Information
-
Patent Grant
-
6737943
-
Patent Number
6,737,943
-
Date Filed
Tuesday, July 16, 200222 years ago
-
Date Issued
Tuesday, May 18, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Tokar; Michael
- Mai; Lam T.
Agents
- Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
-
CPC
-
US Classifications
Field of Search
US
- 333 206
- 333 202
- 333 26
- 333 134
- 333 235
- 333 219
- 333 2191
- 505 210
-
International Classifications
-
Abstract
A dielectric device includes a dielectric substrate that includes at least one resonator unit. An external conductor film covers most of the outer surface of the dielectric substrate, except one end surface. The at least one resonator unit includes a first hole and a second hole. The first hole is provided in the dielectric substrate, extending from the end surface to an opposite surface, being open at the end surface and the opposite surface, and having a first internal conductor inside thereof. The second hole is provided in the dielectric substrate at a predetermined distance from the first hole, extends from the end surface toward the opposite surface, being open at the end surface, closed at the opposite surface, and having a second internal conductor inside thereof. The second internal conductor is connected to the first internal conductor at the end surface.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to dielectric devices of a wide range of devices such as resonators, oscillators, dielectric filters, duplexers and the like.
2. Description of the Related Art
Such dielectric devices are used in a high-frequency range such as sub-microwave band, microwave band, millimeter wave band, or sub-millimeter wave band. More specific examples of applications include satellite communication devices, mobile communication devices, wireless communication devices, high-frequency communication devices, or base stations for such communication devices.
In conventional dielectric devices of this type, for example, in a dielectric filter as a representative example thereof, a plurality of resonator units are composed using a common ceramic dielectric body, those resonator units are interstage capacitively or inductively coupled, and a prescribed frequency component is extracted. The ceramic dielectric body is used commonly in a plurality of resonator units and most of the outer surface thereof, excluding the open end surface, is coated with a conductive film.
Each of the resonator units comprises a first hole passing therethrough to an opposite surface (short circuit surface) which is opposite to the open end surface. The height of the ceramic dielectric body from the open end surface to the short circuit surface is typically selected as (λ/4), where λ is a selected central frequency wavelength. Therefore, the first hole also has a length of about (λ/4).
However, heavy demands are placed upon the decrease in thickness, size, and weight of satellite communication devices, mobile communication devices, wireless communication devices, and high-frequency communication devices using such dielectric devices, and this demand cannot be met by the conventional technology setting (λ/4) as a standard for the height of the ceramic dielectric body from the open end surface to the short circuit surface.
Japanese Patent Publication No. 32321/1992 is known as a reference relating to prior art aimed at miniaturization of dielectric filters. The dielectric filter described in this publicly known reference can be conceptually considered as a dielectric filter obtained by cutting a ceramic dielectric body having a height of about (λ/4) in a position of (λ/8), which is half of (λ/4), arranging the obtained two halves in a row so that the cut surfaces thereof tie at the same side, and then connecting the through conductors divided in two on the cut surfaces.
However, a problem associated with such conventional technology is that the through conductors determining the resonant wavelength matched the height of the ceramic dielectric body and the dimensions thereof were fixed which made it difficult to adjust the resonant frequency.
Furthermore, the open end surface and short circuit surface turn up in a relationship such that each of them takes a half of surface area on the surface opposite to the cut surface. As a result, the external connection structure of input and output terminals was difficult to conform to actual demands.
Thus, in the dielectric filters of this type, because of the demand placed upon miniaturization and decrease in thickness, it was necessary to employ an input and output terminal structure allowing for surface mounting on a circuit substrate.
However, since in the above-described conventional technology, the open end surface and short circuit surface turn up in a relationship such that each of them takes a half of the surface area on the surface opposite to the cut surface, a structure has to be employed in which the surface where the open end surface and short circuit surface are present is directed upward and a lead wire is connected to the through conductor appearing on the open end surface, which makes it difficult to employ a surface mounted structure.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a dielectric device permitting miniaturization and decrease in thickness.
Another object of the present invention is to provide a dielectric device allowing for resonant frequency adjustment.
Still another object of the present invention is to provide a dielectric device suitable for surface mounting.
In order to attain the above-described objects, the dielectric device in accordance with the present invention comprises a dielectric substrate and at least one resonator unit. The dielectric substrate comprises an outer surface covered with an external conductor film, excluding at least one end surface.
The resonator unit comprises a first hole and a second hole. The first hole is provided in the dielectric substrate, directed from the end surface to the surface opposite thereto, and open at the end surface and opposite surface. Thus, the first hole is a through hole. A first internal conductor is provided inside the first hole.
The second hole is provided in the dielectric substrate so that it is spaced apart from the first hole, directed from the end surface toward the surface opposite thereto, open at said end surface, and closed at a bottom portion thereof. Thus, the second hole is a blind hole. A second internal conductor is provided inside the second hole. The second internal conductor is connected to the first internal conductor at the end surface.
As described above, in the dielectric device in accordance with the present invention, the resonator unit comprises the first hole and the second hole, the first hole comprises the first internal conductor, is directed from the end surface of dielectric substrate toward the surface opposite thereto, and is open at the end surface and opposite surface. Furthermore, the second hole is spaced apart from the first hole and is directed from the end surface toward the surface opposite thereto. The second hole is provided with the second internal conductor and the second internal conductor is connected to the first internal conductor at the end surface.
Therefore, in the dielectric device in accordance with the present invention, the resonator length defining the resonant wavelength is a sum (H
1
+H
2
+D
1
) of the length H
1
of the through conductor corresponding to the height from the end surface of the dielectric substrate to the surface opposite thereto, the depth (height) H
2
of the second hole directed from the end surface toward the surface opposite thereto, and the distance D
1
from the second hole to the first hole. This means that when a prescribed resonant wavelength is obtained, the height from the end surface of the dielectric substrate to the surface opposite thereto can be decreased by the sum (H
2
+D
1
) of the depth of the second hole directed from the end surface toward the surface opposite thereto and the distance D
1
from the second hole to the first hole, and the dimensions and thickness of the dielectric substrate can be decreased.
More specifically, when the resonant wavelength is (λ/4), if the sum (H
2
+D
1
)=(λ/8), the height H
1
from the end surface of the dielectric substrate to the surface opposite thereto also becomes (λ/8) and this height can be reduced from the usually required (λ/4) to (λ/8).
Moreover, the second hole is closed rather than open at the opposite surface, and a dielectric material having a thickness equal to a difference (H
1
−H
2
) between the height H
1
of the dielectric substrate and the depth H
2
of the second hole is present between the second hole and the opposite surface. Therefore, the depth H
2
of the second hole can be adjusted and thus the resonant frequency can be adjusted by controlling the thickness of the dielectric material.
Furthermore, since the second hole is disposed at a distance D
1
from the first hole, the resonant frequency can be also adjusted by setting the distance D
1
.
Moreover, the second hole is directed from the end surface toward the surface opposite thereto, is open at the end surface and is closed rather than open at the surface opposite to the end surface. Therefore, a terminal for surface mounting can be provided so as to be electrically insulated from the external conductor film in an appropriate position, for example, on a side surface or the surface opposite to the end surface. With such a structure, the terminal can be mounted onto the mounting substrate. A coupling capacitance is generated between the terminal and the internal conductor of the second hole, this capacitance being defined by the thickness and dielectric constant of the dielectric material therebetween and opposing surface areas thereof. The terminal can be also provided on the side surface of the dielectric substrate to create capacitive coupling with the internal conductor of the first hole.
In case of resonant wavelength (λ/4), the surface opposite to the end surface serves as a surface (short circuit surface) covered with an external conductor film, but in case of resonant wavelength (λ/2), the opposite surface serves as the end surface not covered with an external conductor film.
The dielectric device in accordance with the present invention covers a wide range of devices including resonators, oscillators, dielectric filters, duplexers (also referred to as antenna duplexers). When it is used as a resonator or oscillator, among those applications, one resonator unit may be sufficient. In dielectric filter or duplexer applications, there are a plurality of resonator units.
When the device in accordance with the present invention is used as a dielectric filter, a first terminal and a second terminal are provided and they are employed as input and output terminals. The first terminal is provided in a position opposite, via the dielectric substrate, to the second hole provided in one of the resonator units. The second terminal is provided in a position opposite, via the dielectric substrate, to the second hole provided in another resonator unit. Both those first and second terminals are insulated from the external conductor.
With such configuration, the first and second terminals can be surface mounted onto a mounting substrate. The first and second terminals may be provided on the opposite surface or they may be provided on the side surface of the dielectric substrate, excluding the end surface and opposite surface. Furthermore, the first and second terminals may be also provided so as to be capacitively coupled to the first internal conductor.
In case of application as a duplexer (antenna duplexer), at least three resonator units and first to third terminals are provided. The first to third terminals are installed according to respective different resonator units and are used as an antenna terminal, receive terminal, and transmit terminal.
With such configuration, the first to third terminals can be surface mounted onto a mounting substrate. The first to third terminals may be provided on the opposite surface or they may be provided on the side surface of the dielectric substrate, excluding the end surface and opposite surface. Furthermore, the resonant frequency can be adjusted by setting the depth of the second hole or the distance between the first hole and second hole.
Other objects, configurations, and advantages of the present invention will be described with greater detail hereinbelow with reference to the drawings attached. However, the technological scope of the present invention is obviously not limited to the embodiments thereof illustrated in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of the dielectric filter in accordance with the present invention;
FIG. 2
is a perspective view of the dielectric fitter shown in
FIG. 1
, as viewed from the bottom surface thereof;
FIG. 3
is a cross-sectional view along line
3
—
3
in
FIG. 1
;
FIG. 4
is a cross-sectional view along line
4
—
4
in
FIG. 1
;
FIG. 5
illustrates the relationship between the resonant frequency and resonator length of the dielectric filter shown in
FIGS. 1
to
4
;
FIG. 6
is a cross-sectional view showing the state in which the dielectric filter shown in
FIGS. 1
to
4
is mounted on a substrate;
FIG. 7
is a cross-sectional view illustrating an expanded portion of the dielectric filter shown in
FIGS. 1
to
4
;
FIG. 8
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 9
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention;
FIG. 10
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 11
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention;
FIG. 12
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 13
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention;
FIG. 14
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 15
is a perspective view of the dielectric filter shown in
FIG. 14
, as viewed from the bottom surface thereof;
FIG. 16
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 17
is a perspective view of the dielectric filter shown in
FIG. 16
, as viewed from the bottom surface thereof;
FIG. 18
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 19
is a perspective view of the dielectric filter shown in
FIG. 18
, as viewed from the bottom surface thereof;
FIG. 20
is a cross-sectional view along line
20
—
20
in
FIG. 18
;
FIG. 21
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 22
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 23
is a perspective view of the dielectric filter shown in
FIG. 22
, as viewed from the bottom surface thereof;
FIG. 24
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 25
is a perspective view of the dielectric filter shown in
FIG. 24
, as viewed from the bottom surface thereof;
FIG. 26
is a cross-sectional view along line
26
—
26
in
FIG. 24
;
FIG. 27
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 28
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 29
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 30
is a perspective view of the dielectric filter shown in
FIG. 29
, as viewed from the bottom surface thereof;
FIG. 31
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 32
is a perspective view of the dielectric filter shown in FIG.
31
, as viewed from the bottom surface thereof;
FIG. 33
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 34
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 35
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 36
is a cross-sectional view along line
36
—
36
in
FIG. 35
;
FIG. 37
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 38
is a cross-sectional view along line
38
—
38
in
FIG. 37
;
FIG. 39
illustrates the relationship between the resonant frequency and resonator length of the dielectric filter shown in
FIGS. 35
to
38
;
FIG. 40
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 41
is a perspective view of the dielectric filter shown in
FIG. 40
, as viewed from the bottom surface thereof;
FIG. 42
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 43
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 44
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 45
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 46
is a cross-sectional view along line
46
—
46
in
FIG. 45
;
FIG. 47
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 48
is a perspective view of the dielectric filter shown in
FIG. 47
, as viewed from the bottom surface thereof;
FIG. 49
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 50
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention;
FIG. 51
is a perspective view of the duplexer in accordance with the present invention.
FIG. 52
is a perspective view of the duplexer shown in
FIG. 51
, as viewed from the bottom surface thereof;
FIG. 53
illustrates a frequency response curve of the duplexer shown in
FIGS. 51 and 52
.
FIG. 54
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention;
FIG. 55
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention;
FIG. 56
is a perspective view of the duplexer shown in
FIG. 55
, as viewed from the bottom surface thereof;
FIG. 57
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention;
FIG. 58
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention;
FIG. 59
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention; and
FIG. 60
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to
FIGS. 1
to
4
, an example of a dielectric device comprising two resonator units Q
1
, Q
2
is explained. The resonator units Q
1
, Q
2
include a common dielectric substrate
1
and are integrated via common dielectric substrate
1
. Common dielectric substrate
1
is formed to have a substantially hexagonal shape by using a conventional dielectric material. External conductor film
3
covers most of the outer surface of dielectric substrate
1
, except one surface serving as end surface
21
. External conductive film
3
typically contains copper, silver or the like as the main component and is formed by baking, plating or the like.
Resonator unit Q
1
comprises a first hole
41
and a second hole
51
. First hole
41
is a through hole which is directed from end surface
21
to surface
22
opposite thereto and is open at end surface
21
and opposite surface
22
. A first internal conductor
61
connected to external conductive film
3
located on opposite surface
22
is provided inside first hole
41
. First internal conductor
61
is composed of a conductive film formed on the inner surface of first hole
41
. First internal conductor
61
is formed from the same material and by the same means as external conductive film
3
. Alternatively, first hole
41
may be filled partially or completely with first internal conductor
61
.
Second hole
51
is arranged almost parallel to first hole
41
at a distance D
1
from first hole
41
. Second hole
51
is a blind hole; it is directed from end surface
21
toward surface
22
opposite thereto, but is open only at end surface
21
. Second hole
51
is closed at the side of opposite surface
22
which faces end surface
21
. A dielectric portion
71
with a thickness T
1
is present between the bottom surface of second hole
51
and opposite surface
22
.
Second hole
51
is provided with a second internal conductor
81
. Second internal conductor
81
is connected to first internal conductor
61
with a conductive film
91
on end surface
21
. Second internal conductor
81
is composed of a conductive film formed on the inner surface of second hole
51
. Second internal conductor
81
is formed from the same material and by the same means as first internal conductor
61
. Alternatively, second hole
51
may be filled partially or completely with second internal conductor
81
.
Resonator unit Q
2
comprises a first hole
42
and a second hole
52
. First hole
42
is a through hole which is directed from end surface
21
to surface
22
opposite thereto and is open at end surface
21
and opposite surface
22
. A first internal conductor
62
connected to external conductive film
3
located on opposite surface
22
is provided inside first hole
42
. First internal conductor
62
is composed of a conductive film formed on the inner surface of first hole
42
.
Second hole
52
is a blind hole arranged almost parallel to first hole
42
at a distance D
2
from first hole
42
. Second hole
52
is directed from end surface
21
toward surface
22
opposite thereto, but is open only at end surface
21
. Second hole
52
is closed at the side of opposite surface
22
which faces end surface
21
. A dielectric portion
72
with a thickness T
2
is present between the bottom surface of second hole
52
and opposite surface
22
.
Second hole
52
is provided with a second internal conductor
82
. Second internal conductor
82
is connected to first internal conductor
62
with a conductive film
92
on end surface
21
. Second internal conductor
82
is composed of a conductive film formed on the inner surface of second hole
52
.
Furthermore, in this embodiment, resonator unit Q
1
has a coupling electrode
111
extending from conductive film
91
toward resonator unit Q
2
, and resonator unit Q
2
has a coupling electrode
112
extending from conductive film
92
toward resonator unit Q
1
. An insulating gap G
1
is provided between coupling electrode
111
, conductive film
91
and coupling electrode
112
, conductive film
92
. Therefore, in the present embodiment, resonator units Q
1
, Q
2
are capacitively coupled via insulating gap G
1
between coupling electrode
111
, conductive film
91
and coupling electrode
112
, conductive film
92
.
As shown in FIG.
2
and
FIG. 3
, a first terminal
11
and a second terminal
12
serving as input and output terminals are provided on opposite surface
22
of dielectric substrate
1
. First terminal
11
is provided in a position opposite to second hole
51
via a dielectric portion
71
and is electrically insulated from external conductive film
3
by an insulating gap G
2
.
Second terminal
12
is provided in a position opposite to second hole
52
via a dielectric portion
72
and is electrically insulated from external conductive film
3
by an insulating gap G
3
. More specifically, first and second terminals
11
,
12
are provided on opposite surface
22
at the side thereof opposite to end surface
21
.
A coupling capacitance is generated between first and second terminals
11
,
12
and internal conductors
81
,
82
of second holes
51
,
52
, this capacitance being defined by the thickness of dielectric portions
71
,
72
therebetween, their dielectric constants, and opposing surface areas thereof. It is not necessary that first and second terminals
11
,
12
overlap internal conductors
81
,
82
of second holes
51
,
52
. The terminals may also be provided in positions which partially face the conductors or do not face them at all. Furthermore, insulating gaps g
2
, g
3
may be connected to form a single gap.
The advantages of the dielectric filter shown in
FIGS. 1
to
4
will be described below with reference to resonator unit Q
1
. Resonator unit Q
2
has the same structure as resonator unit Q
1
and the explanation conducted with respect to resonator unit Q
1
is directly applicable thereto.
As has already been described, in resonator unit Q
1
, first hole
41
is directed from end surface
21
of dielectric substrate
1
to surface
22
opposite thereto and is open at end surface
21
and opposite surface
22
. First hole
41
is provided with first internal conductor
61
connected to external conductor film
3
present on opposite surface
22
. Second hole
51
is located at a distance D
1
from first hole
41
and is directed from end surface
21
toward surface
22
opposite thereto. Second hole
51
of resonator unit Q
1
is provided with second internal conductor
81
, and second internal conductor
81
is connected to first internal conductor
61
at end surface
21
.
Therefore, in resonator unit Q
1
, the resonator length determining the resonant wavelength is a sum (H
1
+H
2
+D
1
) of the length H
1
of through hole
41
corresponding to a height from end surface
21
of dielectric substrate
1
to surface
22
opposite thereto, the depth (height) H
2
of second hole
51
directed from end surface
21
toward surface
22
opposite thereto, and the distance D
1
from second hole
51
to first hole
41
.
It means that in order to obtain the prescribed resonant length, the height H
1
from end surface
21
of dielectric substrate
1
to surface
22
opposite thereto can be reduced by the sum (H
2
+D
1
) of the depth H
2
of second hole
51
and the distance D
1
from second hole
51
to first hole
41
. Therefore, dielectric substrate
1
can be made thinner and smaller.
More specifically, in case of a dielectric filter with a resonant wavelength of (λ/4), if the sum (H
2
+D
1
) is considered equal to (λ/8), the height (H
1
) from end surface
21
of dielectric substrate
1
to surface
22
opposite thereto also becomes (λ/8) and a height thereof can be reduced by half from the usually required (λ/4) to (λ/8). The same is true for resonator unit Q
2
having the same configuration as resonator unit Q
1
.
Moreover, second hole
51
is closed rather than open at opposite surface
22
, and dielectric portion
71
with a thickness T
1
corresponding to a difference (H
1
−H
2
) between the height H
1
of dielectric substrate
1
and depth H
2
of second hole
51
is present between second hole
51
and opposite surface
22
. Therefore, the depth H
2
of second hole
51
and therefore the resonant frequency can be adjusted by the thickness T
1
of dielectric portion
71
.
FIG. 5
illustrates the relationship between a resonant frequency and a resonator length. In this figure, the resonator length (H
1
+H
2
+D
1
) is plotted against the abscissa, and the resonant frequency is plotted against the ordinate. As shown in
FIG. 5
, when the depth H
2
of second hole
51
is changed within a range from H
2
=0 to H
2
=H
1
, the resonant frequency changes linearly. Therefore, the resonant frequency can be adjusted by changing the depth H
2
of second hole
51
.
Since second hole
51
is disposed at a distance D
1
from first hole
41
, the resonant frequency can also be adjusted by setting the distance D
1
.
Moreover, in the embodiment comprising two resonator units Q
1
, Q
2
, the above-mentioned frequency adjustment can be conducted independently for each resonator unit Q
1
, Q
2
. Therefore, the adjustment of resonant frequency is facilitated.
Second hole
51
is a blind hole; it is closed at surface
22
opposite to end surface
21
and not open thereat. Therefore, first terminal
11
for surface mounting can be electrically insulated from external conductor film
3
by insulating gap G
2
on opposite surface
22
. With such configuration, first terminal
11
can be surface mounted on a mounting substrate.
The same is true for resonator unit Q
2
having the same configuration as resonator unit Q
1
. Second terminal
12
can be electrically insulated from external conductor film
3
with insulating gap G
3
on opposite surface
22
. Therefore, second terminal
12
can be surface mounted on the mounting substrate.
FIG. 6
is a cross-sectional view illustrating the state in which the dielectric filter shown in
FIGS. 1
to
4
is mounted onto a substrate. The dielectric filter is surface mounted onto print circuit board (PCB) by connecting first terminal
11
and second terminal
12
by a connecting means such as soldering to conductive patterns P
1
, P
2
provided on PCB. External conductor film
3
is connected to a ground pattern provided on PCB.
FIG. 7
is a cross-sectional view illustrating an expanded portion of the dielectric filter shown in
FIGS. 1
to
4
. This embodiment illustrates an example of modification relating to the shape of first hole
41
and second hole
51
. The edge of the end of first hole
41
and second hole
51
is formed as a gradually expanding tilted portion
100
. In the figure, tilted portion
100
is in the form of an arc, but it may also be in the form of a straight line, broken line, and the like.
If such tilted portion
100
is present, the reflection in the transmission line composed of first internal conductor
61
, conductive film
91
, and second internal conductor
81
can be reduced. It can be remarked in advance that a similar structure can be also employed in the below-described embodiments.
Various embodiments of the dielectric filter in accordance with the present invention will be successively described hereinbelow with reference to the attached
FIGS. 8
to
60
. In the aforesaid attached drawings, structural components identical to those shown in the above-described drawings will be assigned with the same reference symbols and the explanation thereof will be omitted.
FIG. 8
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention. In the embodiment shown in
FIG. 8
, first holes
41
,
42
and second holes
51
,
52
are elongated openings with both ends thereof in the form of circular arcs. First holes
41
,
42
and second holes
51
,
52
can also have openings in a variety of other shapes.
Coupling between resonator units Q
1
, Q
2
and also coupling capacitance between second internal conductors
81
,
82
of second holes
51
,
52
(see
FIGS. 1
to
4
) and first terminal
11
and second terminal
12
can be adjusted by selecting the opening shape of first holes
41
,
41
and second holes
51
,
52
.
FIG. 9
is a perspective view illustrating another embodiment of the dielectric fitter in accordance with the present invention. A specific feature of the embodiment shown in
FIG. 9
is in that a conductor film
301
is provided on end surface
21
between resonator unit Q
1
and resonator unit Q
2
, inductively coupling resonator unit Q
1
and resonator unit Q
2
. Conductor film
301
is connected at both ends thereof to external conductor film
3
.
FIG. 10
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention. A specific feature of the embodiment shown in
FIG. 10
is in that a conductor film
302
is provided on end surface
21
between resonator unit Q
1
and resonator unit Q
2
, inductively coupling resonator unit Q
1
to resonator unit Q
2
. Conductor film
302
is connected at one end thereof to external conductor film
3
.
FIG. 11
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention. A specific feature of the embodiment shown in
FIG. 11
is in that the conductor films
303
,
304
provided between adjacent resonator units Q
1
, Q
2
extend inward from the mutually opposite side surfaces and are separated by an insulating gap G
5
provided in the intermediate portion. With such structure, the inductive coupling between adjacent resonator units Q
1
, Q
2
can be adjusted by selecting the size of insulating gap G
5
.
FIG. 12
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention. In this embodiment, a recess
23
is provided between adjacent resonator units Q
1
, Q
2
and a conductor film
302
connected to external conductor film
3
is provided on the bottom surface and inner side surfaces of recess
23
. Conductor film
302
can be formed by coating, fitting, or plating an electrically conductive material containing Cu, Ag and the like as the main component on the inner surface of recess
23
. With such structure, the inductive coupling between adjacent resonator units Q
1
, Q
2
can be adjusted by selecting the position, width, depth, and length of recess
23
.
FIG. 13
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention. A specific feature of the embodiment shown in
FIG. 13
is that resonator units Q
1
, Q
2
comprise respective recesses
23
,
24
. Recesses
23
,
24
are formed so as to be spaced apart in end surface
21
. First hole
41
and second hole
51
constituting resonator unit Q
1
are provided inside recess
23
, and first hole
42
and second hole
52
constituting resonator unit Q
2
are provided inside recess
24
. Furthermore, a conductor film
91
is formed on the bottom surface and vertical surfaces of recess
23
, and conductor film
92
is formed on the bottom surface and vertical surfaces of recess
24
. In the embodiment shown in
FIG. 13
, too, resonator unit Q
1
and resonator unit Q
2
are capacitively coupled to each other.
FIG. 14
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention.
FIG. 15
is a bottom surface view of the dielectric filter shown in FIG.
14
.
A specific feature of the embodiment shown in the figures is in the arrangement of first hole
41
and second hole
51
inside recess
23
and the arrangement of first hole
42
and second hole
52
inside recess
24
. Thus, second hole
51
is displaced outward by a dimension ΔA
1
with respect to first hole
41
, and second hole
52
is displaced outward by a dimension ΔA
2
with respect to first hole
42
.
As shown in
FIG. 15
, first terminal
11
corresponding to second hole
51
and second terminal
12
corresponding to second hole
52
are also shifted outward with respect to first holes
41
,
42
.
In case of the embodiment illustrated by
FIGS. 14 and 15
, resonator unit Q
1
and resonator unit Q
2
are capacitively coupled to each other. The embodiment illustrated by
FIGS. 14 and 15
shows that the capacitive coupling of resonator unit Q
1
and resonator unit Q
2
can be adjusted by selecting the dimension ΔA
1
.
FIG. 16
is a perspective view illustrating another embodiment of the dielectric fitter in accordance with the present invention.
FIG. 17
is a bottom surface view of the dielectric filter shown in
FIG. 16. A
specific feature of the embodiment shown in the figures is in the arrangement of first hole
41
and second hole
51
inside recess
23
and the arrangement of first hole
42
and second hole
52
inside recess
24
. Thus, second hole
51
is displaced inward by a dimension ΔB
1
with respect to first hole
41
, and second hole
52
is displaced inward by a dimension Δb
2
with respect to first hole
42
.
As shown in
FIG. 17
, first terminal
11
corresponding to second hole
51
and second terminal
12
corresponding to second hole
52
are also displaced inward with respect to first holes
41
,
42
. In case of the embodiment illustrated by
FIGS. 16 and 17
, resonator unit Q
1
and resonator unit Q
2
are capacitively coupled to each other. The embodiment illustrated by
FIGS. 16 and 17
shows that the capacitive coupling of resonator unit Q
1
and resonator unit Q
2
can be adjusted by selecting the dimension ΔB
1
.
FIGS. 16 and 17
illustrate a case in which the positions of second holes
51
,
52
are moved so that they approach each other, thereby intensifying coupling of resonator units Q
1
, Q
2
.
By further advancing the embodiments illustrated by
FIGS. 14
to
17
, it is also possible to implement a structure in which first hole
41
and second hole
51
, and/or first hole
42
and second hole
52
, and first hole
41
and second hole
51
, and/or first hole
42
and second hole
52
are arranged in a row along the direction of resonator units Q
1
, Q
2
arrangement.
FIG. 18
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention.
FIG. 19
is a bottom surface view of the dielectric filter shown in FIG.
18
.
FIG. 20
is a cross-sectional view along line
20
—
20
in FIG.
18
.
In the embodiment shown in the figures, first hole
41
comprises a large-diameter portion
411
and a small-diameter portion
412
. Large-diameter portion
411
is open at end surface
21
and small-diameter portion
412
is connected to the lower part of large-diameter portion
411
. First hole
42
also comprises a large-diameter portion
421
and a small-diameter portion
422
. Large-diameter portion
421
is open at end surface
21
and small-diameter portion
422
is connected to the lower part of large-diameter portion
421
. In first holes
41
,
42
, as shown in
FIGS. 19 and 20
, small-diameter portions
412
,
422
are open at opposite surface
22
of dielectric substrate
1
.
In the embodiment shown in
FIGS. 18
to
20
, second holes
51
,
52
also comprise large-diameter portions
511
,
521
and small-diameter portions
512
,
522
. Large-diameter portions
511
,
521
are open at the end surface and small-diameter portions
512
,
522
are connected to the lower parts of large-diameter portions
511
,
521
and front ends thereof are closed.
External conductor film
3
is provided on opposite surface
22
, and first terminal
11
and second terminal
12
are provided in the positions corresponding to small-diameter portions
512
,
522
of second holes
51
,
52
. First terminal
11
and second terminal
12
are electrically insulated from external conductor film
3
by insulating gaps g
2
, g
3
.
In case of the embodiment shown in
FIGS. 18
to
20
, the coupling characteristic between resonator unit Q
1
and resonator unit Q
2
and the resonant frequencies can be adjusted by selecting the diameter of large-diameter portions (
411
,
421
), (
511
,
521
).
FIG. 21
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention. In this embodiment, a trench
40
connecting first holes
41
,
42
open at opposite surface
22
is provided therebetween. External conductor film
3
is formed on the inner surface of trench
40
. With such embodiment, coupling of resonator units Q
1
, Q
2
can be adjusted by selecting, for example, the depth or width of trench
40
.
FIG. 22
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention.
FIG. 23
is a bottom surface view of the dielectric filter shown in FIG.
22
.
In the embodiment shown in the figures, large-diameter portion
411
is open at opposite surface
22
, and small-diameter portion
412
is connected to the upper part of large-diameter portion
411
, that is, in the direction of end surface
21
. First hole
42
also comprises large-diameter portion
421
and small-diameter portion
422
. Large-diameter portion
421
is open at opposite surface
22
, and small-diameter portion
422
is connected to the upper part of large-diameter portion
421
. In first holes
41
,
42
, as shown in
FIG. 22
, small-diameter portions
412
,
422
are open at end surface
21
of dielectric substrate
1
.
External conductor film
3
is provided at opposite surface
22
. First terminal
11
and second terminal
12
are also provided on the opposite surface in the positions corresponding to second holes
51
,
52
. First terminal
11
and second terminal
12
are electrically insulated from external conductor film
3
by insulating gaps g
2
, g
3
.
In case of the embodiment illustrated by
FIGS. 22 and 23
, the coupling characteristic between resonator unit Q
1
and resonator unit Q
2
and the resonant frequencies thereof can be adjusted by selecting the diameter of large-diameter portions
411
,
421
.
FIG. 24
is a perspective view illustrating another embodiment of the dielectric filter in accordance with the present invention.
FIG. 25
is a perspective view of the dielectric filter shown in
FIG. 24
, as viewed from the bottom surface thereof.
FIG. 26
is a cross-sectional view along line
26
—
26
in
FIG. 24. A
specific feature of the embodiment shown in the figures is in that first terminal
11
and second terminal
12
are formed consecutively on the side surface and opposite surface
22
of dielectric substrate
1
.
First terminal
11
is electrically insulated from external conductor film
3
by gap g
2
and, as shown in
FIG. 26
, capacitively coupled to internal conductor
81
of second hole
51
via dielectric portion
71
. Second terminal
12
is electrically insulated from external conductor film
3
by gap g
3
and is capacitively coupled to the internal conductor of second hole
52
via a dielectric portion.
Various embodiments can be considered when first terminal
11
and second terminal
12
are provided on the side surface of dielectric substrate
1
. An example thereof is shown in
FIGS. 27 and 28
.
In the embodiment shown in
FIG. 27
, first terminal
11
and second terminal
12
are provided on the side surface of dielectric substrate
1
so that the upper edges thereof are aligned with end surface
21
.
In the embodiment shown in
FIG. 28
, first terminal
11
and second terminal
12
are provided on two side surfaces constituting a corner of dielectric substrate
1
so that the upper edges thereof are aligned with end surface
21
.
When the dielectric filter shown in
FIGS. 27 and 28
is mounted onto a substrate, surface mounting can be conducted by arranging a side surface where both the first terminal
11
and the second terminal
12
are present so that it faces the substrate.
FIG. 29
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 30
is a perspective view of the dielectric filter shown in
FIG. 29
, as viewed from the bottom surface thereof. In the embodiment shown in the figures, first terminals
11
,
12
electrically insulated from external conductor film
3
by insulating gaps g
2
, g
3
are provided on the side surface of dielectric substrate
1
, and first terminals
11
,
12
are capacitively coupled to first internal conductors
61
,
62
located inside first holes
41
,
42
.
FIGS. 1
to
30
teach to provide first terminal
11
and second terminal
12
on the bottom or side surface of dielectric substrate
1
. However, those examples are not limiting and a structure may be used in which first terminal
11
and second terminal
12
are provided on end surface
21
.
FIG. 31
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 32
is a perspective view of the dielectric filter shown in
FIG. 31
, as viewed from the bottom surface thereof. In this embodiment, first holes
41
,
42
are provided almost on a central line (center in the width direction) O
1
of dielectric substrate
1
. The diameter of second holes
51
,
52
is less than that of first holes
41
,
42
. This embodiment demonstrates that it is not necessary to provide symmetry for the arrangement of first holes
41
,
42
and second holes
51
,
52
and the diameter shape thereof.
In any of the dielectric filters shown in
FIGS. 8
to
32
, the internal structure of the dielectric filter is substantially identical to that of the dielectric filters shown in
FIGS. 1
to
4
. Therefore, it is clear that the operation and effect of all of the dielectric filters shown in
FIGS. 8
to
32
are the same as in the embodiments illustrated by
FIGS. 1
to
4
.
FIG. 33
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention.
FIG. 33
is a perspective view, as viewed from the bottom surface. The structure of the upper surface can be the same as shown in
FIGS. 1
to
31
.
A specific feature of the embodiment shown in
FIG. 33
is in that a dielectric filter with a resonant wavelength (λ/2) is adopted, whereas in the embodiments shown in
FIGS. 1
to
32
, a dielectric filter with a resonant wavelength (λ/4) is adopted. The dielectric filter with a resonant wavelength (λ/2) comprises not only the inherent end surface
21
, but one more end surface composed by surface
22
opposite thereto which has no external conductor film
3
. First holes
41
,
42
are open at opposite surface
22
serving as an end surface. First and second terminals
11
,
21
are formed on opposite surface
22
opposite to the second hole which is not shown in FIG.
33
.
FIG. 34
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 34
is a perspective view, as viewed from the bottom surface. In the figure, structural components identical to those shown in
FIG. 33
are assigned with the same reference symbols. Similarly to the embodiment shown in
FIG. 33
, the upper surface can have a structure shown in
FIGS. 1
to
31
. A common feature of this embodiment and the embodiment shown in
FIG. 33
is in that a dielectric filter with a resonant wavelength (λ/2) is adopted.
A specific feature of the embodiment shown in
FIG. 34
is in that first hole
11
and second terminal
12
are provided in the intermediate portions on the side surface of dielectric substrate
1
, excluding end surface
21
and opposite surface
22
. First and second terminals
11
,
12
can assume a variety of configurations as shown in the preceding figures. In the embodiment shown in
FIGS. 33 and 34
, the upper surface can have a structure shown in
FIGS. 1
to
32
. Furthermore, this embodiment is also identical to the above-described embodiments in terms of the presence of the second hole. Therefore, it is clear that with the embodiments shown in FIG.
33
and
FIG. 34
, the object of the present invention can be attained in a dielectric filter with a resonant wavelength (λ/2).
FIG. 35
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention.
FIG. 36
is a cross-sectional view along tine
36
—
36
in FIG.
35
. In this embodiment, resonator unit Q
1
comprises first hole
41
and two second holes
51
,
52
. First hole
41
is a through hole, and second holes
51
,
52
are blind holes; the holes are disposed at distances D
1
, D
2
. First internal conductor
61
and second internal conductors
81
,
82
provided inside first hole
41
and second holes
51
,
52
are connected to conductor film
91
.
Resonator unit Q
2
has the same structure as resonator unit Q
1
. Thus, resonator unit Q
2
comprises a first hole
42
and two second holes
53
,
54
. First hole
42
is a through hole, and second holes
53
,
54
are blind holes; the holes are disposed at distances D
1
, D
2
. First internal conductor
62
and second internal conductors
83
,
84
provided inside first hole
42
and second holes
53
,
54
are connected to conductor film
92
.
First terminal
11
and second terminal
12
are provided on the side surface of dielectric substrate
1
. First terminal
11
is capacitively coupled to second internal conductor
82
provided in second hole
52
, and second terminal
12
is capacitively coupled to second internal conductor
84
provided in second hole
54
.
FIG. 37
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 38
is a cross-sectional view along line
38
—
38
in FIG.
37
. The dielectric filter shown in
FIGS. 37 and 38
is different from the dielectric filter of the embodiment shown in
FIGS. 35 and 36
only in that first terminal
11
and second terminal
12
are provided on opposite surface
22
of dielectric substrate
1
. As explained above, first terminal
11
and second terminal
12
can assume various arrangements and positions in addition to those shown in
FIGS. 35
to
38
.
In
FIGS. 35
to
38
, the depth H
2
of second hole
51
of resonator unit Q
1
and second hole
53
of resonator unit Q
2
is less than the depth H
3
of second hole
52
of resonator unit Q
1
and second hole
54
of resonator unit Q
2
(H
2
<H
3
), but the inverse relationship (H
2
>H
3
) is also possible. The depths H
2
, H
3
are not necessarily the same in resonator units Q
1
, Q
2
.
FIG. 39
illustrates the relationship between the resonant frequency and resonator length in the dielectric fitter shown in
FIGS. 35
to
38
. In the figure, the resonator length (H
1
+H
2
+H
3
+D
1
+D
2
) is plotted against the abscissa and the resonant frequency is plotted against the ordinate. As shown in
FIG. 39
, in resonator unit Q
1
, the resonant frequency changes linearly when the depth H
2
, H
3
of second holes
51
,
52
changes from H
2
=H
3
=0 to H
2
=H
3
=H
1
. Therefore, it is clear that the resonant frequency can be adjusted by changing the depth H
2
, H
3
of second holes
51
,
52
.
Since first hole
41
and second holes
51
,
52
are successively disposed at distances D
1
, D
2
form each other, the resonant frequency can be also adjusted by setting the distances D
1
, D
2
. It is obvious that the same result can be obtained in resonator unit Q
2
, and the explanation is omitted. Furthermore, it is not necessary that each of resonator units Q
1
, Q
2
be provided with two of second holes
51
to
54
and more holes may be provided.
In the above-described embodiments, dielectric filters with two resonator units Q
1
, Q
2
were described, but the dielectric filter may have any number of resonator units. Specific examples of dielectric filters with increased number of resonator units are described below.
FIG. 40
is a perspective view illustrating a dielectric filter having three resonator units Q
1
, Q
2
, Q
3
.
FIG. 41
is a perspective view of the dielectric filter shown in
FIG. 40
, as viewed from the bottom surface thereof.
Resonator units Q
1
, Q
2
, Q
3
use a common dielectric substrate
1
and are integrated via dielectric substrate
1
. External conductor film
3
covers a large portion of the outer surface of dielectric substrate
1
, except one surface serving as end surface
21
.
Resonator unit Q
1
comprises first hole
41
and second hole
51
. Resonator unit Q
2
comprises first hole
42
and second hole
52
. Resonator unit Q
3
comprises first hole
43
and second hole
53
. Individual structures of first holes
41
to
43
and second holes
51
to
53
and mutual arrangement thereof correspond to those explained with reference to
FIGS. 1
to
4
.
Resonator unit Q
1
and resonator unit Q
2
are capacitively coupled via coupling electrode
111
and coupling electrode
112
, and resonator unit Q
2
and resonator unit Q
3
are capacitively coupled via coupling electrode
112
and coupling electrode
113
.
First terminal
11
is disposed in a position corresponding to second hole
51
in surface
22
opposite to end surface
21
in a state in which it is electrically insulated from external conductor film
3
by insulating gap G
2
.
Second terminal
12
is disposed in a position corresponding to second hole
53
in opposite surface
22
in a state in which it is electrically insulated from external conductor film
3
by insulating gap G
3
.
In the embodiment shown in
FIGS. 40 and 41
, a larger number of resonator units Q
1
to Q
3
are used. Therefore, the frequency selection characteristic is improved.
FIG. 42
illustrates yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 42
shows a modification of the dielectric filter having the surface structure shown in
FIG. 40
, wherein second hole
53
shown in
FIG. 40
is a through hole. Second terminal
12
is directly connected to the internal conductor of this second hole
53
at opposite surface
22
. Second terminal
12
is electrically insulated from external conductor film
3
by insulating gap G
3
. First terminal film
11
electrically insulated from external conductor film
3
by insulating gap G
2
is provided in a position corresponding to second hole
51
among second holes
51
,
52
(see
FIG. 40
) provided in resonator units Q
1
, Q
2
.
In the embodiment shown in
FIG. 42
, second terminal
12
is connected directly to the internal conductor of second hole
53
provided in resonator unit Q
3
, at opposite surface
22
. Therefore, resonator unit Q
3
acts as a resonator for input or output. Otherwise, the operation and effect thereof are the same as in the embodiment shown in
FIGS. 40 and 41
.
FIG. 43
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention. In this embodiment, a conductor film
303
is provided between resonator unit Q
2
and resonator unit Q
3
. Conductor film
303
at one end thereof is connected to external conductor film
3
. As a result, resonator unit Q
2
and resonator unit Q
3
are inductively coupled. Resonator unit Q
1
and resonator unit Q
2
are capacitively coupled via coupling electrode
111
and coupling electrode
112
. Therefore, when resonator units Q
1
to Q
3
are considered as a whole, a structure is obtained which contains capacitive coupling and inductive coupling. The structure shown in
FIGS. 41 and 42
can be employed on the bottom surface of dielectric filter, that is, on opposite surface
22
(this structure is not shown).
FIG. 44
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention. In this embodiment, a conductive film
94
extending in the direction of resonator units Q
1
to Q
3
is provided on end surface
21
at the side of resonator unit Q
2
. With such structure, an additional transmission zero can be achieved and a contribution can be made to the improvement of filter characteristics. The structure shown in
FIGS. 41 and 42
can be employed on opposite surface
22
of the dielectric filter.
FIG. 45
is a perspective view illustrating yet another embodiment of the dielectric filter in accordance with the present invention.
FIG. 46
is a cross-sectional view along line
46
—
46
in FIG.
45
. In the embodiment shown in the figures, resonator units Q
1
to Q
3
have respective step-like recesses
23
to
25
. Recesses
23
to
25
are formed in end surface
21
at a certain distance from each other. First hole
41
and second hole
51
are open inside recess
23
, first hole
42
and second hole
52
are open inside recess
24
, and first hole
43
and second hole
53
are open inside recess
25
.
Furthermore, conductive film
91
is formed on the bottom surface and vertical surfaces of recess
23
, conductive film
92
is formed on the bottom surface and vertical surfaces of recess
24
, and conductive film
93
is formed on the bottom surface and vertical surfaces of recess
25
. With such structure, resonator units Q
1
to Q
3
are capacitively coupled to each other.
Moreover, a recess
26
extending in the direction of resonator units Q
1
to Q
3
is provided at the side of resonator unit Q
2
on end surface
21
, and a conductor film
94
is provided on the inner wall surface of recess
26
. With such structure, an additional transmission zero can be achieved. Therefore, a contribution can be made to the improvement of filter characteristics. The structure shown in
FIGS. 41 and 42
can be employed on opposite surface
22
of the dielectric filter.
FIG. 47
is a perspective view illustrating still another embodiment of the dielectric filter in accordance with the present invention.
FIG. 48
is a perspective view of the dielectric filter shown in
FIG. 47
, as viewed from the bottom surface thereof.
The dielectric filter shown in the figure comprises four resonator units Q
1
to Q
4
. The resonator units Q
1
to Q
4
have a common dielectric substrate
1
and are integrated via dielectric substrate
1
. External conductor film
3
covers a large portion of the outer surface of dielectric substrate
1
, except one surface serving as end surface
21
.
Resonator unit Q
1
comprises first hole
41
and second hole
51
. Resonator unit Q
2
comprises first hole
42
and second hole
52
. Resonator unit Q
3
comprises first hole
43
and second hole
53
. Resonator unit Q
4
comprises first hole
44
and second hole
54
. First holes
41
to
44
are through holes, and second holes
51
to
54
are blind holes.
Resonator unit Q
2
and resonator unit Q
3
are capacitively coupled via coupling electrode
111
and coupling electrode
112
, and resonator unit Q
3
and resonator unit Q
4
are inductively coupled via conductor film
303
.
First terminal
11
is disposed in a position corresponding to second hole
52
in surface
22
opposite to end surface
21
in a state in which it is electrically insulated from external conductor film
3
by insulating gap G
2
.
Second terminal
12
is disposed in a position corresponding to second hole
54
in opposite surface
22
in a state in which it is electrically insulated from external conductor film
3
by insulating gap G
3
.
In the embodiment shown in
FIGS. 47 and 48
, a larger number of resonator units Q
1
to Q
4
are used. Therefore, the frequency selection characteristic is further improved.
The structure of first terminal
11
and second terminal
12
in the dielectric filter with the surface structure shown in
FIG. 47
can be implemented in a variety of modifications, in addition to the basic structure shown in FIG.
48
. An example thereof is shown in
FIGS. 49
,
50
.
First,
FIG. 49
shows an example of modification in which first hole
44
of the dielectric filter shown in
FIG. 47
is a blind hole and second hole
54
shown in
FIG. 47
is a through hole. Second terminal
12
is provided in the position on opposite surface
22
corresponding to second hole
44
. First holes
41
to
43
are through holes and second holes
51
to
53
(see
FIG. 47
) are blind holes.
Then,
FIG. 50
illustrates an example in which second hole
54
of the dielectric filter shown in
FIG. 47
is a through hole and second terminal
12
is connected to second hole
54
. Therefore, resonator unit Q
4
operates as a resonator for input or output. Second terminal
12
is electrically insulated from external conductor film
3
by insulating gap G
3
.
As described above, the dielectric device in accordance with the present invention can be used in a variety of devices including resonators, oscillators, dielectric filters or duplexers. Among them, dielectric filters were described in detail above with reference to
FIGS. 1
to
50
. On account of space consideration, the explanation relating to dielectric filters will be limited to the description presented above. However, it is obvious that a larger number of resonator units can be provided and that there are a large number of possible combinations of the embodiments described above and illustrated by the figures attached.
A duplexer which is an example of another important application of the dielectric device in accordance with the present invention will be described below.
FIG. 51
is a perspective view of the duplexer in accordance with the present invention and
FIG. 52
is a perspective view of the duplexer shown in
FIG. 51
, as viewed from the bottom surface thereof. The duplexer shown in the figures comprises seven resonator units Q
1
to Q
7
. Resonator units Q
1
to Q
7
use a common dielectric substrate
1
and are integrated via dielectric substrate
1
. External conductor film
3
covers a large portion of the outer surface of dielectric substrate
1
, except one surface serving as end surface
21
.
Among resonator units Q
1
to Q
7
, resonator unit Q
1
comprises a combination of first hole
41
and second hole
51
, resonator unit Q
2
comprises a combination of first hole
42
and second hole
52
, and resonator unit Q
3
comprises a combination of first hole
43
and second hole
53
. Resonator unit Q
5
comprises a combination of first hole
45
and second hole
55
, resonator unit Q
6
comprises a combination of first hole
46
and second hole
56
, and resonator unit Q
7
comprises a combination of first hole
47
and second hole
57
. First holes
41
to
43
,
45
to
47
are through holes and second holes
51
to
53
,
55
to
57
are blind holes.
First hole
44
and first hole
54
of intermediate resonator unit Q
4
are through holes and have no blind holes among them. However, first hole
54
may be a blind hole.
Individual structures of first holes (
41
to
47
) and second holes (
51
to
57
) and mutual arrangement thereof are as described in detail with reference to
FIGS. 1
to
50
.
Since duplexers are used as antenna duplexers, resonator units Q
1
to Q
7
are divided into two groups, one for a transmitter and one for a receiver. An explanation will be given below based on an example in which resonator units Q
1
to Q
3
are used for a transmitter and resonator units Q
5
to Q
7
are used for a receiver.
Since the transmit frequency and receive frequency are different from each other, the resonant characteristics of resonator units Q
1
to Q
3
is adjusted to the transmit frequency, and the resonant characteristics of resonator units Q
5
to Q
7
is adjusted to the receive frequency. An antenna is connected to resonator unit Q
4
.
In resonator units Q
1
to Q
3
used for a transmitter, conductor films
301
,
302
are provided on end surface
21
between resonator unit Q
2
and resonator unit Q
3
and between resonator unit Q
3
and resonator unit Q
4
, respectively. Therefore, resonator units Q
1
to Q
3
used for a transmitter are coupled to resonator unit Q
4
by inductive coupling.
In resonator units Q
5
to Q
7
used for a receiver, resonator unit Q
4
and resonator unit Q
5
are capacitively coupled by coupling electrode
111
and coupling electrode
112
, and resonator unit Q
5
and resonator unit Q
6
are capacitively coupled by coupling electrode
112
and coupling electrode
113
.
Among resonator units Q
1
to Q
3
used for a transmitter, first terminal
11
for a transmitter which is provided on opposite surface
22
is capacitively coupled to second hole
52
contained in resonator unit Q
2
via the dielectric portion created by dielectric substrate
1
. Such capacitive coupling was described in detail with reference to
FIGS. 3 and 4
.
Among resonator units Q
5
to Q
7
used for a receiver, second terminal
12
for a receiver which is provided on opposite surface
22
of dielectric substrate
1
is capacitively coupled to second hole
56
contained in resonator unit Q
6
via the dielectric portion created by dielectric substrate
1
. Such capacitive coupling was described in detail with reference to
FIGS. 3 and 4
.
Furthermore, a third terminal
13
for an antenna is connected to through hole
54
of intermediate resonator unit Q
4
on opposite surface
22
. Therefore, intermediate resonator unit Q
4
acts as a resonator connected to an antenna.
First to third terminals
11
to
13
are disposed on opposite surface
22
in a state in which they are electrically insulated from external conductor film
3
by insulating gaps G
2
to G
4
.
With the above-described configuration, first to third terminals
11
to
13
can be surface mounted onto a mounting substrate. Furthermore, the resonant wavelength can be adjusted by setting the depth of second holes
51
to
53
,
55
to
57
, and distance between respective holes in resonator units Q
1
to Q
7
, and the resonant frequency can be matched with the prescribed value with high accuracy.
FIG. 53
illustrates an example of the frequency response curve of the duplexer shown in
FIGS. 51 and 52
. In this figure, the frequency (MHz) is plotted against the abscissa, and the attenuation (dB) is plotted against the ordinate. The characteristic curve Rx represents a receive frequency characteristic and the characteristic curve Tx represents a transmit frequency characteristic.
As shown in the figure, the receive frequency characteristic Rx and transmit frequency characteristic Tx can be provided with different pass band characteristics.
FIG. 54
is a perspective view of terminal arrangement on the bottom surface that can be employed in the duplexer having the surface structure shown in FIG.
51
. In the embodiment shown in
FIG. 54
, second hole
54
of intermediate resonator unit Q
4
is a blind hole, and third terminal
13
is capacitively coupled to the internal conductor of second hole
54
(see FIG.
51
).
FIG. 55
is a perspective view illustrating another embodiment of the duplexer in accordance with the present invention.
FIG. 56
is a perspective view of the duplexer shown in
FIG. 55
, as viewed from the bottom surface thereof. In the figures, structural components identical to those shown in
FIG. 51
are assigned with the same reference symbols.
In this embodiment, first holes
41
to
47
of resonator units Q
1
to Q
7
are through holes and second holes
51
to
57
are blind holes. Opposite surface
22
of dielectric substrate
1
is covered over the entire surface thereof with external conductor film
3
, as shown in FIG.
56
.
First and second terminals
11
,
12
are capacitively coupled to the internal conductors located inside second holes
52
and
56
which are blind holes via the dielectric portion created by dielectric substrate
1
. Third terminal
13
is directly connected to the internal conductor provided in second hole
54
of resonator unit Q
4
via conductor film
94
. Therefore, resonator unit Q
4
is used as a resonator for an antenna.
FIG. 57
is a perspective view illustrating another embodiment of the duplexer in accordance with the present invention. In this embodiment, first to third terminals
11
to
13
are provided on the side surface of dielectric substrate
1
. First and second terminals
11
,
12
are capacitively coupled to the internal conductors of second holes
52
and
56
, which are blind holes, via the dielectric portion created by dielectric substrate
1
. Third terminal
13
serving as an antenna terminal is connected to conductive film
302
provided between resonator unit Q
3
and resonator unit Q
4
. Third terminal
13
serving as an antenna terminal is capacitively coupled to resonator units Q
3
, Q
4
.
FIG. 58
is a perspective view illustrating another embodiment of the duplexer in accordance with the present invention. In this embodiment, first to third terminals
11
to
13
are provided on the side surface of dielectric substrate
1
. First to third terminals
11
to
13
are capacitively coupled to the internal conductors of second holes
52
,
54
, and
56
, which are blind holes, via the dielectric portion created by dielectric substrate
1
.
FIG. 59
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention. In this embodiment, the diameters of first holes
41
to
43
and second holes
51
to
53
contained in resonator units Q
1
to Q
3
used for a transmitter, which are seen on end surface
21
, are less than the respective diameters of first holes
44
to
47
and second holes
54
to
57
contained in resonator units Q
4
to Q
7
used for a receiver. With such structure, the distance between the holes can provide for the difference in resonant frequency between the transmit side and receive side and improve the frequency selection characteristic.
FIG. 60
is a perspective view illustrating yet another embodiment of the duplexer in accordance with the present invention. A specific feature of this embodiment is in that the distance D
11
between first holes
41
to
43
and second holes
51
to
53
contained in resonator units Q
1
to Q
3
used for a transmitter is greater than the distance D
12
between first holes
44
to
47
and second holes
54
to
57
contained in resonator units Q
4
to Q
7
used for a receiver.
With such a structure, the difference between distances D
11
and D
12
can provide for the difference in resonant frequency between the transmit side and receive side and improve the frequency selection characteristic.
It goes without saying that various structures (see
FIGS. 1
to
50
) illustrated by the examples relating to the dielectric filters can be used in duplexers; such modifications are not shown in the figures.
As described above, the following effects can be obtained with the present invention.
(a) A dielectric device can be provided which allows for miniaturization and thickness reduction.
(b) A dielectric device can be provided which can be surface mounted.
(c) A dielectric device can be provided in which the resonant frequency can be adjusted.
Claims
- 1. A dielectric device comprising:a dielectric substrate including at least one resonator unit; said dielectric substrate comprising: an outer surface covered with an external conductor film, excluding at least one end surface, a first hole provided in said dielectric substrate, extending from said at least one end surface to an opposite surface thereto, being open at said at least one end surface and said opposite surface, and having a first internal conductor inside thereof, and a second hole provided in said dielectric substrate at a predetermined distance from said first hole, extending from said at least one end surface toward said opposite surface, being open at said at least one end surface, closed at said opposite surface, and having a second internal conductor inside thereof, said second internal conductor being connected to said first internal conductor at said at least one end surface; and said first hole, said second hole, said first internal conductor, and said second internal conductor forming said at least one resonator unit.
- 2. The dielectric device according to claim 1, whereinsaid opposite surface is covered with said external conductor film; and said first internal conductor is connected to said external conductor film present on said opposite surface.
- 3. The dielectric device according to claim 1, wherein said opposite surface is another end surface.
- 4. The device according to claim 1, further comprising a terminal, said terminal being provided on said dielectric substrate and capacitively coupled to said at least one resonator unit.
- 5. The device according to claim 4, wherein said terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said second internal conductor.
- 6. The device according to claim 4, wherein said terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said first internal conductor.
- 7. The device according to claim 1, wherein a plurality of second holes are provided at respective distances from each other and respective second internal conductors provided in respective second holes are connected at said at least one end surface.
- 8. The device according to claim 1, wherein a plurality of resonator units are provided and adjacent resonator units are electrically coupled.
- 9. The device according to claim 8, comprising a first terminal and a second terminal, whereinsaid first terminal is provided in said dielectric substrate and capacitively coupled to at least one of said plurality of resonator units; and said second terminal is provided in said dielectric substrate and capacitively coupled to at least another one of said plurality of resonator units.
- 10. The device according to claim 9, wherein said first terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said first internal conductor.
- 11. The device according to claim 9, wherein said first terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said second internal conductor.
- 12. The device according to claim 9, wherein said second terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said first internal conductor.
- 13. The device according to claim 9, wherein said second terminal is provided on said outer surface of said dielectric substrate and capacitively coupled to said second internal conductor.
- 14. The device according to claim 9, wherein two adjacent resonator units of said plurality of resonator units are capacitively coupled to each other.
- 15. The device according to claim 9, wherein two adjacent resonator units among said plurality of resonator units are inductively coupled.
- 16. The device according to claim 1, wherein said at least one resonator unit comprises a step-like recess, said recess being formed in said at least one end surface and comprising, in common, said first hole and said second hole inside thereof.
- 17. The dielectric device according to claim 1, wherein said first hole has a large-diameter portion and a small-diameter portion, said large-diameter portion being open at said at least one end surface and said small-diameter portion being connected to a lower part of said large-diameter portion.
- 18. The device according to claim 1, wherein said second bole has a large-diameter portion and a small-diameter portion, said large-diameter portion being open at said at least one end surface and said small-diameter portion being connected to a lower part of said large-diameter portion.
- 19. The dielectric device according to claim 1, wherein said first hole has a large-diameter portion and a small-diameter portion, said large-diameter portion being open at said opposite surface and said small-diameter portion being connected to an upper part of said large-diameter portion.
- 20. The dielectric device according to claim 1, which is a dielectric filter.
- 21. The dielectric device according to claim 1, which is a duplexer.
- 22. The dielectric device according to claim 21, further comprising three or more resonator units and first, second, and third terminals, said first terminal being electrically coupled to at least one of said resonator units, said second terminal being electrically coupled to at least another one of said resonator units, and said third terminal being electrically coupled to at least one of the remaining resonator units.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-225102 |
Jul 2001 |
JP |
|
US Referenced Citations (13)
Foreign Referenced Citations (9)
Number |
Date |
Country |
0 654 841 |
May 1995 |
EP |
0 785 593 |
Jul 1997 |
EP |
0 797 267 |
Sep 1997 |
EP |
0 840 390 |
May 1998 |
EP |
62-213301 |
Sep 1987 |
JP |
2-24606 |
Feb 1990 |
JP |
04-051602 |
Feb 1992 |
JP |
07-249910 |
Sep 1995 |
JP |
09-046108 |
Feb 1997 |
JP |