Wave transmission lines and networks – Coupling networks – Delay lines including long line elements
Reexamination Certificate
1999-10-20
2002-04-23
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Coupling networks
Delay lines including long line elements
C333S026000
Reexamination Certificate
active
06377134
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a phase shifter and, more particularly, to a phase shifter available for a power amplifier, a balance-type modulator/demodulator and a mixer.
DESCRIPTION OF THE RELATED ART
The main function of the phase shifter is an electric power distribution from an unbalanced signal and a balanced signal different in phase from the unbalanced signal at a predetermined angle such as 180 degrees without changing the amplitude. For this reason, the 180-degree phase shifter is called as a balanced-unbalanced converter or simply as balun.
A small wide-band balun is proposed by G. J. Laughlin in “A New Impedance-Matched Wide-Band Balun and Magic Tree”, IEEE Trans. Microwave Theory Tech., vol. MTT-24, No. 3, March 1976, page 135 to page 141, and is illustrated in FIG.
1
. The prior art balun has an input terminal
51
assigned to an unbalance signal and output terminals
52
/
53
assigned to balance signals.
The prior art balun includes an unbalanced transmission line
54
, two balanced transmission lines
58
/
59
, a coupled transmission line
55
with an open-end and coupled transmission lines
56
/
57
each having a grounded end E and an open end. The transmission line
54
and the transmission line
55
connected to the transmission line
54
are coupled through the transmission lines
56
and
57
to the transmission lines
58
and
59
, respectively. The unbalanced signal is supplied to the input terminal
51
, and is propagated through the abovedescribed transmission lines to the output terminals
52
and
53
.
FIGS. 2A and 2B
illustrate the arrangement and the structure of the prior art balun. The transmission lines
54
,
55
,
56
,
57
,
58
and
59
are patterned on a dielectric substrate
63
, and the dielectric substrate
63
(see
FIG. 2B
) is 0.8 millimeter thick. The dielectric substrate
63
is formed of dielectric material, the dielectric constant of which is 2.2. The prior art balun is designed at 2.5 GHz, and introduces the phase difference of 180 degrees.
On the top surface of the dielectric substrate
63
are formed the transmission line
54
connected to the input terminal
51
to which the unbalanced signal is supplied, the open-ended transmission line
55
connected to the transmission line
54
and the transmission lines
58
and
59
respectively connected to the output terminals
52
and
53
from which the balanced signals are respectively output. The outlines of the transmission lines
54
,
55
,
58
and
59
and the input/output terminals
51
,
52
and
53
are indicated by real lines in FIG.
2
A. The other transmission lines
56
and
57
are patterned on the reverse surface of the dielectric substrate
63
. The transmission lines
56
and
57
are open at one ends thereof, and are grounded through a box
60
, as shown in FIG.
2
A. The outlines of the transmission lines
56
and
57
are indicated by broken lines in FIG.
2
A. The transmission line
56
is overlapped with the transmission lines
54
and
58
so as to be coupled through the dielectric substrate
63
with the transmission lines
54
and
58
. On the other hand, the transmission line
57
is overlapped with the transmission lines
55
and
59
so as to be coupled through the dielectric substrate
63
with the transmission lines
55
and
59
. The length of each transmission line is adjusted to a quarter wavelength of the signal at 2.5 GHz. In order to short-circuit one end of the transmission line
56
to one end of the transmission line
57
, a cavity
64
is formed in the box, and the cavity
64
is 1.2 millimeter in depth, as shown in FIG.
2
B.
FIG. 3A
illustrates the transmission lines
54
,
55
,
58
and
59
patterned on the top surface of the dielectric substrate
63
, and
FIG. 3B
illustrates the transmission lines
56
and
57
patterned on the reverse surface of the dielectric substrate
63
. The periphery of the reverse surface is grounded, and is netted in FIG.
3
B.
The prior art 180-degree phase shifter shown in
FIGS. 2A and 2B
is available for a power distribution/power composer of a power amplifier. In this instance, the designer encounters a problem in that he can not optimize the location of the input terminal
51
and the locations of the output terminals
52
/
53
. In detail, the unbalanced signal input terminal
51
is coupled only through the transmission lines
56
and
57
with the balanced signal output terminals
52
and
53
. This means that the unbalanced signal input terminal
51
and the balanced signal output terminals
52
/
53
set the limit on one another. The unbalanced signal is supplied from the input terminal
51
to the transmission line
54
, and the transmission line
54
is coupled through the transmission line
56
serving as a ground electrode with the transmission line
58
from which the balanced signal is output. The open-ended transmission line
55
provides a quasi ground for the unbalanced signal, and is coupled through the transmission line
57
serving as the ground electrode with the transmission line
59
from which the balanced signal is output. Thus, the transmission line
54
on the top is to be overlapped with the transmission line
58
on the reverse surface, and the designer has to locate the transmission line
54
between broken lines A and B (see FIG.
2
A). Thus, the prior art 180-degree phase shifter
The prior art 180-degree phase shifter is further available for a push-pull power amplifier shown in FIG.
4
A. The prior-art push-pull power amplifier includes 180-degree phase shifters
73
and
74
, two power transistors
75
and composite circuit components
76
and
77
. The two power transistors
75
are located between the composite circuit components
76
and
77
, and each of the composite circuit components
76
and
77
has a bias circuit and a transmission line. The two power transistors
75
are shown in FIG.
4
B. Gate electrodes
75
a
are located on one side, and drain electrodes
75
b
are located on the other side. Returning to
FIG. 4A
, gate bias terminals
78
and
79
are connected through the composite circuit component
76
to the gate electrodes
75
a
(see FIG.
4
B), and drain bias terminals
80
and
81
are connected through the composite circuit component
76
to the drain electrodes
75
b
(see FIG.
4
B).
An input power signal is supplied from an input terminal
71
to the prior art 180-degree phase shifter
73
, and the prior art 180-degree phase shifter separates the input power signal into two power signals. The power signals are 180 degrees different in phase from each other, and are supplied through the composite circuit component
76
to the power transistors, respectively. The power transistors
75
operate at the phase difference, i.e., 180 degrees, and carry out the power amplification. The power transistors
75
supply the amplified power signals through the composite circuit component
76
to the prior art 180-degree phase shifter
74
, and the prior art 180-degree phase shifter
74
composes an output power signal. The output power signal is supplied to an output terminal
72
.
The prior art push-pull power amplifier is available for a high-power power amplifier.
FIG. 5
illustrates the prior art high-power power amplifier. Plural prior art push-pull power amplifiers
45
are connected in parallel between a power distributor
43
and a power composer
44
, and an input terminal
1
and an output terminal
21
are connected to the power distributor
43
and the power combiner
44
, respectively. The push-pull power amplifiers
45
are similar in circuit configuration to the prior art push-pull power amplifier shown in
FIG. 4A
, and the 180-degree phase shifters
73
/
74
are incorporated in each of the push-pull power amplifiers
45
. The unbalanced signal terminals of the 180-degree phase shifters
73
/
74
are arranged to be opposite to each other from the aspect that the plural push-pull power amplifiers are combined. However, the unbalanced signal terminal is coupled through transmission lines with the associated balanced signal ter
LandOfFree
Phase shifter having two transmission signal paths... 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 having two transmission signal paths..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase shifter having two transmission signal paths... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2880298