Wave transmission lines and networks – Resonators – Dielectric type
Reexamination Certificate
2001-08-20
2002-11-12
Tokar, Michael (Department: 2819)
Wave transmission lines and networks
Resonators
Dielectric type
C333S219200, C333S202000, C333S204000
Reexamination Certificate
active
06480078
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a resonating apparatus in a dielectric substrate; and, more particularly, to a dielectric substrate resonator, which has a three-dimensional structure for coupling with a microstrip line, for obtaining high Q by reducing dielectric loss and conductivity loss.
BACKGROUND OF THE INVENTION
Recently, there is an increasing demand for communication systems using microwaves in the mobile and satellite communication fields. It is also a trend in the information communication field that devices are downsized and the communication frequency band moved to a higher frequency band. In personal mobile communication systems such as PCS, satellite communication, or satellite broadcasting, a GHz frequency band is used for communication.
An important component of equipment using the high frequency band is the microwave dielectric device, which has been widely developed to be used as a dielectric resonating filter. By microwave is meant frequencies ranging from 300 MHz to 300 GHz.
FIG. 1
illustrates a structure for coupling a microstrip line
12
with a dielectric resonator
14
adhered to a substrate. A dielectric resonator in accordance with the prior art, as shown in
FIG. 1
, is generally used in multi-layer circuits such as monolithic microwave integrated circuits (MMICs) due to its simple structure.
The dielectric resonator
14
in accordance with the prior art is adhered to an upper side of a dielectric substrate
10
, which is made of GaAs. The microstrip line
12
, which is separated horizontally from the dielectric resonator
14
, is arranged on the upper side of the dielectric substrate
10
. When the length of the microstrip line
12
is ½ &lgr;, where &lgr; is the wavelength of the microwave, and when the microstrip line
12
and the dielectric substrate
10
are composed of gold and GaAs respectively, the Q of the microstrip line
12
is calculated by Equation (1).
Q
u
=
β
2
(
α
c
+
α
d
)
=
66.8
Equation
(
1
)
where &bgr; is a propagation constant, &agr;
c
is an attenuation due to conductivity loss and &agr;
d
is the attenuation due to dielectric loss.
&agr;
c
and &agr;
d
in Equation (1) are calculated by Equations (2) and (3), respectively.
α
c
=
R
s
Z
0
W
Equation
(
2
)
where R
s
, Z
0
and W are a surface resistance, a characterization impedance and a width of the microstrip line
12
, respectively.
α
d
=
k
0
ϵ
r
(
ϵ
e
-
1
)
tan
δ
2
ϵ
e
(
ϵ
r
-
1
)
Equation
(
3
)
where &egr;
r
is a relative dielectric permittivity, &egr;
e
is an effective dielectric permittivity and tan&dgr; is a loss tangent of the dielectric substrate.
Referring to Equations (1) to (3) , when Z
0
is 50&OHgr;, tan&dgr; is 0.0006 and the resonant frequency is 10 GHz. The Q of the microstrip line is about 66.
According to Equation (1), the Q of the dielectric resonator
14
depends on two factors, &agr;
c
and &agr;
d
, wherein &agr;
c
is inversely proportional to Z
0
and W. When the dielectric resonator
14
of the prior art is applied to a multiplayer circuit, a fluid dielectric substance is used to configure a microstrip line. In general, the height of the fluid dielectric substance, e.g., BCB, is limited to 40 &mgr;m. The smaller the height of the fluid dielectric substance, the narrower the width of the microstrip line. Therefore, Q becomes smaller.
Further, the conductivity loss of the microstrip line
12
affects the energy loss of the dielectric resonator
14
. Accordingly, the dielectric resonating device in accordance with the prior art is not suitable for obtaining the high Q required in microwave applications.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a resonating apparatus that is suitable for use in microwave including multi-layer circuits such as MMICs that require high integrity and high Q.
In accordance with the present invention, there is provided a resonating apparatus comprising: a dielectric supporting substrate; a dielectric resonator which is formed on the dielectric supporting substrate; a fluid dielectric membrane which overspreads the dielectric resonator; and a microstrip line which is arranged in the fluid substrate membrane so that it is coupled with the dielectric resonator.
REFERENCES:
patent: 4547754 (1985-10-01), Murakami et al.
patent: 4755780 (1988-07-01), Ito et al.
patent: 4774483 (1988-09-01), Miccoli et al.
patent: 4983937 (1991-01-01), Kinoshita et al.
patent: 5334941 (1994-08-01), King
patent: 6016090 (2000-01-01), Iio et al.
patent: 6127907 (2000-10-01), Furuya et al.
Kim Bum-man
Lim Junyoul
Ryu Seonghan
Yim Joung Hyun
Bacon & Thomas
Nguyen Linh Van
Postech Foundation
Tokar Michael
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