Wave transmission lines and networks – Coupling networks – Delay lines including long line elements
Reexamination Certificate
2002-08-20
2004-06-01
Young, Brian (Department: 2819)
Wave transmission lines and networks
Coupling networks
Delay lines including long line elements
C333S164000
Reexamination Certificate
active
06744334
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a phase shifter for switching passing phase of a high-frequency signal with ON/OFF control of a switching element, and, in particular, to a phase shifter, in which a micro-machine switch is used as a switching element.
BACKGROUND OF THE INVENTION
Recently, the possibility of use of micro-machine switches for switching elements used in phase shifter has been indicated. The micro-machine switches are finely machined switching elements. The micro-machine switches are featured in less loss, low cost and small electric power consumption as compared with other elements. This kind of micro-machine switch is disclosed in, for example, Japanese Patent Laid-Open No. 17300/1997.
FIG. 1
is a plan view showing a phase shifter making use of a micro-machine switch described in the above-mentioned Japanese Patent Publication. In addition, a wavelength of a high-frequency signal RF transmitting through a main line
201
is assumed to be &lgr;. The phase shifter shown in
FIG. 1
is a low deadline type phase shifter. More specifically, the main line
201
connects thereto two stubs
202
a
,
202
b
, which are opened at tip ends thereof and spaced away &lgr;/4 from each other. Further, other stubs
203
a
,
203
a
wit tip ends opened are arranged to be spaced from the stubs
202
a
,
202
b
. A micro-machine switch
209
a
having a contact
215
is arranged between the stubs
202
a
,
202
b
. Also, a micro-machine switch
209
b
having a contact
215
is arranged between the stubs
202
b
,
203
b.
The micro-machine switches
209
a
,
209
b
are put in OFF position, only the stubs
202
a
,
202
b
are loaded on the main line
201
. Meanwhile, when the micro-machine switches
209
a
,
209
b
are put in ON positions the stubs
203
a
,
203
b
are further loaded on the main line
201
through the contact
215
of the micro-machine switches
209
a
,
209
b
. Accordingly, the stubs loaded on the main line
201
can be changed in electric length by making ON/OFF control on the micro-machine switches
209
a
,
209
b.
Susceptance on a side of the stubs from the main line
201
varies depending upon the electric length of the stubs being loaded. Meanwhile, passing phase of the main line
201
varies in accordance with such susceptance. Accordingly, the high-frequency signal RF transmitting through the main line
201
can be switched over in passing phase by making ON/OFF control on the micro-machine switches
209
a
,
209
b.
With reference to
FIGS. 2 and 3
, an explanation will be given below to a constitution of and an operation of the micro-machine switch
209
b
shown in FIG.
1
.
FIG. 2
is a plan view showing the micro-machine switch
209
b
in enlarged scale. FIGS.
3
(A) to (C) are cross sectional views of the micro-machine switch
209
b
, FIG.
3
(A) being a cross sectional view taken along the line C-C′ in FIG.
2
. FIG.
3
(B) being a cross sectional view taken along the line D-D′ in
FIG. 2
, and FIG.
3
(C) being a cross sectional view taken along the line E-E′ in FIG.
2
.
The stubs
202
b
,
203
b
are formed on a substrate
210
in a manner to provide a slight gap therebetween. A lower electrode
211
is formed on the substrate
210
in a position spaced from the stubs
202
b
,
203
b
. Also, a post
212
is formed on the substrate
210
in a position on an extension of a line segment connecting the gap between the stubs
202
b
,
203
b
to the lower electrode
211
.
A base portion of an arm
213
is fixed to a top surface of the post
212
. The arm
213
extends from the top surface of the post
212
to a region above the gap between the stubs
202
b
,
203
b
through a region above the lower electrode
211
. The arm
213
is formed from an insulating material. An upper electrode
214
is formed on an upper surface of the arm
213
. The upper electrode
214
extends from a region above the post
212
to a region above the lower electrode
211
. A contact
215
is formed on an underside of a tip end of the arm
213
. The contact
215
is formed to extend from a region above an end of the stub
202
b
to bridge the gap to further extend to a region above an end of the stub
203
b.
Further, a control signal line
204
is connected to the lower electrode
211
. A control signal is applied to the lower electrode
211
from the control signal line
204
. The control signal serves to make ON/OFF control of the micro-machine switch
209
b
for switching of connection of the stubs
202
b
,
203
b.
It is assumed that voltage is applied to the lower electrode
211
as the control signal. In this case, if, for example, positive voltage is applied to the lower electrode
211
, positive charges are generated on a surface of the lower electrode
211
and electrostatic induction causes negative charges to be generated on an underside of the upper electrode
214
, which faces the lower electrode
211
. As a result, attractive forces between the both electrodes cause the upper electrode
214
to be drawn toward the lower electrode
211
. Thereby, the arm
213
bends and the contact
215
displace downward. And when the contact
215
comes into contact with both the stubs
202
b
,
203
b
, the stubs
202
b
,
203
b
connect to each other via the contact
215
in high-frequency fashion.
Meanwhile, when application of positive voltage on the lower electrode
211
is stopped, attractive forces disappear, so that restoring forces of the arm
213
returns the contact
215
to its original position. Thereby, there is produced an opened state between the stubs
202
b
,
203
b.
In addition, the micro-machine switch
209
a
shown in
FIG. 1
is also constituted and operates in the same manner as the micro-machine switch
209
b.
The micro-machine switch
209
b
shown in
FIG. 1
necessitates the post
212
and the arm
213
for supporting of the contact
215
, in addition to the contact
215
for connecting/opening between the stubs
202
b
,
203
b
. Also, the lower electrode
211
and the upper electrode
214
are further needed to control displacement of the contact
215
. Therefore, the micro-machine switch
209
b
is large and complex in three-dimensional structure. The same is the case with the micro-machine switch
209
a.
When such micro-machine swatches
209
a
,
209
b
are used in a phase shifter, there is caused a problem that arrangement of the micro-machine switches
209
a
,
209
b
requires a large area to lead to large-sizing of the entire phase shifter. Also, manufacture of the micro-machine switches
209
a
,
209
b
having a complex construction necessitates many processes, and so the manufacturing processes for phase shifters become complex.
Therefore, an object of the present invention is to miniaturize a phase shifter, which makes use of micro-machine switches as a switching element.
Another object of the present invention is to simplify the construction of a phase shifter, which makes use of micro-machine switches as a switching element.
DISCLOSURE OF THE INVENTION
A phase shifter according to the present invention switches passing phase of a high-frequency signal by means of ON/OFF control of micro-machine switches.
A micro-machine switch according to a first example of the present invention comprises first and second distributed constant lines arranged on a substrate to be spaced from each other, a first control signal line connected electrically to the first or second distributed constant line for application of a first control signal composed of a binary change in voltage. The micro-machine switch also comprises a cantilever, one end of which is fixed to one of the first and second distributed constant lines and the other end of which is formed to be capable of coming toward and away from the other of the first and second distributed constant lines, the cantilever comprising an electrically conductive member. The micro-machine switch further comprises a first insulating section formed in a region where the other of the first and second distributed constant lines faces the cantilever, and a second insulating section for
Lauture Joseph
NEC Corporation
Sughrue & Mion, PLLC
Young Brian
LandOfFree
Phase shifter capable of miniaturizing and method of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Phase shifter capable of miniaturizing and method of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase shifter capable of miniaturizing and method of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3366095