JP2010057117A - Bandpass filter, wireless communication module using the same, and communication equipment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein, in a bandpass filter comprising electrode patterns electrically coupled to a resonance electrode, signals are attenuated only in double and triple frequency bands of a resonant frequency, and if the resonant frequency is reduced by changing a shape of the electrode patterns, since a band of small attenuation between the resonant frequency and the double frequency band of the resonant frequency is excluded from a passband, signals in the passband is considerably attenuated. <P>SOLUTION: The bandpass filter 1 includes: a first capacitance electrode 13 electrically connected to a resonance electrode 7; and a second capacitance electrode 15 electrically connected to the first capacitance electrode and facing the first capacitance electrode via a dielectric layer. The band pass filter 1 further includes: a facing portion where, in planar view of a laminate, the second capacitance electrode faces the first capacitance electrode over all the surface and the first capacitance electrode faces the second capacitance electrode; and a non-facing portion excluding the facing portion. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bandpass filter and a communication device using the same. The communication device can be suitably used for a wireless communication device such as a mobile phone or a wireless LAN.

Conventionally, a bandpass filter used in a communication device or the like is required to attenuate a signal in a frequency band excluding a predetermined passband. Therefore, as disclosed in Patent Document 1, a band-pass filter having an electrode pattern electrically coupled to a resonance electrode has been proposed. The band-pass filter disclosed in Patent Document 1 attenuates a signal in a frequency band twice the resonance frequency by including the above electrode pattern.
JP 2008-118615 A

  However, in recent years, it has been required to have a steep attenuation characteristic, and a signal in a frequency band near the pass band is required to be further attenuated.

  In the bandpass filter disclosed in Patent Document 1, the frequency band capable of greatly attenuating the signal is a frequency band separated from the pass band, which is twice the resonance frequency, for example, the input terminal side and the output Even if the above electrode pattern (capacitance electrode) is arranged on the terminal side and the resonance circuits of these electrode patterns interact with each other, as disclosed in FIG. The signal could be attenuated only in a frequency band that is twice and three times as high. In addition, when the resonance frequency is reduced by changing the shape of these electrode patterns, the band between the resonance frequency and twice the resonance frequency band and having a small attenuation amount is out of the pass band. The signal in the band is greatly attenuated.

  The present invention has been made in view of the above problems, and uses a bandpass filter having an attenuation characteristic that greatly attenuates a signal in a frequency band near the passband while suppressing attenuation of the signal in the passband. It is an object of the present invention to provide a wireless communication module and a communication device apparatus.

  The band-pass filter of the present invention includes a laminated body in which a plurality of dielectric layers including a first dielectric layer are laminated, a reference electrode disposed at one end of the laminated body, and the first A plurality of resonant electrodes arranged in parallel on the principal surface of the dielectric layer; an input terminal for inputting a signal to the plurality of resonant electrodes; and an output terminal for outputting a signal from the plurality of resonant electrodes; A first capacitive electrode electrically connected to the resonant electrode; a second capacitive electrode electrically connected to the first capacitive electrode and facing the first capacitive electrode via the dielectric layer; A capacitor electrode. When the laminate is viewed in plan, the second capacitor electrode is entirely opposed to the first capacitor electrode, and the first capacitor electrode is opposed to the second capacitor electrode. And a non-opposing part excluding the opposing part.

  In the band-pass filter of the present invention, when the multilayer body is viewed in plan, the second capacitor electrode is entirely opposed to the first capacitor electrode, and the first capacitor electrode is opposed to the second capacitor electrode. And a non-opposing part excluding the opposing part. Thereby, it is possible to bring the attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency close to the pass band while suppressing the change in the resonance frequency itself.

  This is because the first capacitive electrode and the reference electrode are capacitively coupled, but at the same time, the first capacitive electrode and the second capacitive electrode are capacitively coupled in a shape different from the capacitive coupling. The coupling state in the capacitive coupling between the first capacitive electrode and the reference electrode changes due to the interaction between the capacitive coupling of the first capacitive electrode and the second capacitive electrode, so that it is twice the resonance frequency. The attenuation band corresponding to the attenuation in the frequency band can be brought close to the pass band. As a result, the attenuation characteristic of the bandpass filter can be made steep.

  Hereinafter, the bandpass filter of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the bandpass filter 1 according to the first embodiment of the present invention includes a laminated body 5 in which a plurality of dielectric layers 3 including a first dielectric layer 3 are laminated, and a laminated body. A first reference electrode 21 disposed at one end in the stacking direction of the body 5, a second reference electrode 23 disposed at the other end in the stacking direction of the stack 5, and a first A plurality of resonance electrodes 7 arranged in parallel on the main surface of the dielectric layer 3, an input terminal 9 for inputting a signal to the plurality of resonance electrodes 7, and an output for outputting a signal from the plurality of resonance electrodes 7 Positioned on the second reference electrode 23 side via the terminal 11, the first capacitive electrode 13 electrically connected via the resonant electrode 7 and the conductive member 18, and the first capacitive electrode 13 and the conductive member 18. And the second capacitor electrode 15 that is electrically connected and faces the first capacitor electrode 13 through the dielectric layer 3. Eteiru.

  Further, when the stacked body 5 is viewed in plan, the second capacitor electrode 15 is opposed to the first capacitor electrode 13, and the first capacitor electrode 13 is opposed to the second capacitor electrode 15. It has the part 13a and the non-opposing part 13b except the opposing part 13a. The first capacitive electrode 13 and the second reference electrode 23 are capacitively coupled. At the same time, the first capacitive electrode 13 is opposed to the second capacitive electrode 15 and the non-excluding portion 13a. Since the opposing portion 13b is provided, the first capacitive electrode 13 and the second capacitive electrode 15 are capacitively coupled in a shape different from the capacitive coupling. Then, the first capacitive electrode is obtained by the interaction between the capacitive coupling between the first capacitive electrode 13 and the second reference electrode 23 and the capacitive coupling between the first capacitive electrode 13 and the second capacitive electrode 15. The degree of coupling in capacitive coupling between the reference electrode and the reference electrode changes. Therefore, the attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency can be brought close to the pass band. Thereby, it is possible to bring the attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency close to the pass band while suppressing the change in the resonance frequency itself.

  Specifically, in the circuit according to the bandpass filter 1 of the present embodiment, as shown in FIG. 4, the coupling electrode 17, the first capacitor electrode 13, And a capacitance C2 between the coupling electrode 17 and the second capacitance electrode 15. And since the 1st capacity electrode 13 and the 2nd capacity electrode 15 are the above-mentioned forms, capacity C4 is made between the 1st capacity electrode 13 and the 2nd capacity electrode 15. Thereby, it is possible to bring the attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency close to the pass band while suppressing the change in the resonance frequency itself. As a result, it is possible to further attenuate the signal in the frequency band near the pass band while suppressing the attenuation of the signal in the pass band.

  In the present embodiment, as shown in FIG. 3, the length of the first capacitive electrode 13 in the direction parallel to the longitudinal direction of the resonant electrode 7 (hereinafter simply referred to as the length of the first capacitive electrode 13, L1 is longer than the length L2 of the second capacitor electrode 15 in the direction parallel to the longitudinal direction of the resonance electrode 7 (hereinafter simply referred to as the length of the second capacitor electrode 15) L2. . Thereby, the 1st capacity electrode 13 can have the counter part 13a which counters the 2nd capacity electrode 15, and the non-opposition part 13b except the counter part 13a. Since the length L2 of the second capacitor electrode 15 is shorter than the length L1 of the first capacitor electrode 13, the pole frequency of λ / 2 in the second capacitor electrode 15 can be changed. The attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency can be brought close to the pass band.

  Further, when the stacked body 5 is viewed in plan, the second capacitor electrode 15 is opposed to the first capacitor electrode 13, and the first capacitor electrode 13 is opposed to the second capacitor electrode 15. In order to have the part 13a and the non-opposing part 13b excluding the opposing part 13a, the length of the second capacitive electrode 15 is made shorter than the length of the first capacitive electrode 13 as shown in FIGS. However, as shown in FIG. 5, the second capacitor electrode 15 has a cutout portion 19 at one end portion thereof, and is a portion facing the cutout portion 19 in the first capacitance electrode 13. The first capacitor electrode 13 and the second capacitor electrode 15 may be disposed so that is the non-opposing portion 13b.

  As shown in FIG. 3, the bandpass filter 1 of this embodiment includes a laminated body 5 in which a plurality of dielectric layers 3 including the first dielectric layer 3 are laminated. The shapes and dimensions of the laminated body 5 and the dielectric layer 3 are set according to the frequency and application used. For example, the thickness of the dielectric layer 3 ensures insulation so that an electrical short circuit does not occur between the first capacitor electrode 13 and the second capacitor electrode 15 that are opposed to each other through the dielectric layer 3. It is preferable to have a sufficient thickness.

  As the dielectric layer 3, for example, an inorganic material such as a ceramic material and a resin material can be used. Specifically, as the ceramic material, for example, alumina ceramics, mullite ceramics, and glass ceramics can be used. Examples of the resin material include tetrafluoroethylene-ethylene resin (polytetrafluoroethylene; PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE), and tetrafluoride. Fluorine resin such as ethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin; PFA), glass epoxy resin, and polyimide can be used.

  In the band pass filter 1 of this embodiment, as shown in FIG. 2, a first reference electrode 21 and a second reference electrode 23 are disposed on the surface of the multilayer body 5. More specifically, the first reference electrode 21 is disposed at one end (upper surface in FIG. 2) of the stacked body 5 in the stacking direction, and the other end of the stacked body 5 in the stacking direction (FIG. 2). In FIG. 2, the second reference electrode 23 is disposed on the lower surface.

  It is preferable that the first reference electrode 21 and the second reference electrode 23 are respectively disposed on the entire upper surface and lower surface of the multilayer body 5. This is because leakage of electromagnetic waves generated with signal transmission inside the laminate 5 can be suppressed. However, when the input terminal 9 and the output terminal 11 (hereinafter also simply referred to as input / output terminals) are taken out to the outside on the upper surface or the lower surface of the multilayer body 5 as in the present embodiment, In order to prevent an electrical short circuit, it is preferable that the input / output terminal is disposed in a portion other than the input port so as to be separated from the input / output terminal.

  The first reference electrode 21 and the second reference electrode 23 are connected to an external wiring (not shown) so as to have a reference potential such as a ground potential. At this time, the first reference electrode 21 and the second reference electrode 23 may be separated from each other, and the first reference electrode 21 and the second reference electrode 23 may be connected to the external wiring, respectively. A third reference electrode 25 is disposed on the side surface of the body 5, and the first reference electrode 21 and the second reference electrode 23 are connected via the third reference electrode 25, and the first reference electrode 21. Alternatively, it is preferable that an external wiring is connected to one of the second reference electrodes 23. This is because the number of external wirings can be reduced, and the number of steps for manufacturing the bandpass filter 1 can be reduced.

  In addition, as shown in FIG. 2, the band-pass filter 1 of the present embodiment is located between the first capacitor electrode 13 and the second capacitor electrode 15, and the first pass through the dielectric layer 3. A coupling electrode 17 facing the capacitive electrode 13 and the second capacitive electrode 15 is provided. By providing such a coupling electrode 17, capacitive coupling between the plurality of resonance electrodes 7 can be adjusted.

  On the main surface of the first dielectric layer 3, a pair of resonance electrodes 7 are arranged in parallel. The resonance electrode 7 is electrically connected to the first capacitor electrode 13 and the second capacitor electrode 15 through the conductive member 18. When the adjacent resonance electrodes 7 are electromagnetically coupled, the wavelength component corresponding to the pass band in the input signal can be extracted. At this time, the wavelength shortening effect of the grounded capacitor C3 between the first capacitor electrode 13 and the second reference electrode 23, and the length of the resonant electrode 7 is approximately ¼ of the wavelength component corresponding to the pass band. The wavelength component corresponding to the passband in the input signal can be efficiently extracted by using the λ / 4 resonance due to the existence. As the resonance electrode 7, the same metal material as that of the first reference electrode 21 can be used.

  The bandpass filter 1 of this embodiment includes an input terminal 9 for inputting a signal to the plurality of resonance electrodes 7 and an output terminal 11 for outputting a signal from the plurality of resonance electrodes 7. More specifically, the input terminal 9 in the present embodiment is electrically connected to one of the pair of resonance electrodes 7 and is drawn to the upper surface of the multilayer body 5. Further, the output terminal 11 in the present embodiment is electrically connected to the other of the pair of resonance electrodes 7 and is drawn out to the upper surface of the multilayer body 5.

  By inputting a signal to the resonance electrode 7 via the input terminal 9 and outputting a signal from the resonance electrode 7 via the output terminal 11, the signal in the frequency band excluding the pass band is attenuated and peaks in the pass band. The signal it has can be taken out.

  Next, the band pass filter 1 concerning the 2nd Embodiment of this invention is demonstrated.

  As shown in FIGS. 6 to 8, in the band pass filter 1 of the present embodiment, the second capacitor electrode 15 has a notch 19 at one end as compared with the first embodiment. A portion facing the notch portion 19 of the first capacitor electrode 13 is a non-facing portion 13b. Furthermore, the second capacitor electrode 15 in the bandpass filter 1 of the present embodiment is electrically connected to the first capacitor electrode 13 at one end. More specifically, in the band pass filter 1 of the present embodiment, the first capacitor electrode 13 is connected to the second capacitor electrode 15 at one end, and the second capacitor electrode 15. And a connection portion connected to the resonance electrode 7 through the notch 19.

  As described above, the second capacitor electrode 15 is electrically connected to the resonance electrode 7 via the first capacitor electrode 13, and the second capacitor electrode 15 is not directly connected to the resonance electrode 7. Therefore, since the input terminal 9 and the output terminal 11 and the resonance electrode 7 are connected via the capacitor C4 formed between the first capacitor electrode 13 and the second capacitor electrode 15, the input terminal 9 and the output terminal 11 looks capacitive. Thus, the second capacitive electrode 15 is electrically connected to the resonant electrode 7 via the first capacitive electrode 13, and the second capacitive electrode 15 is not directly connected to the resonant electrode 7. It is possible to improve the attenuation characteristic on the lower frequency side than the pass band.

  Next, a band pass filter 1 according to a third embodiment of the present invention will be described.

  As shown in FIGS. 9 to 11, the bandpass filter 1 of the present embodiment is opposed to the second capacitor electrode 15 via the dielectric layer 3 and the input terminal 9 or the comparison with the first embodiment. A counter electrode 27 connected to the output terminal 11 is provided. That is, when the input terminal 9 and the output terminal 11 are connected to the counter electrode 27 and the counter electrode 27 and the second capacitor electrode 15 are electromagnetically coupled via the dielectric layer 3, signals are input and output. Further, the attenuation characteristic on the lower frequency side than the pass band is further improved.

  Next, the high frequency module 29 and the wireless communication device 37 of the present invention will be described below.

  As shown in FIG. 12, the high-frequency module 29 according to the present embodiment is disposed on the band-pass filter 1 described above and on the second end side (the upper surface side in FIG. 12) of the band-pass filter 1. The integrated circuit 33 electrically connected to the bandpass filter 1 through the bumps 31 and the first end portion side (the lower surface side in FIG. 12) of the bandpass filter 1 are disposed. And a printed circuit board 35 electrically connected to the band-pass filter 1.

  The wireless communication device 37 according to the present embodiment includes the high-frequency module 29 described above, a baseband unit 39 electrically connected to the bandpass filter 1 through the printed circuit board 35, and a bandpass through the printed circuit board 35. And an antenna 41 electrically connected to the filter 1.

  According to the high-frequency module 29 and the wireless communication device 37 of the present embodiment, the first capacitive electrode 13 and the second capacitive electrode 15 are provided as compared with the conventional bandpass filter 1, and the multilayer body 5 is viewed in plan view. In this case, the entire surface of the second capacitor electrode 15 faces the first capacitor electrode 13, and the first capacitor electrode 13 faces the second capacitor electrode 15. And a non-opposing portion 13b excluding 13a. Therefore, it is possible to bring the attenuation band corresponding to the attenuation in the frequency band twice the resonance frequency close to the pass band while suppressing the change in the resonance frequency itself. Thereby, the reception sensitivity is improved and the amplification degree of the transmission signal and the reception signal can be reduced, so that power consumption in the amplifier circuit is reduced. As a result, a high-performance high-frequency module 29 and a wireless communication device 37 with high reception sensitivity and low power consumption can be obtained.

  In the present embodiment, the integrated circuit 33 is disposed on the second end side of the bandpass filter 1 and is electrically connected to the bandpass filter 1 via the bumps 31. A printed circuit board 35 is disposed on the first end side of the bandpass filter 1 and is electrically connected to the bandpass filter 1 via the bumps 31. Here, the integrated circuit 33 is disposed on the second end portion side of the base body using the substrate having the bandpass filter 1 incorporated therein, and is electrically connected to the base body via the bumps 31. In addition, it may be disposed on the first end side of the base body and electrically connected to the base body via the bumps 31.

  The transmission characteristics of the bandpass filter 1 according to the embodiment shown in FIG. 5 were calculated by electromagnetic field simulation.

  As shown in FIG. 5, in the bandpass filter 1 of the present embodiment, the second capacitor electrode 15 has a notch 19 at one end, and the notch in the first capacitor electrode 13 described above. The first capacitor electrode 13 and the second capacitor electrode 15 are arranged so that a portion facing the portion 19 is a non-facing portion 13b.

  A laminated body 5 was formed by laminating five dielectric layers 3 having thicknesses of 150 μm, 75 μm, 25 μm, 25 μm, and 25 μm in order from the top. At this time, the third dielectric layer 3 from the top was used as the first dielectric layer. A first reference electrode 21 and a second reference electrode 23 are disposed at one end and the other end in the stacking direction of the stacked body 5, respectively. The dimensions of the first reference electrode 21 and the second reference electrode 23 were 2.4 mm × 1.2 mm. The first reference electrode 21 was formed with two 0.5 mm × 0.5 mm openings for arranging the input terminal 9 and the output terminal 11.

  As the resonance electrode 7, an electrode having dimensions of 0.8 mm × 0.15 mm and a resonance frequency in the 5 GHz band was used. Two resonant electrodes 7 were arranged side by side on the main surface of the first dielectric layer 3 at intervals of 0.125 mm. One end of each resonance electrode 7 is electrically connected to the first reference electrode 21 and the second reference electrode 23. The first capacitor electrode 13 having a size of 3.5 mm × 1.225 mm was used. As the second capacitive electrode 15, one having a dimension of 3.5 mm × 1.225 mm and having a notch of 0.25 mm × 0.2 mm at the end connected to the resonance electrode 7 was used. . The dimensions of the input terminal 9 and the output terminal 11 were 0.2 mm × 0.2 mm. The input terminal 9 and the output terminal 11 are connected to the end of the second capacitor electrode 15, respectively.

  FIG. 13 shows the filter characteristics of the bandpass filter according to the embodiment having the above shape. In FIG. 13, the solid line is the characteristic curve of the filter characteristics of the bandpass filter according to this embodiment. Moreover, a broken line is a characteristic curve of the filter characteristic of a comparative example. Here, as a comparative example, a structure in which the second capacitor electrode 15 does not have a notch and the first capacitor electrode 13 includes only the facing portion 13a as compared with the present embodiment is used.

  As can be seen from FIG. 13, in the bandpass filter according to this example, the attenuation band in the 10 GHz band, which is a frequency band twice the resonance frequency, is the passband as compared with the bandpass filter according to the comparative example. It is close to the 5 GHz band. As a result, it can be seen that the band-pass filter according to the present example has a steep attenuation characteristic as compared with the band-pass filter according to the comparative example.

It is a perspective view which shows the band pass filter in the 1st Embodiment of this invention. It is a disassembled perspective view of embodiment shown in FIG. It is AA sectional drawing of embodiment shown in FIG. FIG. 2 is an equivalent circuit diagram of the embodiment shown in FIG. 1. It is a disassembled perspective view which shows the modification of the band pass filter in the 1st Embodiment of this invention. It is a disassembled perspective view which shows the band pass filter in the 2nd Embodiment of this invention. It is AA sectional drawing of embodiment shown in FIG. It is BB sectional drawing of embodiment shown in FIG. FIG. 7 is an equivalent circuit diagram of the embodiment shown in FIG. 6. It is a disassembled perspective view which shows the band pass filter in the 3rd Embodiment of this invention. It is AA sectional drawing of embodiment shown in FIG. FIG. 10 is an equivalent circuit diagram of the embodiment shown in FIG. 9. The conceptual diagram which shows the high frequency module and radio | wireless communication apparatus concerning one Embodiment of this invention It is a filter characteristic of the band pass filter shown in FIG. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Band pass filter 3 ... Dielectric layer 5 ... Laminated body 7 ... Resonant electrode 9 ... Input terminal 11 ... Output terminal 13 ... 1st capacity electrode 13a ... -Opposing part 13b-Non-opposing part 15-Second capacitive electrode 17-Coupling electrode 18-Conductive member 19-Notch part 21-First reference electrode 23- Second reference electrode 25 ... third reference electrode 27 ... counter electrode 29 ... high frequency module 31 ... bump 33 ... integrated circuit 35 ... printed circuit board 37 ... wireless communication Equipment 39 ... Baseband part 41 ... Antenna

Claims (8)

A laminated body in which a plurality of dielectric layers including the first dielectric layer are laminated;
A reference electrode disposed at one end of the laminate;
A plurality of resonant electrodes arranged in parallel on the main surface of the first dielectric layer;
An input terminal for inputting a signal to the plurality of resonant electrodes;
An output terminal for outputting a signal from the plurality of resonance electrodes;
A first capacitive electrode electrically connected to the resonant electrode;
A band pass filter comprising a second capacitor electrode electrically connected to the first capacitor electrode and facing the first capacitor electrode through the dielectric layer;
When the laminate is viewed in plan, the entire surface of the second capacitor electrode is opposed to the first capacitor electrode, and the first capacitor electrode is opposite to the second capacitor electrode. And a non-opposing part excluding the opposing part.   The first capacitor electrode has a notch at one end, and a portion of the first capacitor electrode facing the notch is a non-opposing portion. The described bandpass filter.   The band-pass filter according to claim 2, wherein the second capacitor electrode is electrically connected to the first capacitor electrode at the one end.   The length of the second capacitive electrode in a direction parallel to the longitudinal direction of the resonant electrode is shorter than the length of the first capacitive electrode in a direction parallel to the longitudinal direction of the resonant electrode. Item 2. A bandpass filter according to Item 1.   The band-pass filter according to claim 1, wherein the second capacitor electrode is electrically connected to the resonance electrode through the first capacitor electrode.   The band-pass filter according to claim 1, wherein at least one of the input terminal and the output terminal is connected to the second capacitor electrode.   A high-frequency module comprising the band-pass filter according to claim 1. A radio communication device comprising the high frequency module according to claim 7.