Oscillators – With distributed parameter resonator
Reexamination Certificate
1999-07-13
2001-01-09
Lee, Benny (Department: 2817)
Oscillators
With distributed parameter resonator
C331S1170FE, C333S219100, C333S202000, C333S134000
Reexamination Certificate
active
06172572
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a dielectric resonator, a dielectric filter, a dielectric duplexer, and an oscillator.
BACKGROUND ART
Recently, a sharply increasing demand for and multimedia-systemization of mobile communication systems requires large-scale and high-speed communication systems. According to the increasing amount of information to be communicated, frequency bands to be used are being widened from microwave bands to millimeter-wave (milliwave) bands. In such milliwave bands, conventionally-known TE01&dgr;-mode dielectric resonators composed of a cylindrical dielectric device can be used in a manner similar to the case of microwave bands. In this case, since the frequency of the TE01&dgr;-mode dielectric resonator is defined according to the outer dimension of the cylindrical dielectric device, strict processing accuracy is required.
Also, suppose a dielectric filter is configured by arranging a plurality of the TE01&dgr;-mode dielectric resonators to be apart from each other with a predetermined spacing in a metal housing. In such a case, coupling between an input/output means such as a metal loop and a dielectric resonator or between a dielectric resonator and a dielectric resonator is determined according to the distance therebetween. Therefore, the arrangement requires high positional accuracy.
Then, in Japanese Unexamined Patent Application Publication No. 7-62625, U.S. Pat. No. 5,764,116 the present applicant proposed a dielectric resonator and a dielectric filter that allow improved processing accuracy, solving the problems described above.
The dielectric filter according to the above patent application is shown FIG.
12
.
FIG. 12
is an exploded perspective view of the dielectric filter according to the above patent application.
As shown in
FIG. 12
, a dielectric filter
101
is constituted of a dielectric substrate
102
and conductor plates
104
a
and
104
b.
The dielectric substrate
102
has a constant relative dielectric constant, on which electric conductors
102
a
and
102
b
having circular openings on their two main faces are formed so that that the openings on the two main faces oppose each other.
An input coplanar line
105
a
and an output coplanar line
105
b
are formed so as to be in proximity to two ends of the five openings on one of the main faces of the dielectric substrate
102
(the upper side in FIG.
12
).
The dielectric plates
104
a
and
104
b
are immobilized such that they are spaced apart by a predetermined distance from the dielectric substrate
102
and so that they sandwich the dielectric substrate
102
. The input coplanar line
105
a
and the output coplanar line
105
B are projected from the dielectric plates
104
a
and
104
b
. Cutouts are arranged on the conductor plate
104
a
so that the input coplanar line
105
a
and the output coplanar line
105
b
are not connected. The conductor plate
104
a
and the electric conductor
102
a
of the dielectric substrate
102
are electrically connected, and the conductor plate
104
b
and the electric conductor
102
b
of the dielectric substrate
102
are electrically connected.
In the configuration as described above, electromagnetic-field energy is confined in the dielectric substrate
102
in the vicinity sandwiched by the openings opposing the electric conductors
102
a
and
102
b
, and five resonating sections are formed. Further adjacent resonating sections are coupled; thus, a dielectric filter having resonating sections in five steps is configured.
As described above, the resonating section can be defined according to the size of the opening of an electrode. This enables a processing means such as etching to be used in production and allows production of a dielectric resonator, a dielectric filter, and the like that have precisely reproduced dimensional accuracy of the resonating section.
In the dielectric filter
101
as described above, confinement of electromagnetic-field energy is high in the resonating sections formed by the dielectric substrate
102
sandwiched by the openings on the opposing electric conductors
102
a
and
102
b
. Therefore, when an input/output terminal means is formed of the coplanar lines
105
a
and
105
b
, coupling is weak between the resonating sections and the input/output terminal means. Therefore the distance between the openings of the electrodes
102
a
and
102
b
and the input coplanar lines
104
a
and
104
b
is shortened as much as possible so as to strengthen coupling between the resonating sections and the input/output terminal means.
Also, in the dielectric filter
101
as described above, since confinement of electromagnetic-field energy is high in the resonating sections, coupling is weak between the adjacent resonating sections. Therefore the distance between the openings is shortened as much as possible so as to strengthen coupling between the resonating sections.
In addition, a conventionally as an apparatus using a dielectric resonator, namely a voltage-controlled oscillator, is shown in FIG.
13
.
As shown in
FIG. 13
, a voltage-controlled oscillator
111
uses a cylindrical TE01&dgr;-mode dielectric resonator
112
.
The TE01&dgr;-mode dielectric resonator
112
is mounted on a wiring substrate
113
via a supporting base
112
a
. On a lower face of the wiring substrate
113
, ground electrodes, not shown, are formed. The wiring substrate
113
is housed within an upper metal housing
130
and a lower metal housing
131
.
On the wiring substrate
113
, a microstrip line
114
composing a primary line and a microstrip line
115
composing a secondary line are formed so as to overlap each other as viewed downward from points over the TE01&dgr;-mode dielectric resonator
112
and FIG.
13
.
The microstrip line
114
is arranged such that one end thereof is connected to a ground electrode
117
via a chip resistor
116
, and the other end thereof is connected to a gate of a field-effect transistor
118
.
A resonating section is formed by electromagnetic-field coupling between the primary line composing the primary line and the TE01&dgr;-mode dielectric resonator
112
.
The microstrip line
115
is arranged such that one end thereof is connected to the ground electrode
117
via a varactor diode
119
, and the other end thereof is an open end.
A variable oscillation frequency circuit is comprised of the microstrip line
115
composing the primary line and the varactor diode
119
.
The field-effect transistor
118
is arranged such that a drain thereof is connected to an input terminal
122
via a microstrip line
121
, and a source thereof is connected to one end of a microstrip line
123
.
The microstrip line
121
is connected to a matching stub
124
at a point of connection with the drain of the field-effect transistor
118
.
The other end of the microstrip line
123
is connected to the ground electrode
117
via a chip resistor
125
. The microstrip
123
is formed so as to be parallel from a point with a microstrip line
126
with a constant distance so as to be electrically coupled.
The microstrip line
126
is connected to an output terminal electrode
128
via a chip resistor
127
.
The matching stub
124
is connected to the input terminal electrode
122
in parallel with the microstrip line
121
.
A chip capacitor
129
is connected to the output terminal electrode
128
in parallel with the chip resistor
127
.
In a configuration such as that described above, the varactor diode
119
serves as a variable capacitor according to application voltages to vary resonance frequency, by which oscillation frequency varies.
As described above, in the dielectric filter
101
shown in
FIG. 12
, the distance between the openings of the electric conductors
102
a
and
102
b
and the input and output coplanar lines
105
a
and
105
b
is shortened as much as possible so as to strengthen coupling between the resonating sections and the input/output terminal means.
However, because of a limit to shortening of the distance between the openings of the electric conductors
102
a
and
102
b
and the in
Kajikawa Takehisa
Sakamoto Koichi
Yamashita Sadao
Choe Henry
Lee Benny
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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