Wave transmission lines and networks – Plural channel systems – Having branched circuits
Reexamination Certificate
1999-07-28
2001-08-28
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Plural channel systems
Having branched circuits
C333S219000, C333S202000, C333S219100
Reexamination Certificate
active
06281763
ABSTRACT:
TECHNICAL FIELD
This invention relates to a dielectric resonator, dielectric filter, dielectric duplexer and manufacturing method of such. More particularly, this invention relates to a dielectric resonator, dielectric filter, dielectric duplexer, etc. to be used in the microwave and milliwave frequency bands and utilized in the field of mobile communication.
BACKGROUND ART
In recent years, with the rapid development of mobile communication systems the demand for small-sized and high performance mobile communication equipment is going up more and more. In order to satisfy such a demand, the applicant of the application concerned proposed earlier a thin film multi-layer electrode of thin film conductor layers and thin film dielectric layers having fixed thickness which are alternately laminated, to realize a low-loss electrode.
For example, in a circular TM mode resonator, a thin film multi-layer electrode formed in a method to be described hereinafter has been used.
That is, as shown in
FIG. 6
, the circular TM mode resonator
53
with open-ended side comprises a thin film multi-layer electrode
52
of layers of thin film conductor and dielectric substance alternately formed by sputtering and using a metal mask on the main surface of a circular dielectric substrate
51
both the main surfaces of which have been ground to be flat. Further, although not illustrated in
FIG. 6
, a thin film multi-layer electrode is formed on the lower side of the circular dielectric substrate
51
as on the upper side.
FIG. 7
is an expanded sectional view in the vicinity of the external portion of the resonator
53
. A thin film multi-layer electrode
52
is formed in such a way that as shown in
FIG. 7
, a couple of thin film conductor layers
54
and thin film dielectric layers
55
are alternately given on the dielectric substrate
51
. In the vicinity of the external portion (the righthand side of FIG.
7
), the thin film conductor layers
54
and thin film dielectric layers
55
are in a tapered shape. This is because sputtered particles migrate into a very little gap between the metal mask and dielectric substrate
51
when the thin films are formed by sputtering. Further, in the external portion
56
of the dielectric substrate
51
the thin film multi-layer electrode
52
is not formed because the external portion is pressed and covered by a metal mask fixed to the dielectric substrate in the formation of thin films by sputtering. Line X—X in
FIG. 7
shows a masking line defined by the metal mask.
However, the above-mentioned conventional circular TM mode resonator
53
has had a problem to be described hereinafter.
First, regarding the thin film multi-layer electrode
52
to be formed on both the main surfaces of the dielectric substrate
51
, it is difficult to form the thin film multi-layer electrode formed on one main surface and the thin film multi-layer electrode formed on the other main surface so that both of the electrodes lie exactly one on top of another, on opposite surfaces of the dielectric substrate
51
. That is, there are cases in which the electrodes are displaced from each other.
Further, in the conventional circular TM mode resonator
53
, because the external portion
56
of the dielectric substrate
51
remains as an excessive dielectric material, the stray capacitance between the thin film multi-layer electrodes formed on both the main surfaces has become large.
More, although the thin film conductor layers
54
should be electrically insulated from each other, there is a chance of an electrical short-circuit at the tapered part of the external portion of the thin film multi-layer electrode
52
.
The three things pointed out in the above have caused the conventional thin film multi-layer electrode to be deviated from a boundary condition for its original low-loss operation. For example, in an open-ended circular TM mode resonator
53
, the conductor loss inside the resonator is increased and no-load Q of the resonator is degraded.
Further, although the resonance frequency of the open-ended circular TM mode resonator
53
is determined by the diameter of the circular thin film multi-layer electrode
52
, when the thin film multi-layer electrode
52
is formed by using a metal mask, as described above, and because the diameter of the thin film multi-layer electrode becomes larger than the diameter of the metal mask, for example, due to sputtered particles migrated between the metal mask and the dielectric substrate
51
, it is difficult to form an electrode
52
having a desired diameter.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to solve the above-mentioned technical problems and to present a dielectric resonator to be able to make effective use of the characteristic of low loss shown by a thin film multi-layer electrode.
In order to attain the above-mentioned object, a dielectric resonator according to a first aspect of the present invention comprises electrodes formed on both the main surfaces of a dielectric substrate, and has for at least one of the electrodes a thin film multi-layer electrode of thin film conductor layers and thin film dielectric layers having fixed thickness which are alternately laminated, and is characterized in that at the end portion of the thin film conductor layers the layers are electrically open from each other, and in that each of the end portions of the dielectric substrate, the thin film conductor layers, and the thin film dielectric layers is aligned nearly with the same surface.
Further, a dielectric resonator according to a second aspect of the present invention comprises electrodes formed on both of the main surfaces of a dielectric substrate, and has for at least one of the electrodes a thin film multi-layer electrode of thin film conductor layers and thin film dielectric layers having fixed thickness which are alternately laminated, and is characterized in that abrasive or etching treatment is given to the external portion of the dielectric substrate and the external portion of the electrodes formed on both the main surfaces of the dielectric substrate in order to place the end portion of the electrodes is in an electrically open-circuited condition.
In this way, a dielectric resonator under a uniform boundary condition is able to be obtained.
Further, a dielectric resonator according to a third aspect of the present invention is characterized in that a dielectric substrate constituting a dielectric resonator according to the first or second aspect of the present invention is made in a cylindrical form.
In this way, it is made easier to give dimensionally high-precision abrasive treatment to dielectric resonators.
In addition, a dielectric resonator according to a fourth aspect of the present invention is characterized in that the thickness of each film of the thin film conductor layers and the thin film dielectric layers of the thin film multi-layer electrode formed on at least one main surface of the dielectric substrate of a dielectric resonator according to the first, second or third aspect of the present invention is nearly uniform all over the entire surface of the thin film multi-layer electrode.
In this way, a dielectric resonator under a more uniform boundary condition than a dielectric resonator according to the first three aspects of the present invention is able to be obtained.
And a dielectric filter according to a fifth aspect of the present invention is characterized in that input-output connections are provided in a dielectric resonator according to one of the first through fourth aspects of the present invention.
In this way, a dielectric filter making the best use of the strong points of the dielectric resonator of the first through fourth aspects of the present invention is able to be obtained.
Further, a dielectric duplexer according to a sixth aspect of the present invention comprises a first group of resonators made up of at least one dielectric resonator as in one of the first through fourth aspects of the present invention, a second group of resonators made up of at
Hidaka Seiji
Ise Tomoyuki
Ishikawa Yohei
Matsui Norifumi
Glenn Kimberly E
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Pascal Robert
LandOfFree
Dielectric resonator, dielectric filter, dielectric... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dielectric resonator, dielectric filter, dielectric..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dielectric resonator, dielectric filter, dielectric... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2531330