JP2999946B2 - Block type dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block type dielectric filter having a dielectric resonator.

[0002]

2. Description of the Related Art In recent years, the demand for duplexers used in the range of about 500 MHz to 2 GHz has increased due to the spread of mobile communications such as automobile telephones and broadcasting networks using satellites, and block type dielectrics widely used for such duplexers have been increasing. There is an increasing demand for smaller and lighter body filters.

[0003] This type of dielectric filter, two or more dielectric resonators 15R _A and R _B and the capacitor 14C1, C2, C3 as shown in FIG. 8 in combination with a ladder and a main component.

As disclosed in Japanese Patent Application Laid-Open No. Hei 5-226909, a dielectric resonator is formed on an end face 16 on a driving side along an outer periphery of a through hole as shown in a sectional view of the dielectric resonator in FIG. It is known that the shape of the concave portion 2 is reduced by providing the concave portion 2.

FIG. 10 shows an example in which a plurality of dielectric resonators having such a shape are combined to form a block type dielectric filter. A dielectric filter that constitutes a plurality of dielectric resonators with one dielectric block has a simple structure, and is small and lightweight.

[0006]

This block-type dielectric filter is usually molded by a mold composed of an upper mold, a lower mold, a thin mold, and a round bar, and is provided with a circle mounted on the lower mold or the upper mold. A through hole is provided with a rod. It is installed on the lower or upper mold. A cup-shaped or step-shaped convex portion is provided at a portion where the lower or upper round bar provided with the through hole is provided, and a concave portion of the dielectric block is molded.

FIG. 11 shows a block type dielectric filter a
A cutaway view taken at -a 'is shown.

In such a mold, the influence of abrasion of the mold generated during molding is apt to occur, and burrs 17 are generated on the outer peripheral portion of the dielectric block, the concave portion 2 and the like as shown in FIG. These burrs 17 generated on the outer portion can be easily removed by a process such as brushing.
It is difficult to remove the burrs 17 generated by the method, and if the method such as a normal brushing treatment and sand blasting is not performed with great care, the dielectric block body may be chipped or the dimensions of the concave portion 2 may be changed. There is.

If the burrs 17 are left without being removed, the silver coating layer 18 used for the outer conductor or the inner conductor may be cut by the burrs as shown in FIG. This causes deterioration of its own Q, variation in resonance frequency, variation in interstage coupling, and the like.

[0010] In the future, as the size of the device is further reduced, there is a great possibility that the degree of defects will be further increased.

Further, in the concave portion and the resonator portion (through hole portion),
Since the molding densities at the time of molding differ, a difference in sintering density occurs after firing, so that the dielectric block is partially bent, deformed, and the like, and a mounting problem is likely to occur. Furthermore, the dielectric constant partially varies due to the difference in the sintering density, and the characteristic may not be stable.

Therefore, according to the present invention, burrs and the like do not occur at the time of molding, and since the sintering density is uniform, there is no variation in characteristics and no problems, and there is no deformation or the like in the outer shape. An object of the present invention is to provide a block-type dielectric filter that is easy to mount.

[0013]

In order to solve the above-mentioned problems, a block type dielectric filter according to the present invention has a plurality of through-holes from one surface of a dielectric block having an outer conductor to an opposite surface. A block-type dielectric filter including a plurality of dielectric resonators in which an inner conductor electrically connected to the outer conductor at one end of the through hole is provided inside the through hole. The molded bodies of a plurality of dielectric blocks having through holes are stacked and fired and integrated, an outer conductor is provided around the integrated dielectric block, and an inner conductor is provided inside the through holes.

Further, in order to achieve the above object, a dielectric block having an external conductor has a plurality of through holes from one surface to an opposing surface, and one end of the through hole is provided inside the through hole. In a method of manufacturing a block-type dielectric filter including a plurality of dielectric resonators provided with an inner conductor electrically connected to the outer conductor, a plurality of dielectric blocks having through holes of different shapes are formed. A method of manufacturing a block-type dielectric filter, comprising: stacking, firing and integrating, providing an outer conductor around the integrated dielectric block, and providing an inner conductor inside a through hole.

[0015]

The through holes having different shapes are separately formed in the dielectric block having the concave portions. Since there is no portion having a different shape such as a concave portion in the through hole in each dielectric block, a mold for molding is not complicated, and burr treatment is easy. In addition, there is no problem caused by partially different molding densities.

As described above, if the molded dielectric blocks are stacked and fired and integrated so that the respective through holes are aligned with each other, concavities with uniform density and no burrs are provided at the end surfaces of the through holes. A dielectric block can be provided.

If the dielectric blocks are stacked and fired and integrated so that the through holes of the respective dielectric blocks are parallel, the density is uniform, so that the occurrence of deformation or the like can be prevented.

As described above, when the above-described superposition is superposed in various directions to form a dielectric block and integrated by firing, for example, a plurality of through-holes having different shapes are provided, and an end of each through-hole is provided. A dielectric block having a complicated structure in which a concave portion is provided can be provided without burrs or deformation.

Here, if the green sheet is sandwiched between the joining surfaces during firing integration, deformation or the like at the time of firing on the joining surfaces can be absorbed, and a dielectric block with less deformation can be provided.

[0020]

Next, an embodiment of the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an embodiment according to the present invention.

FIG. 1 shows a block type dielectric filter in which a concave portion 2 is provided on an end face of a through hole. As shown in FIG. , A concave block) and a dielectric block 3 having a through-hole 4 (hereinafter, referred to as a resonance block), molded and then combined as shown in FIG.

Since the dielectric block has a through hole of a single shape, burrs are less likely to occur due to the wear of the mold, and even if burrs are formed, they can be easily removed by ordinary brushing or the like. Therefore, there is no occurrence of characteristic failure due to cutting the conductor layer provided on the dielectric block.

In addition, since there is little difference in sintered density for the same reason, there is no deformation as a dielectric filter.

As described above, by combining the dielectric blocks of various shapes into one through hole, even if the resonance part of the dielectric filter has a special shape and is difficult to manufacture by the conventional technology. It can be easily manufactured.

FIG. 3 shows a dielectric filter having a resonance part of a special shape. Recessed Block 1 and Resonant Block 3
In addition, the dielectric block 5 having a tapered hole may be combined, fired and integrated, and manufactured.

FIGS. 4A and 4B show a further embodiment according to the present invention, in which FIG. 4A is an external view, and FIG.

Dielectric block 7 having circular through hole 8
And a dielectric block 9 having an elliptical through-hole 10 and are integrated by firing. Conventionally, since the final sintering density is different from the pressure difference at the time of molding, deformation and variation in characteristics have been caused.However, since it is molded and fired integrally for each dielectric block having a different shape, Such problems as are eliminated.

As described above, the combination is performed for one dielectric filter, and a more complicated dielectric filter can be manufactured.

FIG. 5 shows an embodiment using a dielectric filter in which the shape of the resonance portion is different and the shape and depth of the concave portion are also partially different.

The dielectric block 7 having a circular through-hole and the dielectric block 9 having an elliptical through-hole are connected, and furthermore, the recesses 11 and 12 having different shapes are connected and integrated by firing.

Here, when the molded dielectric blocks are combined and integrated, the joint surface may be deformed due to variations in the shape of the joint surface.

In this case, as shown in FIGS. 6 and 7, the buffer material 13 is sandwiched between the joining surfaces, and the variation in the shape of the joining surface is absorbed by the buffer material 13, so that the firing and integration can be performed more stably. Can be.

The buffer material 13 is formed by molding a dielectric into a green sheet having a thickness of 0.07 to 0.25 mm using a resin binder and a solvent. The dielectric is equivalent to a dielectric block. It is preferable to use an acrylic material for the binder and ethyl alcohol, isopropyl alcohol, toluene, xylene, methyl ethyl ketone, or the like as the solvent.

[0035]

According to the present invention, it is possible to provide a block-type dielectric filter which has no variation in characteristics even if the dielectric filter has a complicated shape and which is not deformed. This is particularly effective when providing

Further, since there is almost no burrs, the working time is shortened and the cost is reduced.

[Brief description of the drawings]

FIG. 1 shows an embodiment according to the present invention.

FIG. 2 is an assembly view of an embodiment according to the present invention.

FIG. 3 shows an embodiment having a complex through-hole according to the present invention.

FIG. 4 shows a further embodiment according to the invention.

FIG. 5 shows an embodiment with a more complex through-hole according to the invention.

FIG. 6 is a first embodiment according to the present invention using a buffer material.

FIG. 7 is a second embodiment according to the present invention using a buffer material.

FIG. 8 is a configuration diagram of a dielectric filter.

FIG. 9 is a configuration diagram of a dielectric resonator.

FIG. 10 is an external view of a conventional dielectric filter.

FIG. 11 is a cross-sectional view of a conventional dielectric filter during molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concave block 2 Concave part 3 Resonator filter 4 Through hole 5 Dielectric block having a tapered hole 6 Tapered through hole 7 Dielectric block having a circular through hole 8 Circular through hole 9 Dielectric block having an elliptical through hole DESCRIPTION OF SYMBOLS 10 Elliptic through hole 11 Concave block 12 Concave block 13 Buffer material 14 Capacitor 15 Dielectric resonator 16 End face 17 Burr 18 Coating layer

Continuation of front page (56) References JP-A-3-108801 (JP, A) JP-A-4-207502 (JP, A) JP-A-2-94901 (JP, A) JP-A-7-283608 (JP) JP-A-7-263914 (JP, A) JP-A-7-263913 (JP, A) JP-A-7-86815 (JP, A) JP-A-63-184401 (JP, A) 2-92001 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 1/205 H01P 1/212 H01P 11/00

Claims (2)

(57) [Claims] 1. A dielectric block having an external conductor has a plurality of through holes from one surface to an opposite surface, and is electrically connected to the external conductor at one end of the through hole inside the through hole. In a block-type dielectric filter configured with a plurality of dielectric resonators provided with connected internal conductors,
The molded body of a plurality of dielectric blocks having through holes of different shapes is superposed and fired and integrated, an outer conductor is provided around the integrated dielectric block, and an inner conductor is provided inside the through hole. Characteristic block type dielectric filter. 2. A dielectric block having an external conductor having a plurality of through holes extending from one surface to an opposing surface, and electrically connected to the external conductor at one end of the through hole inside the through hole. In a method of manufacturing a block-type dielectric filter including a plurality of dielectric resonators provided with connected internal conductors, a plurality of dielectric blocks having through holes of different shapes are stacked, and then fired integrally. A method of manufacturing a block-type dielectric filter, comprising: providing an outer conductor around a dielectric block integrated into one, and providing an inner conductor inside a through hole.