JP5171710B2 - BANDPASS FILTER, RADIO COMMUNICATION MODULE AND RADIO COMMUNICATION DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a bandpass filter, a wireless communication module and a wireless communication device using the same, and more particularly to a bandpass filter having two pass bands, a wireless communication module and a wireless communication device using the same. is there.

  In recent years, UWB has attracted attention as a new communication means. UWB realizes large-capacity data transfer using a wide frequency band over a short distance of about 10 m. For example, according to US FCC (Federal Communication Commission) regulations, a plan to use a frequency band of 3.1 to 10.6 GHz It has become. Thus, the feature of UWB is that it uses a very wide frequency band.

  In recent years, research on ultra-wideband filters that can be used for UWB has been actively conducted. For example, a bandpass filter that applies the principle of a directional coupler has a passband width of a specific bandwidth (bandwidth / center). There is a report that a broadband characteristic exceeding 100% is obtained in (frequency) (for example, see Non-Patent Document 1).

  On the other hand, as a filter often used conventionally, there is known a band-pass filter configured by connecting a plurality of quarter-wavelength stripline resonators to each other (see, for example, Patent Document 1).

JP 2004-180032 A

“Ultra-wideband bandpass filter using microstrip-CPW broadside coupling structure” Proceedings of the March 2005 IEICE General Conference C-2-114 p.147

  However, the band-pass filters proposed in Non-Patent Document 1 and Patent Document 1 each have problems, and are not suitable for UWB band-pass filters.

  For example, the bandpass filter proposed in Non-Patent Document 1 has a problem that the passband width is too wide. In other words, UWB basically uses a frequency band of 3.1 GHz to 10.6 GHz, but the International Telecommunication Union wireless communication section is about 3.1 to 4.7 GHz avoiding 5.3 GHz used in IEEE802.11.a. A plan that divides into a low band using a band and a high band using a band of about 6 GHz to 10.6 GHz has been developed. Therefore, the filters used for the UWB Low Band and High Band each require a pass bandwidth of about 40% to 50% in the specific band and attenuation at 5.3 GHz. The band-pass filter proposed in Non-Patent Document 1 having characteristics exceeding 100% cannot be used because its pass band width is too wide.

  Further, the pass band width of a bandpass filter using a conventional quarter wavelength resonator is too narrow, and even if the pass band width of the band pass filter described in Patent Document 1 is intended to be wide, it is 10 It was less than%. Therefore, it cannot be used as a band-pass filter for UWB requiring a wide pass bandwidth corresponding to 40% to 50% in the specific band.

  The present invention has been devised in view of such problems in the prior art, and the purpose thereof is wide, which can cover a UWB low band filter and a high band filter with a single filter. An object of the present invention is to provide a bandpass filter having two passbands and having an attenuation pole formed between the two passbands, and a radio communication module and a radio communication device using the same.

  The band-pass filter of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a ground electrode disposed on at least one of the upper surface and the lower surface of the laminated body, a base, and first and second strips. 1st and 2nd composite resonance electrode each comprised by the projection part, Comprising: One end of the said base is earth | grounded, The said 1st and 2nd projection part is the other end of the said base, and each one end is Connected side by side, the one end of the base becomes one end of each composite resonance electrode, the other end of the projection becomes the other end of each composite resonance electrode, and each of the composite resonance electrodes The base portion and the projection portion of the whole function as a resonator that resonates at a first frequency, and the projection portion of each composite resonance electrode has a second frequency higher than the first frequency. Both The one end of each of the composite resonance electrodes is located on the opposite side, and the second protrusion of the first composite resonance electrode and the first of the second composite resonance electrode And a second layer different from the first layer of the laminate, the first and second composite resonance electrodes arranged side by side between the first layer of the laminate so that the protrusions of the laminate are adjacent to each other The first to third resonance electrodes, which are arranged side by side and are grounded at one end and function as a quarter-wave resonator, and the first layer sandwiching the second layer therebetween, A band-shaped first portion that is disposed in parallel with the second resonance electrode and is electromagnetically coupled to the second resonance electrode disposed between layers opposite to the layer, and is disposed in parallel with the third resonance electrode to be electromagnetic. A band-like second portion that is field coupled and said first and second The first resonance electrode is formed between a first resonance layer and a second resonance layer, and a fourth resonance electrode that functions as a half-wavelength resonator. A first input / output point that is electromagnetically coupled to face a region extending between at least half of the lengths of the first resonance electrodes and disposed between the layers and to which an electric signal is input or output. The first input / output coupling electrode and the first protrusion of the first composite resonance electrode disposed between the first interlayer and the second interlayer of the laminate. And a length of the third resonance electrode disposed between the second input / output coupling electrode which is electromagnetically coupled and the layer between the first layer and the second layer of the multilayer body. Electromagnetic field coupling is performed in opposition to a region extending over half of the vertical direction, and an electric signal is input. Or a third input / output coupling electrode having a second input / output point to be output, and the interlayer disposed between the first layer and the second layer of the stacked body, A fourth input / output coupling electrode that is electromagnetically coupled to face the second protrusion in the second composite resonance electrode; and the first layer with the second layer of the laminate interposed therebetween A resonance electrode coupling conductor having a region for mainly capacitive electromagnetic coupling facing each of the first and third resonance electrodes and disposed between layers located on opposite sides, The one end of the resonance electrode and the other end of the second resonance electrode are located on the same side, and the other end of the first portion of the second resonance electrode and the first portion of the fourth resonance electrode The end is located on the same side, and the one end of the third resonance electrode and the front of the fourth resonance electrode The other end of the second portion is located on the same side, and the first input / output point is located in a length direction of the first input / output coupling electrode and is opposite to the first resonance electrode. The second input / output point is located farther from the one end of the first resonance electrode than the center, and the second input / output point is located in the length direction of the third input / output coupling electrode. Each of the protrusions of the first to third resonance electrodes and each of the composite resonance electrodes is located farther from the one end of the third resonance electrode than the center of the portion facing the electrode. Are arranged so as to be orthogonal to each other when viewed from the stacking direction of the stacked body, and the second input / output coupling electrode is at a portion of the first input / output coupling electrode facing the first resonance electrode. Connected to the side farther from the first input / output point than the center in the length direction, the first An electric signal is input or output through the input / output coupling electrode, and the fourth input / output coupling electrode is arranged in a length direction at a portion of the third input / output coupling electrode facing the third resonance electrode. An electrical signal is input or output via the third input / output coupling electrode connected to the side farther from the second input / output point than the center, and in the pass characteristic, the first to fourth resonance electrodes It has a first passband formed and a second passband formed by the first and second composite resonance electrodes.

  In the band-pass filter of the present invention, in the above configuration, the second input / output coupling electrode is on the one end side with respect to the center in the length direction of the first resonance electrode when viewed from the stacking direction of the stacked body. The fourth input / output coupling electrode is arranged so as to intersect the one end side with respect to the center in the length direction of the third resonance electrode when viewed from the lamination direction of the laminate. It is characterized by being.

  A wireless communication module according to the present invention includes the band-pass filter according to the present invention having any one of the above-described configurations.

  A wireless communication device of the present invention includes an RF unit including the bandpass filter of the present invention having any one of the above-described configurations, a baseband unit connected to the RF unit, and an antenna connected to the RF unit. It is characterized by this.

  According to the bandpass filter of the present invention, the whole of the base portion and the protrusion portion functions as a resonator that resonates at the first frequency, and the protrusion portion resonates at a second frequency higher than the first frequency. A first passband is formed using the first and second composite resonant electrodes. Thereby, the first and second frequencies can be arbitrarily set to some extent. For this reason, it is possible to obtain a bandpass filter that can easily set the width of the second passband to a desired value.

  The band-pass filter according to the present invention includes first to third resonance electrodes that function as a quarter-wavelength resonator with one end grounded, and are disposed in close proximity to the second resonance electrode in an electromagnetic field coupling manner. The first part and the second resonance electrode arranged in parallel to each other and electromagnetically coupled to each other, and a connection part for connecting one ends of the first and second parts. A functioning fourth resonance electrode, and a resonance electrode coupling conductor having a region for mainly capacitive electromagnetic coupling facing each of the first and third resonance electrodes are provided. Further, one end of the first resonance electrode and the other end of the second resonance electrode are located on the same side, and one end of the second resonance electrode and the other end of the first portion of the fourth resonance electrode. Are located on the same side, and one end of the third resonance electrode and the other end of the second portion of the fourth resonance electrode are located on the same side. As a result, the electrical signal transmitted between the first and third resonant electrodes via the resonant electrode coupling conductor and the electrical signal transmitted by the electromagnetic coupling between the adjacent first to fourth resonant electrodes. A phenomenon in which a phase difference occurs between signals and cancels each other can be generated at frequencies near both sides of the passband. For this reason, in the pass characteristics of the bandpass filter, it is possible to form an attenuation pole that hardly transmits a signal in the vicinity of both sides of the first passband formed by the first to fourth resonance electrodes.

  Furthermore, according to the band-pass filter of the present invention, the first to third resonance electrodes and the protrusions of the composite resonance electrodes are disposed so as to be orthogonal to each other when viewed from the stacking direction of the stacked body. . Thereby, even when the thickness of the laminated body is thin and the first to fourth resonance electrodes and the first and second composite resonance electrodes are close to each other, the first to fourth resonance electrodes and the first and second resonance electrodes Electromagnetic field coupling generated between the protrusions in the composite resonance electrode can be minimized. For this reason, it is possible to prevent the deterioration of pass characteristics caused by strong electromagnetic coupling between the first to fourth resonance electrodes and the first and second composite resonance electrodes.

  Still further, according to the bandpass filter of the present invention, the second input / output coupling electrode has a first length greater than the center in the length direction of the first input / output coupling electrode facing the first resonance electrode. An electrical signal is input or output via the first input / output coupling electrode connected to the side far from the input / output point. Further, the fourth input / output coupling electrode is connected to a side farther from the second input / output point than the center in the length direction in the portion of the third input / output coupling electrode facing the third resonance electrode, An electrical signal is input or output via the third input / output coupling electrode. As a result, the electromagnetic coupling between the first input / output coupling electrode and the first resonant electrode can be strengthened, and the electromagnetic coupling between the third input / output coupling electrode and the third resonant electrode can be strengthened. Therefore, the first passband formed by the first to fourth resonance electrodes can be made flat and low-loss over the entire wide passband.

  Furthermore, according to the band-pass filter of the present invention, the second input / output coupling electrode is arranged so as to intersect one end side from the center in the length direction of the first resonance electrode when viewed from the stacking direction of the stacked body. When the fourth input / output coupling electrode is arranged so as to cross one end side from the center in the length direction of the third resonance electrode when viewed from the stacking direction of the stacked body, Since the coupling due to the electric field between the output coupling electrode and the first resonance electrode can be reduced, and the coupling due to the electric field between the fourth input / output coupling electrode and the third resonance electrode can be reduced, the second It is possible to prevent deterioration of filter characteristics due to an increase in coupling between the input / output coupling electrode and the first resonance electrode due to an electric field and coupling between the fourth input / output coupling electrode and the third resonance electrode due to an electric field. it can.

  According to the wireless communication module of the present invention and the wireless communication device of the present invention, the loss of the signal passing over the entire area of the two wide passbands is small, and the attenuation is formed by the attenuation pole formed between the two passbands. By using the band-pass filter of the present invention with a sufficient amount for filtering the communication signal, the attenuation of the communication signal passing through the band-pass filter is reduced and the noise is also reduced. For this reason, the reception sensitivity is improved and the amplification degree of the communication signal can be reduced, so that the power consumption in the amplifier circuit is reduced. Furthermore, signals of two communication bands can be filtered with the band-pass filter of the present invention. Therefore, it is possible to obtain a high-performance wireless communication module and wireless communication device that are small in size, high in reception sensitivity, and low in power consumption.

It is an external appearance perspective view which shows typically the band pass filter of the 1st example of embodiment of this invention. It is a typical exploded perspective view of the band pass filter shown in FIG. It is a top view which shows typically the upper and lower surfaces and interlayer of a band pass filter shown in FIG. FIG. 2 is a cross-sectional view taken along line P-P ′ in FIG. 1. It is an external appearance perspective view which shows typically the band pass filter of the 2nd example of embodiment of this invention. FIG. 6 is a schematic exploded perspective view of the bandpass filter shown in FIG. 5. It is a top view which shows typically the upper and lower surfaces and interlayer of a band pass filter shown in FIG. FIG. 6 is a cross-sectional view taken along the line Q-Q ′ of FIG. 5. It is an external appearance perspective view which shows typically the band pass filter of the 3rd example of embodiment of this invention. FIG. 10 is a schematic exploded perspective view of the bandpass filter shown in FIG. 9. FIG. 10 is a plan view schematically showing upper and lower surfaces and layers of the bandpass filter shown in FIG. 9. FIG. 10 is a cross-sectional view taken along line R-R ′ in FIG. 9. It is a block diagram which shows typically the radio | wireless communication module and radio | wireless communication apparatus of the 4th example of embodiment of this invention. It is a figure which shows the simulation result of the electrical property of the bandpass filter of the 3rd example of embodiment of this invention.

Hereinafter, a bandpass filter of the present invention will be described in detail with reference to the accompanying drawings.
(First example of embodiment)
FIG. 1 is an external perspective view schematically showing a band-pass filter of a first example of an embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the bandpass filter shown in FIG. FIG. 3 is a plan view schematically showing the upper and lower surfaces and the layers of the bandpass filter shown in FIG. 4 is a cross-sectional view taken along the line PP ′ of FIG.

  As shown in FIGS. 1 to 4, the band-pass filter of this example includes a laminate 10, a first ground electrode 21, a second ground electrode 22, a first annular ground electrode 23, and a second Annular ground electrode 24, first to fourth resonance electrodes 30a, 30b, 30c and 30d, first and second composite resonance electrodes 29a and 29b, and first and second input / output coupling electrodes 40a, 41a, third and fourth input / output coupling electrodes 40b and 41b, a resonance electrode coupling conductor 35, a first input / output terminal electrode 60a, and a second input / output terminal electrode 60b are provided.

  The laminate 10 is formed by laminating a plurality of dielectric layers 11. The first ground electrode 21 is disposed on the lower surface of the multilayer body 10. The second ground electrode 22 is disposed on the upper surface of the multilayer body 10. The first annular ground electrode 23 is disposed between the first layers of the laminate 10 so as to surround the first and second composite resonance electrodes 29a and 29b. The second annular ground electrode 24 is disposed between the second layers of the multilayer body 10 so as to surround the first to third resonance electrodes 30a, 30b, 30c.

  The first and second composite resonance electrodes 29a and 29b are arranged between the first layers of the multilayer body 10, and are constituted by a base 27 and strip-shaped first and second protrusions 28a and 28b, respectively. . One end of the base 27 is connected to the first annular ground electrode 23 and is grounded via the first annular ground electrode 23. The first and second protrusions 28 a and 28 b are arranged side by side with one end connected to the other end of the base 27. Therefore, one end of the base portion 27 becomes one end of each composite resonance electrode 29a, 29b, and the other end of each of the first and second protrusions 28a, 28b becomes the other end of each composite resonance electrode 29a, 29b. Yes. Then, one end of each of the composite resonance electrodes 29a and 29b is grounded, so that the whole of the base 27 and the first and second protrusions 28a and 28b functions as a resonator that resonates at the first frequency. In addition, each of the protrusions 28a and 28b functions as a resonator that resonates at a second frequency higher than the first frequency. The first and second composite resonance electrodes 29a and 29b have one end located on the opposite side, and the second protrusion 28b and the second composite resonance electrode of the first composite resonance electrode 29a. The first protrusions 28a of 29b are arranged side by side so as to be adjacent to each other.

  The first to third resonance electrodes 30 a, 30 b, 30 c are sequentially arranged side by side between the second layers of the multilayer body 10. One end of each of the first to third resonance electrodes 30a, 30b, 30c is connected to the second annular ground electrode 24, and is grounded via the second annular ground electrode 24 so that 1/4 wavelength resonance occurs. Functions as a vessel.

  The fourth resonant electrode 30d is disposed in the interlayer A located on the opposite side of the first interlayer with the second interlayer interposed therebetween. The fourth resonance electrode 30d is disposed in parallel with the second resonance electrode 30b in close proximity to the band-shaped first portion 30d1 and is electromagnetically coupled to the third resonance electrode 30c. A band-shaped second portion 30d2 to be coupled and a connection portion 30d3 that connects one ends of the first and second portions 30d1 and 30d2 are formed. Both ends of the fourth resonance electrode 30d are open ends and function as a half-wave resonator.

  The first input / output coupling electrode 40a is disposed in an interlayer B located between the first interlayer and the second interlayer of the stacked body 10, and more than half the length of the first resonance electrode 30a. Electromagnetic field coupling is performed in opposition to the region extending over. The first input / output coupling electrode 40 a is connected to the first input / output terminal electrode 60 a disposed on the upper surface of the multilayer body 10 through the through conductor 50. A connection point between the first input / output coupling electrode 40a and the through conductor 50 is a first input / output point 45a, which is a point where an electric signal is input to or output from the first input / output coupling electrode 40a. .

  The second input / output coupling electrode 41a is disposed in the layer B of the multilayer body 10 so as to be electromagnetically coupled so as to face the first protrusion 28a in the first composite resonance electrode 29a in parallel. Further, one end of the second input / output coupling electrode 41a is connected to the first input / output coupling electrode 40a, and the other end of the second input / output coupling electrode 41a is the first end of the first composite resonance electrode 29a. It is located on the opposite side to the other end of the one projection 28a.

  The third input / output coupling electrode 40b is disposed between the layers B of the stacked body 10, and is electromagnetically coupled so as to face a region extending over half of the length direction of the third resonance electrode 30c. The third input / output coupling electrode 40b is connected to the second input / output terminal electrode 60b disposed on the upper surface of the multilayer body 10 through the through conductor 50. The connection point between the third input / output coupling electrode 40b and the through conductor 50 is a second input / output point 45b, which is a point where an electric signal is input to or output from the third input / output coupling electrode 40b. .

  The fourth input / output coupling electrode 41b is disposed in the layer B of the multilayer body 10 so as to be electromagnetically coupled so as to face the second projecting portion 28b of the second composite resonance electrode 29b in parallel. One end of the fourth input / output coupling electrode 41b is connected to the third input / output coupling electrode 40b, and the other end of the fourth input / output coupling electrode 41b is the second end of the second composite resonance electrode 29b. It is located on the opposite side to the other end of the one projection 28a.

  The resonant electrode coupling conductor 35 is disposed in an interlayer C located on the opposite side of the first interlayer with the second interlayer of the multilayer body 10 interposed therebetween, and mainly opposed to the first resonant electrode 30a. A first coupling portion 35a that performs capacitive electromagnetic field coupling, a second coupling portion 35b that mainly performs capacitive electromagnetic field coupling opposite to the third resonance electrode 30c, and a first coupling portion 35a. And a connecting portion 35c for connecting the second coupling portion 35b.

  The band-pass filter of this example having such a configuration has an external circuit connected to the first input / output point 45a of the first input / output coupling electrode 40a via the first input / output terminal electrode 60a and the through conductor 50, for example. When the electric signal from the first input electrode is input, the first resonance electrode 30a electromagnetically coupled to the first input / output coupling electrode 40a is excited, whereby the first to fourth resonance electrodes that are electromagnetically coupled to each other are excited. The through conductor 50 and the second input / output terminal electrode from the second input / output point 45b of the second input / output coupling electrode 40b in which 30a, 30b, 30c, 30d resonate and electromagnetically couple with the fourth resonant electrode 30d. An electrical signal is output to an external circuit via 60b. At this time, a signal in a frequency band including a frequency at which the first to fourth resonance electrodes 30a, 30b, 30c, and 30d resonate selectively passes, thereby forming a first pass band.

  Further, when an electric signal from an external circuit is input to the first input / output point 45a of the first input / output coupling electrode 40a via the first input / output terminal electrode 60a and the through conductor 50, the first input The first and second composite resonance electrodes 29a electromagnetically coupled to each other when the first composite resonance electrode 29a electromagnetically coupled to the second input / output coupling electrode 41a connected to the output coupling electrode 40a is excited. 29b resonate, and the through conductor 50 extends from the second input / output point 45b of the third input / output coupling electrode 40b to which the fourth input / output coupling electrode 41b electromagnetically coupled to the second composite resonance electrode 29b is connected. An electric signal is output to an external circuit through the second input / output terminal electrode 60b. At this time, a signal in a frequency band including a frequency at which the first and second composite resonance electrodes 29a and 29b resonate selectively passes, so that a second pass band is formed.

  In this way, the bandpass filter of this example functions as a bandpass filter having two passbands having different frequencies.

  According to the bandpass filter of this example having such a configuration, the base 27 and the whole of the first and second protrusions 28a and 28b function as a resonator that resonates at the first frequency, and the first The first and second protrusions 28a and 28b form a second passband using the composite resonance electrodes 29a and 29b that resonate at a second frequency higher than the first frequency. Thereby, the first and second frequencies can be arbitrarily set to some extent. Therefore, it is possible to obtain a band-pass filter in which the width of the second pass band formed by the first and second composite resonance electrodes 29a and 29b can be easily set to a desired value.

  Further, according to the bandpass filter of this example, the first to fourth resonance electrodes 30a, 30b, 30c, 30d are mainly capacitive electromagnetic fields in which adjacent resonators are arranged in an interdigital manner. Have a bond. The first to third resonance electrodes 30a, 30b, 30c function as a quarter wavelength resonator, and the fourth resonance electrode 30d functions as a half wavelength resonator. Further, the resonance electrode coupling conductor 35 is mainly capacitively electromagnetically coupled to the first resonance electrode 30a and the third resonance electrode 30c. With such a configuration, the electrical signal transmitted through the resonant electrode coupling conductor 35 between the first resonant electrode 30a and the third resonant electrode and the adjacent first to fourth resonant electrodes 30a, The first to fourth resonance electrodes 30a, 30b, 30c, and 30d form a phenomenon in which a phase difference occurs between the electrical signals transmitted by electromagnetic coupling between 30b, 30c, and 30d and cancel each other. Can occur at frequencies near both sides of the passband. Therefore, in the pass characteristics of the band pass filter, attenuation poles that hardly transmit signals are formed near both sides of the first pass band formed by the first to fourth resonance electrodes 30a, 30b, 30c, and 30d. be able to.

  Further, according to the bandpass filter of the present example, the first to third resonance electrodes 30a, 30b, 30c, the first portion 30d1 and the second portion 30d2 of the fourth resonance electrode 30d, and the first and second input electrodes. The output coupling electrodes 40a and 41a are disposed so as to face each other across the first and second protrusions 28a and 28b in the first and second composite resonance electrodes 29a and 29b. As a result, the phenomenon in which electrical signals transmitted through a plurality of routes cancel each other due to the phase difference between them is a frequency near both sides of the second passband formed by the first and second composite resonance electrodes 29a and 29b. Can be generated. For this reason, in the pass characteristic of the band pass filter, an attenuation pole that hardly transmits a signal can be formed near both sides of the second pass band formed by the first and second composite resonance electrodes 29a and 29b. .

  Furthermore, according to the band-pass filter of this example, the first passband is provided between the first and second input / output coupling electrodes 40a and 41a and the third and fourth input / output coupling electrodes 40b and 41b. The first to fourth resonance electrodes 30a, 30b, 30c, 30d forming the first and second composite resonance electrodes 29a, 29b forming the second passband are electrically connected in parallel. . In the first and second composite resonance electrodes 29a and 29b, adjacent resonance electrodes are mainly capacitively coupled by interdigital electromagnetic field coupling. Further, the first and third input / output coupling electrodes 40a, 40b are mainly capacitively coupled to the first and third resonance electrodes 30a, 30c by interdigital electromagnetic field coupling, and the second The input / output coupling electrode 41a is mainly capacitively coupled to the first protrusion 28a of the first composite resonance electrode 29a by interdigital electromagnetic field coupling, and the fourth input / output coupling electrode 41b is the second input / output coupling electrode 41b. The second projecting portion 28b of the second composite resonance electrode 29b is mainly capacitively coupled by interdigital electromagnetic field coupling. Furthermore, the first to third resonance electrodes 30a, 30b, 30c and the first and second composite resonance electrodes 29a, 29b function as a quarter wavelength resonator, and the fourth resonator has a half wavelength. Functions as a resonator. With such a configuration, the phenomenon in which electrical signals transmitted through a plurality of routes cancel each other due to the phase difference between each other is described as follows. The attenuation pole near the high frequency side of the first passband described above and the second passband described above. Can be generated in a frequency region located between the attenuation poles in the vicinity of the low frequency side. Therefore, in the pass characteristic of the bandpass filter, a signal is present in a frequency region located between the attenuation pole near the high frequency side of the first passband and the attenuation pole near the low frequency side of the second passband. An attenuation pole that is hardly transmitted can be formed.

  Therefore, according to the bandpass filter of this example, in the pass characteristic, three attenuation poles can be formed in the frequency region located between the first passband and the second passband. A bandpass filter having good pass characteristics in which an attenuation amount between the passband and the second passband is ensured can be obtained.

  Further, according to the bandpass filter of this example, the first to third resonance electrodes 30a, 30b, 30c, the first portion 30d1 and the second portion 30d2 of the fourth resonance electrode 30d, and the respective composite resonance electrodes 29a, The protrusions 28a and 28b in 29b are arranged so as to be orthogonal to each other when viewed from the stacking direction of the stacked body 10. Thus, even when the thickness of the multilayer body 10 is thin and the first to fourth resonance electrodes 30a, 30b, 30c, 30d and the first and second composite resonance electrodes 29a, 29b are close to each other, the first to the first resonance electrodes 30a, 30b, 30c, 30d are close to each other. Electromagnetic field coupling generated between the four resonance electrodes 30a, 30b, 30c, 30d and the respective projections 28a, 28b of the first and second composite resonance electrodes 29a, 29b can be minimized. For this reason, it is possible to prevent the deterioration of pass characteristics caused by strong electromagnetic coupling between the first to fourth resonance electrodes 30a, 30b, 30c, 30d and the first and second composite resonance electrodes 29a, 29b. it can.

  Furthermore, according to the bandpass filter of the present example, the second input / output coupling electrode 41a has a first length greater than the center in the length direction at the portion of the first input / output coupling electrode 40a facing the first resonance electrode 30a. 1 is connected to a side far from the input / output point 45a, and an electric signal is input or output through the first input / output coupling electrode 40a. The fourth input / output coupling electrode 41b is located farther from the second input / output point 45b than the center in the length direction at the portion of the third input / output coupling electrode 40b facing the third resonance electrode 30c. Connected and an electric signal is input or output via the third input / output coupling electrode 40b. Thereby, the electromagnetic coupling between the first input / output coupling electrode 40a and the first resonance electrode 30a can be strengthened, and the electromagnetic field between the third input / output coupling electrode 40b and the third resonance electrode 30c. Since the coupling can be strengthened, the first passband formed by the first to fourth resonance electrodes 30a, 30b, 30c, and 30d is flat and has low loss over the entire wide passband. can do.

  This effect has been found by the inventors through various studies. The reason why this effect is obtained is that the first input / output point 45a is connected to the first input / output coupling electrode 40a and the second input / output coupling electrode. Compared with the case where it is at a branch point with 41a, it is possible to increase the current flowing through the portion of the first input coupling electrode facing the first resonant electrode 30a, and the second input / output point 45b has a third input point. Compared with the case where the output coupling electrode 40b and the fourth input / output coupling electrode 41b are at the branch point, the current flowing through the portion of the third input / output coupling electrode 40b facing the third resonance electrode 30c can be increased. This is probably because of this.

  Furthermore, according to the bandpass filter of this example, the second input / output coupling electrode 41a intersects with one end side from the center in the length direction of the first resonance electrode 30a when viewed from the stacking direction of the stacked body. When the fourth input / output coupling electrode 41b is arranged so as to cross one end side from the center in the length direction of the third resonance electrode 30c when viewed from the stacking direction of the stacked body, The coupling by the electric field between the second input / output coupling electrode 41a and the first resonance electrode 30a is reduced, and the coupling by the electric field between the fourth input / output coupling electrode 41b and the third resonance electrode 30c is reduced. Therefore, the coupling by the electric field between the second input / output coupling electrode 41a and the first resonance electrode 30a and the coupling by the electric field between the fourth input / output coupling electrode 41b and the third resonance electrode 30c are increased. Prevents deterioration of filter characteristics caused by Door can be.

  In the band-pass filter of this example, the length of the first protrusion 28a and the length of the second protrusion 28b of the first and second composite resonance electrodes 29a and 29b may be equal. It is desirable to make it somewhat different. That is, the length of the first protrusion 28a of the first composite resonance electrode 29a electromagnetically coupled to the second input / output coupling electrode 41a is equal to the length of the second protrusion 28b of the first composite resonance electrode 29a. It is desirable to make it shorter. As a result, it is possible to correct a decrease in the resonance frequency of the first protrusion 28a of the first composite resonance electrode 29a due to electromagnetic coupling with the second input / output coupling electrode 41a. Similarly, the length of the second protrusion 28b of the second composite resonance electrode 29b electromagnetically coupled to the fourth input / output coupling electrode 41b is the length of the first protrusion 28a of the second composite resonance electrode 29b. It is desirable to make it shorter. Thereby, it is possible to correct a decrease in the resonance frequency of the second protrusion 28b of the second composite resonance electrode 29b caused by electromagnetic coupling with the fourth input / output coupling electrode 41b.

In the band-pass filter of this example, as the material of the dielectric layer 11, for example, a resin such as an epoxy resin or a ceramic such as a dielectric ceramic can be used. For example, a dielectric ceramic material such as BaTiO ₃ , Pb ₄ Fe ₂ Nb ₂ O ₁₂ , or TiO ₂ and a glass material such as B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , or ZnO, and 800 to 1200 ° C. Glass-ceramic materials that can be fired at relatively low temperatures are preferably used. The thickness of the dielectric layer 11 is set to about 0.01 to 0.1 mm, for example.

  Examples of the materials for the various electrodes and through conductors described above include conductive materials mainly composed of Ag alloys such as Ag, Ag-Pd, and Ag-Pt, Cu-based, W-based, Mo-based, and Pd-based conductive materials. Are preferably used. The thickness of various electrodes is set to 0.001 to 0.2 mm, for example.

The band pass filter of this example can be manufactured as follows, for example. First, an appropriate organic solvent or the like is added to and mixed with the ceramic raw material powder to produce a slurry, and a ceramic green sheet is formed by a doctor blade method. Next, a through hole for forming a through conductor is formed on the obtained ceramic green sheet using a punching machine or the like, and a conductive paste containing a conductor such as Ag, Ag-Pd, Au, Cu is filled and the ceramic The same conductive paste as described above is applied to the surface of the green sheet using a printing method to produce a ceramic green sheet with a conductive paste. Next, these ceramic green sheets with a conductive paste are laminated, pressed using a hot press device, and fired at a peak temperature of about 800 ° C. to 1050 ° C.
(Second example of embodiment)
FIG. 5 is an external perspective view schematically showing the band-pass filter of the second example of the embodiment of the present invention. 6 is a schematic exploded perspective view of the bandpass filter shown in FIG. FIG. 7 is a plan view schematically showing the upper and lower surfaces and layers of the bandpass filter shown in FIG. 8 is a cross-sectional view taken along the line QQ ′ of FIG. Note that in this example, only differences from the first example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  As shown in FIGS. 5 to 8, the band-pass filter of this example includes resonance auxiliary electrodes 32a, 32b, 32c, 32d1, and 32d2. The resonance auxiliary electrodes 32a, 32b, and 32c are disposed between the layers B of the multilayer body 10 so as to face the second annular ground electrode 24, and the first to third resonance electrodes 30a, 30b, and 30c, respectively. Is connected to the other end of each through a through conductor 50. Further, the resonance auxiliary electrodes 32d1 and 32d2 are arranged to face the first ground electrode 21 in an interlayer D located on the opposite side of the interlayer C with the interlayer A of the laminate 10 in between. The fourth resonance electrode 30d is connected to the other ends of the first portion 30d1 and the second portion 30d2 through a through conductor 50.

  According to the band-pass filter of this example having such a configuration, the first to third resonance electrodes are generated by the capacitance generated between the resonance auxiliary electrodes 32a, 32b, 32c and the second annular ground electrode 24. The length of 30a, 30b, 30c can be shortened. The length of the fourth resonance electrode 30d can be shortened by the capacitance generated between the resonance auxiliary electrodes 32d1 and 32d2 and the first ground electrode 21. Therefore, a smaller bandpass filter can be obtained.

  The band pass filter of this example includes a first coupling auxiliary electrode 46a and a second coupling auxiliary electrode 46b. The first coupling auxiliary electrode 46a is disposed between the first layers of the multilayer body 10 so as to face the resonance auxiliary electrode 32a. The first coupling auxiliary electrode 46a has one end connected to the first input / output point 45a of the first input / output coupling electrode 40a via the through conductor 50 and the other end connected to the other through-hole. The conductor 50 is connected to the first input / output terminal electrode 60a. The second coupling auxiliary electrode 46b is disposed between the first layers of the multilayer body 10 so as to face the resonance auxiliary electrode 32c. The second coupling auxiliary electrode 46b has one end connected to the second input / output point 45b of the third input / output coupling electrode 40b through the through conductor 50, and the other end connected to the other penetration. The conductor 50 is connected to the second input / output terminal electrode 60b.

According to the bandpass filter of this example having such a configuration, the joined body of the first resonance electrode 30a and the resonance auxiliary electrode 32a, and the junction of the first input / output coupling electrode 40a and the first coupling auxiliary electrode 46a. The body is generally broadside and strongly electromagnetically coupled to the interdigital type. Further, the joined body of the third resonance electrode 30c and the auxiliary resonance electrode 32c and the joined body of the third input / output coupling electrode 40b and the second coupling auxiliary electrode 46b are interdigital on the broad side. Strong electromagnetic coupling. As a result, a bandpass filter having excellent pass characteristics with flatness and low loss over the entire wide first passband formed by the first to fourth resonance electrodes 30a, 30b, 30c, and 30d is obtained. be able to.
(Third example of embodiment)
FIG. 9 is an external perspective view schematically showing the band-pass filter of the third example of the embodiment of the present invention. FIG. 10 is a schematic exploded perspective view of the bandpass filter shown in FIG. FIG. 11 is a plan view schematically showing the upper and lower surfaces and layers of the bandpass filter shown in FIG. FIG. 12 is a cross-sectional view taken along the line RR ′ of FIG. In this example, only points different from the second example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  According to the bandpass filter of this example, as shown in FIGS. 9 to 12, the second input / output coupling electrode 41 a and the fourth input / output coupling electrode 41 b are connected to the first layer and the layer B of the laminate 10. The first coupling auxiliary electrode 46a and the second coupling auxiliary electrode 46b are arranged in the interlayer F located between the interlayer E and the interlayer B of the stacked body 10. ing. The second input / output coupling electrode 41a is connected to the first input / output coupling electrode 40a via the through conductor 50, and the fourth input / output coupling electrode 41b is connected to the third input / output coupling electrode 41a via the through conductor 50. Are connected to the input / output coupling electrode 40b.

  According to the bandpass filter of this example having such a configuration, the distance between the first input / output coupling electrode 40a and the third input / output coupling electrode 40b and the first resonance electrode 30a and the third resonance electrode 30c. The first to fourth resonances are maintained while maintaining the distances between the second input / output coupling electrode 41a and the fourth input / output coupling electrode 41b and the first composite resonance electrode 29a and the second composite resonance electrode 29b. The distance between the electrodes 30a, 30b, 30c, 30d and the first and second composite resonance electrodes 29a, 29b can be increased. Thereby, it is possible to further reduce the adverse effects caused by too strong electromagnetic field coupling between the first to fourth resonance electrodes 30a, 30b, 30c, 30d and the first and second composite resonance electrodes 29a, 29b. .

(Fourth example of embodiment)
FIG. 13 is a block diagram schematically showing a wireless communication module 80 and a wireless communication device 85 of the fourth example of the embodiment of the present invention.

  The wireless communication module 80 of this example includes a baseband unit 81 that processes baseband signals, and an RF unit 82 that is connected to the baseband unit 81 and processes RF signals after modulation of the baseband signals and before demodulation. I have. The RF unit 82 includes the band-pass filter 821 of the present invention described above. The band-pass filter 821 attenuates signals other than the communication band in the RF signal obtained by modulating the baseband signal or the received RF signal. Yes.

  Specifically, a baseband IC 811 is disposed in the baseband unit 81, and an RF IC 822 is disposed between the bandpass filter 821 and the baseband unit 81 in the RF unit 82. Note that another circuit may be interposed between these circuits. Then, by connecting the antenna 84 to the bandpass filter 821 of the wireless communication module 80, the wireless communication device 85 of this example that transmits and receives RF signals is configured.

  According to the wireless communication module 80 and the wireless communication device 85 of this example having such a configuration, the loss is low over the entire two wide passbands, and three attenuation poles are provided between the two passbands. By using the bandpass filter 821 of the present invention that is formed and sufficiently secured in attenuation, signals in two communication bands can be filtered. As a result, the attenuation of the communication signal can be reduced and the noise can be reduced, so that the reception sensitivity is improved and the amplification degree of the communication signal can be reduced, so that the power consumption in the amplifier circuit is reduced. Furthermore, since the filtering of the two communication bands can be performed by one filter, the circuit configuration can be simplified and the number of parts can be reduced. Therefore, it is possible to obtain a high-performance wireless communication module 80 and a wireless communication device 85 that are small in size, have high reception sensitivity, and consume less power.

(Modification)
The present invention is not limited to the first to fourth examples of the embodiment described above, and various modifications and improvements can be made without departing from the gist of the present invention.

  For example, in the first to third examples of the above-described embodiment, an example in which the first input / output terminal electrode 60a and the second input / output terminal electrode 60b are provided has been described. However, when a band-pass filter is formed in one region of the module substrate, the first input / output terminal electrode 60a and the second input / output terminal electrode 60b are not necessarily required. A wiring conductor from an external circuit may be directly connected to the first input / output coupling electrode 40a and the third input / output coupling electrode 40b. In this case, the connection points between the first input / output coupling electrode 40a and the third input / output coupling electrode 40b and the wiring conductor are the first input / output point 45a and the second input / output point 45b.

  In the first to third examples of the above-described embodiment, the first ground electrode 21 is disposed on the lower surface of the multilayer body 10 and the second ground electrode 22 is disposed on the upper surface of the multilayer body 10. However, for example, a dielectric layer may be further disposed below the first ground electrode 21, or a dielectric layer may be further disposed on the second ground electrode 22. Further, only one of the first ground electrode 21 and the second ground electrode 22 may be provided.

  Furthermore, in the first to third examples of the above-described embodiment, the example in which the bandpass filter is configured in one laminated body 10 is shown, but a plurality of laminated bodies laminated in the thickness direction. Alternatively, a band pass filter may be formed across the two.

  Furthermore, in the first to third examples of the above-described embodiment, the first input / output coupling electrode 40a and the third input / output coupling electrode 40b are arranged between the same layers of the stacked body 10, and the fourth The example in which the first portion 30d1 and the second portion 30d2 of the resonant electrode 30d are arranged between the same layers of the multilayer body 10 is shown. However, the first input / output coupling electrode 40a and the third input / output coupling electrode 40b are arranged between different layers as long as they are between the first layer and the second layer of the stacked body 10. It doesn't matter. Similarly, the first portion 30d1 and the second portion 30d2 of the fourth resonance electrode 30d may be disposed between different layers of the stacked body 10.

  Furthermore, although the bandpass filter used for UWB has been exemplified and described so far, it goes without saying that the bandpass filter of the present invention is effective in other applications.

  Next, a specific example of the bandpass filter of the present invention will be described.

  The electrical characteristics of the bandpass filter of the third example of the embodiment of the present invention shown in FIGS. 9 to 12 were calculated by simulation using the finite element method. The simulation results are shown in FIG. The horizontal axis of the graph is frequency, and the vertical axis is attenuation, and shows the pass characteristic (S21) and reflection characteristic (S11) of the bandpass filter.

  In the pass characteristic shown in FIG. 14, two wide and flat passbands are formed, and three attenuation poles are formed between the first passband and the second passband. It can be seen that a sufficient amount of attenuation is secured in the frequency region between the two passbands. Thereby, the effectiveness of the present invention was confirmed.

  In this simulation, the first to third resonance electrodes 30a, 30b, and 30c have a rectangular shape with a width of 0.175 mm and a length of 4.05 mm. The fourth resonance electrode 30d has a U-shape in which a first portion 30d1 and a second portion 30d2 having a width of 0.125 mm and a length of 3.9 mm are connected to a connection portion 30d3 having a width of 0.125 mm and a length of 0.4 mm. The shape of the mold. The first composite resonance electrode 29a has a first protrusion 28a having a width of 0.25 mm and a length of 0.97 mm and a width of 0.25 mm on the other end of the base 27 having a width of 0.76 mm and a length of 0.98 mm. A second protrusion 28b having a length of 2.22 mm was connected. The second composite resonance electrode 29b has a first protrusion 28a having a width of 0.25 mm and a length of 2.22 mm and a width of 0.25 mm on the other end of the base 27 having a width of 0.76 mm and a length of 0.98 mm. A second protrusion 28b having a length of 0.97 mm was connected. The first input / output coupling electrode 40a and the third input / output coupling electrode 40b each have a rectangular shape with a width of 0.15 mm and a length of 3.7 mm. The second input / output coupling electrode 41a and the fourth input / output coupling electrode 41b each have a rectangular shape with a width of 0.25 mm and a length of 0.45 mm. The resonant electrode coupling conductor 35 has a crank shape in which the first and second coupling portions 35a and 35b having a width of 0.075 mm and a length of 0.7 mm are connected by a connection portion 35c having a width of 0.075 mm and a length of 0.7 mm. The structure is as follows. The first coupling auxiliary electrode 46a and the second coupling auxiliary electrode 46b each have a rectangular shape with a width of 0.15 mm and a length of 0.9 mm. The thickness of each electrode was 0.01 mm. The diameter of the through conductor 50 was 0.1 mm. The laminate 10 was a rectangular parallelepiped having a width of 4 mm, a length of 5 mm, and a thickness of 0.49 mm. The distance between the upper surface of the laminate and the first interlayer (the distance between the electrodes disposed on each of the layers) is 0.19 mm, the distance between the interlayer A, the interlayer C, and the interlayer D is 0.065 mm, and the lower surface and the interlayer D And the distance between other adjacent layers was 0.015 mm, respectively. The relative dielectric constant of the dielectric layer 11 was 9.45.

10: Laminate
11: Dielectric layer
27: Base
28a: first protrusion
28b: second protrusion
29a: first composite resonant electrode
29b: second composite resonance electrode
30a: first resonance electrode
30b: second resonant electrode
30c: third resonant electrode
30d: Fourth resonant electrode
30d1: 1st part
30d2: Second part
30d3: Connection part
35: Resonant electrode coupling conductor
40a: first input / output coupling electrode
41a: second input / output coupling electrode
40b: third input / output coupling electrode
41b: Fourth input / output coupling electrode
45a: First input / output point
45b: Second input / output point
80: Wireless communication module
81: Baseband
82: RF section
821: Band pass filter
84: Antenna
85: Wireless communication equipment

Claims (4)

A laminate in which a plurality of dielectric layers are laminated;
A ground electrode disposed on at least one of the upper surface and the lower surface of the laminate;
A first and second composite resonance electrodes each constituted by a base and strip-shaped first and second protrusions, wherein one end of the base is grounded, and the first and second protrusions are One end of each base is connected to the other end of the base and arranged side by side, the one end of the base becomes one end of each of the composite resonance electrodes, and the other end of the projections of each of the composite resonance electrodes The other end of the composite resonance electrode functions as a resonator that resonates at a first frequency, and the projection of each composite resonance electrode is the first end. Functioning as a resonator that resonates at a second frequency higher than the first frequency, the one end of each of the composite resonance electrodes is located on the opposite side, and the second protrusion of the first composite resonance electrode and Above Said first protrusion of the second composite resonance electrodes are arranged side by side on the first interlayer of the laminated body so as to be adjacent, the first and second complex resonance electrode,
Band-shaped first to third resonance electrodes which are sequentially arranged side by side between second layers different from the first layer of the laminate, and each end is grounded and functions as a quarter wavelength resonator. When,
A band-shaped first portion that is disposed adjacent to and parallel to the second resonance electrode and is electromagnetically coupled to the second layer disposed between layers on the opposite side of the first layer with the second layer interposed therebetween; A band-shaped second portion that is disposed in parallel and close to the third resonance electrode and electromagnetically couples, and a connection portion that connects one ends of the first and second portions, and functions as a half-wave resonator A fourth resonant electrode that
Electromagnetic field coupling opposite to a region extending over half the length direction of the first resonance electrode, disposed between the first and second layers of the laminate. And a first input / output coupling electrode having a first input / output point to which an electrical signal is input or output;
A first electromagnetic field coupled opposite to the first protrusion of the first composite resonance electrode disposed between the first layer and the second layer of the multilayer body; Two input / output coupling electrodes;
Electromagnetic field coupling opposite to a region extending over half of the length of the third resonance electrode disposed between the first and second layers of the laminate. And a third input / output coupling electrode having a second input / output point to which an electric signal is input or output,
A first electromagnetic field coupled opposite to the second protrusion of the second composite resonance electrode disposed between the first and second layers of the multilayer body; 4 input / output coupling electrodes;
Mainly capacitive facing each of the first and third resonance electrodes, which are disposed on the opposite side of the first layer with the second layer of the laminate interposed therebetween. A resonant electrode coupling conductor having a region for electromagnetic coupling,
The one end of the first resonance electrode and the other end of the second resonance electrode are located on the same side, and the one end of the second resonance electrode and the first end of the fourth resonance electrode The other end of one part is located on the same side, the one end of the third resonance electrode and the other end of the second part of the fourth resonance electrode are located on the same side,
The first input / output point is a side farther from the one end of the first resonance electrode than the center of the portion facing the first resonance electrode in the length direction of the first input / output coupling electrode. The second input / output point is located in the length direction of the third input / output coupling electrode, and the second input / output point of the third resonance electrode is more than the center of the portion facing the third resonance electrode. Located on the side far from the one end,
The first to third resonance electrodes and each protrusion in each composite resonance electrode are arranged to be orthogonal to each other when viewed from the stacking direction of the stacked body,
The second input / output coupling electrode is connected to a side farther from the first input / output point than the center in the length direction at the portion of the first input / output coupling electrode facing the first resonance electrode. An electrical signal is input or output through the first input / output coupling electrode, and the fourth input / output coupling electrode is at a portion of the third input / output coupling electrode facing the third resonance electrode. An electrical signal is input or output via the third input / output coupling electrode connected to a side farther from the second input / output point than the center in the length direction,
In the pass characteristic, it has a first pass band formed by the first to fourth resonance electrodes and a second pass band formed by the first and second composite resonance electrodes. Bandpass filter to be used.   The second input / output coupling electrode is disposed so as to cross the one end side with respect to the center in the length direction of the first resonance electrode when viewed from the stacking direction of the stacked body. 2. The output coupling electrode according to claim 1, wherein the output coupling electrode is disposed so as to intersect the one end side with respect to the center in the length direction of the third resonance electrode when viewed from the stacking direction of the stacked body. Bandpass filter.   A wireless communication module comprising the bandpass filter according to claim 1.   A radio communication device comprising: an RF unit including the bandpass filter according to claim 1; a baseband unit connected to the RF unit; and an antenna connected to the RF unit. .

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