Integral dielectric filter

Details Integral dielectric filter Integral dielectric filter

1999-06-11

2001-05-08

Lee, Benny (Department: 2817)

Wave transmission lines and networks

Coupling networks

Wave filters including long line elements

C333S202000

Reexamination Certificate

active

06229410

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an integral type dielectric filter which removes noises or adjacent channel signals from a signal stream in a portable communication apparatus. Particularly, the present invention relates to an integral type dielectric filter in which the insertion loss is minimized, and the damping characteristics desired by the user are satisfied.
2. Description of the Prior Art
Recently, various portable communication apparatuses are flooded. In the midst of this flooding, users want portable communication apparatuses which do not just have communication functions, but also are cheaper and more miniaturized so as to make it more convenient to carry with them. To cater to this trend, manufacturers are producing portable communication apparatuses of small volume and light weight.
As a conventional dielectric filter, there is U.S. Pat. No. 5,537,082 as illustrated in
FIG. 1
a
. In this filter, two through holes
101
and
102
are formed side by side in a dielectric block, and a conductive electrode is formed on the entire surface of the dielectric block. On an upper face
300
which is parallel with the through holes
101
and
102
, there are formed input/output electrodes
301
and
302
. The conductive electrode of the first face
100
is removed, and a non-metallic coupling region
201
is formed on a second face
200
(which is lying opposite to the first face
100
) between the through holes
101
and
102
by regionally removing the conductive electrode. Thus a capacitance coupling is formed between the through holes
101
and
102
which serve as resonators.
This dielectric filter is a capacitance coupling filter which has pass characteristics over the low frequency bands. In this dielectric filter, if a damping characteristic of −30 dB or less is to be satisfied at a low frequency band (about 903 MHz) as desired by users, the pass band shows a damping of −4.0 dB as illustrated in
FIG. 1
b
, with the result that the insertion loss is aggravated.
Japanese Patent Laid-open Gazette No. Hei-10-126107 discloses another structure of the dielectric filter as shown in
FIG. 2
a
. In this dielectric filter, a conductive electrode is formed on the entire surface of the dielectric block in which through holes
101
and
102
are formed. Further, non-metallic regions
101
a
and
102
a
are formed respectively within the through holes
101
and
102
by removing the conductive materials, thereby forming an electrical coupling between the through holes
101
and
102
.
In this dielectric filter, the insertion loss at the mean frequency (about 927 MHz) is −2.5 dB, and thus its insertion loss is lower than that of the dielectric filter of
FIG. 1
a
. At the damping point (about 903 MHz or about 949 MHz), however, a maximum damping characteristic of −19 dB is seen. Thus, if a satisfactory damping characteristic of −30 dB or less is to be obtained, the insertion loss is aggravated up to −4.0 dB.
Further, conventionally in order to satisfy the damping characteristics, the insertion loss has to be allowed to be increased as described above. However, in view of the price competitions between the manufacturers and the limitation of the frequency resources, there is a demand for a dielectric filter which is accompanied by a low manufacturing cost and shows a superior damping characteristic.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional techniques.
Therefore it is an object of the present invention to provide an integral type dielectric filter in which the insertion loss is decreased, but the damping characteristics are improved.
In achieving the above object, the integral type dielectric filter according to the present invention includes: a dielectric block having first and second faces facing toward each other and having a plurality of side faces; a ground electrode coated on the entire faces of the dielectric block except the first face; a plurality of through holes passing through the first and second faces, with their surfaces being coated with a conductive material; input and output electrodes formed on a face of the dielectric block insulatingly from the ground electrode, for forming an electromagnetic coupling with internal electrodes of the plurality of the through holes; and at least one metallic coupling region formed between the input and output electrodes and between the through holes of the first face insulatingly from the ground electrode and from the input and output electrodes to form a capacitive coupling between the input and output electrodes and the through holes, whereby the integral type dielectric filter as a band pass filter can improve the damping rate at a low frequency side.
Or the integral type dielectric filter according to the present invention includes a non-metallic coupling region formed on a side face, for forming an inductive coupling between the through holes, whereby the integral type dielectric filter as a band pass filter can improve a damping rate at a high frequency side.
In another aspect of the present invention, the integral type dielectric filter according to the present invention includes: a dielectric block having first and second faces facing toward each other and having a plurality of side faces; a ground electrode coated on the entire faces of the dielectric block except the first face; a plurality of through holes passing through the first and second faces, with their surfaces being coated with a conductive material; input and output electrodes formed on a face of the dielectric block insulatingly from the ground electrode, for forming an electromagnetic coupling with internal electrodes of the plurality of the through holes; at least one metallic coupling region formed between the input and output electrodes and between the through holes of the first face insulatingly from the ground electrode and from the input and output electrodes to form a capacitive coupling between the input and output electrodes and the through holes; at least a non-metallic coupling region formed on a side face of the dielectric block with the shape of a closed loop; and at least one metallic region insulated from the ground electrode by forming a non-metallic coupling region.
In still another aspect of the present invention, the integral type dielectric filter according to the present invention includes: a dielectric block having first and second faces facing toward each other and having a plurality of side faces; a ground electrode coated on the entire faces of the dielectric block except the first face; a plurality of through holes passing through the first and second faces, with their surfaces being coated with a conductive material; input and output electrodes formed on a face of the dielectric block insulatingly from the ground electrode, for forming an electromagnetic coupling with internal electrodes of the plurality of the through holes; and at least one non-metallic coupling region formed along an arrangement direction of the plurality of the through holes, for forming an inductive coupling between the plurality of the through holes.


REFERENCES:
patent: 5327108 (1994-07-01), Hoang et al.
patent: 5436602 (1995-07-01), McVeety et al.
patent: 5721520 (1998-02-01), McVeety et al.
patent: 5850168 (1998-12-01), McVeety et al.
patent: 5977848 (1999-11-01), Nakaguchi et al.

Affiliated with

Also associated with

Rating

Integral dielectric filter does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Integral dielectric filter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integral dielectric filter will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2443875