JP5047101B2 - Filter device, wireless communication module and wireless communication device using the same - Google Patents

Description

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

Conventionally, filter devices using λ / 4 resonance have been used in high-frequency circuits in wireless communication devices and the like. However, such a filter device using λ / 4 resonance has a problem that resonance due to harmonics occurs. Therefore, as described in Patent Document 1, a filter device has been proposed in which a hole is provided in a strip conductor (resonant electrode) and the width of the strip conductor is partially reduced. Thereby, since resonance due to harmonics is suppressed, attenuation of the wavelength component in the attenuation region can be increased.
Japanese Utility Model Publication No. 5-63103

  However, when a hole is provided in the resonator as in the filter device described in Patent Document 1, the width of the resonance electrode in a portion where the hole is provided is partially reduced. In order to enhance the effect of suppressing the resonance of the harmonic component due to the provision of the hole, it is necessary to increase the width of the hole. However, as a result of increasing the width of the hole, the resonant electrode may be disconnected, and the wavelength component in the passband may be greatly attenuated.

  The present invention has been made in view of the above problems, and provides a filter device that suppresses the attenuation of wavelength components in the passband and has a large attenuation of harmonic components, and a radio communication module and a communication device using the same. The purpose is to do.

The filter device of the present invention includes a laminate in which a plurality of dielectric layers are laminated, a reference electrode arranged on the surface of the laminate, and a plurality of dielectric layers, each having one end. A plurality of resonance electrodes whose part is a short-circuited end and the other end is an open end; an input electrode for inputting a signal to the resonance electrode; and an output electrode for outputting a signal from the resonance electrode; It has. And a branch portion connected to at least one of the plurality of resonance electrodes, and electrically connected to the resonance electrode via the branch portion, and opposed to the reference electrode via the dielectric layer. And a counter electrode. In addition, the resonance electrodes are disposed between the plurality of first resonance electrodes and the plurality of first resonance electrodes, and are disposed alternately with the first resonance electrodes. 2 resonant electrodes.

  According to the filter device of the present invention, it is possible to increase the attenuation of the harmonic component while suppressing the attenuation of the wavelength component in the pass band by having the counter electrode. Since the capacitor is formed between the counter electrode and the reference electrode by providing the counter electrode facing the reference electrode through the dielectric layer, the harmonic component can be attenuated. Also, since the resonant electrode is not provided with a hole but is provided with a counter electrode electrically connected to the resonant electrode via the branch portion, the possibility that the resonant electrode is disconnected can be greatly reduced. . Therefore, attenuation of the wavelength component in the pass band can be suppressed.

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

  As shown in FIGS. 1-3, the filter apparatus 1 concerning the 1st Embodiment of this invention was arrange | positioned on the surface of the laminated body 5 in which the several dielectric material layer 3 was laminated | stacked, and the laminated body 5 A plurality of resonance electrodes 9 disposed between the reference electrode 7 and the plurality of dielectric layers 3, each having one end portion being a short-circuit end and the other end portion being an open end, and a signal to the resonance electrode 9 Are input electrodes 11 and an output electrode 13 for outputting a signal from the resonance electrode 9. Further, the branch part 15 connected to at least one of the plurality of resonance electrodes 9 is electrically connected to the resonance electrode 9 via the branch part 15 and is opposed to the reference electrode 7 via the dielectric layer 3. The counter electrode 17 is further provided.

 As described above, the filter device 1 according to the present embodiment includes the branch portion 15 connected to at least one of the plurality of resonance electrodes 9, and is electrically connected to the resonance electrode 9 via the branch portion 15. Since the counter electrode 17 facing the reference electrode 7 via the body layer 3 is further provided, the harmonic component can be attenuated while the disconnection of the resonance electrode 9 is suppressed.

  As shown in FIG. 2, the filter device 1 of the present embodiment includes a laminated body 5 in which a plurality of dielectric layers 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. In particular, in order to prevent an electrical short circuit between the counter electrode 17 and the second reference electrode 7b, the thickness of the dielectric layer 3 positioned between the counter electrode 17 and the second reference electrode 7b is: It is preferable to have a thickness sufficient to ensure insulation between the counter electrode 17 and the ground electrode.

  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 filter device 1 of the present embodiment, the first reference electrode 7 a and the second reference electrode 7 b are disposed on the surface of the multilayer body 5. More specifically, the first reference electrode 7a 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, a second reference electrode 7b is disposed on the lower surface. In the filter device 1 of the present embodiment, the second reference electrode 7 b is opposed to the counter electrode 17 with the dielectric layer 3 interposed therebetween.

  The first reference electrode 7a and the second reference electrode 7b are preferably disposed on the entire upper surface and lower surface of the multilayer body 5, respectively. This is because leakage of electromagnetic waves generated with signal transmission inside the laminate 5 can be suppressed. However, when the input electrode 11 and the output electrode 13 (hereinafter also simply referred to as input / output electrodes) are taken 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 to dispose the input / output electrode at a portion other than the input / output electrode so as to be separated from the input / output electrode.

  The first reference electrode 7a and the second reference electrode 7b 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 7a and the second reference electrode 7b may be separated from each other, and the first reference electrode 7a and the second reference electrode 7b may be connected to the external wiring, respectively. A third reference electrode is disposed on the side surface of the body 5, and the first reference electrode 7 a and the second reference electrode 7 b are connected via the third reference electrode, and the first reference electrode 7 a or the second reference electrode 7 b is connected. It is preferable that an external wiring is connected to one of the two reference electrodes 7b. This is because the number of external wirings can be reduced, and the number of steps for manufacturing the filter device 1 can be reduced.

  Between the plurality of dielectric layers 3, a plurality of resonance electrodes 9 are arranged side by side so that one end is a short-circuited end and the other end is an open end. When the adjacent resonance electrodes 9 are electromagnetically coupled, the wavelength component corresponding to the pass band in the input signal can be extracted. At this time, since the length of the resonant electrode 9 is approximately ¼ of the wavelength component corresponding to the pass band, the wavelength component corresponding to the pass band in the input signal can be efficiently obtained using λ / 4 resonance. It can be taken out.

  In the present embodiment, the resonance electrode 9 is arranged in parallel from the first side surface of the multilayer body 5 to the second side surface located on the opposite side of the first side surface, and one end portion of each of the resonance electrodes 9 is mutually connected. A plurality of first resonance electrodes 9a, which are electrically connected short-circuited ends and the other end is an open end, are positioned between the plurality of first resonance electrodes 9a, respectively. 9a and a plurality of second resonance electrodes 9b that are arranged alternately. Thus, by arranging the resonance electrode 9 in a so-called interdigital type, the electromagnetic field coupling between the adjacent resonance electrodes 9 can be strengthened, so that the pass band of the filter device 1 can be widened. .

  Further, as in the present embodiment, it is preferable that the internal reference electrode 9c is provided so as to surround the first resonance electrode 9a and the second resonance electrode 9b when the multilayer body 5 is viewed in plan. This is because by providing such an internal reference electrode 9c, leakage of electromagnetic waves generated from the first resonance electrode 9a and the second resonance electrode 9b to the surroundings can be reduced.

  In addition, as the first resonance electrode 9a and the second resonance electrode 9b, the same metal material as that of the first reference electrode 7a can be used.

  In addition, the filter device 1 of the present embodiment includes a branch portion 15 connected to at least one of the plurality of resonance electrodes 9. The branch portion 15 may be formed in a direction parallel to the main surface of the dielectric layer 3, but as in the present embodiment, it faces the second reference electrode 7b side rather than the plurality of resonance electrodes 9. It is preferable to be formed. Thereby, since the distance between the counter electrode 17 and the second reference electrode 7b can be reduced, the capacitance between the counter electrode 17 and the second reference electrode 7b can be increased.

  In the filter device 1 according to the present embodiment, as shown in FIG. 3, N and M are arbitrary natural numbers satisfying a relationship of 0 <N ≦ M, and one end of the resonance electrode 9 is connected to the other. When the distance to the end portion is L1, and the distance from one end portion of the resonance electrode 9 to the branch portion 15 is L2, the branch portion 15 is in a portion where L2 = L1 · (2N−1) / (2M + 1). It is located. As shown in FIG. 4, a λ / 4 resonance is used in which one end that is a short-circuited end is a fixed end for a signal and the other end that is an open end is a free end for a signal. In the resonant electrode 9, not only λ / 4 resonance but also harmonic components of 3λ / 4, 5λ / 4, ..., (2n + 1) λ / 4, ... (n is an arbitrary natural number) resonate simultaneously. To do.

  By connecting the counter electrode 17 facing the second reference electrode 7b via the dielectric layer 3 to the resonance electrode 9, the apparent resonance wavelength of the resonance electrode 9 can be increased. In other words, the apparent frequency at which resonance occurs can be reduced. Therefore, the branch portion 15 that electrically connects the counter electrode 17 and the resonance electrode 9 has L2 = L1 · (2N−1) / (2M + 1) corresponding to the antinode position of the resonance of the harmonic component. The resonance frequency of the corresponding harmonic component of the resonance electrode 9 having the counter electrode 17 among the plurality of resonance electrodes 9 is the resonance frequency of the resonance electrode 9 that does not have the counter electrode 17. Shift to the lower frequency side. As a result, the corresponding harmonic components can be effectively suppressed while reducing the influence on other frequency components.

  In order to perform good communication in a wireless communication device or the like, among the above harmonic components, it is particularly required to suppress the harmonic component due to 3λ / 4 resonance closest to the passband frequency. The position of the antinode of the harmonic that causes the 3λ / 4 resonance is a portion that is one third of the distance between one end of the resonance electrode 9 and the other end of the resonance electrode 9. is there. For this reason, as in the present embodiment, the branching portion 15 extends from one end of the resonance electrode 9 to a portion that is 1/3 of the distance between one end of the resonance electrode 9 and the other end. By being positioned, it is possible to suppress the harmonic component due to the 3λ / 4 resonance closest to the passband frequency.

  Furthermore, the filter device 1 of the present embodiment includes a counter electrode 17 that is electrically connected to the resonance electrode 9 via the branch portion 15 and faces the second reference electrode 7b via the dielectric layer 3. ing. As already shown, a capacitance is formed between the counter electrode 17 and the second reference electrode 7b. The counter electrode 17 is electrically connected to the resonance electrode 9 via the branch portion 15, whereby the harmonic component can be attenuated while suppressing disconnection of the resonance electrode 9.

  The counter electrode 17 preferably has a flat plate shape whose main surface is parallel to the second reference electrode 7b. Thereby, since the capacity | capacitance between the counter electrode 17 and the 2nd reference electrode 7b can be enlarged, the effect which suppresses a harmonic component can be heightened.

  One counter electrode 17 may be provided, but a plurality of counter electrodes 17 are preferably provided as in the present embodiment. This is because by providing a plurality of counter electrodes 17, the effect of suppressing harmonic components can be further enhanced. At this time, the plurality of counter electrodes 17 are preferably separated from each other. This is because a signal is transmitted from one of the resonance electrodes 9 to another resonance electrode 9 and the suppression effect of the harmonic component by the counter electrode 17 does not decrease.

  Further, as in this embodiment, the distance from one end of the first resonance electrode 9a to one end and the other end of the first resonance electrode 9a is approximately 1/3. The first counter electrode 17a is electrically connected to the portion via the branch portion 15, and from one end of the second resonance electrode 9b to one end and the other end of the second resonance electrode 9b It is preferable that the second counter electrode 17b is electrically connected to the portion that is approximately ３ of the distance from the end portion via the branch portion 15. This makes it possible to more reliably suppress the harmonic component due to the 3λ / 4 resonance that is closest to the passband frequency.

  The counter electrode 17 is preferably opposed to the resonance electrode 9 in the stacking direction of the stacked body 5 with the dielectric layer 3 interposed therebetween. Thereby, the electrostatic capacitance between the counter electrode 17 and the second reference electrode 7b can be increased, and the possibility of an electrical short circuit with the second reference electrode 7b is suppressed. Because.

  Further, the filter device 1 of the present embodiment includes an input electrode 11 for inputting a signal to the first resonance electrode 9a and an output electrode 13 for outputting a signal from the second resonance electrode 9b. A signal is input to the input electrode 11 via the input wiring 19. The input electrode 11 in the present embodiment is opposed to the first resonance electrode 9a located on the first side surface side with the dielectric layer 3 interposed therebetween.

  The input electrode 11 may be directly connected to the first resonance electrode 9a, but it is preferable that the input electrode 11 is opposed via the dielectric layer 3 as in the present embodiment. This is because insertion loss at frequencies located between the resonance frequencies of the resonance modes can be suppressed. As a result, it is possible to obtain a filter device 1 having a flat and low-loss pass characteristic over the entire passband.

  Further, the input electrode 11 may be opposed to the first resonance electrode 9a other than the first resonance electrode 9a located closest to the first side surface with the dielectric layer 3 interposed therebetween. Thus, it is preferable to face the first resonance electrode 9a located on the most side surface side with the dielectric layer 3 interposed therebetween.

  The filter device 1 according to the present embodiment includes an output electrode 13 for outputting a signal from the second resonance electrode 9b. A signal is output from the output electrode 13 via the output wiring 21. The output electrode 13 in the present embodiment is opposed to the second resonance electrode 9b that is located closest to the second side surface with the dielectric layer 3 interposed therebetween.

  Although the output electrode 13 may be directly connected to the second resonance electrode 9b, it is preferable that the output electrode 13 is opposed via the dielectric layer 3 as in the present embodiment. This is because insertion loss at frequencies located between the resonance frequencies of the resonance modes can be suppressed. As a result, it is possible to obtain a filter device 1 having a flat and low-loss pass characteristic over the entire passband.

  The output electrode 13 may be opposed to the second resonance electrode 9b other than the second resonance electrode 9b located closest to the second side surface with the dielectric layer 3 interposed therebetween. Thus, it is preferable to face the second resonance electrode 9b located closest to the second side face with the dielectric layer 3 interposed therebetween.

  As the input electrode 11 and the output electrode 13, the same metal material as that of the first reference electrode 7a described above can be used.

  Next, a second embodiment of the present invention will be described.

  As shown in FIGS. 5 and 6, the filter device 1 according to the present embodiment is different from the first embodiment in that the counter electrode 17 and the second reference electrode 7 b are larger than the distance between the resonance electrode 9 and the counter electrode 17. It is characterized in that the distance between and is small.

  Thus, since the distance Z2 between the counter electrode 17 and the second reference electrode 7b is smaller than the distance Z1 between the resonance electrode 9 and the counter electrode 17, the counter electrode 17 is not changed without changing the size of the stacked body 5. And the capacity of the second reference electrode 7b can be increased.

  FIG. 7 shows filter characteristics when the filter device 1 of the present embodiment is used.

  In FIG. 7, the vertical axis represents insertion loss (unit: dB), and the horizontal axis represents frequency (unit: GHz). The broken line is the filter characteristic in the present embodiment, and the solid line is the filter characteristic in the comparative example. The comparative example is manufactured in the same manner as the present embodiment except that the counter electrode 17 is not provided. In the filter device 1 of the present embodiment, the thickness of the dielectric layer 3 located between the resonance electrode 9 and the counter electrode 17 is 0.21 mm, and the resonance electrode 9 and the second reference electrode The thickness of the dielectric layer 3 positioned between them was 0.03 mm. Thus, the distance Z2 between the counter electrode 17 and the second reference electrode 7b is made smaller than the distance Z1 between the resonance electrode 9 and the counter electrode 17.

  As shown in FIG. 7, the present embodiment with the counter electrode 17 and the comparative example without the counter electrode 17 both have λ / 4 resonance around 5 kHz corresponding to λ / 4. Loss is small. However, in the comparative example that does not include the counter electrode 17, since the counter electrode 17 is not included, the harmonic component is not suppressed and the attenuation is insufficient. On the other hand, in this embodiment provided with the counter electrode 17, since the counter electrode 17 is provided, the harmonic component is suppressed and the attenuation can be ensured. Therefore, when the frequency band corresponding to λ / 4 is a pass band, it can be extracted as a signal with less noise.

  From the above, according to the filter device of the present embodiment, it is electrically connected to at least one of the resonance electrodes 9 via the branch portion 15 and faces the reference electrode 7b via the dielectric layer 3. Since the counter electrode 17 is provided, the resonance frequency of the resonance electrode 9 having the counter electrode 17 can be suppressed by suppressing higher harmonic components than the resonance frequency of the resonance electrode 9 not having the counter electrode 17. it can.

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

  As shown in FIG. 8, the wireless communication module 23 of the present embodiment is disposed on the filter device 1 described above and the first end portion side (the upper surface side in FIG. 8) of the filter device 1. The integrated circuit 27 electrically connected to the filter device 1 via the bumps 25 and the second end side (the lower surface side in FIG. 8) of the filter device 1 are disposed on the filter device 1 via the bumps 25. A printed circuit board 29 electrically connected to the apparatus 1 is provided.

  The wireless communication device according to the present embodiment includes the wireless communication module 23, the baseband unit 33 electrically connected to the filter device 1 through the printed circuit board 29, and the filter device 1 through the printed circuit board 29. And an antenna 35 electrically connected to the antenna.

  According to the wireless communication module 23 and the wireless communication device of the present embodiment, compared to the conventional filter device 1, the attenuation of the wavelength component in the pass band is suppressed while the attenuation of the harmonic component is large. The described filter device 1 is used. Therefore, it is easy to extract a wavelength component in a desired pass band. In other words, noise is decreasing. Thereby, the reception sensitivity is improved and the amplification degree of the transmission signal and the reception signal can be reduced, so that the power consumption in the amplifier circuit is reduced. As a result, a high-performance wireless communication module 23 and a wireless communication device with high reception sensitivity and low power consumption can be obtained.

  In the present embodiment, the integrated circuit 27 is disposed on the first end side of the filter device 1 and is electrically connected to the filter device 1 via the bumps 25. The printed circuit board 29 is disposed on the second end side of the filter device 1 and is electrically connected to the filter device 1 via the bumps 25. Here, the integrated circuit 27 is disposed on the first end portion side of the substrate using the substrate incorporating the filter device 1 and is electrically connected to the substrate via the bumps 25. You may arrange | position to the 2nd edge part side of a base | substrate, and may electrically connect with a base | substrate via the bump 25. FIG.

It is a perspective view which shows the filter apparatus in the 1st Embodiment of this invention. It is a disassembled perspective view of embodiment shown in FIG. It is the disassembled perspective view which expanded a part of filter apparatus in embodiment shown in FIG. It is the conceptual diagram which showed the relationship between the resonant electrode and signal wave in embodiment shown in FIG. It is a disassembled perspective view which shows the filter apparatus in the 2nd Embodiment of this invention. It is sectional drawing of embodiment shown in FIG. It is a figure which shows the filter characteristic at the time of using the filter apparatus of 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Filter apparatus 3 ... Dielectric layer 5 ... Laminate 7 ... Reference electrode 9 ... Resonance electrode 11 ... Input electrode 13 ... Output electrode 15 ... Branch part 17 ... Counter electrode 19 ... Input wiring 21 ... Output wiring 23 ... Wireless communication module 25 ... Bump 27 ... Integrated circuit 29 ... Printed circuit board 31 ... Wireless communication equipment 33 ..Baseband part 35 ... antenna

Claims (6)

A laminated body in which a plurality of dielectric layers are laminated; a reference electrode disposed on a surface of the laminated body; and a plurality of dielectric layers, each having one end portion being a short-circuited end. The filter device includes a plurality of resonance electrodes whose other end is an open end, an input electrode for inputting a signal to the resonance electrode, and an output electrode for outputting a signal from the resonance electrode. And
A branch portion connected to at least one of the plurality of resonance electrodes, and a counter electrode electrically connected to the resonance electrode via the branch portion and facing the reference electrode via the dielectric layer And further comprising
The resonance electrode includes a plurality of first resonance electrodes, and a plurality of second resonance electrodes that are positioned between the plurality of first resonance electrodes and arranged alternately with the first resonance electrodes. Consisting of resonant electrodes,
N and M are arbitrary natural numbers satisfying the relationship of 0 <N ≦ M, the distance from one end of the resonance electrode to the other end is L1, and the branch from one end of the resonance electrode to the branch The filter device is characterized in that the branching portion is located in a portion where L2 = L1 · (2N−1) / (2M + 1), where L2 is the distance to the portion.   The branch portion is located at a portion that is 1/3 of the distance between one end portion of the resonance electrode and the other end portion from one end portion of the resonance electrode. The filter device according to claim 1.   The filter device according to claim 1, wherein a distance between the counter electrode and the reference electrode is smaller than a distance between the resonance electrode and the counter electrode.   The filter device according to claim 1, wherein the counter electrode is opposed to the resonance electrode in a stacking direction of the stacked body through a dielectric layer.   5. The filter device according to claim 1, the bumps disposed at the first end portion and the second end portion of the filter device, and the first end portion side of the filter device. An integrated circuit electrically connected to the filter device via the bumps and disposed on the second end side of the filter device and electrically connected to the filter device via the bumps And a printed circuit board. 6. The wireless communication module according to claim 5, a baseband unit electrically connected to the filter device via the printed board, and an antenna electrically connected to the filter device via the printed board. Wireless communication equipment equipped with.