JP5219858B2 - BANDPASS FILTER, RADIO COMMUNICATION MODULE AND COMMUNICATION DEVICE DEVICE USING THE SAME - Google Patents

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. In the band-pass filter disclosed in Patent Document 1, since the electrode pattern is provided, an attenuation pole is formed in the vicinity of the pass band, and a signal in this frequency band is attenuated.

JP-A-6-77704

  In a bandpass filter using a resonance electrode, a harmonic component is generated in a frequency band that is an integral multiple of the passband. On the other hand, in recent years, it has been demanded to attenuate signals in a frequency band excluding a predetermined pass band more greatly. However, in the bandpass filter described in Patent Document 1, a signal in a frequency band that is twice the passband can be attenuated by the above-described attenuation pole. It is insufficient.

  Further, by connecting not only the electrode pattern electrically coupled to the resonance electrode but also the shortening capacitor electrode to the resonator electrode, an attenuation pole by this shortening capacitor electrode can be formed. However, when a shortening capacitor electrode is simply added, it is necessary to enlarge the shortening capacitor electrode in order to attenuate a signal in a frequency band three times the pass band, and it is difficult to reduce the size of the bandpass filter. It was.

  The present invention has been made in view of the above problems, and is formed in a frequency band excluding a predetermined pass band by forming attenuation poles in frequency bands twice and three times the pass band while being small. An object of the present invention is to provide a band-pass filter capable of greatly attenuating the above signal, and a wireless communication module and a communication device apparatus using the same.

  The band-pass filter of the present invention includes a dielectric substrate in which a plurality of dielectric layers are laminated, a main surface and a back surface, a resonator electrode embedded in the dielectric substrate, and the back surface side of the resonator electrode. And a capacitor electrode embedded in the dielectric substrate, a shortened capacitor electrode positioned on the back side of the capacitor electrode and embedded in the dielectric substrate, the resonator electrode, and the capacitor electrode, And a second connection conductor for electrically connecting the capacitor electrode and the shortened capacitor electrode. And when the said capacity electrode is planarly viewed, the connection location with the said 1st connection conductor and the connection location with the said 2nd connection conductor are mutually spaced apart, It is characterized by the above-mentioned.

  According to the bandpass filter of the present invention, when the capacitive electrode is viewed in plan, the connection location with the first connection conductor and the connection location with the second connection conductor are separated from each other. In other words, the shortened capacitance electrode is not directly connected to the resonator electrode via the first connection conductor and the second connection conductor, but is indirectly connected via the capacitance electrode. . Therefore, the capacitor electrode and the shortened capacitor electrode do not act independently on the resonator electrode, but the shortened capacitor electrode acts on the resonator electrode via the capacitor electrode.

  Thereby, since the resonator electrode is connected to the shortened capacitor electrode via the inductance component of the capacitor electrode, the inductance component can be adjusted by appropriately changing the connection position. Therefore, since the frequency band of the attenuation pole by this shortened capacity electrode can be adjusted without increasing the shortened capacity electrode, the attenuation pole can be formed in a frequency band three times the pass band. As a result, the signal in the frequency band excluding the pass band can be attenuated more greatly.

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. It is a disassembled perspective view which shows the modification of embodiment shown in FIG. It is a disassembled perspective view which shows the band pass filter in the 2nd Embodiment of this invention. It is sectional drawing of embodiment shown in FIG. It is a conceptual diagram at the time of planarly viewing the capacity electrode and the first shortened capacity electrode in the embodiment shown in FIG. It is a 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.

  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 dielectric substrate 5 in which a plurality of dielectric layers 3 are stacked and has a main surface and a back surface, and a dielectric substrate. 5 is embedded in the resonator electrode 7, is located on the back side of the resonator electrode 7, is embedded in the dielectric substrate 5, is located on the back side of the capacitor electrode 9, and is dielectric substrate 5, the shortened capacitor electrode 11 (first shortened capacitor electrode 11), the first connection conductor 13 that electrically connects the resonator electrode 7 and the capacitor electrode 9, the capacitor electrode 9, and the shortened capacitor electrode 11 and a second connection conductor 15 that electrically connects the terminal 11 and the second connection conductor 15.

  When the capacitor electrode 9 is viewed in plan, the connection location with the first connection conductor 13 and the connection location with the second connection conductor 15 are separated from each other.

  As shown in FIGS. 1 to 3, the bandpass filter 1 according to the present embodiment includes a dielectric substrate 5 having a plurality of dielectric layers 3 stacked and having a main surface and a back surface. The shapes and dimensions of the dielectric layer 3 and the dielectric substrate 5 are set according to the used frequency and application. For example, the thickness of the dielectric layer 3 ensures insulation so that an electrical short circuit does not occur between the input electrode 25 and the output electrode 27 facing each other through the dielectric layer 3 and the capacitor electrode 9. It is preferable to have a sufficient thickness to do this.

  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.

  As shown in FIG. 2, the bandpass filter 1 according to the present embodiment includes a first reference electrode 17 and a second reference electrode 19 disposed on the surface of the dielectric substrate 5. More specifically, the first reference electrode 17 is disposed on the main surface (upper surface in FIG. 3) of the dielectric substrate 5, and the second reference electrode is disposed on the rear surface (lower surface in FIG. 3) of the dielectric substrate 5. An electrode 19 is provided.

  It is preferable that the first reference electrode 17 and the second reference electrode 19 are respectively disposed on the entire main surface and back surface of the dielectric substrate 5. This is because leakage of electromagnetic waves generated with signal transmission inside the dielectric substrate 5 can be suppressed. However, when the input terminal 21 and the output terminal 23 (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 dielectric substrate 5, an electrical short-circuit with the input / output terminals is prevented. In order to prevent this, it is preferable that the input / output terminal is disposed at a portion other than the input port so as to be separated from the input / output terminal.

  The first reference electrode 17 and the second reference electrode 19 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 17 and the second reference electrode 19 are separated from each other, and the first reference electrode 17 and the second reference electrode 19 are connected to each other after being connected to the external wiring. Alternatively, the third reference electrode 20 is disposed on the side surface of the dielectric substrate 5, and the first reference electrode 17 and the second reference electrode 19 are connected via the third reference electrode 20. It is preferable that an external wiring is connected to either the first reference electrode 17 or the second reference electrode 19. 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.

  As the first reference electrode 17, the second reference electrode 19, and the third reference electrode 20, it is preferable to use members having good conductivity. As a member having good conductivity, for example, a metal member such as Au, Ag, Cu, Al, Pt, Pd, W, and Mo can be used.

  The bandpass filter 1 according to this embodiment includes a resonator electrode 7 embedded in a dielectric substrate 5. In the present embodiment, a pair of resonator electrodes 7 are arranged in parallel on one main surface of the laminated dielectric layers 3. When these parallel resonator electrodes 7 are electromagnetically coupled, the wavelength component corresponding to the passband in the input signal can be extracted. At this time, the wavelength component corresponding to the pass band in the input signal is efficiently extracted by using λ / 4 resonance, which is that the length of the resonator electrode 7 is approximately ¼ of the wavelength component corresponding to the pass band. be able to. For the resonator electrode 7, the same metal material as that of the first reference electrode 17 can be used.

  Further, in the present embodiment, since the shortened capacitance electrode 11 is connected to the open end side of the resonance electrode 7, even if the length of the resonance electrode 7 is shortened, the input is efficiently performed using λ / 4 resonance. The wavelength component corresponding to the passband in the signal can be extracted. Therefore, the band pass filter can be further downsized.

  The bandpass filter 1 according to the present embodiment includes a capacitive electrode 9 that is located on the back side of the resonator electrode 7 and is embedded in the dielectric substrate 5. The capacitive electrode 9 is electrically connected to the resonator electrode 7 through the first connection conductor 13. As the capacitor electrode 9, the same metal material as that of the first reference electrode 17 can be used.

  The bandpass filter 1 according to the present embodiment includes a shortened capacitor electrode 11 (first shortened capacitor electrode 11) that is located on the back side of the capacitor electrode 9 and is embedded in the dielectric substrate 5. The shortened capacitor electrode 11 is electrically connected to the capacitor electrode 9 through the second connection conductor 15. As the capacitor electrode 9, the same metal material as that of the first reference electrode 17 can be used.

  In the present embodiment, the shortened capacitor electrode is a capacitor electrode that is capacitively coupled by facing a reference electrode represented by the first reference electrode 17, the second reference electrode 19, and the third reference electrode 20. Thus, by electrically connecting to the open end side of the resonator electrode 7, it means an electrode capable of generating λ / 4 resonance while shortening the length of the resonator electrode 7. .

  In the band-pass filter 1 of the present embodiment, when the capacitive electrode 9 is viewed in plan, the first connection conductor 13 and the second connection conductor 15 are separated from each other by the first connection conductor 13 and the second connection conductor 15. The connection conductor 13 and the second connection conductor 15 are located. In other words, the shortened capacitance electrode 11 is not directly connected to the resonator electrode 7 via the first connection conductor 13 and the second connection conductor 15 but indirectly via the capacitance electrode 9. It is connected to the. Therefore, the capacitor electrode 9 and the shortened capacitor electrode 11 do not act independently on the resonator electrode 7, but the shortened capacitor electrode 11 acts on the resonator electrode 7 via the capacitor electrode 9. .

  Thereby, since the resonator electrode 7 is connected to the shortened capacity electrode 11 via the inductance component of the capacity electrode 9, the inductance component can be adjusted by appropriately changing the connection position. Therefore, since the frequency band of the attenuation pole by the shortened capacitance electrode 11 can be adjusted without increasing the size of the shortened capacitance electrode 11, the attenuation pole can be formed in a frequency band three times the pass band. As a result, the signal in the frequency band excluding the pass band can be attenuated more greatly.

  The bandpass filter 1 of this embodiment includes an input terminal 21 for inputting a signal to the resonator electrode 7 and an output terminal 23 for outputting a signal from the plurality of resonator electrodes 7. More specifically, the input terminal 21 in this embodiment includes an input electrode 25 facing the capacitor electrode 9 with the dielectric layer 3 interposed therebetween. Although the capacitive electrode 9 and the input terminal 21 may be directly electrically connected, the input electrode 25 and the capacitive electrode are provided by providing the input electrode 25 as in the band-pass filter 1 according to the present embodiment. 9 can be capacitively coupled. One end of the input terminal 21 is exposed on the surface of the dielectric substrate 5. In this exposed portion, a signal can be input from the outside via an external conductor (not shown).

  Further, the output terminal 23 in the present embodiment includes an output electrode 27 facing the capacitor electrode 9 with the dielectric layer 3 interposed therebetween. Similarly to the input terminal 21, the capacitor electrode 9 and the output terminal 23 may be directly electrically connected. However, the output electrode 27 is provided as in the band-pass filter 1 according to the present embodiment. The capacitive coupling between the output electrode 27 and the capacitive electrode 9 can be achieved. One end of the output terminal 23 is exposed on the surface of the dielectric substrate 5. In the exposed portion, a signal can be output to the outside via an external conductor (not shown).

  By inputting a signal to the resonator electrode 7 via the input terminal 21 and outputting a signal from the resonator electrode 7 via the output terminal 23, the signal in the frequency band excluding the pass band is attenuated, and the pass band is obtained. A signal having a peak can be extracted.

  As shown in FIG. 2, the bandpass filter 1 of the present embodiment includes a multipass electrode 29 that faces the input electrode 25 and the output electrode 27 with the dielectric layer 3 interposed therebetween. By providing such a multi-pass electrode 29, an attenuation pole can be generated in the vicinity of the pass band due to the multi-pass effect. Further, since the frequency of the attenuation pole can be adjusted by adjusting the multi-pass electrode 29, the attenuation characteristic can be adjusted.

  Further, as shown in FIG. 4, it is located between the multi-pass electrode 29 and the shortened capacitor electrode 11 and is connected to the reference potential, and faces the multi-pass electrode 29 and the shortened capacitor electrode 11 through the dielectric layer 3. It is preferable that an internal reference electrode 31 is further provided.

  Since the multipass electrode 29 faces the internal reference electrode 31, a shortened capacitance can be formed in the multipass electrode 29. Therefore, even if the length of the resonance electrode 7 is shortened, the wavelength component corresponding to the passband in the input signal can be efficiently extracted using λ / 4 resonance. Further, when the shortened capacitor electrode 11 faces the internal reference electrode 31, a shortened capacitor can be formed in the shortened capacitor electrode 11. Therefore, even if the length of the resonance electrode 7 is shortened, the wavelength component corresponding to the passband in the input signal can be efficiently extracted using λ / 4 resonance. As described above, the shortened capacitance electrode 11 can be made small, and the length of the resonator electrode 7 can be shortened, so that the entire size can be reduced.

  Next, the band pass filter 11 concerning the 2nd Embodiment of this invention is demonstrated.

  As shown in FIGS. 5 to 7, the band-pass filter 1 of the present embodiment is located on the back side of the first shortened capacitance electrode 11 and embedded in the dielectric substrate 5 as compared with the first embodiment. And a third connection conductor 35 for electrically connecting the first shortened capacitor electrode 11 and the second shortened capacitor electrode 33 to each other. And when the 1st shortening capacity electrode 11 is planarly viewed, the connection location with the 2nd connection conductor 15 and the connection location with the 3rd connection conductor 35 are separated from each other.

  As described above, the connection portion with the second connection conductor 15 and the connection portion with the third connection conductor 35 are separated from each other, so that the second shortened capacitor electrode 33 is connected to the first shortened capacitor electrode 11. It can be electrically connected to the resonator electrode 7 via The second shortened capacitor electrode 33 is connected to the resonator electrode 7 via the inductance component of the capacitor electrode 9 and the inductance component of the first shortened capacitor electrode 11. As described above, since the second shortened capacitor electrode 33 is connected to the resonator electrode 7 not only through the inductance component of the capacitor electrode 9 but also through the inductance component of the first shortened capacitor electrode 11, the adjustment of the inductance component is further improved. It can be done easily. Therefore, the attenuation pole resulting from the first shortened capacitor electrode 11 and the second shortened capacitor electrode 33 can be easily formed in a frequency band three times the overband.

  In particular, when the capacitor electrode 9 and the first shortened capacitor electrode 11 are viewed in plan as in the band-pass filter 1 according to the present embodiment, the connection location with the first connection conductor 13 and the third connection conductor 35 are shown. It is preferable that the connection location of As a result, the band-pass filter 1 can be reduced in size, and the attenuation pole caused by the first shortened capacitor electrode 11 and the second shortened capacitor electrode 33 can be easily formed in a frequency band three times the overband. can do.

  In the band-pass filter 1 according to the present embodiment, the connection point between the first connection conductor 13 and the connection point with the third connection conductor 35 is the same as the first connection conductor 13. This means that the connection location between the third connection conductor 35 and the third connection conductor 35 is not separated, and at least a part of these connection locations overlap.

  Next, the high frequency module 37 and the wireless communication device 45 of the present invention will be described below.

  As shown in FIG. 8, the high-frequency module 37 of the present embodiment is disposed on the main surface side (the upper surface side in FIG. 8) of the bandpass filter 1 described above and the bandpass filter 1, and bumps The integrated circuit 41 electrically connected to the band-pass filter 1 via 39, the back surface side (the lower surface side in FIG. 8) of the band-pass filter 1, and the band-pass filter 1 via the bump 39 And a printed circuit board 43 electrically connected.

  The wireless communication device 45 of the present embodiment includes the high-frequency module 37 described above, a baseband unit 47 electrically connected to the bandpass filter 1 through the printed circuit board 43, and a bandpass through the printed circuit board 43. And an antenna 49 electrically connected to the filter 1.

  According to the high-frequency module 37 and the wireless communication device 45 of the present embodiment, compared with the conventional bandpass filter 1, when the capacitive electrode 9 is viewed in plan, the connection location with the first connection conductor 13 and the second The connection places with the connection conductor 15 are separated from each other. Therefore, the attenuation pole can be formed not only in the frequency band twice the resonance frequency but also in a frequency band larger than this frequency band without increasing the size of the bandpass filter 1. 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 37 and a wireless communication device 45 with high reception sensitivity and low power consumption can be obtained.

  In the present embodiment, the integrated circuit 41 is disposed on the main surface side of the bandpass filter 1 and is electrically connected to the bandpass filter 1 through the bumps 39. A printed circuit board 43 is disposed on the back side of the bandpass filter 1 and is electrically connected to the bandpass filter 1 through bumps 39. Here, the integrated circuit 41 is disposed on the main surface side of the base body and electrically connected to the base body via the bumps 39 by using the substrate having the bandpass filter 1 incorporated therein. It may be disposed on the back surface side and electrically connected to the substrate via the bumps 39.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  The transmission characteristics of the bandpass filter 1 according to the embodiment shown in FIG. 2 were calculated by electromagnetic field simulation.

  As shown in FIG. 2, in the band-pass filter 1 of the present embodiment, when the capacitive electrode 9 is viewed in plan, the connection location with the first connection conductor 13 and the connection location with the second connection conductor 15 are different. The first connection conductor 13 and the second connection conductor 15 are located so as to be separated from each other.

  The dielectric layer 3 has a dielectric constant of 7.5. A dielectric substrate 5 was formed by laminating six dielectric layers 3 having a thickness of 110 μm, 40 μm, 10 μm, 10 μm, 12 μm, and 10 μm in order from the top. Thus, the dielectric substrate 5 having a main surface of 2.5 mm × 1.5 mm and a thickness of 0.3 mm was obtained. A first reference electrode 17 and a second reference electrode 19 are disposed on the entire main surface and the entire back surface of the dielectric substrate 5, respectively.

  As the resonator electrode 7, an electrode having a size of 1.2 mm × 0.08 mm was used. Two resonator electrodes 7 were arranged side by side on the main surface of the dielectric layer 3 at intervals of 0.07 mm. The resonator electrode 7 is arranged so that the longitudinal direction is the short direction of the dielectric substrate 5. A capacitor electrode 9 having a size of 1.1 mm × 0.8 mm was used. As the shortened capacitance electrode 11, one having a dimension of 1.05 mm × 0.65 mm was used. The first connection conductor 13 is connected to the capacitor electrode 9 at one end of the capacitor electrode 9. The second connection conductor 15 is connected to the capacitor electrode 9 at the other end of the capacitor electrode 9. The multipath electrode 29 is disposed on the main surface side of the dielectric substrate 5 with respect to the resonator electrode 7. The multi-pass electrode 29 has a size of 1.6 mm × 0.32 mm, and has a shape having a convex portion with a height of 0.22 mm at one end and the other end as shown in FIG. A thing was used.

  FIG. 9 shows filter characteristics of the bandpass filter 1 according to the embodiment having the above shape. FIG. 9A is a characteristic curve of the filter characteristics of the bandpass filter 1 according to the present example. FIG. 9B is a characteristic curve of the filter characteristics of the bandpass filter according to the comparative example. Here, as a comparative example, in comparison with the present embodiment, when the capacitive electrode 9 is viewed in plan, the connection location with the first connection conductor 13 and the connection location with the second connection conductor 15 are the capacitance electrodes. 9 having a structure positioned so as to coincide with each other at one end. In FIG. 9, the horizontal axis indicates the frequency [GHz], and the vertical axis indicates the attenuation characteristic.

  As can be seen from FIG. 9, the bandpass filter 1 according to this example has a frequency band three times the passband without increasing the shortened capacitance electrode 11 compared to the bandpass filter 1 according to the comparative example. It can be seen that an attenuation pole can be provided. It can also be seen that this has good harmonic attenuation characteristics. As a result, the band-pass filter 1 according to the present embodiment can attenuate the signal in a frequency band excluding a predetermined pass band more greatly than the band-pass filter according to the comparative example. I understand.

DESCRIPTION OF SYMBOLS 1 ... Band pass filter 3 ... Dielectric layer 5 ... Dielectric substrate 7 ... Resonator electrode 9 ... Capacitance electrode 11 ... Shortening capacity electrode (1st shortening capacity electrode)
13 ... 1st connection conductor 15 ... 2nd connection conductor 17 ... 1st reference electrode 19 ... 2nd reference electrode 20 ... 3rd reference electrode 21 ... Input Terminal 23 ... Output terminal 25 ... Input electrode 27 ... Output electrode 29 ... Multi-pass electrode 31 ... Internal reference electrode 33 ... Second shortening capacitor electrode 35 ... Third Connecting conductor 37... High frequency module 39... Bump 41... Integrated circuit 43... Printed circuit board 45.

Claims (6)

A dielectric substrate having a plurality of dielectric layers stacked and having a main surface and a back surface; a resonator electrode embedded in the dielectric substrate; and the dielectric substrate positioned on the back surface side with respect to the resonator electrode A capacitor electrode embedded in the capacitor, a shortened capacitor electrode positioned on the back surface side of the capacitor electrode and embedded in the dielectric substrate, and a first electrode for electrically connecting the resonator electrode and the capacitor electrode. A connection conductor, and a second connection conductor for electrically connecting the capacitor electrode and the shortened capacitor electrode,
The band pass filter according to claim 1, wherein when the capacitive electrode is viewed in plan, a connection location with the first connection conductor and a connection location with the second connection conductor are separated from each other. When the shortened capacitor electrode is a first shortened capacitor electrode, the second shortened capacitor electrode is located on the back surface side of the first shortened capacitor electrode and embedded in the dielectric substrate; A third connection conductor that electrically connects one shortening capacitor electrode and the second shortening capacitor electrode;
The connection location with the second connection conductor and the connection location with the third connection conductor are separated from each other when the first shortened capacitance electrode is viewed in plan. Bandpass filter described in 1.   When the capacitor electrode and the first shortened capacitor electrode are viewed in plan, a connection location with the first connection conductor is coincident with a connection location with the third connection conductor. The band pass filter according to claim 2.   And further comprising an internal reference electrode positioned between the capacitor electrode and the shortened capacitor electrode and connected to a reference potential and opposed to the capacitor electrode and the shortened capacitor electrode through the dielectric layer. The band-pass filter according to claim 1.   A high-frequency module comprising the bandpass filter according to claim 1. A wireless communication device comprising the high-frequency module according to claim 5.

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