electrode 6 causes the input coupling electrode 4 and the output coupling electrode 5 to be Since the equivalent electrical length of the input coupling electrode 4 and the output coupling electrode 5 can be increased by increasing the amount of C coupling between the electrode and the electrode connected to the ground potential, the input coupling electrode 4 and the output coupling electrode 5 can shift the attenuation pole of λ / 2 resonance to the low frequency side. The equivalent electrical length is adjusted by adjusting the amount of C coupling, and the λ / 2 resonance attenuation pole by the input coupling electrode 4 and the output coupling electrode 5 is shifted to the vicinity of the frequency at which the jump occurs. Thus, it is possible to obtain a filter device having an excellent attenuation characteristic from which unnecessary jumping is removed.

  As shown in the example shown in FIG. 3, the filter device of the present invention has a plurality of resonator electrodes 3 a to 3 c in a plan view between the dielectric layers 1 a and 1 a where the resonator electrodes 3 a to 3 c are arranged. It is preferable to include an internal ground electrode 2b formed so as to surround. As described above, the internal ground electrode 2b surrounds the resonator electrodes 3a to 3c, thereby reducing leakage of electromagnetic waves generated from the resonator electrodes 3a to 3c to the periphery. This effect is particularly useful in preventing adverse effects on other areas of the module substrate when the filter device of the present invention is formed in a partial area of the module substrate.

  Further, in the filter device of the present invention, as in the example shown in FIG. 2, in each of the above configurations, the auxiliary coupling electrode 6 connected to the input coupling electrode 4 is connected to the first-stage resonator electrode 3a with the dielectric layer 1a interposed therebetween. The auxiliary coupling electrode 6 connected to the output coupling electrode 5 is preferably disposed so as to be electromagnetically coupled to the final-stage resonator electrode 3c across the dielectric layer 1a. In such a configuration, the resonator electrode 3a, 3c that forms a resonator with the input coupling electrode 4 or the output coupling electrode 5 in addition to having an excellent attenuation characteristic that eliminates unnecessary jumping at a desired frequency. Therefore, it is possible to provide a filter device having a flatter pass characteristic over the entire wide passband with reduced reflection characteristics.

  In the filter device of the present invention, when the auxiliary coupling electrode 6 faces the internal ground electrode 2b in each of the above configurations, the auxiliary coupling electrode 6 may be disposed in the same layer as the input coupling electrode and the output coupling electrode. Since it is possible, it is not necessary to form a through conductor penetrating the dielectric layer 1a in order to electrically connect the auxiliary coupling electrode 6, the input coupling electrode 4 and the output coupling electrode 5, and it is easier by printing or the like. Thus, the auxiliary coupling electrode 6 can be formed with high positional accuracy, and a filter device with little variation in attenuation characteristics can be obtained.

  Further, as in the examples shown in FIGS. 4 and 5, the filter device of the present invention has one end opposed to the short-circuited end of the first-stage resonator electrode 3a with the dielectric layer 1a interposed therebetween, and the other end in each configuration described above. Is disposed opposite to the short-circuited end of the resonator electrode 3c in the final stage with the dielectric layer 1a interposed therebetween, and electrically connected to the short-circuited ends of the resonator electrodes 3a and 3c with one end and the other end facing each other. It is preferable to have a coupled electrode 7 connected. In such a configuration, since the coupling between the first-stage resonator electrode 3a and the last-stage resonator electrode 3c, which are weakly coupled, can be strengthened, the frequency closer to the passband of the filter (the passband An attenuation pole can be formed on the low frequency side or the high frequency side, and a filter device having a steeper attenuation characteristic can be provided.

  Further, as in the example shown in FIGS. 4 and 5, the filter device of the present invention includes a ground electrode 2a sandwiching a dielectric layer 1a between the ground electrode 2a and the resonator electrodes 3a, 3b, 3c, 3d. It is preferable to have a plurality of capacitive electrodes 8 that face each other and are electrically connected to the open ends of the plurality of resonator electrodes 3a, 3b, 3c, 3d, respectively. In such a configuration, the distance between the capacitive electrode 8 and the ground electrode 2a is shorter than the distance between the resonator electrodes 3a, 3b, 3c, 3d, and 3e and the ground electrode 2a, whereby the resonator electrodes 3a, 3b, Since the coupling between 3c, 3d, 3e and the ground electrode 2a becomes stronger and the C coupling between the resonator electrodes 3a, 3b, 3c, 3d, 3e and the ground electrode 2a is strengthened, each resonator electrode 3a , 3b, 3c, 3d, 3e can be shortened, and a smaller filter device can be provided.

  Further, in the filter device of the present invention, as in the example shown in FIGS. 5 and 6, in the above configuration, a part of the capacitive electrode 8 is opposed to the internal ground electrode 2b with the dielectric layer 1a interposed therebetween, and is electromagnetically coupled. It is preferable to arrange so as to. As in the example shown in FIG. 5, the internal ground electrode 2b is normally formed between the dielectric layers 1a and 1a that are the same as the dielectric layers 1a and 1a on which the resonator electrodes 3a to 3d are formed. When the electrode 8 is opposed so as to be coupled to the internal ground electrode 2b, it is compared with the case where the capacitor electrode 8 is opposed so as to be coupled only to the ground electrode 2a (in the case of the capacitor electrode 8a shown by the broken line in FIG. 6). As a result, the wiring length of a through conductor or the like for electrical connection between the resonator electrodes 3a to 3d and the capacitor electrode 8 can be shortened, so that unnecessary inductance due to this wiring can be reduced, and the wiring between the electrodes can be reduced. A filter device having excellent filter characteristics free from secondary resonance due to inductance can be obtained. In addition, even when the wiring length of the through conductor or the like for electrical connection between the resonator electrodes 3a to 3d and the capacitive electrode 8 is the same, electrostatic capacitance is added between the capacitive electrode 8 and the internal ground electrode 2b. Therefore, 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. The filter device can be obtained.

  Further, as in the examples shown in FIGS. 7 and 8, the filter device of the present invention is opposed to the capacitor electrode 8 connected to the first-stage resonator electrode 3a with the dielectric layer 1a interposed therebetween in each of the above configurations. The electromagnetic coupling is performed so as to oppose the input coupling reinforcing electrode 4b connected to the input coupling electrode 4 or the capacitive electrode 8 connected to the resonator electrode 3c at the final stage across the dielectric layer 1a. The output coupling reinforcing electrode 5b connected to the output coupling electrode 5 is preferably provided. The electromagnetic coupling between the capacitive electrode 8 connected to the first stage resonator electrode 3a and the input coupling reinforcing electrode 4b connected to the input coupling electrode 4 is between the first stage resonator electrode 3a and the input coupling electrode 4. Similarly, the electromagnetic field coupling between the capacitive electrode 8 connected to the resonator electrode 3c at the final stage and the output coupling reinforcing electrode 5b connected to the output coupling electrode 5 is performed in the final stage. Is added to the electromagnetic field coupling between the resonator electrode 3c and the output coupling electrode 5, so that the electromagnetic coupling between the input coupling electrode 4 and the first stage resonator electrode 3a, and the output coupling electrode 5 and the last stage The electromagnetic coupling with the resonator electrode 3c is further strengthened, and even with a very wide passband width, the increase in insertion loss is further reduced, flatter and lower across the wide passband. A filter device with lossy pass characteristics can be obtained. . Further, the resonator electrode is further increased by the electromagnetic field coupling between the input coupling electrode 4 and the first stage resonator electrode 3a and the electromagnetic field coupling between the output coupling electrode 5 and the last stage resonator electrode 3c. Since 3a-3d can also be shortened, a small filter apparatus can be obtained.

  The ground electrodes 2a and 2a are arranged on almost the entire surface excluding the periphery of the input terminal electrode 4a and the output terminal electrode 5a on the upper and lower surfaces of the laminate 1 in which the dielectric layers 1a are laminated, and are connected to the ground potential. ing.

  The resonator electrodes 3a, 3b, 3c, 3d are arranged side by side between one layer of the multilayer body 1 and are electromagnetically coupled (edge coupled) to each other. It is preferable that the distance between the adjacent resonator electrodes 3a, 3b, 3c, 3d, and 3e is small because strong coupling can be obtained and the pass band can be easily widened. For example, the thickness is set to about 0.05 to 0.5 mm in order to satisfactorily form at regular intervals. The resonator electrodes 3a, 3b, 3c, and 3d are preferably formed in an elongated strip shape so that they are arranged side by side and are electromagnetically coupled to each other. The resonator electrodes 3a to 3e may be aligned side by side in a plan view so as to be electromagnetically coupled to each other in the multilayer body 1. Usually, as in the example shown in FIG. 1, for example, the four resonator electrodes 3a to 3d are arranged between one dielectric layer 1a and 1a, but the resonator electrodes 3a and 3c are arranged in one dielectric layer 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. 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.

  When the resonator electrodes 3a to 3d are arranged in an interdigital manner as in the examples shown in FIGS. 1 to 4, 7 and 8, the coupling between the resonator electrodes 3a to 3d is coupled by a magnetic field and by an electric field. Are added to each other so that stronger coupling occurs between the resonator electrodes 3a to 3d, and the frequency interval between the resonance frequencies in the respective resonance modes is used by using a conventional quarter wavelength resonator. The filter device can be adjusted beyond the band that can be realized by the filter, and a filter device having a wide passband can be obtained. 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.

  In addition, when the resonator electrodes 3a to 3d are arranged in the comb line type as in the example shown in FIG. 5, the coupling between the resonator electrodes 3a to 3d is weaker than that of the interdigital type. Since narrow and steep characteristics can be obtained and the pattern width of each of the resonator electrodes 3a to 3d can be reduced, the size can be reduced. Therefore, the filter device is suitable for relatively small wireless devices such as mobile phones and wireless LANs.

The ground electrodes 2a and 2a are arranged on almost the entire surface excluding the periphery of the input terminal electrode 4a and the output terminal electrode 5a on the upper and lower surfaces of the laminate 1 in which the dielectric layers 1a are laminated, and are connected to the ground potential. ing.

  The resonator electrodes 3a, 3b, 3c, and 3d form a stripline resonator together with the upper and lower ground electrodes 2a and 2a, and the short-circuit ends are connected to the upper and lower ground electrodes 2a and 2a and connected to the ground potential. This functions as a quarter wavelength resonator. The connection between the resonator electrodes 3a, 3b, 3c, 3d, and 3e and the upper and lower ground electrodes 2a and 2a is performed between the resonator electrodes 3a and 3a formed between the layers where the resonator electrodes 3a to 3d are formed as shown in FIG. A conductor layer for connecting the short-circuited ends of 3b, 3c, and 3d is provided, and this conductor layer is connected to a through conductor (not shown), or this conductor layer is extended to the end of the dielectric layer 1a. The connection may be made by an end face conductor (not shown) formed on the end face of the dielectric layer 1a (side face of the multilayer body 1). When the conductor layer for connecting the short-circuit ends of the resonator electrodes 3a, 3b, 3c, and 3d is not provided, the resonator electrodes 3a, 3b, 3c, and 3d are connected to the ground electrodes 2a and 2a through the through conductors. Alternatively, the short-circuit ends of the resonator electrodes 3a to 3d may be extended to the end portion of the dielectric layer 1a, and the ground electrodes 2a and 2a may be formed by the end surface conductor formed on the end surface of the dielectric layer 1a (side surface of the multilayer body 1). You may connect to. 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-circuit ends of the resonator electrodes 3a, 3b, 3c, 3d is provided as in the example shown in FIG. 1, the short-circuit ends of the resonator electrodes 3a, 3b, 3c, 3d are connected to the ground electrode. Since it becomes easy to connect to 2a * 2a, it is preferable.

  The internal ground electrode 2b includes a conductor layer for connecting the short-circuit ends of the resonator electrodes 3a, 3b, 3c, and 3d and a conductor layer formed on both sides of the array of the resonator electrodes 3a, 3b, 3c, and 3d. It is a circular thing consisting of. If the connection between the ground electrode 2a and the resonator electrodes 3a, 3b, 3c, 3d is also performed at the portions of the internal ground electrode 2b located on both sides of the array of the resonator electrodes 3a, 3b, 3c, 3d, the resonator electrode 3a Leakage of electromagnetic waves generated from ˜3d to the surroundings can be reduced more effectively.

  In the example shown in FIGS. 1 to 3, 7, and 8, three resonator electrodes 3 (3 a to 3 c) are provided. For example, as shown in FIGS. 4 and 5, four resonator electrodes 3 are provided. The electrodes 3 (3a to 3d) may be provided, or may be provided in a larger number as long as the loss does not increase. For UWB low-band applications, four are preferred from the balance of loss and attenuation characteristics.

  Since the input coupling electrode 4 and the output coupling electrode 5 are electromagnetically coupled to the first-stage resonator electrode 3a and the final-stage resonator electrode 3c, respectively, the first-stage resonator electrode 3a and the final-stage resonator electrode 3 respectively. It is the shape along 3c. As described above, since the resonator electrodes 3a to 3c are preferably formed in an elongated band shape, the input coupling electrode 4 and the output coupling electrode 5 are also preferably formed in an elongated band shape.

  In the example shown in FIGS. 1 to 5, the input coupling electrode 4 and the output coupling electrode 5 are both the same dielectric layers 1a and 1a on the upper side of the resonator electrodes 3a to 3d with the dielectric layer 1a interposed therebetween. However, as in the example shown in FIGS. 7 and 8, the resonator layers 3a to 3e may be disposed between the upper and lower dielectric layers 1a and 1a with the dielectric layer 1a interposed therebetween. Good.

  The input coupling electrode 4 and the output coupling electrode 5 are connected to the input terminal electrode 4a and the output terminal electrode 5a formed on the outer surface of the multilayer body 1, respectively. In the example shown in FIGS. 1 to 8, the input terminal electrode 4 a and the output terminal electrode 5 a formed on the upper surface and the lower surface of the multilayer body 1 are connected by a through conductor, but the end surface conductor formed on the side surface of the multilayer body 1. You may connect by. Further, the input terminal electrode 4 a and the output terminal electrode 5 a formed on the side surface of the multilayer body 1 may be connected by a conductor layer drawn from the input coupling electrode 4 and the output coupling electrode 5. In order to suppress the generation of unnecessary stray capacitance, it is preferable to connect the input terminal electrode 4a and the output terminal electrode 5a formed on the upper and lower surfaces of the multilayer body 1 with through conductors.

  As in the example shown in FIG. 7, the input coupling reinforcing electrode 4b and the output coupling reinforcing electrode 5b are different from the dielectric layers 1a and 1a in which the input coupling electrode 4 and the output coupling electrode 5 are formed. It may be formed between the dielectric layers 1a and 1a that are formed between the dielectric layers 1a and 1a on which the input coupling electrode 4 and the output coupling electrode 5 are formed, as in the example shown in FIG. May be.

  For example, as in the example shown in FIG. 7, the same dielectric between the dielectric layers 1a and 1a in which the input coupling electrode 4 and the output coupling electrode 5 are formed so that the capacitive electrode 8 is mainly coupled to the internal ground electrode 2b. When the capacitive electrode 8 is formed between the body layers 1a and 1a, the input coupling reinforcing electrode 4b and the output coupling reinforcing electrode 5b may be formed between the capacitive electrode 8 and the ground electrodes 2a and 2a. In this example, the input coupling electrode 4 and the input terminal electrode 4a are connected via the input coupling reinforcing electrode 4b, and the input coupling reinforcing electrode 4b is connected to the electric signal input point of the input coupling electrode 4. It will be a point. The output coupling electrode 5 and the output terminal electrode 5a are connected via the output coupling electrode 5. The electrical signal output point of the output coupling electrode 5 is a point to which the output coupling reinforcing electrode 5b is connected. .

  The input coupling reinforcing electrode 4b is formed such that the internal ground electrode 2b is not formed or the capacitive electrode 8 is mainly coupled to the ground electrode 2a even if the internal ground electrode 2b is formed as in the example shown in FIG. When the capacitive electrode 8 is formed between the dielectric layers 1a and 1a between the output coupling reinforcing electrode 5b and the ground electrodes 2a and 2a, the open end of the first-stage resonator electrode 3a of the input coupling electrode 4 The input coupling reinforcing electrode 4b may be disposed on the side and connected to the input coupling electrode 4 with a connection conductor layer. For example, as shown in FIG. 8, the connection conductor layer is configured not to be short-circuited with the through conductor connecting the capacitor electrode 8 and the first-stage resonator electrode 3a. The output coupling reinforcing electrode 5b may be connected in the same manner, and the shape of the connecting conductor layer may be a shape like the connecting conductor layer of the output coupling reinforcing electrode 5b as shown in FIG.

Input coupling reinforcing electrode 4b and the output coupling reinforcing electrode 5b is a similar figure with a capacitor electrode 8, 8 facing, by the small round, while bound to the capacitance electrodes 8, 8, Ya ground electrode 2a by input coupling reinforcing electrodes 4b and output coupling reinforcing electrodes 5b between the internal ground electrode 2b and the capacitance electrodes 8, 8 are disposed, the capacitance electrodes 8, 8 ground electrodes 2a and internal ground electrode 2b It is possible to suppress a significant decrease in the electromagnetic field coupling.

When the input coupling reinforcing electrode 4b and the output coupling reinforcing electrode 5b are arranged between the ground electrode 2a and the capacitive electrodes 8 and 8 as in the example shown in FIG. 7, the input coupling reinforcing electrode 4b and the capacitive electrode The electromagnetic field coupling between the input coupling reinforcing electrode 4b and the output coupling reinforcing electrode 5b and the ground electrodes 2a and 2a is strengthened. In order to weaken relatively, the thickness between the input coupling reinforcing electrode 4b and the capacitive electrode 8 is larger than the thickness of the dielectric layer 1a between the input coupling reinforcing electrode 4b and the input coupling reinforcing electrode 4b and the ground electrodes 2a and 2a. It is preferable to reduce the thickness of the dielectric layer 1a and the dielectric layer 1a between the input coupling reinforcing electrode 4b and the capacitive electrode 8. In addition, since the electromagnetic coupling between the ground electrodes 2a and 2a and the capacitive electrode 8 is weakened, the dielectric layers 1a and 1a between them are also thinned to strengthen the electromagnetic coupling between the capacitive electrode 8 and the internal ground electrode 2b. Thus, it is preferable that this electromagnetic field coupling is dominant.

  The auxiliary coupling electrode 6 is electromagnetically coupled opposite to the electrode connected to the ground potential. The electrodes connected to the ground potential are the ground electrode 2a, the internal ground electrode 2b, and the resonator electrodes 3a to 3d. That is.

  The auxiliary coupling electrode 6 only needs to be electrically connected to at least one of the input coupling electrode 4 and the output coupling electrode 5. However, as in the examples shown in FIGS. It is preferable to be connected to both of the coupling electrodes 5. Since the attenuation pole shifted to a desired frequency by the auxiliary coupling electrode 6 is an attenuation pole of λ / 2 resonance by the input coupling electrode 4 or the output coupling electrode 5, the auxiliary coupling electrode 6 is changed to the input coupling electrode 4 and the output coupling electrode. By connecting to both of them, the large attenuation pole formed by both the input coupling electrode 4 and the output coupling electrode 5 can be shifted, and it is possible to remove a large jump. Further, when the jump is small, it is possible to remove the jump even if the shift amount is small, so that the degree of freedom in design increases.

  When the amount of C coupling between the auxiliary coupling electrode 6 and the electrode connected to the ground potential increases, the frequency at which the attenuation pole is generated by the input coupling electrode 4 or the output coupling electrode 5 is shifted to a lower frequency side. The amount of the C bond is proportional to the area where the auxiliary coupling electrode 6 and the electrode connected to the ground potential overlap each other, and the distance (dielectric layer 1a) between the auxiliary coupling electrode 6 and the electrode connected to the ground potential. Therefore, it can be adjusted by these.

  Even if the area where the auxiliary coupling electrode 6 and the electrode connected to the ground potential overlap each other and the distance between the auxiliary coupling electrode 6 and the electrode connected to the ground potential is constant, the auxiliary coupling electrode 6 and the input coupling electrode 4 and the output coupling electrode 5 are placed on the open end side of the input coupling electrode 4 and the output coupling electrode 5, the electric lengths of the input coupling electrode 4 and the output coupling electrode 5 become longer, so that attenuation occurs. The amount of pole shift increases. At this time, if the connection point between the input coupling electrode 4 and the output coupling electrode of the auxiliary coupling electrode 6 is at the end of the auxiliary coupling electrode 6 as in the example shown in FIGS. can do.

  When the auxiliary coupling electrode 6 faces the resonator electrodes 3a and 3c, the auxiliary coupling electrode 6 is disposed between the input coupling electrode 4 and the output coupling electrode 5 and the resonator electrodes 3a and 3c. The C coupling between the input coupling electrode 4 and the output coupling electrode 5 and the resonator electrodes 3a and 3c is reduced by the area. Therefore, in order to further increase the shift amount, the input coupling electrode 4 and the input coupling electrode 4 and the output coupling electrode 5 are reduced so that the overlap between the auxiliary coupling electrode 6 and the input coupling electrode 4 and the output coupling electrode 5 is reduced as in the example shown in FIG. The output coupling electrode 5 may be connected to the auxiliary coupling electrode 6 at the open end, and the auxiliary coupling electrode 6 may extend in a direction extending from the open end.

  Further, when the auxiliary coupling electrode 6 faces the resonator electrodes 3a and 3c, as in the example shown in FIG. 4, when the auxiliary coupling electrode 6 faces the open end side of the resonator electrodes 3a and 3c, Since the open-field side of the resonator electrodes 3a and 3c has a stronger electric field, the C-coupling between the resonator electrodes 3a and 3c and the auxiliary coupling electrode 6 becomes stronger, and the effect of reducing reflection becomes greater as a filter characteristic. preferable.

  Depending on the difference between the frequency at which the jump occurs and the frequency at which the attenuation pole of λ / 2 resonance is generated by the input coupling electrode 4 or the output coupling electrode 5, and in consideration of the reflection characteristics, the auxiliary coupling electrode as described above The arrangement and dimensions of 6 may be adjusted.

  The coupling electrode 7 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 3d 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 2a deviates. The characteristic changes, and the design of the attenuation characteristic by adding the coupling electrode 7 becomes complicated. Further, if 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 3c in the coupling electrode 7 is large, the coupling electrode 7 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 3c faces the second-stage and third-stage resonator electrodes 3b and 3d therebetween. In order to reduce the area and 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-stage and third-stage resonator electrodes 3b and 3c. Further, in order to reduce the coupling by increasing the distance to the part facing the first-stage resonator electrode 3a and the last-stage resonator electrode 3c, this orthogonal part 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 3c by a through conductor.

  Depending on the number of dielectric layers 1a between the coupling electrode 7 and the resonator electrodes 3a and 3d, the distance between the coupling electrode 7 and the resonator electrodes 3a and 3c can be changed, or the pattern width and length of the coupling electrode 7 can be changed. The electromagnetic field between the coupling electrode 7 and the resonator electrodes 3a and 3c is changed by changing the area where the coupling electrode 7 and the resonator electrodes 3a and 3c 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 3c, and the resonator electrodes 3b and 3d other than the first-stage resonator electrode 3a and the final-stage resonator electrode 3d and The portion of the coupling electrode 7 that faces the first-stage resonator electrode 3a and the portion that faces the last-stage resonator electrode 3c have the shape of the resonator electrodes 3a and 3c. It is good to make it the shape which has a width | variety smaller than resonator electrode 3a * 3c with the strip | belt shape along.

The capacitive electrode 8 and the resonator electrodes 3a to 3d are electrically connected by through conductors, and it is preferable that their arrangement be as small as possible in plan view. When the capacitive electrode 8 and the resonator electrodes 3a to 3d overlap in plan view, the coupling between the resonator electrodes 3a to 3d and the ground electrode 2a is reduced by the overlapped area, and for example, the first-stage resonator When the capacitive electrode 8 connected to the electrode 3a and the other resonator electrodes 3b to 3d overlap in plan view, the coupling amount between the first-stage resonator electrode 3a and the other resonator electrodes 3b to 3d changes. It is. Therefore, as in the example shown in FIGS. 4 and 5, the capacitive electrode 8 has an elongated shape such as a rectangle or an ellipse, and the open ends of the resonator electrodes 3 a to 3 d and one end of the capacitive electrode 8 And the other end of the capacitive electrode 8 may be oriented in the direction of extending the open ends of the resonator electrodes 3a to 3d. Also, as in the example shown in FIGS. 7 and 8, small width of the portion overlapping the resonator electrode 3a~3c in a plan view of the capacitor electrode 8, the width of the portion overlapping the ground electrode 2 a and the internal grounding electrode 2 b Is larger, for example, a convex shape (T-shape), which is more preferable because the above-described problems do not occur and even the short capacitive electrode 8 can easily be coupled to the ground electrode 2a and the internal ground electrode 2b.

  In the example shown in FIG. 5, the capacitor electrode 8 is provided one above the resonator electrodes 3 a to 3 d with the dielectric layer 1 a interposed therebetween, but below the resonator electrodes 3 a to 3 e. One may be provided, or one may be provided above or below the resonator electrodes 3a to 3e as in the examples shown in FIGS. 7 and 8, or as shown in FIG. As an example, each of the plurality of resonator electrodes 3a to 3d may be provided on both the upper side and the lower side. When the capacitive electrode 8 has the above-described convex shape (T-shape), as in the example shown in FIGS. 7 and 8, the resonator electrode 3 a to 3 c are positioned above and below the dielectric layer 1 a. It is preferable to separately arrange the capacitive electrode 8 because the width of the portion overlapping the ground electrode 2a and the internal ground electrode 2b can be increased.

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 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, and organic resin material such as polyimide are 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.

  Ground electrode 2a, internal ground electrode 2b, resonator electrodes 3a to 3d, input coupling electrode 4, input terminal electrode 4a, input coupling reinforcing electrode 4b, output coupling electrode 5, output terminal electrode 5a, output coupling reinforcing electrode 5b, auxiliary coupling When the dielectric layer 1a is made of a ceramic material, the electrode 6, the coupling electrode 7 and the capacitor electrode 8 are formed of a metallized layer mainly composed of a metal such as W, Mo, Mo—Mn, Au, Ag, or Cu. The 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. For example, Cu layer, Cr—Cu alloy layer, Cr—Cu alloy layer with Ni plating layer and Au plating layer deposited, TaN layer with Ni—Cr alloy layer and 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, ground electrode 2a, internal ground electrode 2b, resonator electrodes 3a-3d, input coupling electrode 4, input terminal electrode 4a, input coupling reinforcement electrode 4b, output coupling electrode 5, output terminal electrode 5a, output coupling reinforcement Formation of the electrode 5b, the auxiliary coupling electrode 6, the coupling electrode 7, and the capacitor electrode 8 may be performed by a conventionally known method. 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. Apply and ground electrode 2a, internal ground electrode 2b, resonator electrodes 3a-3d, input coupling electrode 4, input terminal electrode 4a, input coupling reinforcing electrode 4b, output coupling electrode 5, output terminal electrode 5a, output coupling reinforcing electrode 5b The electrode patterns of the auxiliary coupling electrode 6, the coupling electrode 7 and the capacitive electrode 8 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, the ground electrode 2a, the internal ground electrode 2b, the resonator electrodes 3a to 3d, the input coupling electrode 4, the input terminal electrode 4a, and the input coupling reinforcement are formed on the organic resin sheet. The Cu foil processed into the electrode pattern shape of the electrode 4b, the output coupling electrode 5, the output terminal electrode 5a, the output coupling reinforcing electrode 5b, the auxiliary coupling electrode 6, the coupling electrode 7 and the capacitive electrode 8 is transferred, and the Cu foil is transferred. The organic resin sheets are laminated and bonded with an adhesive.

  The connection conductor connecting the ground electrode 2a and the short-circuit ends of the resonator electrodes 3a to 3d is a through conductor formed in the dielectric layer 1a located between them or an end face formed on the end face of the dielectric layer 1a. By forming in the form of a 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.

  When the dielectric layer 1a is made of ceramics such as glass ceramics, the through conductors and the side conductors serving as the connection conductors are, for example, the ground electrode 2a, the internal ground electrode 2b, the resonance in the manufacturing method described above. 3a-3d, input coupling electrode 4, input terminal electrode 4a, input coupling reinforcing electrode 4b, output coupling electrode 5, output terminal electrode 5a, output coupling reinforcing electrode 5b, auxiliary coupling electrode 6, coupling electrode 7, and capacitive electrode 8 Before forming each electrode pattern, it is possible to form the end face by filling the green sheet with a similar conductor paste into the through holes previously formed by mold processing or laser processing. For example, after forming a green sheet laminate in which the short-circuit ends of the electrode patterns of the resonator electrodes 3a to 3e are exposed on the end faces, It can be formed by printing on the side surface of the green sheet laminate. Further, the end face conductor is formed so that through holes having a width about the width of the resonator electrodes 3a to 3d are formed in the green sheet, and the short-circuit ends of the electrode patterns of the resonator electrodes 3a to 3d are in contact with the through holes. 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 through hole portion. Similarly, when the dielectric layer 1a is made of a resin-based 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 stacked body, 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 is used, and ground electrode 2a, internal ground electrode 2b, resonator electrodes 3a to 3d, input coupling electrode 4, input terminal electrode 4a, input coupling reinforcing electrode 4b, output coupling electrode 5, output terminal It is obtained by using Ag metallization for the electrode 5a, the output coupling reinforcing electrode 5b, the auxiliary coupling electrode 6, the coupling electrode 7, the capacitive 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 was 350 μm, 50 μm, 50 μm, 100 μm, and 350 μm in order from the top. The ground electrodes 2a and 2a have dimensions of 3.1 mm × 3.6 mm, and the internal ground electrode 2b has an outer dimension of 3.1 mm × 3.6 mm and an inner dimension (opening dimension) of 2.7 mm × 1.85 mm. In this opening, resonator electrodes 3a, 3b, 3c, and 3d having dimensions of 0.4 mm × 1.7 mm are aligned side by side at intervals of 0.25 mm, 0.17 mm, and 0.25 mm, and each short-circuit end is connected to the internal ground electrode 2b. The distance between each open end and the internal ground electrode 2b is 0.15 mm, and the distance between the resonator electrodes 3a and 3d and the internal ground electrode 2b is 0.215 mm. The internal ground electrode 2b and the ground electrodes 2a and 2a 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 coupling electrode 4 has a size of 0.3 mm × 2.25 mm, and is arranged so as to overlap with the open end side of the first-stage resonator electrode 3 a in a range of 0.3 mm × 1.7 mm in plan view, and has an input terminal of 0.2 mm × 0.2 mm The center of the electrode 4a was connected with a through conductor having a diameter of 0.1 mm. Similarly, the output coupling electrode 5 has a size of 0.3 mm × 2.25 mm and is arranged so as to overlap 0.3 mm × 1.7 mm in plan view with the open end side of the resonator electrode 3 c at the final stage, and an output terminal of 0.2 mm × 0.2 mm The center of the electrode 5a was connected with a through conductor having a diameter of 0.1 mm. The auxiliary coupling electrode 6 has a size of 0.3 mm × 1.2 mm, the open end of the input coupling electrode 4 and one end of the auxiliary coupling electrode 6 are aligned, and the open end side of the first-stage resonator electrode 3a is 0.3 mm × in plan view. They were arranged so as to overlap each other in a range of 1.2 mm, and the positions 0.1 mm from the open end of the input coupling electrode 4 and one end of the auxiliary coupling electrode 6 were connected by a through conductor having a diameter of 0.1 mm. Further, one end of the auxiliary coupling electrode 6 having the same size and the open end of the output coupling electrode 5 are matched and arranged so as to overlap with the open end side of the final-stage resonator electrode 3c in a range of 0.3 mm × 1.2 mm in plan view. The positions of 0.1 mm from the open end of the output coupling electrode 5 and one end of the auxiliary coupling electrode 6 were connected by a through conductor having a diameter of 0.1 mm. The coupling electrode 7 has a crank shape in which two 0.1 mm × 0.975 mm ends are connected by a conductor layer having a width of 1.97 mm × 0.1 mm, and the short-circuit end side of each of the first-stage and final-stage resonator electrodes 3a and 3c. And arranged so as to overlap in a range of 0.1 mm × 0.875 mm in plan view, and connected by a through conductor having a diameter of 0.1 mm at the center of a 0.1 mm × 0.1 mm portion overlapping the internal ground electrode 2b. The capacitive electrode 8 having a size of 0.2 mm × 0.72 mm overlaps with the open ends of the resonator electrodes 3 a and 3 c in a range of 0.2 mm × 0.2 mm in plan view, and is 0.2 mm × 0.37 mm from the internal ground electrode 2 b. The resonator electrodes 3a and 3c at the first stage and the last stage are disposed above and below the resonator electrodes 3a and 3c so as to overlap each other, and are connected by a through conductor having a diameter of 0.1 mm at the center of the portion overlapping the open ends of the resonator electrodes 3a and 3c. Further, the capacitive electrode 8 having a size of 0.2 mm × 0.6 mm is overlapped with the open ends of the second and third stage resonator electrodes 3b and 3d within a range of 0.2 mm × 0.2 mm in plan view, and the internal ground electrode 2b is disposed above and below the resonator electrodes 3b and 3d so as to overlap each other in the range of 0.2 mm × 0.25 mm, and at the center of the portion overlapping the open ends of the second-stage and third-stage resonator electrodes 3b and 3d. They were connected by a through conductor having a diameter of 0.1 mm.

  The filter characteristics of the filter device (example) of the present invention in such an example are 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 only the auxiliary coupling electrode 6 with respect to the filter properties of the filter device of the present invention in such an example are shown by the dashed characteristic curve in FIG. It will be like that. Further, the reflection characteristic in the pass band of the filter device of the present invention at this time is as shown by a solid line in FIG. 10, and similarly, the reflection characteristic of the comparative example is as shown by a broken line in FIG. The one-dot chain line and the two-dot chain line in FIG. 10 indicate the filter characteristic of the filter device of the present invention and the filter characteristic of the filter device of the comparative example, respectively. In the diagrams shown in FIGS. 9 and 10, the vertical axis represents insertion loss (unit: dB), and the horizontal axis represents frequency (unit: GHz).

  From the filter characteristics shown in FIG. 9, the filter characteristic of the comparative example has an attenuation pole of λ / 2 resonance by the input coupling electrode 4 or the output coupling electrode 5 at about 19 GHz, and the attenuation characteristic by the coupling electrode 7 at about 15.3 GHz. Whereas the filter characteristic of the embodiment of the filter device of the present invention has a jumping up, the attenuation pole of λ / 2 resonance by the input coupling electrode 4 or the output coupling electrode 5 is shifted to 15.3 GHz. You can see that the bounce is canceled.

  From the above, according to the filter device of the present invention, it is electrically connected to at least one of the input coupling electrode 4 and the output coupling electrode 5 and is electromagnetically coupled opposite to the electrode connected to the ground potential. Since the auxiliary coupling electrode 6 is provided, when the attenuation pole of the λ / 2 resonance by the input coupling electrode 4 or the output coupling electrode 5 is located on the higher frequency side than the frequency at which unnecessary jumping occurs, the input is performed by the auxiliary coupling electrode 6. The amount of C coupling between the coupling electrode 4 and the output coupling electrode 5 and the electrode connected to the ground potential is increased, and the equivalent electrical length of the input coupling electrode 4 and the output coupling electrode 5 is changed to the input coupling electrode 4 and the output coupling electrode. Therefore, the attenuation pole of λ / 2 resonance by the input coupling electrode 4 and the output coupling electrode 5 can be shifted to the low frequency side. Then, by adjusting the amount of C coupling, the equivalent electrical length is adjusted, and the attenuation pole of λ / 2 resonance by the input coupling electrode 4 and the output coupling electrode 5 is shifted to the vicinity of the frequency at which the jump occurs. Thus, it can be seen that it has excellent damping characteristics from which unnecessary jumping is removed.

  In addition, in the conventional filter device that does not further include the capacitive electrode 8 with respect to the comparative example, 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), resonance is required. The device electrodes 3a to 3d have to be lengthened, and not only the size of the filter device is increased, but also the attenuation characteristic jumps to a higher frequency side than the attenuation pole, and the band used in the wireless LAN is increased. The filter characteristic is not sufficiently attenuated in the attenuation band.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 1a ... Dielectric layer 2a ... Ground electrode 2b ... Internal ground electrode 3a, 3b, 3c, 3d ... Resonator electrode 4 ... Input coupling electrode 4a ... Input terminal electrode 4b ... Input coupling reinforcing electrode 5 ... Output coupling electrode 5a ... Output terminal electrode 5b ... Output coupling reinforcing electrode 6 ... Auxiliary coupling electrode 7 ... Coupling electrode 8 ... Capacitance electrode

Claims (8)

A laminate in which a plurality of dielectric layers are laminated;
A ground electrode disposed so as to face each other with the laminate interposed therebetween;
A plurality of resonator electrodes that are arranged side by side so as to be electromagnetically coupled in the laminate, each having one end short-circuited and the other end open;
The multilayer body is formed between layers different from the dielectric layer in which the resonator electrode is disposed, and is opposed to the electromagnetic field in a shape along the first-stage resonator electrode, and the first-stage in the plan view. An input coupling electrode having an electric signal input point to which an electric signal is input from an external circuit on the open end side of the resonator electrode;
The multilayer body is formed between layers different from the dielectric layer where the resonator electrode is disposed, and is opposed to the electromagnetic field in a shape along the resonator electrode in the final stage, and in the plan view, the final stage. An output coupling electrode having an electrical signal output point at which an electrical signal is output to an external circuit on the open end side of the resonator electrode;
An input terminal electrode provided directly above the end of the input coupling electrode and electrically connected to the input coupling electrode;
An output terminal electrode provided immediately above an end of the output coupling electrode and electrically connected to the output coupling electrode;
In the laminate, it is electrically connected to at least one of the input coupling electrode and the output coupling electrode, and is not directly connected to the input terminal electrode and the output terminal electrode, but to an electrode connected to a ground potential. A filter device comprising: an auxiliary coupling electrode facing and electromagnetically coupling.   2. The filter device according to claim 1, further comprising an internal ground electrode formed so as to surround the plurality of resonator electrodes in a plan view between the dielectric layers on which the resonator electrodes are arranged.   The auxiliary coupling electrode connected to the input coupling electrode is the first stage resonator electrode across the dielectric layer, and the auxiliary coupling electrode connected to the output coupling electrode is the final stage across the dielectric layer. 3. The filter device according to claim 1, wherein the filter device is disposed so as to be electromagnetically coupled to each of the resonator electrodes.   The filter device according to claim 2, wherein the auxiliary coupling electrode is opposed to the internal ground electrode.   One end faces the short-circuited end of the first-stage resonator electrode across the dielectric layer, and the other end faces the short-circuited end of the last-stage resonator electrode across the dielectric layer, 5. The filter device according to claim 1, further comprising a coupling electrode that is electrically connected to a short-circuited end of the resonator electrode facing the one end and the other end.   It has a plurality of capacitance electrodes which are opposed to the ground electrode with the dielectric layer interposed between the ground electrode and the resonator electrode, and are respectively connected to open ends of the plurality of resonator electrodes. The filter device according to any one of claims 1 to 5.   The filter device according to claim 6, wherein a part of the capacitive electrode is disposed so as to be electromagnetically coupled to the internal ground electrode across the dielectric layer.   An electromagnetic coupling between the capacitive electrode connected to the resonator electrode in the first stage across the dielectric layer and an input coupling reinforcing electrode connected to the input coupling electrode, or the dielectric layer sandwiched 8. An output coupling reinforcing electrode connected to the output coupling electrode by being electromagnetically coupled opposite to the capacitor electrode connected to the resonator electrode at the last stage. The filter device according to 1.

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