JP2019047434A - Dielectric filter - Google Patents

Abstract

To provide a dielectric filter capable of eliminating the need to considerably change design of a dielectric block, suppressing the number of components, designing a band width of frequency characteristics large and improving an attenuation property.SOLUTION: A dielectric filter comprises multiple through-holes 6 covering an inner conductor 3 between first and second opposite end faces 1a and 1b of a dielectric block 1, and multiple resonators are configured by covering an outer conductor on an outer surface of the dielectric block 1 excluding the first end face 1a. An input/output electrode end 4a is insulated from an outer conductor 5 on the first end face and capacitively coupled with the resonator on an input/output stage and extends to a side face. A connection electrode part 4b is enclosed by the outer conductor 5 and insulated from the outer conductor 5 and extends to the first end face 1a and a mounting surface. An input/output terminal part 4c is disposed adjacent to a side face of the mounting surface, enclosed by the outer conductor 5 and insulated from the outer conductor 5. An input/output electrode 4 is configured by connecting the input/output electrode end 4a, the connection electrode part 4b and the input/output terminal part 4c. A boundary in contact with the first end face 1a on a mounting surface 7 is entirely covered by the outer conductor 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dielectric filter formed by forming a plurality of resonators in a dielectric block.

  In a mobile communication device such as a mobile phone, various dielectric filters including a transceiver and the like are used. As a dielectric filter, there exist a dielectric filter described, for example in patent document 1, patent document 2, and patent document 3.

  FIG. 5 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 1. As shown in FIG. As shown in FIG. 5, the dielectric filter 10 shown in FIG. 5 has a substantially hexahedral dielectric block 1 having a first end face 1a and a second end face 1b, and the first end face 1a to the second end face. A plurality of through holes 6 formed in the dielectric block 1 to the end face 1b of the second embodiment, the inner conductor 3 formed on the inner wall of each through hole 6, and the inner conductor 3 extend to the first end face 1a (open end face) A bonding electrode 13, an outer conductor 5 formed on the outer surface of the dielectric block 1, and an input / output electrode 4 are provided. The coupling electrode 13 couples the resonators. In particular, coupling electrodes (coupling electrodes at both left and right ends) 13 formed in the resonators of the input / output stage are also used to obtain external coupling with the input / output electrodes 4. The input / output electrode 4 comprises an input / output electrode end 4a formed on the first end face 1a and an input / output terminal 4c. The input / output terminal 4 c of the input / output electrode 4 is connected to an external circuit on the mounting surface 7.

  FIG. 6 shows a state in which the dielectric filter 10 is mounted on a mounting substrate 30 having a coplanar signal line 31 and a ground (ground) electrode 32.

  FIG. 7 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 2. As shown in FIG. The dielectric filter shown in FIG. 7 has a substantially hexahedral dielectric block 1 having a first end face 1a and a second end face 1b, and a dielectric block 1 extending from the first end face 1a to the second end face 1b. The inner wall has a plurality of through holes 6 in which the inner conductor is formed, and the outer conductor 5 is formed on the outer surface of the dielectric block 1 excluding the first end face 1a (open end face). The input / output electrode 4 to be connected to the external circuit is surrounded by the outer conductor and insulated from the outer conductor across the side surface facing the inner conductor 3 formed in the through hole 6 and the mounting surface Is formed. The outer periphery of the first end face 1 a which is the open end face is entirely surrounded by the outer conductor 5.

  FIG. 8 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 3. As shown in FIG. As shown in FIG. 8, the dielectric filter 101 shown in FIG. 8 has a dielectric block 1 in which three stages of resonators are formed, and the dielectric block 1 is an open face of the dielectric block 1. And an input / output electrode 4 provided from the side surface to the mounting surface. From the front surface to the back surface of the dielectric block 1, an inner conductor forming hole penetrating the inside of the dielectric block 1 is provided. An inner conductor 3 is provided on the inner surface of the inner conductor forming hole. One end of the inner conductor 3 is open at the front of the dielectric block 1 and the other end is connected to the outer conductor 5 at the back of the dielectric block 1. When the dielectric filter 101 is mounted on the mounting substrate 30, the outer conductor 5 is connected to the ground (ground) electrode 32 of the mounting substrate 30 on the mounting surface of the dielectric block 1. Further, the input / output electrode 4 is connected to the coplanar signal line 31 of the mounting substrate 30 on the mounting surface of the dielectric block 1.

Japanese Patent Laid-Open No. 2004-328118 (FIG. 6) JP-A-5-167310 (FIG. 4) WO 2009/013929 (FIG. 1)

  In order to prevent an increase in communication capacity and interference between carriers, the dielectric filter is required to have a wide pass bandwidth and a dielectric filter with good attenuation characteristics.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric filter which can suppress isolation and crosstalk without increasing the number of parts, has excellent attenuation characteristics, and can achieve large input / output coupling and a wide pass bandwidth. It is in.

(1) According to the present invention, in order to achieve the above object, a plurality of through holes coated with an inner conductor is provided between opposing first and second end faces of a dielectric block, A resonator comprising an outer conductor coated on the outer surface of the dielectric block except for the end face of
A coupling electrode extending from the inner conductor at the first end face and coupling resonators formed correspondingly to the through holes;
And an input / output electrode,
The input / output electrode has an input / output electrode end coupled to the resonator of the input / output stage at the first end face;
An input / output terminal section formed on the first outer surface of either one of the dielectric blocks parallel to the arrangement direction of the through holes, the first conductor being insulated from the outer conductor;
And a connection electrode formed on the second outer surface of the dielectric block perpendicular to the arrangement direction of the through holes, the connection electrode being insulated from the outer conductor,
The connection electrode is connected to the input / output electrode end at a boundary where the first end surface and the second outer surface contact each other, and the input / output at a boundary where the first outer surface and the second outer surface contact each other A dielectric filter connected to the terminal portion is provided.

  (2) In the dielectric filter of (1), the outer conductor formed on the first outer surface is formed to cover the entire boundary where the first outer surface and the first end face are in contact with each other. Is desirable.

  (3) In the dielectric filter of (1) or (2), the connection electrode is formed on the second outer surface so as to face an inner conductor formed in the through hole of the resonator of the input / output stage. Is desirable.

  (4) In the dielectric filter according to any one of (1) to (3), the input / output terminal portion is connected to a signal line of the mounting substrate, and the signal line extends in the arrangement direction of the through holes Is desirable.

  According to the present invention, isolation and crosstalk can be suppressed, attenuation characteristics can be excellent, input / output coupling can be made large, and a dielectric filter with a wide pass bandwidth can be obtained.

FIG. 1 is a perspective view showing a configuration of an embodiment of a dielectric filter according to the present invention. It is a perspective view of the condition which mounts the dielectric material filter of this embodiment on a mounting substrate. FIG. 3 is a top view showing a mounting substrate 30. It is a frequency characteristic view of the dielectric material filter of this embodiment shown in FIG. 2, and the dielectric material filter shown in FIG. FIG. 5 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 1. It is a perspective view of the condition which mounts the dielectric material filter shown in FIG. 5 on a mounting substrate. FIG. 6 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 2. FIG. 6 is a perspective view showing a dielectric filter based on the dielectric filter described in Patent Document 3.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the configuration of an embodiment of a dielectric filter according to the present invention. In FIG. 1, the shape of the dielectric block other than the input / output electrode 4 for connection to an external circuit, and the number of through holes are substantially the same as the configuration of the dielectric filter shown in FIG. That is, the dielectric filter 20 of the present embodiment has a plurality of through holes 6 in which the inner conductor 3 is coated between the opposing first end face 1a and the second end face 1b of the dielectric block 1, and A resonator formed by coating the outer conductor 5 on the outer surface of the dielectric block 1 excluding the end face 1a of 1 and extending from the inner conductor 3 of each resonator at the first end face 1a, corresponding to the through hole 6 And a coupling electrode 13 for capacitively coupling between the resonators.

The first difference between the dielectric filter 20 of this embodiment shown in FIG. 1 and the dielectric filter 10 shown in FIG. 5 is that the input / output electrode 4 is added to the input / output electrode end 4a and the input / output terminal 4c. And the connection electrode portion 4b.
The input / output electrode end 4a is capacitively coupled to the resonator of the input / output stage at the first end face 1a, and the side face (the second outer surface) 8 of the first end face 1a and the arrangement direction of the resonators And extended to the boundary with The connection electrode portion 4b is disposed on the side surface 8, surrounded by the outer conductor 5, insulated from the outer conductor 5, and perpendicular to the arrangement direction of the through holes from the boundary between the first end surface 1a and the side surface 8 It extends in the longitudinal direction of the side surface 8 and then bends in the direction of the mounting surface 7 so as to extend to the boundary between the side surface 8 and the mounting surface 7. Input / output terminal portion 4c is disposed on mounting surface 7 adjacent to side surface 8 (which will be the first outer surface of one of the dielectric blocks parallel to the arrangement direction of through holes), surrounded by outer conductor 5, and It is insulated from the outer conductor 5. The input / output electrode end 4 a, the connection electrode 4 b, and the input / output terminal 4 c are connected to form an input / output electrode 4. The boundary between the first end surface 1a and the side surface 8 and the boundary between the side surface 8 and the mounting surface 7 are sides if the first end surface 1a, the mounting surface 7, and the side surface 8 are square such as a square.

  Like the dielectric filter 10 shown in FIG. 5, the input / output electrode end 4a formed on the first end face 1a extends to the boundary with the mounting surface 7 and is directly connected to the input / output terminal 4c. Instead, it is extended to the boundary with the mounting surface 7 through the connection electrode portion 4 b provided on the side surface 8 and connected to the input / output terminal portion 4 c disposed on the side surface 8 side of the mounting surface 7. This allows the distance between the input and the output to be increased, and the isolation to be improved.

The second difference between the dielectric filter 20 of the present embodiment and the dielectric filter 10 shown in FIG. 5 is that the input / output terminal portion 4 c is disposed on the side surface 8 side of the mounting surface 7. The part (boundary) in contact with the end face 1 a of 1 is covered with the outer conductor 5.
Since the dielectric filter 10 shown in FIG. 5 is formed from the first end face 1a where the input / output electrode 4 is an open surface to the mounting surface 7, the distance between the input / output electrode is short. On the other hand, in the dielectric filter of the present embodiment, the input / output terminal portion 4c is not disposed at the boundary between the first end face 1a and the mounting surface 7, and the outer conductor 5 in the mounting surface 7 becomes an open surface. Since all the portions where the end face 1a and the mounting face 7 are in contact are covered, the connection between the input / output terminal 4c connected to the external signal and the first end face 1a is interrupted by the ground by the outer conductor, and the isolation is further enhanced. Be improved.

  The third difference between the dielectric filter 20 of this embodiment and the dielectric filter 10 shown in FIG. 5 is that the side surface 8 is opposed to the inner conductor 3 formed in the through hole 6 of the input / output stage resonator. It is to have the connection electrode part 4b which has the part which was carried out. Since connection electrode portion 4 b extends in the direction (longitudinal direction of side surface 8) perpendicular to the arrangement direction of the through holes from the boundary between first end face 1 a and side surface 8, it opposes inner conductor 3 formed in through hole 6. Have a part to Then, a part of the connection electrode portion 4b disposed on the side surface 8 is formed to face the inner conductor 3 formed in the through hole 6 of the input / output stage resonator, whereby the resonator of the input / output stage and the capacitance Construct a bond. Therefore, the coupling capacitance can be designed larger by controlling the electrode pattern area.

  FIG. 2 shows the situation when the dielectric filter 20 of the present embodiment is mounted on a mounting substrate 30 having a coplanar signal line 31 and a ground (ground) electrode 32. FIG. 3 is a top view showing the mounting substrate 30. As shown in FIG. FIG. 6 shows a state in which the dielectric filter 10 shown in FIG. 5 is mounted on a mounting substrate 30 having a coplanar signal line 31 and a ground electrode 32.

  In the dielectric filter 10 shown in FIG. 5, since the input / output terminal 4c is connected to the coplanar signal line 31 drawn out perpendicularly to the first end face 1a, the input and output signal lines are arranged in parallel. Cross talk may occur between the coplanar signal lines 31 to deteriorate the attenuation characteristics. Further, dielectric filter 10 shown in FIG. 5 is formed from the first end face 1a where the input / output electrode 4 is an open surface to the mounting surface (which will be the first outer surface) 7, so The distance is short, and isolation improvement is desired. In order to suppress and improve such crosstalk and isolation, the surface (upper surface) opposite to the mounting surface is connected to the ground electrode 32 of the mounting substrate 30 on the front surface of the first end surface 1a which is an open end surface. It is conceivable to attach a conductive cover. However, when the conductive cover is attached, the number of parts increases and the number of operation steps increases. On the other hand, as shown in FIG. 2, the dielectric filter 20 according to the present embodiment is connected to the coplanar signal line 31 in which the input / output terminal portion 4c is drawn to the side surface 8 (which becomes the second outer surface). . Since the coplanar signal lines 31 extend in the arrangement direction of the through holes, the input and output signal lines are not arranged in parallel, and crosstalk is suppressed.

FIG. 4 shows the frequency characteristic of the dielectric filter of the present embodiment shown in FIG. The frequency characteristic of the dielectric filter shown in FIG. 6 as a comparative example is also shown in FIG. 4 for comparison.
In FIG. 4, the solid line is the frequency characteristic obtained in the present embodiment, and the broken line is the frequency characteristic of the comparative example. It can be seen that, in the dielectric filter of this embodiment in which the input / output electrode configuration is changed, a large amount of attenuation is secured on both the low frequency side and the high frequency side closest to the passband as compared with the comparative example.

  Although the dielectric filter having four through holes, that is, four resonators has been described in this embodiment described above, the number of resonators may be applied to five or more or three or less dielectric filters. Further, the input / output electrodes of the dielectric filter of the present embodiment may be formed on both of the two input / output electrodes, or may be formed on any one of the input / output electrodes. Furthermore, although the input / output electrode configuration of the dielectric filter of the present embodiment has been described for the dielectric band pass filter, the input / output electrode configuration of the present embodiment can be applied to a duplexer.

  The duplexer comprises two dielectric filters, and the input electrode, the output electrode and the common electrode are formed in the same block. The configuration of the transmission / reception unit is described in, for example, JP-A-2011-249987, JP-A-2010-239413, and JP-A-2010-239414.

1 Dielectric block 1a first end face (open end face)
1b Second end face 3 Inner conductor 4 Input / output electrode 4a Input / output electrode end 4b Connection electrode 4c Input / output terminal 5 Outer conductor 6 Through hole 7 Mounting surface (first outer surface)
8 side (second outer surface)
10, 20, 101 dielectric filter 13 coupling electrode 30 mounting substrate 31 coplanar signal line 32 ground electrode

Claims (4)

A plurality of through holes coated with an inner conductor is provided between the opposing first end surface and the second end surface of the dielectric block, and the outer surface of the dielectric block is excluded except for the first end surface. A resonator configured by coating a conductor;
A coupling electrode extending from the inner conductor at the first end face and coupling resonators formed correspondingly to the through holes;
And an input / output electrode,
The input / output electrode has an input / output electrode end coupled to the resonator of the input / output stage at the first end face;
An input / output terminal section formed on the first outer surface of either one of the dielectric blocks parallel to the arrangement direction of the through holes, the first conductor being insulated from the outer conductor;
And a connection electrode formed on the second outer surface of the dielectric block perpendicular to the arrangement direction of the through holes, the connection electrode being insulated from the outer conductor,
The connection electrode is connected to the input / output electrode end at a boundary where the first end surface and the second outer surface contact each other, and the input / output at a boundary where the first outer surface and the second outer surface contact each other Dielectric filter connected to terminal.   The outer conductor formed on the first outer surface is formed to cover all the boundaries where the first outer surface and the first end face are in contact with each other. Dielectric filter.   The dielectric filter according to claim 1, wherein the connection electrode is formed on the second outer surface so as to face an inner conductor formed in the through hole of the resonator of the input / output stage. The input / output terminal unit is connected to a signal line of a mounting substrate,
The dielectric filter according to any one of claims 1 to 3, wherein the signal line extends in the arrangement direction of the through holes.