JPWO2015068493A1 - Dielectric filter and method for adjusting attenuation characteristic of dielectric filter - Google Patents

Abstract

The present invention relates to a dielectric filter and a method for adjusting attenuation characteristics of the dielectric filter. A first resonator hole (18a) and a second resonator hole having an inner conductor (16) formed on the inner surface through a pair of opposed end faces (14a) and (14b) of the dielectric block (12). In the first dielectric filter (10A) having (18b), between the first resonator hole (18a) and the second resonator hole (18b) in the dielectric block (12), the first resonator hole ( One through hole (28) is formed at a twisted position with respect to 18a) and the second resonator hole (18b).

Description

  The present invention relates to a dielectric filter used in, for example, a duplexer and a method for adjusting attenuation characteristics of the dielectric filter.

  Conventionally, a plurality of resonator holes having inner conductors formed on the inner surface are formed in parallel through a pair of opposing end faces of the dielectric block, and outer conductors are formed on the outer surface of the dielectric block. A dielectric filter is known in which one end face of a block is a short-circuit end face (see Japanese Patent Application Laid-Open No. 2000-165106).

  In particular, the dielectric filter described in Japanese Patent Laid-Open No. 2000-165106 includes a groove extending in the arrangement direction of the resonator holes and a groove extending in a direction perpendicular to the grooves, between the resonator holes on the short-circuit end face side. Forming a cross-shaped groove. Thereby, the coupling between the resonator holes can be easily set and adjusted.

  However, in the conventional dielectric filter, only the depth and width of the groove can be changed, and it is difficult to obtain an attenuation pole at a desired position, and there is a problem that the degree of freedom in design is low.

  The present invention has been made in consideration of such problems, and can adjust the position of the attenuation pole and the adjustment range of the attenuation amount, and can increase the degree of design freedom. An object of the present invention is to provide a method for adjusting attenuation characteristics of a body filter.

[1] A dielectric filter according to a first aspect of the present invention is a dielectric filter having a plurality of resonator holes in which inner conductors are formed on an inner surface through a pair of opposing end surfaces of a dielectric block. In the dielectric block, one or more through holes are formed between the plurality of resonator holes at positions twisted with respect to the plurality of resonator holes.

  Thereby, the position of the attenuation pole and the amount of attenuation can be adjusted according to the formation position of the through hole and the size of the through hole. That is, the adjustment range of the position of the attenuation pole and the attenuation amount can be widened, and the degree of freedom in design can be improved.

[2] In the first aspect of the present invention, the plurality of resonator holes may be formed in parallel.

[3] In the first aspect of the present invention, the resonator hole when projecting the through hole on a first virtual plane that extends along the axial direction of the resonator hole and bisects the resonator hole; The angle formed with the through hole may be 60 ° to 120 °.

[4] In this case, an angle formed by the through hole and the resonator hole when the through hole is projected onto the first virtual plane may be 90 °.

[5] In the first aspect of the present invention, a line segment having two resonator holes and connecting the central axes of the two resonator holes to a second virtual plane parallel to the end face of the dielectric filter. When the line segment projected onto the second virtual plane and the virtual line orthogonal to the midpoint of the line segment are set, the through-hole when projecting the through-hole onto the second virtual plane and the The angle formed with the imaginary line may be −20 ° to + 20 °.

[6] In this case, an angle formed between the through hole and the imaginary line when the through hole is projected onto the second imaginary plane may be 0 °.

[7] In the first aspect of the present invention, the two through holes may be provided, and the two through holes may be formed in parallel.

  Thereby, the position of the attenuation pole and the amount of attenuation can be adjusted by the formation position of the two through holes, the relative positional relationship between the two through holes, and the size of the two through holes. That is, the adjustment range of the position of the attenuation pole and the attenuation amount can be widened compared with the case where one through hole is provided, and the degree of freedom in design can be improved.

[8] In the first aspect of the present invention, the pair of end faces of the dielectric block may be open end faces, and the resonator holes may constitute a half-wave resonator.

[9] In the first aspect of the invention, of the pair of end faces of the dielectric block, one end face is an open end face, the other end face is a short-circuit end face, and the resonator hole is a quarter wavelength resonator. May be configured.

[10] In the first aspect of the present invention, a groove may be provided between the plurality of resonator holes on the open end surface of the dielectric block. In this case, the position of the attenuation pole and the amount of attenuation can be adjusted by the through hole, and the position of the attenuation pole and the amount of attenuation can also be adjusted by the width and depth of the groove. The amount adjustment range can be widened.

[11] In the first aspect of the present invention, although a person skilled in the art has a well-known configuration, the first conductor may be formed on a plurality of side surfaces excluding the pair of end surfaces of the dielectric block. The first conductor may be formed only on one side surface, or the first conductor may be formed on a part of the side surface.

[12] Of course, the first conductor may be formed on the entire surface of the plurality of side surfaces.

[13] Of course, a second conductor that is electrically connected to the first conductor may be formed on the entire inner wall of the through hole or a part of the inner wall.

[14] At least one of the pair of end surfaces may be formed with an electrode that is electrically connected to the inner conductor of the resonator hole and that forms a capacitance with the first conductor. .

[15] Alternatively, an electrode that is electrically connected to the first conductor and forms a capacitance with the resonator hole may be formed on at least one of the pair of end surfaces.

[16] In addition, a third conductor that forms at least a capacitance between adjacent resonator holes may be formed on at least one of the pair of end surfaces.

[17] A third conductor that forms at least inductance between adjacent resonator holes may be formed on at least one of the pair of end surfaces.

[18] A third conductor that forms a capacitance and an inductance in parallel between adjacent resonator holes may be formed on at least one of the pair of end surfaces.

[19] Of the pair of end faces, at least one end face may be formed with a terminal electrode coupled with the resonator hole and a capacity, or an inductance, or a capacity and an inductance.

[20] A method for adjusting attenuation characteristics of a dielectric filter according to a second aspect of the present invention is the method for adjusting attenuation characteristics of a dielectric filter having a plurality of resonator holes in a dielectric block. One or more through holes are formed between the resonator holes at a twisted position with respect to the plurality of resonator holes.

[21] In the second aspect of the present invention, the amount of attenuation on the lower frequency side than the center frequency may be increased by forming the through hole.

[22] In the second aspect of the present invention, the position of the attenuation pole may be adjusted by adjusting the formation position of the through hole.

[23] In the second aspect of the present invention, the position of the attenuation pole may be adjusted by adjusting the dimension of the through hole.

  As described above, according to the dielectric filter and the method for adjusting the attenuation characteristic of the dielectric filter according to the present invention, the adjustment range of the attenuation pole position and attenuation amount can be widened, and the degree of freedom in design is improved. Can be made.

FIG. 1A is a perspective view showing a dielectric filter (first dielectric filter) according to the first embodiment, and FIG. 1B is a longitudinal sectional view showing the first dielectric filter. FIG. 2A is an explanatory view showing the degree of vertical inclination of the through hole with respect to the dielectric block, and FIG. 2B is an explanatory view showing the degree of horizontal inclination of the through hole with respect to the dielectric block. It is a longitudinal cross-sectional view which shows the other connection form of an input terminal and an output terminal. FIG. 4A is a perspective view showing a dielectric filter (second dielectric filter) according to the second embodiment, and FIG. 4B is a longitudinal sectional view showing the second dielectric filter. FIG. 5A is an explanatory diagram showing the vertical inclination of the first through-hole and the second through-hole with respect to the dielectric block, and FIG. 5B is an explanatory diagram showing the lateral inclination of the first through-hole with respect to the dielectric block. FIG. 5C is an explanatory view showing the degree of inclination in the lateral direction with respect to the dielectric block of the second through hole. It is a longitudinal cross-sectional view which shows the dielectric material filter (3rd dielectric material filter) which concerns on 3rd Embodiment. FIG. 7A is a perspective view showing a dielectric filter (fourth dielectric filter) according to a fourth embodiment, and FIG. 7B is a longitudinal sectional view showing the fourth dielectric filter. FIG. 8A is a perspective view showing a dielectric filter (fifth dielectric filter) according to a fifth embodiment, and FIG. 8B is a longitudinal sectional view showing a fifth dielectric filter. FIG. 9A is a perspective view showing a dielectric filter (sixth dielectric filter) according to a sixth embodiment, and FIG. 9B is a longitudinal sectional view showing the sixth dielectric filter. 10A to 10C are longitudinal sectional views showing dielectric filters (seventh dielectric filter to ninth dielectric filter) according to seventh to ninth embodiments. FIG. 11A is a perspective view showing a dielectric filter (tenth dielectric filter) according to the tenth embodiment, and FIG. 11B is a longitudinal sectional view showing the tenth dielectric filter. 12A is a perspective view showing a dielectric filter (eleventh dielectric filter) according to the eleventh embodiment, and FIG. 12B is a longitudinal sectional view showing the eleventh dielectric filter. FIG. 13A is a longitudinal sectional view showing a modified example of the eleventh dielectric filter, and FIG. 13B is a sectional view taken along line XIIIB-XIIIB in FIG. 13A. FIG. 14A is a longitudinal sectional view showing another modification of the eleventh dielectric filter, and FIG. 14B is a sectional view taken along the line XIVB-XIVB in FIG. 14A. FIG. 15A is a plan view showing a dielectric filter (a twelfth dielectric filter) according to the twelfth embodiment as viewed from above, and FIG. 15B is a cross-sectional view taken along line XVB-XVB in FIG. 15A. FIG. 16A is a perspective view showing a modification of the twelfth dielectric filter, and FIG. 16B is a longitudinal sectional view thereof. FIG. 17A is a plan view showing a dielectric filter (a thirteenth dielectric filter) according to the thirteenth embodiment as viewed from above, and FIG. 17B is a cross-sectional view taken along line XVIIB-XVIIB in FIG. 17A. FIG. 18A is a plan view showing a dielectric filter (fourteenth dielectric filter) according to a fourteenth embodiment as viewed from above, and FIG. 18B is a plan view showing a modification of the fourteenth dielectric filter. FIG. 18C is a plan view showing another modification of the fourteenth dielectric filter. FIG. 19A is a plan view showing a dielectric filter (fifteenth dielectric filter) according to a fifteenth embodiment as viewed from above, and FIG. 19B is a plan view showing a modification of the fifteenth dielectric filter, FIG. 19C is a plan view showing another modification of the fifteenth dielectric filter. 20A is a plan view showing an example in which two fourteenth dielectric filters are connected in series, and FIG. 20B is a plan view showing an example in which two fifteenth dielectric filters are connected in series. 6 is a perspective view showing a dielectric filter according to Comparative Example 1. FIG. 22A is a perspective view showing a dielectric filter according to Reference Example 1, and FIG. 22B is a longitudinal sectional view showing the dielectric filter according to Reference Example 1. FIG. 6 is an equivalent circuit diagram showing a dielectric filter according to Comparative Example 1, Reference Example 1, Example 1 and Example 2. FIG. 24A is a graph showing the attenuation characteristic of Comparative Example 1, and FIG. 24B is a graph showing the attenuation characteristic of Reference Example 1. FIG. FIG. 25A is a graph showing the attenuation characteristic of the first embodiment, and FIG. 25B is a graph showing the attenuation characteristic of the second embodiment. In the reference example 1, it is a graph which shows the attenuation | damping characteristic at the time of changing the depth of a 1st groove | channel and a 2nd groove | channel. In Example 2, it is a graph which shows the attenuation | damping characteristic at the time of changing the position of a 1st through-hole and a 2nd through-hole. In Example 2, it is a graph which shows the attenuation | damping characteristic at the time of changing the size of a 1st through-hole and a 2nd through-hole.

  Hereinafter, embodiments of a dielectric filter and a method for adjusting the attenuation characteristic of the dielectric filter according to the present invention will be described with reference to FIGS. 1A to 28. In the present specification, “˜” indicating a numerical range is used as a meaning including numerical values described before and after the numerical value as a lower limit value and an upper limit value.

  First, as shown in FIGS. 1A and 1B, a dielectric filter according to the first embodiment (hereinafter, referred to as a first dielectric filter 10A) includes a rectangular parallelepiped dielectric block 12 and the dielectric block. Two resonator holes (first resonator hole 18a and second resonator hole 18b) having inner conductors 16 formed on the inner surface thereof through a pair of twelve opposing end surfaces 14a and 14b, and a dielectric block Of the 12 side surfaces, an input terminal 22 formed on the first side surface 20a adjacent to the first resonator hole 18a and an output terminal 24 formed on the second side surface 20b adjacent to the second resonator hole 18b. Have. In the first resonator hole 18a and the second resonator hole 18b, the central axes 26a and 26b are parallel to each other. The cross-sectional shape of the first resonator hole 18a and the second resonator hole 18b may be circular, or may be a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. In this embodiment, it is circular.

  The first dielectric filter 10A is provided between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12, with respect to the first resonator hole 18a and the second resonator hole 18b. One through hole 28 is formed at the position of twist.

  The pair of end faces 14a and 14b of the first dielectric filter 10A are both open end faces 30a and 30b, and the first resonator hole 18a and the second resonator hole 18b are both ½ wavelength resonators. Configure.

  The through hole 28 may be formed in a horizontal direction with respect to the dielectric block 12 or may be formed in a tilted vertical direction. One end of the through hole 28 may be formed closer to the input side or closer to the output side.

  Specifically, as shown in FIG. 2A, for example, a through hole 28 is formed in a first virtual surface 32a that extends along the central axis 26a of the first resonator hole 18a and bisects the first resonator hole 18a. Think about projecting. In this case, 60 ° to 120 ° can be selected as the angle θ1 formed by the central axis 26a of the first resonator hole 18a and the axis 34 of the through hole 28 (projected image). In the present embodiment, the angle θ1 formed is 90 °.

  Further, as shown in FIG. 2B, for example, it is considered that the through hole 28 is projected onto a second virtual surface 32b parallel to one open end surface 30a of the dielectric block 12. In this case, a line segment 36 that projects the line segment connecting the center axis 26a of the first resonator hole 18a and the center axis 26b of the second resonator hole 18b onto the second virtual plane 32b, An imaginary line 38 orthogonal to the point is set. At this time, −20 ° to + 20 ° can be selected as the angle θa formed between the axis 34 of the through hole 28 (projected image) and the virtual line 38. In the present embodiment, the angle θa formed is 0 °.

  Similarly to the first resonator hole 18a and the second resonator hole 18b, the cross-sectional shape of the through hole 28 may be a circle, or may be a polygon such as a triangle, a rectangle, a pentagon, or a hexagon. In this embodiment, it is rectangular.

  In the first dielectric filter 10A, since one through hole 28 is provided between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12, the formation position of the through hole 28 Depending on the size of the hole 28, the position of the attenuation pole and the amount of attenuation can be adjusted. Incidentally, in the dielectric filter 102 according to Reference Example 1 described later, as shown in FIGS. 22A and 22B, the first groove 40a formed on one end surface 14a and the second groove 40b formed on the other end surface 14b. It is conceivable to adjust the position of the attenuation pole and the amount of attenuation, but the only part that can be adjusted is the size (width and depth) of the first groove 40a and the second groove 40b. It is fixed. On the other hand, in the first dielectric filter 10A, in addition to the size of the through hole 28, the position of the through hole 28 can be listed as an adjustment item, so that the position of the attenuation pole and the adjustment range of the attenuation amount can be widened. And the degree of freedom in design can be improved.

  Further, since the structure in which the through hole 28 is formed can be designed to have higher mechanical strength than the structure in which the groove is formed, dimensional distortion with respect to a change in ambient temperature is small. Therefore, the amount of change in characteristics with respect to temperature change can be reduced. In addition, it is possible to reduce the crack risk for reliability tests such as thermal shock.

  In the above example, the input terminal 22 is formed on the first side surface 20a of the dielectric block 12, the input terminal 22 and the first resonator hole 18a are electrically connected via the capacitor, and the output terminal 24 is connected to the first side. It is formed on the two side surfaces 20b and is electrically connected to the output terminal 24 and the second resonator hole 18b via a capacitor. In addition, as shown in FIG. 3, the input terminal 22 and the output terminal 24 are formed on one open end face 30a, for example, and the input terminal 22 and the first resonator hole 18a are directly connected, and the output terminal 24 and the second terminal The resonator hole 18b may be directly connected. The same applies to dielectric filters described later.

  Next, a dielectric filter according to a second embodiment (hereinafter referred to as a second dielectric filter 10B) will be described with reference to FIGS. 4A to 5C.

  As shown in FIGS. 4A and 4B, the second dielectric filter 10B has substantially the same configuration as the first dielectric filter 10A described above, but has two through holes (a first through hole 28a and a second through hole). 28b) is different.

  That is, the second dielectric filter 10B is provided between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12, with respect to the first resonator hole 18a and the second resonator hole 18b. The first through hole 28a and the second through hole 28b are formed at the twisted position.

  The first through hole 28a and the second through hole 28b may be formed in the horizontal direction with respect to the dielectric block 12, or may be formed inclined in the vertical direction. Further, one end of each of the first through hole 28a and the second through hole 28b may be formed closer to the input side or closer to the output side.

  Specifically, as shown in FIG. 5A, for example, the first through-hole is formed in the first virtual surface 32a that extends along the central axis 26a of the first resonator hole 18a and bisects the first resonator hole 18a. Consider projecting 28a and the second through hole 28b. In this case, 60 ° to 120 ° can be selected as the angle θ1 formed by the central axis 26a of the first resonator hole 18a and the axis 34a of the first through hole 28a (projected image). Similarly, an angle θ2 formed by the central axis 26a of the first resonator hole 18a and the axis 34b of the second through hole 28b (projected image) can be selected from 60 ° to 120 °. The angles θ1 and θ2 formed may be the same or different. In the present embodiment, the angles θ1 and θ2 formed are both 90 °.

  Further, as shown in FIGS. 5B and 5C, for example, the first through hole 28a and the second through hole 28b are projected onto the second virtual surface 32b parallel to one open end surface 30a of the dielectric block 12. . In this case, as in FIG. 2B, a line segment 36 obtained by projecting a line segment connecting the central axis 26a of the first resonator hole 18a and the central axis 26b of the second resonator hole 18b onto the second virtual plane 32b; A virtual line 38 orthogonal to the midpoint of the line segment 36 is set. At this time, as shown in FIG. 5A, −20 ° to + 20 ° can be selected as the angle θa formed by the axis 34a of the first through hole 28a (projected image) and the virtual line 38, as shown in FIG. 5B. Furthermore, −20 ° to + 20 ° can be selected as the angle θb formed between the axis 34b of the second through hole 28b (projected image) and the virtual line 38. The angles θa and θb formed may be the same or different. In the present embodiment, the angles θa and θb formed are both 0 °.

  The cross-sectional shapes of the first through hole 28a and the second through hole 28b may be circular like the first dielectric filter 10A, or may be other polygons such as a triangle, a rectangle, a pentagon, and a hexagon. In this embodiment, it is rectangular.

  In the second dielectric filter 10B, in the dielectric block 12, two through holes (a first through hole 28a and a second through hole 28b) are provided between the first resonator hole 18a and the second resonator hole 18b. Since it is provided, depending on the formation position of the first through hole 28a and the second through hole 28b, the relative positional relationship between the first through hole 28a and the second through hole 28b, the size of the first through hole 28a and the second through hole 28b, The position of the attenuation pole and the amount of attenuation can be adjusted. That is, the adjustment range of the position of the attenuation pole and the attenuation amount can be made wider than that of the first dielectric filter 10A, and the degree of freedom in design can be improved.

  Next, a dielectric filter according to a third embodiment (hereinafter referred to as a third dielectric filter 10C) will be described with reference to FIG.

  As shown in FIG. 6, the third dielectric filter 10C has substantially the same configuration as the first dielectric filter 10A described above, but has one through hole 28 and two grooves (the first groove 40a and the second groove). The difference is that a groove 40b) is provided.

  In this case, the position of the attenuation pole and adjustment of the attenuation amount can be adjusted by one through hole 28, and the adjustment of the position of the attenuation pole and the attenuation amount can also be performed according to the width and depth of the first groove 40a and the second groove 40b. And the adjustment range of the attenuation pole position and attenuation amount can be widened.

  In the above-described example, the embodiment having two resonator holes (the first resonator hole 18a and the second resonator hole 18b) has been mainly described. However, the following embodiments are also preferable. Can be adopted.

  In other words, the dielectric filter according to the fourth embodiment (hereinafter referred to as the fourth dielectric filter 10D) is, as shown in FIGS. 7A and 7B, the first dielectric filter 10A (FIG. 1A and FIG. 1B), but is different in the following points.

  In other words, the dielectric block 12 has four resonator holes (first resonator hole 18a to fourth resonator hole 18d). Further, in the dielectric block 12, between the first resonator hole 18a and the second resonator hole 18b, between the second resonator hole 18b and the third resonator hole 18c, and between the third resonator hole 18c and the fourth resonator. There are through holes 28 between the holes 18d.

  Next, as shown in FIGS. 8A and 8B, the dielectric filter according to the fifth embodiment (hereinafter referred to as the fifth dielectric filter 10E) is the first dielectric filter 10A (FIG. 1A and FIG. 1B), but is different in the following points.

  In other words, the resonator block 12 has two resonator holes (first input resonator hole 18a1 and second input resonator hole 18a2) on the input side, and two resonator holes (on the output side of the dielectric block 12). A first output resonator hole 18b1 and a second output resonator hole 18b2). Further, in the dielectric block 12, a through-hole penetrating between the first input resonator hole 18 a 1 and the first output resonator hole 18 b 1 and penetrating between the second input resonator hole 18 a 2 and the second output resonator hole 18 b 2. 28 is formed.

  Next, as shown in FIGS. 9A and 9B, the dielectric filter according to the sixth embodiment (hereinafter referred to as the sixth dielectric filter 10F) is the fifth dielectric filter 10E (see FIGS. 8A and 8B). The configuration is almost the same as that shown in FIG. 8B, except for the following points.

  That is, in the dielectric block 12, the first input resonator hole 18a1 and the first output resonator hole 18b1 pass through, and the second input resonator hole 18a2 and the second output resonator hole 18b2 pass through the first. A through hole 28a is formed. Further, in the dielectric block 12, a second that penetrates between the first input resonator hole 18 a 1 and the second input resonator hole 18 a 2 and penetrates between the first output resonator hole 18 b 1 and the second output resonator hole 18 b 2. A through hole 28b is formed. That is, the first through hole 28a and the second through hole 28b are formed so as to be twisted with each other.

  Also in the fourth dielectric filter 10D to the sixth dielectric filter 10F, the adjustment range of the attenuation pole position and attenuation amount can be widened, and the degree of freedom in design can be improved.

  Next, dielectric filters according to seventh to ninth embodiments (hereinafter referred to as seventh dielectric filter 10G to ninth dielectric filter 10I) will be described with reference to FIGS. 10A to 10C.

  In the seventh dielectric filter 10G to the ninth dielectric filter 10I, the first dielectric filter 10A described above is that the first resonator hole 18a and the second resonator hole 18b are respectively applied to the quarter wavelength resonator. Different from the sixth dielectric filter 10F.

  That is, in the seventh dielectric filter 10G to the ninth dielectric filter 10I, as shown in FIGS. 10A to 10C, the outer conductor 42 is formed on the outer surface of the dielectric block 12, and, for example, one end surface of the dielectric block 12 14 a is an open end face 30, and the other end face 14 b is a short-circuit end face 44.

  Then, as shown in FIG. 10A, the seventh dielectric filter 10G is located between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12, and at a position close to the short-circuit end face 44. It has one through hole 28 similar to the first dielectric filter 10A.

  As shown in FIG. 10B, the eighth dielectric filter 10H has two penetrations similar to those of the second dielectric filter 10B between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12. It has a hole (first through hole 28a and second through hole 28b). For example, the first through hole 28 a is formed at a position close to the open end face 30, and the second through hole 28 b is formed at a position close to the short-circuit end face 44.

  As shown in FIG. 10C, the ninth dielectric filter 10I has one penetration similar to the third dielectric filter 10C between the first resonator hole 18a and the second resonator hole 18b in the dielectric block 12. It has a hole 28 and one groove 40. For example, the groove 40 is formed on the open end surface 30, and the through hole 28 is formed at a position close to the short-circuit end surface 44.

  Also in the seventh dielectric filter 10G to the ninth dielectric filter 10I, the adjustment range of the attenuation pole position and attenuation amount can be widened, and the degree of freedom in design can be improved.

  Next, a dielectric filter according to a tenth embodiment (hereinafter referred to as a tenth dielectric filter 10J) will be described with reference to FIGS. 11A and 11B.

  As shown in FIGS. 11A and 11B, the tenth dielectric filter 10J has substantially the same configuration as the first dielectric filter 10A described above, but a pair of end faces (one open end face and the other end of the dielectric block). The difference is that the first conductor 52 is formed on four side surfaces (first side surface 20a to fourth side surface 20d) except for the open end surface. In particular, the example of FIGS. 11A and 11B shows an example in which the first conductor 52 is formed over the entire surface of the first side surface 20a to the fourth side surface 20d.

  For example, when the first dielectric filter 10A has a shield structure, an external shield, for example, a metal housing is separately prepared, and the first dielectric filter 10A is accommodated in the housing. However, such a shield structure has a problem that the size increases.

  On the other hand, the tenth dielectric filter 10J can have a shield structure by applying a constant potential (for example, ground potential) to the first conductor 52 formed on the four side surfaces 20a to 20d. There is no need to accommodate the 10 dielectric filter 10J in a metal casing. That is, it is not necessary to prepare an external shield or the like separately. This is advantageous in reducing the size of the dielectric filter and reducing the cost.

  Next, a dielectric filter according to an eleventh embodiment (hereinafter referred to as an eleventh dielectric filter 10K) will be described with reference to FIGS. 12A to 14B.

  As shown in FIGS. 12A and 12B, the eleventh dielectric filter 10K has substantially the same configuration as the tenth dielectric filter 10J described above, but the entire inner wall of the through hole 28 (see FIG. 12B) or one of the inner walls. The point (refer FIG. 13A-FIG. 14B) differs by the point by which the 2nd conductor 54 electrically connected with the 1st conductor 52 is formed. In this case, in addition to the formation position of the through hole 28 and the size of the through hole 28, the position of the attenuation pole and the adjustment of the attenuation amount are adjusted according to the formation position and formation range (formation amount) of the second conductor 54. Can do. That is, the adjustment range of the position of the attenuation pole and the attenuation amount can be widened, and the degree of freedom in design can be improved. Further, the amount of adjustment of coupling between the resonators is widened, and a dielectric filter having a steeper attenuation characteristic can be obtained.

  As an example of forming the second conductor 54 on a part of the inner wall of the through hole 28, resonator holes 18 a and 18 b of the inner wall of the through hole 28, for example, like the dielectric filter 10 Ka shown in FIGS. 13A and 13B. For example, the second conductor 54 may be formed on the entire inner wall facing the axial direction, and only a part of the second conductor 54 may be formed on the inner wall facing the arrangement direction of the resonator holes 18a and 18b.

  As another example, like the dielectric filter 10Kb shown in FIGS. 14A and 14B, among the inner walls of the through hole 28, the second conductor 54 is formed on the inner wall facing the axial direction of the resonator holes 18a and 18b. The second conductor 54 may be formed on the entire inner wall facing the arrangement direction of the resonator holes 18a and 18b. Of course, there are various other forms.

  Next, a dielectric filter according to a twelfth embodiment (hereinafter referred to as a twelfth dielectric filter 10L) will be described with reference to FIGS. 15A and 15B.

  As shown in FIGS. 15A and 15B, the twelfth dielectric filter 10L has substantially the same configuration as the tenth dielectric filter 10J described above, but differs in the following points.

  That is, of the pair of end faces 14a and 14b (a pair of open end faces 30a and 30b) of the dielectric block 12, at least one open end face, for example, one open end face 30a is connected to the inner conductor 16 of the first resonator hole 18a. A first electrode 56a that conducts and a second electrode 56b that conducts to the inner conductor 16 of the second resonator hole 18b are formed. Both the first electrode 56 a and the second electrode 56 b form a capacitance with the first conductor 52. Of course, you may form the 1st electrode 56a and the 2nd electrode 56b also in the other open end surface 30b.

  In this case, in the equivalent circuit of FIG. 23 described later, a capacitor is added in parallel with the capacitor C1 constituting the resonator 48a, and a capacitor is added in parallel with the capacitor C2 constituting the resonator 48b. The resonance frequencies of 48a and 48b are lowered. As a result, the resonator lengths of the resonators 48a and 48b can be shortened, and the twelfth dielectric filter 10L can be downsized. In addition, after the first electrode 56a and the second electrode 56b are formed on the dielectric block 12, the dimensions of the first electrode 56a and the second electrode 56b are adjusted to adjust the resonance frequency of the resonators 48a and 48b. It becomes possible. In addition, electrical connection with an external circuit is facilitated through the first electrode 56a and the second electrode 56b.

  As the first electrode 56a and the second electrode 56b, one end face of the first electrode 56a extends to the first side face 20a of the dielectric block 12, as in the dielectric filter 10La shown in FIGS. 16A and 16B. One end face of the second electrode 56 b may extend to the second side face 20 b of the dielectric block 12. In this case, notches 58a and 58b are provided in the first conductor 52 formed on the first side surface 20a and the second side surface 20b, respectively, so as not to contact the first electrode 56a and the second electrode 56b. The range in which the notches 58a and 58b are formed is such that a capacitance is formed between the first electrode 56a and the first conductor 52, and a capacitance is formed between the second electrode 56b and the first conductor 52. preferable.

  Next, a dielectric filter according to a thirteenth embodiment (hereinafter referred to as a thirteenth dielectric filter 10M) will be described with reference to FIGS. 17A and 17B.

  As shown in FIGS. 17A and 17B, the thirteenth dielectric filter 10M has substantially the same configuration as the tenth dielectric filter 10J described above, but differs in the following points.

  That is, of the pair of end faces 14a and 14b (a pair of open end faces 30a and 30b) of the dielectric block 12, at least one open end face, for example, one open end face 30a is electrically connected to the first conductor 52, and A difference is that an electrode 60 is formed which forms a capacitance with the inner conductor 16 of the first resonator hole 18a and further forms a capacitance with the inner conductor 16 of the first resonator hole 18a.

  Also in this case, similarly to the twelfth dielectric filter 10L described above, the resonator lengths of the resonators 48a and 48b can be shortened, and the twelfth dielectric filter 10L can be downsized. In addition, after the electrodes are formed on the dielectric block 12, the resonance frequency of each of the resonators 48a and 48b can be adjusted by adjusting the dimensions of the electrodes.

  Next, a dielectric filter according to a fourteenth embodiment (hereinafter referred to as a fourteenth dielectric filter 10N) will be described with reference to FIGS. 18A to 18C.

  As shown in FIG. 18A, the fourteenth dielectric filter 10N has substantially the same configuration as the twelfth dielectric filter 10L (see FIG. 15A) described above, but differs in the following points.

  That is, among the pair of end surfaces 14a and 14b (the pair of open end surfaces 30a and 30b) of the dielectric block 12, the first resonator hole 18a and the second adjacent to at least one open end surface, for example, one open end surface 30a. A third conductor 62 that forms a capacitance between the resonator holes 18b is formed. Specifically, one third conductor 62a is formed on the side surface of the first electrode 56a facing the second electrode 56b, and the other side of the second electrode 56b on the side surface facing the first electrode 56a. The three conductors 62b are formed, and the one third conductor 62a and the other third conductor 62b face each other, whereby a capacitance is formed between the adjacent first resonator hole 18a and second resonator hole 18b. .

  In this case, it is possible to adjust the degree of coupling between the resonators 48a and 48b by adjusting the dimensions of the third conductors 62.

  Of course, like the dielectric filter 10Na shown in FIG. 18B, a third conductor 62 that forms an inductance between the adjacent first resonator hole 18a and the second resonator hole 18b may be formed. In this case, it is possible to adjust the degree of coupling between the resonators 48a and 48b by adjusting the dimension of the third conductor 62 forming the inductance.

  Further, like the dielectric filter 10Nb shown in FIG. 18C, a third conductor 62 that forms a capacitance between the adjacent first resonator hole 18a and the second resonator hole 18b, and a third conductor 62 that forms an inductance are provided. It may be formed. In this case, the degree of coupling between the resonators 48a and 48b can be adjusted by adjusting the dimensions of the third conductor 62 that forms the capacitance and the third conductor 62 that forms the inductance.

  Next, a dielectric filter according to the fifteenth embodiment (hereinafter referred to as the fifteenth dielectric filter 10P) will be described with reference to FIGS. 19A to 20B.

  As shown in FIG. 19A, the fifteenth dielectric filter 10P has substantially the same configuration as the above-described fourteenth dielectric filter 10N (see FIG. 18A), but differs in the following points.

  That is, of the pair of end faces 14a and 14b (a pair of open end faces 30a and 30b) of the dielectric block 12, at least one open end face, for example, one open end face 30a is provided with the first electrode on the first resonator hole 18a side. 56a and the first side surface 20a of the dielectric block 12, a first terminal electrode 64a is formed, and between the second electrode 56b on the second resonator hole 18b side and the second side surface 20b of the dielectric block 12 A second terminal electrode 64b is formed.

  A capacitance is formed between the first electrode 56a and the first terminal electrode 64a, and similarly, a capacitance is formed between the second electrode 56b and the second terminal electrode 64b.

  Here, for example, a case where a plurality of dielectric filters are connected in series is assumed. As shown in FIG. 20A, when two 14th dielectric filters 10N are connected in series, the second electrode 56b of one 14th dielectric filter 10N and the first electrode 56a of the other 14th dielectric filter 10N. Are electrically connected to each other through a wiring 66. In such a case, in order to adjust the electrical coupling constant between the two fourteenth dielectric filters 10N, it is necessary to prepare an external board (not shown) on which a dedicated matching circuit 68 is mounted, and there is a limit to downsizing. Occurs.

  On the other hand, as shown in FIG. 20B, in the fifteenth dielectric filter 10P, a first terminal electrode 64a that is coupled to the first resonator hole 18a by a capacitor, and a second terminal electrode that is coupled to the second resonator hole 18b by a capacitor. 64b, the electric coupling constant between the fifteenth dielectric filters 10P can be adjusted without the dedicated matching circuit 68. As a result, the second terminal electrode 64b in one fifteenth dielectric filter 10P and the first terminal electrode 64a in the other fifteenth dielectric filter 10P need only be directly connected by the wiring 66, and a dedicated matching circuit 68 is required. There is no need to prepare an external board on which is mounted. Thereby, size reduction of the various apparatuses which installed the several dielectric filter can be achieved.

  Of course, as in the dielectric filter 10Pa shown in FIG. 19B, fourth inductances are formed between the first electrode 56a and the first terminal electrode 64a and between the second electrode 56b and the second terminal electrode 64b, respectively. The conductor 70 may be formed. Also in this case, the electrical coupling constant between the fifteenth dielectric filters 10P can be adjusted without the dedicated matching circuit 68.

  Further, as in the dielectric filter 10Pb shown in FIG. 19C, a fourth capacitor is formed between the first electrode 56a and the first terminal electrode 64a and between the second electrode 56b and the second terminal electrode 64b. You may form the conductor 70 and the 4th conductor 70 which forms an inductance. Also in this case, the electrical coupling constant between the fifteenth dielectric filters 10P can be adjusted without the dedicated matching circuit 68.

[First embodiment]
The attenuation characteristics of the comparative example, the reference example, the example 1 and the example 2 were confirmed. For example, as shown in FIG. 21, the dimensions of the vertical Da, the horizontal Db, and the height H of the dielectric block 12 are 12 mm, 24 mm, and 19 mm. The distance Dc between the central axis 26a of the first resonator hole 18a and the central axis 26b of the second resonator hole 18b is 12 mm.

(Comparative Example 1)
As shown in FIG. 21, the dielectric filter 100 according to the comparative example includes a dielectric block 12, a first resonator hole 18a, a second resonator hole 18b, and an input terminal, like the first dielectric filter 10A. 22 and the output terminal 24, but the through hole 28 is not provided.

(Reference Example 1)
As shown in FIGS. 22A and 22B, the dielectric filter 102 according to Reference Example 1 is similar to the first dielectric filter 10A, and includes the dielectric block 12, the first resonator hole 18a, and the second resonator hole 18b. The input terminal 22 and the output terminal 24 are different in the following points. That is, in each of the open end faces 30a and 30b, the first groove 40a and the second groove 40b are formed between the first resonator hole 18a and the second resonator hole 18b, respectively. The through hole 28 is not provided. The dimensions of the first groove 40a and the second groove 40b in Reference Example 1 are a width w of 3 mm and a depth h of 4 mm.

Example 1
Example 1 has the same configuration as the first dielectric filter 10A shown in FIGS. 1A and 1B. The cross-sectional shape of the through hole 28 according to the first embodiment is a rectangle in which the height direction of the dielectric block 12 is one side 46a and the horizontal direction of the dielectric block 12 is the other side 46b. The length da of one side 46a is 4 mm, and the length db of the other side 46b is 3 mm.

(Example 2)
Example 2 has the same configuration as the second dielectric filter 10B shown in FIGS. 4A and 4B. Each cross-sectional shape of the first through hole 28a and the second through hole 28b in the second embodiment is similar to the first embodiment in that the height direction of the dielectric block 12 is one side 46a and the horizontal direction of the dielectric block 12 is the same. It is a rectangle with the other side 46b. The length da of one side 46a is 4 mm, and the length db of the other side 46b is 3 mm. The position of the axis 34a of the first through hole 28a is a point 3 mm (= dc) from one open end face 30a, and the position of the axis 34b of the second through hole 28b is 3 mm (= dc) from the other open end face 30b. ).

(Equivalent circuit)
As shown in FIG. 23, the equivalent circuits of Comparative Example 1, Reference Example 1, Example 1 and Example 2 are an input side resonator 48a by the first resonator hole 18a and an output side by the second resonator hole 18b. It has a resonator 48b, an input side capacitor Ca inserted and connected between the input terminal 22 and the input side resonator 48a, and an output side capacitor Cb inserted and connected between the output terminal 24 and the output side resonator 48b. Further, a resonator 50 by electric field coupling and magnetic field coupling between the first resonator hole 18a and the second resonator hole 18b is connected between the input side resonator 48a and the output side resonator 48b. Both the input-side resonator 48a and the output-side resonator 48b are configured by a parallel resonant circuit having a capacitor C1 and an inductance L1, and the resonator 50 is configured by a parallel resonant circuit having a capacitor C2 and an inductance L2.

(Attenuation characteristics)
The attenuation characteristics of Comparative Example 1, Reference Example 1, Example 1 and Example 2 are shown in FIGS. 24A, 24B, 25A and 25B. 24A to 25B, P represents an attenuation pole.

  In the reference example 1, as shown in FIG. 24B, the attenuation pole P appears on the lower frequency side than the center frequency fc as compared with the characteristic of the comparative example 1 (see FIG. 24A). This is because the capacitive coupling between the input-side resonator 48a and the output-side resonator 48b is weakened by the formation of the grooves 40a and 40b (see FIGS. 22A and 22B), and the low-frequency attenuation pole P ( This is probably because the center frequency fc has moved to the vicinity of the center frequency fc. However, the amount of attenuation on the lower frequency side than the center frequency fc is almost the same as that of the comparative example 1, and the attenuation cannot be reduced. Further, although the attenuation pole P appears in the vicinity of the center frequency fc on the high frequency side, the attenuation amount on the high frequency side is smaller than that of the first comparative example.

  On the other hand, Example 1 has substantially the same attenuation characteristics as Comparative Example 1, as shown in FIG. 25A. However, in Comparative Example 1, an external circuit is required for adjusting the position of the attenuation pole P and adjusting the attenuation amount on the low frequency side. However, in Example 1, the position and size of the through hole 28 (one side) By appropriately adjusting the length da of the side 46a and the length db) of the other side 46b, the position of the attenuation pole P and the amount of attenuation on the low frequency side can be adjusted.

  In the second embodiment, as shown in FIG. 25B, the attenuation pole P appears on the lower side of the center frequency fc and in the vicinity of the center frequency fc, and near the center frequency fc on the higher side of the center frequency fc. An attenuation pole P appears. In addition, the amount of attenuation on the lower frequency side than the center frequency fc is larger than those of Comparative Example 1, Reference Example 1, and Example 1. This is probably because the electric field coupling and magnetic field coupling between the input-side resonator 48a and the output-side resonator 48b can be adjusted by forming the first through-hole 28a and the second through-hole 28b. Moreover, in the second embodiment, the positions where the first through holes 28a and the second through holes 28b are formed, the relative positional relationship between the first through holes 28a and the second through holes 28b, and the first through holes 28a and the second through holes 28b. The position of the attenuation pole P and the amount of attenuation can be adjusted depending on the size.

[Second Embodiment]
For Reference Example 1 and Example 2 described above, the adjustment range of the attenuation pole position was confirmed.

(Reference Example 1)
The attenuation characteristics were confirmed when the depth h of the first groove 40a and the second groove 40b in Reference Example 1 was 2 mm, 4 mm, and 6 mm. This attenuation characteristic is shown in FIG. In FIG. 26, a curve Ia (shown by a broken line) shows a characteristic of a depth of 2 mm, a curve Ib (shown by a solid line) shows a characteristic of a depth of 4 mm, and a curve Ic (shown by a one-dot chain line) shows a depth of 6 mm Show properties.

(Example 2)
Attenuation characteristics when the positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b in the second embodiment are changed, and one side of each of the first through hole 28a and the second through hole 28b. The attenuation characteristic when the length da of 46a was changed and the attenuation characteristic when the length db of each other side 46b of the first through hole 28a and the second through hole 28b was changed were confirmed. These attenuation characteristics are shown in FIGS.

  In FIG. 27, curves Ja, Jb, Jc, Jd and Je indicate the following attenuation characteristics.

Curve Ja (indicated by a solid line): the positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b are at a point (referred to as a specific point) 3 mm from one open end surface 30a and the other open end surface 30b. .
Curve Jb (shown by a broken line): The positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b are at a position deeper by 0.5 mm than the specific point.
Curve Jc (indicated by the alternate long and short dash line): The positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b are 1.0 mm deeper than the specific point.
Curve Jd (indicated by a two-dot chain line): The positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b are shallower by 0.5 mm than the specific point.
Curve Je (indicated by a dotted line): The positions of the axis 34a of the first through hole 28a and the axis 34b of the second through hole 28b are shallower by 1.0 mm than the specific point.

  In FIG. 28, curves Ka, Kb and Kc show the following attenuation characteristics.

Curve Ka (shown by a solid line): The length da of each one side 46a of the first through hole 28a and the second through hole 28b is 4 mm, and the length db of each other side 46b is 3 mm.
Curve Kb (indicated by a broken line): The length da of each one side 46a of the first through hole 28a and the second through hole 28b is 3 mm, and the length db of each other side 46b is 3 mm.
Curve Kc (indicated by the alternate long and short dash line): The length da of each one side 46a of the first through hole 28a and the second through hole 28b is 4 mm, and the length db of each other side 46b is 3.5 mm.

(result)
In Reference Example 1, as shown in FIG. 26, the change in the position of the attenuation pole on the lower frequency side than the center frequency fc is in the range of 100 MHz, and the change in the position of the attenuation pole on the higher frequency side from the center frequency fc is The range was 50 MHz.

  On the other hand, in the second embodiment, as shown in FIGS. 27 and 28, the change in the position of the attenuation pole on the lower frequency side than the center frequency fc is in the range of 150 MHz, which is higher on the higher frequency side than the center frequency fc. The change in the position of the attenuation pole was in the range of 300 MHz.

  Thus, it can be seen that the second embodiment can adjust the position of the attenuation pole in a wider range than the first reference example.

  It should be noted that the dielectric filter and the method for adjusting the attenuation characteristic of the dielectric filter according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention. .

Claims (23)

In a dielectric filter having a plurality of resonator holes (18a, 18b) in which inner conductors (16) are formed on an inner surface through a pair of opposed end surfaces (14a, 14b) of a dielectric block (12) ,
In the dielectric block (12), between the plurality of resonator holes (18a, 18b), one or more through holes (28) are disposed at a twisted position with respect to the plurality of resonator holes (18a, 18b). A dielectric filter characterized by being formed. The dielectric filter according to claim 1, wherein
The dielectric filter, wherein the plurality of resonator holes (18a, 18b) are formed in parallel. The dielectric filter according to claim 1 or 2,
The resonator hole when the through hole (28) is projected onto a first virtual plane (32a) that extends along the axial direction of the resonator hole (18a) and bisects the resonator hole (18a). An angle (θ1) formed by (18a) and the through hole (28) is 60 ° to 120 °. The dielectric filter according to claim 3, wherein
An angle (θ1) formed by the resonator hole (18a) and the through hole (28) when the through hole (28) is projected onto the first imaginary plane (32a) is 90 °. A dielectric filter. The dielectric filter according to any one of claims 1 to 4,
Two resonator holes (18a, 18b),
A line segment connecting the central axes (26a, 26b) of the two resonator holes (18a, 18b) to the second virtual surface (32b) parallel to the end face (30a) of the dielectric filter is defined as the second segment. When the line segment (36) projected on the virtual plane (32b) and the virtual line (38) orthogonal to the midpoint of the line segment (36) are set, the through hole (28) is moved to the second virtual An angle (θa) formed by the through hole (28) and the imaginary line (38) when projected onto the surface (32b) is -20 ° to + 20 °. The dielectric filter according to claim 5, wherein
An angle (θa) formed by the through hole (28) and the virtual line (38) when the through hole (28) is projected onto the second virtual plane (32b) is 0 °. Dielectric filter. In the dielectric filter according to any one of claims 1 to 6,
Two through holes (28a, 28b),
The dielectric filter, wherein the two through holes (28a, 28b) are formed in parallel. In the dielectric filter according to any one of claims 1 to 7,
Both of the pair of end faces (14a, 14b) of the dielectric block (12) are open end faces (30a, 30b);
The dielectric filter, wherein the resonator holes (18a, 18b) constitute a half-wave resonator. In the dielectric filter according to any one of claims 1 to 6,
Of the pair of end faces (14a, 14b) of the dielectric block (12), one end face (14a) is an open end face (30a), and the other end face (14b) is a short-circuit end face (44),
The dielectric filter, wherein the resonator holes (18a, 18b) constitute a quarter wavelength resonator. In the dielectric filter according to any one of claims 1 to 9,
A dielectric filter having a groove between the plurality of resonator holes (18a, 18b) on the end face of the dielectric block (12). In the dielectric filter according to any one of claims 1 to 10,
A dielectric filter, wherein a first conductor (52) is formed on a plurality of side surfaces excluding the pair of end surfaces (14a, 14b) of the dielectric block (12). The dielectric filter according to claim 11, wherein
The dielectric filter, wherein the first conductor (52) is formed on the entire surface of the plurality of side surfaces. The dielectric filter according to claim 11 or 12,
A dielectric filter, wherein a second conductor (54) electrically connected to the first conductor (52) is formed on the entire inner wall of the through hole (28) or a part of the inner wall. The dielectric filter according to any one of claims 11 to 13,
Of the pair of end faces (14a, 14b), at least one end face (14a) is electrically connected to the inner conductor of the resonator hole (18a, 18b), and between the first conductor (52). A dielectric filter, wherein electrodes (56a, 56b) for forming capacitors are formed. The dielectric filter according to any one of claims 11 to 13,
Of the pair of end faces (14a, 14b), at least one end face (14a) is electrically connected to the first conductor (52) and forms a capacitance between the resonator holes (18a, 18b). A dielectric filter, characterized in that an electrode (60) is formed. The dielectric filter according to claim 14, wherein
Of the pair of end faces (14a, 14b), at least one end face (14a) is formed with a third conductor (62) that forms at least a capacitance between adjacent resonator holes (18a, 18b). A dielectric filter characterized by the above. The dielectric filter according to claim 14, wherein
Of the pair of end faces (14a, 14b), at least one end face (14a) is formed with a third conductor (62) that forms at least an inductance between adjacent resonator holes (18a, 18b). A dielectric filter characterized by the above. The dielectric filter according to claim 14, wherein
A third conductor (62) for forming a capacitance and an inductance in parallel between adjacent resonator holes (18a, 18b) is formed on at least one end surface (14a) of the pair of end surfaces (14a, 14b). A dielectric filter characterized by being made. The dielectric filter according to any one of claims 16 to 18, wherein
Of the pair of end faces (14a, 14b), at least one end face (14a) is coupled to the resonator hole (18a, 18b) with the capacitance, or the inductance, or the terminal electrode (64a, 64b) with the capacitance and the inductance. A dielectric filter characterized by being formed. In the method for adjusting the attenuation characteristics of a dielectric filter having a plurality of resonator holes (18a, 18b) in the dielectric block (12),
In the dielectric block (12), between the plurality of resonator holes (18a, 18b), one or more through holes (28) are disposed at a twisted position with respect to the plurality of resonator holes (18a, 18b). A method for adjusting the attenuation characteristic of a dielectric filter, comprising: forming a dielectric filter. The method for adjusting attenuation characteristics of a dielectric filter according to claim 20,
A method for adjusting an attenuation characteristic of a dielectric filter, wherein the attenuation amount on a lower frequency side than a center frequency is increased by forming the through hole (28). The method for adjusting attenuation characteristics of a dielectric filter according to claim 20 or 21,
A method for adjusting the attenuation characteristic of a dielectric filter, wherein the position of the attenuation pole is adjusted by adjusting the formation position of the through hole (28). The method for adjusting attenuation characteristics of a dielectric filter according to any one of claims 20 to 22,
A method for adjusting the attenuation characteristic of a dielectric filter, wherein the position of the attenuation pole is adjusted by adjusting the dimension of the through hole (28).

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