Information
-
Patent Grant
-
6636126
-
Patent Number
6,636,126
-
Date Filed
Wednesday, February 27, 200222 years ago
-
Date Issued
Tuesday, October 21, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 333 117
- 333 246
- 333 238
- 333 26
-
International Classifications
-
Abstract
The present invention relates to a four port hybrid comprising a first set (10) of N coupled transmission lines (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I) and a second set (20) of N coupled transmission lines (20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I) where N≧4. Said coupled transmission lines in said first set (10) are electrically connected to said coupled transmission lines in said second set (20) to form a first spiral shaped electrical conductive path, a second spiral shaped electrical conductive path and N−1 electrically isolated transposition portions (30, 40, 50, 60, 70, 80, 90, 110) of said first and second spiral shaped electrical conductive paths. A first end of the first spiral being an input port (P1). A first end of the second spiral being a port (P4) connectable to ground. A second end of the first spiral being a first output port (P3) and a second end of the second spiral being a second output port (P2).
Description
This is a nationalization of PCT/SE00/01621 filed Aug. 23, 2000 and published in English.
FIELD OF THE INVENTION
The present invention relates to microwave radio frequency transmission line circuits generally and more specifically to four port hybrids.
DESCRIPTION OF THE RELATED ART
The requirement to integrate as much as possible in even smaller volumes calls for the study and development of new types of hybrids.
Hybrids are per se well known and well understood in this art in its waveguide, coaxial, microstrip and stripline forms. Typical prior art hybrids are branch directional coupler, Lange coupler and tandem coupler. These hybrids are fundamentally four port devices that accept a signal at an input port, divide the signal in half internally and then supply the divided signal to two output ports. In an ideal quadrature hybrid, the difference in phase angle between the output ports remains at 90 degrees and the amplitude of the output signals remain equal across the useful bandwidth of the device. There is essentially no output from the fourth port as it is isolated from the input port, and in many instances said port is terminated internally. Once the input port is selected the others are defined automatically.
The most common hybrid structure is a branch directional coupler. The problem with said hybrid is too large to be of any interest at a frequency band used in mobile telephones, e.g. a GSM or a PCS frequency band.
Another hybrid is the one based on coupled lines arranged on one side of a dielectric substrate. The problem with said hybrid is that it cannot be realised using standard PCB technology due to too narrow gap between.
Yet another hybrid is the one based on coupled lines arranged on opposite sides of a dielectric substrate. The problem with said hybrid is that the physical dimensions are too large and the necessity to use both sides of said substrate with the added problem of double sided alignment.
A further hybrid is the so called Lange coupler. The problem with said hybrid is that the required 3 dB coupling between the transmission lines has to be done with narrow transmission lines which are too narrow to be cross connected by commercially available PCB (Printed Circuit Board)-jumpers. Another problem with the lange coupler is that the physical dimension is too large to be of any interest in applications demanding small is space.
Still another hybrid is the so called tandem coupler. The problem with said hybrid is that the physical dimension is too large.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a four port hybrid which overcomes or at least reduces the above mentioned problems.
Another object of the present invention is to provide a hybrid with comparably small physical dimensions and improved electrical parameters.
According to the present invention there is provided a four port hybrid as claimed in claim 1.
One advantage with the present invention is that the hybrid can be manufactured in stripline or microstrip with comparably wide strips and comparably wide gaps between said strips that results in a high Q-factor of the transmission lines which in turn leads to small insertion loss.
Another advantage with the present invention is that the hybrid is less sensitive to fabrication tolerances and by that is inexpensive to manufacture.
Yet another advantage is that the present invention being small enough to make an implementation in MMIC (Monolithic Microwave Integrated circuit) technology possible.
Still another advantage is that the present invention has improved both reflection and insertion loss compared to already existing hybrids.
The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
shows a schematic view of a first embodiment of a four port hybrid according to the present invention.
FIG. 2
shows a schematic view of a second embodiment of a four port hybrid according to the present invention.
FIG. 3
shows a schematic view of a third embodiment of a four port hybrid according to the present invention.
FIG. 4
shows a schematic view of a fourth embodiment of a four port hybrid according to the present invention.
FIG. 5
shows a first physical layout of a four port hybrid according to the first embodiment of the present invention.
FIG. 6
shows a schematic view of a fifth embodiment of a four port hybrid according to the present invention.
DESCRIPTION OF A PREFERRED EMBODIMENTS
With reference to
FIG. 1
, a schematic view of a first embodiment of a four port hybrid
100
A according to the invention is shown. The hybrid
100
A comprising a first set
10
and a second set
20
of multiple coupled transmission lines. Said first set of multiple coupled transmission lines
10
comprising a first transmission line
10
A, a second transmission line
10
B, a third transmission line
10
C and a fourth transmission line
10
D. Said second set of multiple coupled transmission lines
20
comprising a first transmission line
20
A, a second transmission line
20
B, a third transmission line
20
C and a fourth transmission line
20
D. In the present embodiment the transmission lines
10
A,
10
B,
10
C,
10
D,
20
A,
20
B,
20
C,
20
D are C-shaped. The first transmission line
10
A,
20
A is the longest one and the second
10
B,
20
B, third
10
C,
20
C and fourth
10
D,
20
D are decreasing by gradual stages. All transmission lines
10
A,
10
B,
10
C,
10
D in the first set
10
are mutually coupled and said coupling between said transmission lines is of electromagnetic nature. The same applies to the second set of multiple coupled transmission lines
20
. A first end of the first transmission line
10
A in the first set of coupled transmission lines
10
being an input port P
1
. A second end of said transmission line
10
A is electrically connected to a second end of the second transmission line in the second set of coupled transmission lines via an electrical conductor
32
. A first end of the second transmission line
20
B in the second set of coupled transmission lines
20
is electrically connected to a first end of the third transmission line
10
C in the first set of coupled transmission lines
10
via an electrical conductor
52
. A second end of the third transmission line in the first set of coupled transmission lines is electrically connected to a fourth transmission line
20
D in the second set of multiple coupled transmission lines
20
via an electrical conductor
42
. A first end of the fourth transmission line in the second set of coupled transmission lines being a first output port P
3
. The first transmission line
10
A in the first set
10
, the second transmission line
20
B in the second set
20
, is the third transmission line
10
C in the first set
10
and the fourth transmission line
20
D in the second set
20
coupled electrically to each other via said electrical conductors
32
,
42
,
52
are forming a first spiral shaped electrical conductive path.
A first end of the first transmission line
20
A in the second set of coupled lines
20
being a terminated (isolated) port. A second end of the first transmission line
20
A in the second set of coupled transmission lines
20
is electrically connected to a second end of the second transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
34
. A first end of the second transmission line
10
B in the first set of multiple coupled transmission lines
10
is electrically connected to a first end of a third transmission line
20
C in the second set of coupled transmission lines
20
via an electrical conductor
54
. A second end of the third transmission line
20
C in the second set of coupled transmission lines
20
is electrically connected to a second end of a fourth transmission line
10
D in the first set of coupled transmission lines via an electrical conductor
44
. A first end of the fourth transmission line
10
D in the first set of coupled lines being a second output port P
2
. The first transmission line
20
A in the second set
20
, the second transmission line
10
B in the first set
10
, the third transmission line
20
C in the second set
20
and the fourth transmission line
10
D in the first set of multiple coupled transmission lines
20
are coupled electrically to each other via said electrical conductors
34
,
44
,
54
are forming a second spiral shaped electrical conductive path.
In the spiral shaped electrical conductive paths every second half turn of said spiral are belonging to the first set of coupled transmission lines and between said half turns the transmission lines belonging to the second set of transmission lines are arranged.
In the embodiment shown in
FIG. 1
there are three electrically isolated transposition portions
30
,
40
,
50
of the first and second spiral shaped conductive paths. Said electrically isolated transposition portions can be looked upon as four port lumped cross connectors. In a first transposition portion
30
the electrical conductors
32
,
34
connecting the second end of the first transmission line
10
A in the first set of coupled lines
10
to the second end of the second transmission line
20
B in the second set of coupled lines
20
and the second end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the second end of the first transmission line
20
A in the second set of coupled transmission lines
20
respectively. In a second transposition portion
40
the electrical conductors
42
,
44
connecting the second end of the third transmission line
10
C in the first set of coupled lines
10
to the second end of the fourth transmission line
20
D in the second set of coupled lines
20
and the second end of the fourth transmission line
10
D in the first set of coupled transmission lines
10
to the second end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively. In a third transposition portion
50
the electrical conductors
52
,
54
connecting the first end of the second transmission line
10
B in the first set of coupled lines
10
to the first end of the third transmission line
20
C in the second set of coupled lines
20
and the first end of the third transmission line
10
C in the first set of coupled transmission lines
10
to the first end of the second transmission line
20
B in the second set of coupled transmission lines
20
respectively.
With reference to
FIG. 2
, another embodiment of a four pore hybrid
100
B according to the invention is shown. The structure of the hybrid
100
B is the same as the one shown in
FIG. 1
except for the only difference of further comprising six capacitors
31
,
33
,
41
,
43
,
51
,
53
. A first capacitor
31
is coupled between the second end of the first transmission line
10
A in the first set of coupled lines
10
and the second end of the first transmission line
20
A in the second set of coupled transmission lines. A second capacitor
32
is coupled between the second end of the second transmission line
10
B in the first set of coupled lines
10
and the second end of the second transmission line
20
B in the second set of coupled transmission lines
20
. A third capacitor
41
is coupled between the second end of the third transmission line
10
C in the first set of coupled lines
10
and the second end of the third transmission line
20
C in the second set of multiple coupled transmission lines
20
. A fourth capacitor
43
is coupled between the second end of the fourth transmission line
10
D in , the first set of coupled lines
10
and the second end of the fourth transmission line
20
D in the second set of coupled transmission lines
20
. A fifth capacitor
51
is coupled between the first end of the third transmission line
10
C in the first set of coupled lines
10
and the first end of the third transmission line
20
C in the second set of coupled transmission lines
20
. A sixth capacitor
53
is coupled between the first end of the second transmission line
10
B in the first set of coupled lines
10
and the first end of the second transmission line
20
B in the second set of coupled transmission lines
20
. Said capacitors are forming further RF connections between the transmission lines in the first and second set of coupled transmission lines. Said capacitors will improve directivity of the hybrid by equalizing phase velocities of different modes propagating in the hybrid.
With reference to
FIG. 3
, yet another embodiment of a four port hybrid
100
C according to the invention is shown. The hybrid
100
C comprising a first set
10
and a second set
20
of coupled transmission lines. Said first set of coupled transmission lines
10
comprising a first transmission line
10
A, a second transmission line
10
B, a third transmission line
10
C, a fourth transmission line
10
D, a fifth transmission line
10
E, a sixth transmission line
10
F, a seventh transmission line
10
G, a eighth transmission line
10
H and a ninth transmission line
101
. Said second set of transmission lines
20
comprising a first transmission line
20
A, a second transmission line
20
B, a third transmission line
20
C, a fourth transmission line
20
D, a fifth transmission line
20
E, a sixth transmission line
20
F, a seventh transmission line
20
G, a eighth transmission line
20
H and a ninth transmission line
20
I. In the present embodiment the transmission lines
10
A,
10
B,
10
C,
10
D,
10
E,
10
F,
10
G,
10
H,
10
I,
20
A,
20
B,
20
C,
20
D,
20
E,
20
F,
20
G,
20
H,
20
I are C-shaped. The first transmission lines
10
A,
20
A are the longest ones and the second
10
B and
20
B, third
10
C and
20
C, fourth
10
D and
20
D, fifth
10
E and
20
E, sixth
10
F and
20
P, seventh
10
G and
20
G, the eighth
10
H and
20
H and the ninth
101
and
20
I are decreasing by gradual stages. All transmission lines
10
A,
10
B,
10
C,
10
D,
10
E,
10
F,
10
G,
10
H
10
I in the first set
10
are mutually coupled and said coupling between the transmission lines is of electromagnetic nature. The same applies to the transmission lines in the second set of coupled transmission lines
20
. A first end of the first transmission line
10
A in the first set of coupled transmission lines
10
being an input port P
1
. A second end of said transmission line
10
A is electrically connected to a second side of the second transmission line
20
B in the second set of coupled transmission lines
20
via an electrical conductor
32
. A first side of the second transmission line
20
B in the second set of coupled transmission lines
20
is electrically connected to a first side of the third transmission line
10
C in the first set of coupled transmission lines
10
via an electrical conductor
112
. A second end of the third transmission line
10
C in the first set of coupled transmission lines is electrically connected to a second end of the fourth transmission line
20
D in the second set of coupled transmission lines via an electrical conductor
42
. A first end of the fourth transmission line
20
D in the second set of coupled transmission lines
20
is electrically connected to a first side of the fifth transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
92
. A second end of the fifth transmission line
10
E in the first set of coupled transmission lines
10
is electrically connected to a second end of the sixth transmission line
20
F in the second set of coupled transmission lines via an electrical conductor
52
. A first side of the sixth transmission line
20
F in the second set of coupled transmission lines
20
is electrically connected to a first side of the seventh transmission line
10
G in the first set of coupled transmission lines
10
via an electrical conductor
82
. A second end of the seventh transmission line
10
F in the first set of coupled transmission lines
10
is electrically connected to a second end of the eighth transmission line
20
H in the second set of coupled transmission lines via an electrical conductor
62
. A first side of the eighth transmission line
20
H in the second set of coupled transmission lines
20
is electrically connected to a first side of the ninth transmission line
100
in the first set of coupled transmission lines
10
via an electrical conductor
72
.
The first transmission line
10
A in the first set
10
, the second transmission line
20
B in the second set
20
, the third transmission line
10
C in the first set
10
and the fourth transmission line
20
D in the second set
20
The fifth transmission line
10
E in the first set
10
, the sixth transmission line
20
F in the second set
20
, the seventh transmission line
10
G in the first set
10
and the eighth transmission line
20
H in the second set
20
and the ninth transmission line in the first set are coupled electrically to each other via said electrical conductors
32
,
112
,
42
,
92
,
52
,
82
,
62
,
72
are forming a first spiral shaped electrical conductive path.
A first end of the first transmission line
20
A in the second set of coupled lines
20
being a terminated (isolated) port. Said termination is usually made with a system impedance which commonly is 50Ω. A second end of the first transmission line
20
A in the second set of coupled transmission lines
20
is electrically connected to a second end of the second transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
34
. A first end of the second transmission line
10
B in the first set of coupled transmission lines
10
is electrically connected to a first end of a third transmission line
20
C in the second set of coupled transmission lines
20
via an electrical conductor
114
. A second end of the third transmission line
20
C in the second set of coupled transmission lines
20
is electrically connected to a second end of a fourth transmission line
10
D in the first set of coupled transmission lines via an electrical conductor
44
. A first end of the fourth transmission line
20
D in the first set of coupled transmission lines
10
is electrically connected to a first side of the fifth transmission line
10
E in the second set of coupled transmission lines
10
via an electrical conductor
94
. A second end of the fifth transmission line
20
E in the second set of coupled transmission lines
20
is electrically connected to a second end of the sixth transmission line
10
F in the first set of coupled transmission lines via an electrical conductor
54
. A first end of the sixth transmission line
10
F in the first set of coupled transmission lines
10
is electrically connected to a first side of the seventh transmission line
20
G in the second set of coupled transmission lines
20
via an electrical conductor
84
. A second end of the seventh transmission line
20
F in the second set of coupled transmission lines
20
is electrically connected to a second end of the eighth transmission line
10
H in the first set of coupled transmission lines via an electrical conductor
64
. A first side of the eighth transmission line
10
H in the first set of coupled transmission lines
10
is electrically connected to a first side of the ninth transmission line
20
I in the second set of coupled transmission lines
20
via an electrical conductor
74
.
A second end of the ninth transmission line
20
I in the second set of coupled lines being a second output port P
3
.
The first transmission line
20
A in the second set
20
, the second transmission line
10
B in the first set
10
, the third transmission line
20
C in the second set
20
and the fourth transmission line
10
D in the first set
10
, the fifth transmission line
20
E in the second set
20
, the sixth transmission line
10
F in the first set
10
, the seventh transmission line
20
G in the second set
20
, the eighth transmission line
10
H in the first set
10
and the ninth transmission line
201
in the second set
20
are coupled electrically to each other via said electrical conductors
34
,
114
,
44
,
94
,
54
,
84
,
64
,
74
and forming a second spiral shaped electrical conductive path.
In the spiral shaped electrical conductive paths every second half turn of said spiral are belonging to the first set of coupled transmission lines and between said half turns the transmission lines belonging to the second set of transmission lines are arranged.
In the embodiment shown in
FIG. 3
there are eight electrically isolated transposition portions
30
,
40
,
50
,
60
,
70
,
80
,
90
,
110
of the first and second spiral shaped electrical conductive paths. Said electrically isolated transposition portions can be looked upon as four port cross connectors. In a first transposition portion
30
the electrical conductors
32
,
34
connecting the second end of the first transmission line
10
A in the first set of coupled lines
10
to the second end of the second transmission line
20
B in the second set of coupled lines
20
and the second end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the second end of the first transmission line
20
A in the second set of coupled transmission lines
20
respectively.
In a second transposition portion
40
the electrical conductors
42
,
44
connecting the second end of the third transmission line
10
C in the first set of coupled lines
10
to the second end of the fourth transmission line
20
D in the second set of coupled lines
20
and the second end of the fourth transmission line
10
D in the first set of coupled transmission lines
10
to the second end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively. In a third transposition portion
50
the electrical conductors
52
,
54
connecting the second end of the fifth transmission is line
10
E in the first set of coupled lines
10
to the second end of the sixth transmission line
20
F in the second set of coupled lines
20
and the second end of the sixth transmission line
10
F in the first set of coupled transmission lines
10
to the second end of the fifth transmission line
20
E in the second set of coupled transmission lines
20
respectively. In a fourth transposition portion
60
the electrical conductors
62
,
64
connecting the second end of the seventh transmission line
10
G in the first set of coupled lines
10
to the second end of the eight transmission line
20
H in the second set of coupled lines
20
and the second end of the eight transmission line
10
H in the first set of coupled transmission lines
10
to the second end of the seventh transmission line
20
G in the second set of coupled transmission lines
20
respectively. In a fifth transposition portion
70
the electrical conductors
72
,
74
connecting the first end of the ninth transmission line
10
I in the first set of coupled lines
10
to the first end of the eight transmission line
20
H in the second set of coupled lines
20
and the first end of the eight transmission line
10
H in the first set of coupled transmission lines
10
to the first end of the ninth transmission line
201
in the second set of coupled transmission lines
20
respectively.
In a sixth transposition portion
80
the electrical conductors
62
,
84
connecting the second end of the seventh transmission line
10
G in the first set of coupled lines
10
to the second end of the sixth transmission line
20
F in the second set of coupled lines
20
and the second end of the sixth transmission line
10
F in the first set of coupled transmission lines
10
to the second end of the seventh transmission line
20
G in the second set of coupled transmission lines
20
respectively. In a seventh transposition portion
90
the electrical conductors
92
,
94
connecting the first end of the fifth transmission line
10
E in the first set of coupled lines
10
to the first end of the fourth transmission line
20
D in the second set of coupled lines
20
and the first end of the fourth transmission line
10
D in the first set of coupled transmission lines
10
to the first end of the fifth transmission line
20
E in the second set of coupled transmission lines
20
respectively.
In a eighth transposition portion
110
the electrical conductors
112
,
114
connecting the first end of the third transmission line
10
C in the first set of coupled lines
10
to the first end of the second transmission line
20
B in the second set of coupled lines
20
and the first end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the first end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively.
With reference to
FIG. 4
, a schematic view of a fourth embodiment of a four port hybrid
100
D according to the invention is shown. The hybrid
100
D comprising a first set
10
and a second set
20
of coupled transmission lines. Said first set of coupled transmission lines
10
comprising a first transmission line
10
A, a second transmission line
10
B, a third transmission line
10
C and a fourth transmission line
10
D. Said second set of transmission lines
20
comprising a first transmission line
20
A, a second transmission line
20
B, a third transmission line
20
C and a fourth transmission line
20
D. In the present embodiment the transmission lines
10
A,
10
B,
10
C,
10
D,
20
A,
20
B,
20
C,
20
D are C-shaped. The first transmission lines
10
A,
20
A and the second transmission line
10
B,
20
B are the longest ones and the third transmission lines
10
C,
20
C and fourth transmission lines
10
D,
20
D are the shortest ones. All transmission lines
10
A,
10
B,
10
C,
10
D in the first set
10
are mutually coupled and said coupling is of electromagnetic nature. The same applies to every transmission line in the second set of coupled transmission lines
20
A first end of the first transmission line
10
A in the first set of coupled transmission lines
10
being an input port P
1
. A second end of said transmission line
10
A is electrically connected to a second side of the second transmission line
20
B in the second set of coupled transmission lines via an electrical conductor
32
. A first side of the second transmission line
20
B in the second set of coupled transmission lines
20
is electrically connected to a first side of the third transmission line
10
C in the first set of coupled transmission lines
10
via an electrical conductor
52
. A second side of the third transmission line
10
C in the first set of coupled transmission lines
10
is electrically connected to a fourth transmission line
20
D in the second set of coupled transmission lines
20
via an electrical conductor
42
. A first side of the fourth transmission line in the second set of coupled transmission lines being a first output port P
3
. The first transmission line
10
A in the first set
10
, the second transmission line
202
in the second set
20
, the third transmission line
10
C in the first set
10
and the fourth transmission line
20
D in the second set
20
coupled electrically to each other via said electrical conductors
32
,
42
,
52
are forming a first spiral shaped electrical conductive path The first and third transmission lines
10
A and
10
C belonging to the first set of coupled transmission lines are arranged on a first side of a dielectric substrate and the second and third transmission lines
20
B and
20
C belonging to the second set of transmission lines are arranged on a second side of said dielectric substrate.
A first end of the first transmission line
20
A in the second set of coupled lines
20
being a terminated (isolated) port. A second end of the first transmission line
20
A in the second set of coupled transmission lines
20
is electrically connected to a second end of the second transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
34
. A first end of the second transmission line
10
B in the first set of coupled transmission lines
10
is electrically connected to a first end of a third transmission line
20
C in the second set of coupled transmission lines
20
via an electrical conductor
54
. A second end of the third transmission line
20
C in the second set of coupled transmission lines
20
is electrically connected to a second end of a fourth transmission line
10
D in the first set of coupled transmission lines via an electrical conductor
44
. A first end of the fourth transmission line
10
D in the first set of coupled lines being a second output port P
2
. The first transmission line
20
A in the second set
20
, the second transmission line
10
B in the first set
10
, the third transmission line
20
C in the second set
20
and the fourth transmission line
10
D in the first set
20
connected electrically to each other via said electrical conductors
34
,
44
,
54
are forming a second spiral shaped electrical conductive path.
The first and third transmission lines
20
A and
20
C belonging to the second set of coupled transmission lines are arranged on the second side of the dielectric substrate and the second and third transmission lines
10
B and
10
C belonging to the first set of transmission lines are arranged on a first side of said dielectric substrate.
In the spiral shaped electrical conductive paths every second a half turn of said spiral are belonging to the first set of coupled transmission lines and between said half turns the transmission lines belonging to the second set of transmission lines are arranged.
In the embodiment shown in
FIG. 1
there are three transposition portions
30
,
40
,
50
of the first and second spiral shaped conductive paths.
In a first transposition portion
30
the electrical conductors
32
,
34
connecting the second end of the first transmission line
10
A in the first set of coupled lines
10
to the second end of the second transmission line
20
B in the second set of coupled lines
20
and the second end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the second end of the first transmission line
20
A in the second set of coupled transmission lines
20
respectively.
In a second transposition portion
40
the electrical conductors
42
,
44
connecting the second end of the third transmission line
10
C in the first set of coupled lines
10
to the second end of the fourth transmission line
20
D in the second set of coupled lines
20
and the second end of the fourth transmission line
10
D in the first set of coupled transmission lines
10
to the second end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively.
In a third transposition portion
50
the electrical conductors
52
,
54
connecting the first end of the second transmission line
10
B in the first set of coupled lines
10
to the first end of the third transmission line
20
C in the second set of coupled lines
20
and the first end of the third transmission line
10
C in the first set of coupled transmission lines
10
to the first end of the second transmission line
20
B in the second set of coupled transmission lines
20
respectively.
With reference to
FIG. 5
, a physical layout of a four port hybrid
100
D according to the invention is shown. The hybrid
100
D comprising a first set
10
and a second set
20
of coupled transmission lines. Said first set of coupled transmission lines
10
comprising a first transmission line
10
A, a second transmission line
10
B, a third transmission line
10
C and a fourth transmission line
10
D. Said second set of transmission lines
20
comprising a first transmission line
20
A, a second transmission line
20
B, a third transmission line
20
C and a fourth transmission line
20
D. In the present embodiment the transmission lines
10
A,
10
B,
10
c,
10
D,
20
A,
20
B,
20
C,
20
D are C-shaped. The first transmission line
10
A,
20
A is the longest one and the second
10
B,
20
B, third
10
C,
20
C and fourth
10
D,
20
D are decreasing by gradual stages. Every transmission line
10
A,
10
B,
10
C,
10
D in the first set
10
is interacting with each other, that means they are more or less capacitively coupled to each other, the closer the transmission lines are to each other the bigger the coupling between said transmission lines. The same applies to every transmission line in the second set of coupled transmission lines
20
.
A first end of the first transmission line
10
A in the first set of coupled transmission lines
10
being an input port P
1
. Said input port P
1
in this physical implementation is a pad electrically connected to the end of the first transmission line
10
A. Said pad like the transmission lines in the hybrid pattern is for example manufactured by printing, sputtering or etching. A second end of said transmission line
10
A is electrically connected to a second end of the second transmission line in the second set of coupled transmission lines via an electrical conductor
32
. A first end of the second transmission line
20
B in the second set of coupled transmission lines
20
is electrically connected to a first end of the third transmission line
10
C in the first set of coupled transmission lines
10
via an electrical conductor
52
. A second end of the third transmission line in the first set of coupled transmission lines is electrically connected to a fourth transmission line in the second set of coupled transmission lines via an electrical conductor
42
. A first end of the fourth transmission line in the second set of coupled transmission lines being a first output port P
3
being formed as a pad and connected to said end of said transmission line. The first transmission line
10
A in the first set
10
, the second transmission line
20
B in the second set
20
, the third transmission line
10
C in the first set
10
and the fourth transmission line
201
in the second set
20
coupled electrically to each other via said electrical conductors
32
,
42
,
52
are forming a first spiral shaped electrical conductive path.
A first end of the first transmission line
20
A in the second set of coupled lines
20
being a port connectable to ground. A second end of the first transmission line
20
A in the second set of coupled transmission lines
20
is electrically connected to a second end of the second transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
34
. A first end of the second transmission line
10
B in the first set of coupled transmission lines
10
is electrically connected to a first end of a third transmission line
20
C in the second set of coupled transmission lines
20
via an electrical conductor
54
. A second end of the third transmission line
20
C in the second set of coupled Ad transmission lines
20
is electrically connected to a second end of a fourth transmission line
10
D in the first set of coupled transmission lines via an electrical conductor
44
. A first end of the fourth transmission line
10
D in the first set of coupled lines being a second output port P
2
being like the first output port formed like a pad and connected to the end of said transmission line. The first transmission line
20
A in the second set
20
, the second transmission line
10
B in the first set
10
, the third transmission line
20
C in the second set
20
and the fourth transmission line
10
D in the first set
20
coupled electrically to each other via said electrical conductors
34
,
44
,
54
are forming a second spiral shaped electrical conductive path.
In the spiral shaped electrical conductive paths every second half turn of said spiral are belonging to the first set of coupled transmission lines and between said half turns the transmission lines belonging to the second set of transmission lines are arranged.
In the embodiment shown in
FIG. 5
there are three electrically isolated transposition portions
30
,
40
,
50
of the first and second spiral shaped conductive paths. In a first transposition portion
30
the electrical conductors
32
,
34
connecting the second end of the first transmission line
10
A in the first set of coupled lines
10
to the second end of the second transmission line
20
B in the second set of coupled lines
20
and the second end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the second end of the first transmission line
20
A in the second set of coupled transmission lines
20
respectively. In a second transposition portion
40
the electrical conductors
42
,
44
connecting the second end of the third transmission line
10
C in the first set of coupled lines
10
to the second end of the fourth transmission line
20
D in the second set of coupled lines
20
and the second end of the fourth transmission line
10
D in the first set of coupled transmission lines
10
to the second end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively. In a third transposition portion
50
the electrical conductors
52
,
54
connecting the first end of the second transmission line
10
B in the first set of coupled lines
10
to the first end of the third transmission line
20
C in the second set of coupled lines
20
and the first end of the third transmission line
10
C in the first set of coupled transmission lines
10
to the first end of the second transmission line
20
B in the second set of coupled transmission lines
20
respectively.
In every transposition portion in
FIG. 5
one of the electrical conductors connecting two transmission lines from different set of coupled transmission lines is printed like the rest of the pattern of the hybrid. The other electrical conductors, isolated from the printed ones are for example bonding wires between the two transmission lines.
Capacitors
51
,
53
,
57
,
43
,
41
,
33
,
31
are arranged like a meander shaped pattern at both ends of the second, third and fourth transmission lines. The meander shaped pattern at the ends of the transmission lines in the first set of coupled transmission lines are adapted to the meander shaped pattern at the ends of the transmission lines in the second set of coupled transmission lines.
In the embodiment in
FIG. 5
a capacitor
57
is arranged between the first and second output port. Said capacitor will also contribute to the equalization of the different modes propagating across the hybrid.
With reference to
FIG. 6
, a schematic view of a fifth embodiment of a four port hybrid
100
F according to the invention is shown. Different layers in the hybrid are separated in the figure for the purpose of clarity, in reality said layers are closely arranged to each other. The hybrid
100
F comprising a first set
10
and a second set
20
of coupled transmission lines. Said first set of coupled transmission lines
10
comprising a first transmission line
10
A, a second transmission line
10
B and a third transmission line
10
C. Said second set of transmission lines
20
comprising a first transmission line
20
A, a second transmission line
20
B and a third transmission line. In the present embodiment the transmission lines
10
A,
10
B,
10
C,
20
A,
20
B,
20
C are C-shaped. The first transmission lines
10
A,
20
A are arranged on a first layer X in a dielectric substrate, the second transmission lines
10
B,
20
B are arranged on a second layer Y in the dielectric substrate and the third transmission lines
10
C,
20
C are arranged on a third layer Z in the dielectric substrate. The different layers X, Y, Z in the substrate are electrically isolated from each other. Every transmission line
10
A,
10
B,
10
C in the first set
10
is interacting with each other, that means they are more or less capacitively coupled to each other, the closer the transmission lines are to each other the bigger the coupling between said transmission lines. The same applies to every transmission line in the second set of coupled transmission lines
20
. The shape of the transmission lines in the first set
10
and the second set could as indicated in
FIG. 6
be equal. However the length and shape could be different for the different transmission lines
10
A,
10
B,
10
C,
20
A,
20
B,
20
C.
A first end of the first transmission line
10
A in the first set of coupled transmission lines
10
being an input port P
1
. A second end of said transmission line
10
A is electrically connected to a second side of the second transmission line
20
B in the second set of coupled transmission lines
20
via an electrical conductor
32
. A first side of the second transmission line
20
B in the second set of coupled transmission lines
20
is electrically connected to a first side of the third transmission line
10
C in the first set of coupled transmission lines
10
via an electrical conductor
44
. A second side of the third transmission line
10
C in the first set of coupled transmission lines
10
being a first output port P
2
. The first transmission line
10
A in the first set
10
, the second transmission line
20
B in the second set
20
and the third transmission line
10
C in the first set
10
are coupled electrically to each other via said electrical conductors
32
,
44
and forming a first spiral (helix) shaped electrical conductive path.
A first end of the first transmission line
20
A in the second set of coupled lines
20
being a port P
4
connectable to ground. A second end of the first transmission line
20
A in the second set of coupled transmission lines
20
is electrically connected to a second end of the second transmission line
10
B in the first set of coupled transmission lines
10
via an electrical conductor
34
. A first end of the second transmission line
10
B in the first set of coupled transmission lines
10
is electrically connected to a first end of a third transmission line
20
C in the second set of coupled transmission lines
20
via an electrical conductor
42
. A second end of the third transmission line
20
c in the second set of coupled transmission lines
20
being a second output port P
3
. The first transmission line
20
A in the second set
20
, the second transmission line
10
B in the first set
10
and the third transmission line
20
C in the second set
20
are coupled electrically to each other via said electrical conductors
34
,
42
and forming a second spiral (helix) shaped electrical conductive path.
In the spiral shaped electrical conductive paths every second half turn of said spiral are belonging to the first set of coupled transmission lines and between said half turns the transmission lines belonging to the second set of transmission lines are arranged. In this embodiment every second half turn of the spirals are belonging to a different layer compared to the previous half turn if any such half turn is existing in the structure and the next coming half turn if any such half turn in the structure is existing.
In the embodiment shown in
FIG. 6
there are two electrically isolated transposition portions
30
,
40
of the first and second spiral shaped conductive paths. Said electrically isolated transposition portions
30
,
40
can be looked upon as four port cross connectors. In a first transposition portion
30
the electrical conductors
32
,
34
connecting the second end of the first transmission line
10
A in the first set of coupled lines
10
to the second end of the second transmission line
20
B in the second set of coupled lines
20
and the second end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the second end of the first transmission line
20
A in the second set of coupled transmission lines
20
respectively.
In a second transposition portion
40
the electrical conductors
42
,
44
connecting the first end of the third transmission line
10
C in the first set of coupled lines
10
to the first end of the second transmission line
20
B in the second set of coupled lines
20
and the first end of the second transmission line
10
B in the first set of coupled transmission lines
10
to the first end of the third transmission line
20
C in the second set of coupled transmission lines
20
respectively.
The hybrid with N coupled transmission lines will have (N−1) transposition portions.
The hybrid can have a first capacitor coupled between ground and the input port.
The transmission lines can be of any shape for example straight lines or meander shaped instead of the above mentioned C shaped transmission lines
The invention being thus described, it will be obvious that the same may be varied in a plurality of ways. Such variations are not to be regarded as a departure from the scope of the invention. All such modifications as would be obvious to one skilled in the art are intended to be included within the cope of the appended claims.
Claims
- 1. A four port hybrid comprising a first set (10) of N coupled transmission lines (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I) and a second set (20) of N coupled transmission lines (20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I) where N≧3, said coupled transmission lines in said first set (10) are electrically connected to said coupled transmission lines in said second set (20) to form a first spiral shaped electrical conductive path, a second spiral shaped electrical conductive path and N−1 electrically isolated transposition portions (30, 40, 50, 60, 70, 80, 90, 110) of said first and second spiral shaped electrical conductive paths, where a first end of the first spiral being an input port (P1), a first end of the second spiral being a terminated port (P4), a second end of the first spiral being a first output port (P3), a second end of the second spiral being a second output port (P2).
- 2. A four port hybrid according to claim 1, characterised in that said first set (10) of N coupled transmission lines is a mirror image of said second set (20) of N coupled lines.
- 3. A four port hybrid according to claim 1, characterised in that said transmission lines in said first and second set (10) of coupled transmission lines are C-shaped.
- 4. A four port hybrid according to claim 1, characterised in that the first (10) and second (20) set of transmission lines and the electrical connection between them are arranged on one side of a dielectric substrate.
- 5. A four port hybrid according to claim 1, characterised in that at least one of the transmission lines is arranged on a first side of the dielectric substrate and the rest of the transmission lines are arranged on the second side of said dielectric substrate.
- 6. A four port hybrid according to claim 1, characterised in that a first transmission line (10A, 20A) in the first and second set (10, 20) are arranged on a first layer (X) in the dielectric substrate, a second transmission line (103, 20B) in the first and second set (10, 20) are arranged on a second layer (Y) in the dielectric substrate and a N:th transmission line in the first and second set (10, 20) are arranged on a N:th layer in the dielectric substrate, where said layers are electrically isolated from each other.
- 7. A four port hybrid according to claim 1, characterised in that at least one isolated transposition portion (30, 40, 50, 60, 70, 80, 90110) having two capacitors (51, 53, 41, 43, 31, 33) being arranged between the ends of the transmission lines in such a manner to form further RF connections, which capacitors will equalise phase velocities for all modes propagating in the hybrid.
- 8. A four port hybrid according to claim 1, characterised in that a capacitor (57) is arranged between the first output port and the second output port (P2, P3).
PCT Information
| Filing Document |
Filing Date |
Country |
Kind |
| PCT/SE00/01621 |
|
WO |
00 |
| Publishing Document |
Publishing Date |
Country |
Kind |
| WO01/17058 |
3/8/2001 |
WO |
A |
US Referenced Citations (8)
