JPH1168407A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric filter with reduced costs for parts and mounting, and also eliminating the necessity of an earth plate. SOLUTION: Plural grooves 42 extending in a direction rectangular to the array direction of through holes 11 to 20 are respectively formed between adjacent through holes 11 and 12, 13 and 14, and 15 and 16 on the open side face of a dielectric block 2 and conductive films 43 are respectively formed in these grooves 42. Both ends of each conductive film 43 are electrically connected to an external conductor 6 of the dielectric filter 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric filter,
In particular, the present invention relates to a dielectric filter provided with a plurality of dielectric resonators in a single dielectric block.

[0002]

2. Description of the Related Art In general, a dielectric filter of this type includes a plurality of dielectric resonators formed in a rectangular parallelepiped dielectric block made of a dielectric material, and these dielectric resonators are electromagnetically coupled to each other. For example, a filter disclosed in Japanese Patent Application Laid-Open No. 8-512187 is known. The dielectric filter is disposed between an antenna of a wireless communication device such as a mobile phone and a transmission system and a reception system, and supplies a transmission signal having a predetermined transmission frequency from the transmission system to the antenna. It is used as a duplexer for supplying a reception signal having a predetermined frequency from a received signal to a reception system.

[0003] As shown in FIG. 3, a dielectric filter 1 comprises:
It has a single dielectric block 2 having a rectangular parallelepiped shape, and a total of 10
The individual through holes 11 to 20 are formed. Through holes 11 and 2
Each of the cross-sections 0 has a constant width and both ends have an arc-shaped oval shape. These through holes 11
20 are arranged in a line in the longitudinal direction of the dielectric block 2. The dielectric block 2 leaves its upper surface 3
An outer conductor 6 is formed on the outer wall surface. Through holes 11 and 2
, 5 are formed on each of the inner wall surfaces. The through holes 11 to 20 and the inner conductors 5,..., 5 thereof together with the outer conductor 6 and the dielectric block 2 constitute ten dielectric resonators. The inner conductor 5 is electrically opened (separated) from the outer conductor 6 on the upper surface 3 (hereinafter, referred to as open side surface 3), and is electrically short-circuited to the outer conductor 6 on the bottom surface 4 (hereinafter, referred to as short side surface 4). (Conduction).

On the open side surface 3 of the dielectric block 2, concave portions 21,..., 21 for coupling capacitance adjustment for adjusting the coupling capacitance between adjacent dielectric resonators to adjust the pass bandwidth.
Are provided in contact with one of the openings of the through holes 11 to 20, and frequency adjusting recesses 22,..., 22 for adjusting the resonance frequency of the dielectric resonator are provided on the ridge of the dielectric block 2. Have been. Further, the coupling capacitor electrode 23 connected to the antenna, the coupling capacitor electrode 24 connected to the input terminal of the receiving circuit system, and the coupling capacitor electrode 25 connected to the output terminal of the transmitting circuit system are respectively provided with the through holes 1
It is provided to face one end of the opening of 7, 11, 20.

[0005] As shown in FIG.
The outer conductor 6 of the dielectric block 2 is placed on the printed circuit board 31 by bringing the outer conductor 6 of the dielectric block 2 into contact with the ground pattern 32 of the printed circuit board 31 so that the axial direction of each through hole 11 to 20 is parallel to the surface of the printed circuit board. The outer conductor 6 is soldered to the ground pattern 32. Then, a ground plate 33 is arranged to face the open side surface 3 of the dielectric filter 1. The reason is that the grounding plate 33 sufficiently secures the ground of the dielectric filter 1 to ensure attenuation outside the pass band of the dielectric filter 1 so that high-quality communication can be performed. The ground plate 33 has one end 33 a bent at a right angle and soldered to the outer conductor 6 of the dielectric filter 1.
b is bent at a right angle and soldered to the ground pattern 32 of the printed circuit board 31.

[0006]

However, in the conventional dielectric filter 1, the ground plate 33 must be provided when the dielectric filter 1 is mounted on the printed circuit board 31, so that the number of components increases and the mounting of the ground plate 33 is difficult. This requires a space and a process for mounting the same, and there is a problem that the cost of a product using the dielectric filter 1 increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric filter which does not require a ground plate and has low component and mounting costs.

[0008]

In order to achieve the above objects, a dielectric filter according to the present invention comprises a dielectric block extending from a first surface of a dielectric block to a second surface opposed to the first surface. A plurality of through-holes penetrate, and an inner conductor is formed on each of the inner wall surfaces of the through-hole, and an outer conductor is formed on an outer wall surface of the dielectric block except for the first surface. Then, a conductor extending in a direction substantially perpendicular to the arrangement direction of the through holes is disposed on the first surface of the dielectric block, and both ends of the conductor are connected to the outer conductor. Electrically connected.

With the above configuration, the first of the dielectric blocks is
Is an open side surface of the dielectric resonator formed in the dielectric block, and a conductor is disposed on the open side surface. This conductor provides sufficient grounding for the dielectric filter,
Attenuation outside the pass band of the dielectric filter is ensured.

The dielectric filter according to the present invention is characterized in that the conductor is provided in a groove provided on the first surface of the dielectric block. Thereby, the width of the conductor can be set wide without increasing the size of the dielectric filter, and the ground of the dielectric filter can be more sufficiently obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the dielectric filter according to the present invention will be described with reference to the accompanying drawings.

[First Embodiment, FIG. 1] FIG. 1 shows one embodiment of a dielectric filter according to the present invention. This dielectric filter 41 is the same as the dielectric filter 1 described with reference to FIG.
3 is provided. That is, the adjacent through holes 1 of the series of through holes 11 to 20 formed in the dielectric block 2
1 and 12, 13 and 14, 15 and 16
Groove 4 extending in a direction orthogonal to the arrangement direction of
2 are formed, and a conductor film 43 is formed in these grooves 42. That is, the conductor film 43 in the groove 42
Are formed in the short side direction of the open side surface 3, and both ends are electrically connected to the outer conductor 6 of the dielectric filter 41. As the material of the conductor film 43, for example, silver, copper, or the like, which is the same as that of the inner conductor 5 and the outer conductor 6, is used. In FIG. 1, the portions corresponding to those in FIG. 3 are denoted by the corresponding reference numerals, and redundant description will be omitted.

The dielectric filter 4 having such a configuration
When 1 is mounted on a printed board or the like, the conductive film 43 is connected to the ground pattern of the printed board via the outer conductor 6 and grounded. As a result, sufficient grounding of the dielectric filter 41 is obtained by the conductive film 43, and the dielectric filter 41 of FIG. 1 can be used in a frequency range outside the pass band without using the ground plate 33 as described in FIG. Sufficient attenuation can be obtained. In particular, since the conductive film 43 is formed on the bottom and side surfaces of the groove 42, the dielectric filter 4
The width of the conductive film 43 can be set wide without increasing the size of 1 and a sufficient grounding of the dielectric filter 41 can be obtained.

[Second Embodiment, FIG. 2] FIG. 2 shows another embodiment of the dielectric filter according to the present invention. This dielectric filter 51 is obtained by providing a conductor line 53 on the open side surface 3 of the dielectric block 2 in the dielectric filter 1 described with reference to FIG. That is, a series of through holes 11 to 20 formed in the dielectric block 2 are arranged between the adjacent through holes 11 and 12, between 13 and 14, between 15 and 16, in the arrangement direction of the through holes 11 to 20. A conductor line 53 extending in a direction orthogonal to the conductor line 53 is formed.
Both ends of each of the conductor lines 53 are electrically connected to the outer conductor 6 of the dielectric filter 51. Note that FIG.
In FIG. 3, the portions corresponding to those in FIG. 3 are indicated by the corresponding reference numerals, and the duplicate description will be omitted.

The dielectric filter 5 having such a configuration
When 1 is mounted on a printed board or the like, the conductor line 53 is connected to the ground pattern of the printed board via the outer conductor 6 and grounded. Thereby, the dielectric filter 51
Provides a sufficient ground by the conductor line 53,
Sufficient attenuation can be obtained in a frequency region outside the pass band without using the ground plate 33 as described in FIG. Further, in the second embodiment, since the conductor line 53 is not formed in the groove 42 as in the dielectric filter 41 of FIG. 1, the formation is easier.

[Other Embodiments] The dielectric filter according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention. For example, in the dielectric filter 41 of FIG. 1, the groove 42 and the conductive film 43 can be formed in places other than the through holes 11 and 12, 13 and 14, 15 and 16, and the number thereof is at least one place. I just need more. Dielectric filter 5 of FIG.
The same applies to 1. In the above-described embodiment, the dielectric filter used as a duplexer has been described as an example. However, a dielectric filter used as a band-pass filter, a band rejection filter, or the like may be used.

[0017]

As is apparent from the above description, according to the present invention, the conductor is disposed on the open side surface of the dielectric block so as to extend in a direction substantially perpendicular to the arrangement direction of the through holes. In addition, since the both ends of the conductor are electrically connected to the outer conductor, sufficient grounding of the dielectric filter can be obtained by the conductor, and independent parts for shielding such as a ground plate must be used. Thus, a dielectric filter having a sufficient attenuation in a frequency region outside the pass band can be obtained.

Further, by forming the conductor in the groove provided on the open side surface of the dielectric block, the conductor is formed on the bottom surface and the side surface of the groove, and without increasing the size of the dielectric filter, The width of the conductor can be set wider, and greater attenuation can be obtained in a frequency region outside the pass band.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a first embodiment of a dielectric filter according to the present invention.

FIG. 2 is a perspective view showing a configuration of a second embodiment of the dielectric filter according to the present invention.

FIG. 3 is a perspective view showing a configuration of a conventional dielectric filter.

FIG. 4 is a perspective view showing a state in which the dielectric filter shown in FIG. 3 is mounted on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 ... Dielectric block 3 ... Open side surface (1st surface) 4 ... Short circuit side surface (2nd surface) 5 ... Inner conductor 6 ... Outer conductor 11-20 ... Through hole 41 ... Dielectric filter 42 ... Groove 43 ... Conduction Body film 51: Dielectric filter 53: Conductor line

Claims (2)

[Claims] 1. A plurality of through-holes penetrating from a first surface of a dielectric block to a second surface facing the first surface,
An inner conductor is formed on an inner wall surface of the through hole, and an outer conductor is formed on an outer wall surface of the dielectric block except for the first surface. Surface, a conductor extending in a direction substantially orthogonal to the arrangement direction of the through holes is provided, and both ends of the conductor are electrically connected to the outer conductor. Characteristic dielectric filter. 2. The dielectric filter according to claim 1, wherein said conductor is provided in a groove provided on a first surface of said dielectric block.