US 3,939,430 AGranted

Integrated circuit, image and sum enhanced balanced mixer

AssigneeWestinghouse Electric Corp.

InventorsLawrence E. Dickens, Douglas W. Maki

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Abstract

A balanced microwave diode mixing circuit utilizes the junction of a slot transmission line and a coplanar strip transmission line as the point of diode modulation to provide heterodyne mixing. By the use of slot line type elements formed on one side of a dielectric substrate and strip line type elements formed on the other side, the following features are achieved: (A) input of the local oscillator (LO) signal and output of the intermediate frequency (I.F.) signal are achieved through a common coupling to and from the coplanar strip line at the end of the latter which is remote from the hybrid junction; (B) low reactance at the "sum frequency" is presented at the hybrid junction; (C) low reactance at the image frequency is presented at the hybrid junction; and (D) high impedance at the input signal frequency is presented at the hybrid junction.

Claims13

Dependent claims

Microwave mixer apparatus, comprising;

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. means for coupling a first signal at a first frequency into said slot line,
e. a coplanar strip line comprising said layer of conductor material forming a center strip aligned along said reference axis, and said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
f. means for coupling a second signal at a second frequency into said coplanar strip line,
g. said slot line and said coplanar strip line being disposed in end-to-end relationship and at their adjacent ends cooperating to form a hybrid junction,
h. heterodyne circuit means operatively associated with said hybrid junction to derive a third signal at a frequency different from either that of the first and second frequencies,
i. means cooperative with said coplanar strip line to suppress derivation of a fourth signal at a fourth frequency different from any of the first, second and third frequencies,
j. means cooperative with said slot line to suppress derivation of a fifth signal at a fifth frequency different from any of the first, second, third and fourth frequencies,
k. said means cooperative with said coplanar strip line comprising a pair of first and second transversely aligned outwardly extending slot stubs of equal predetermined length formed in said side conductors of the coplanar strip line, said first and second slot stubs being formed at right angled appendages to the first longitudinal gap and to the second longitudinal gap, respectively, said slot stubs being formed at a longitudinal location along the coplanar strip line which is spaced from the hybrid junction end thereof by a predetermined distance,
l. said means cooperative with said slot line comprising a plurality of strips of conductor material affixed to the opposite side of said dielectric substrate, each strip of said plurality of strips passing transversely across said slot line, said plurality of strips being collectively constructed and arranged to present a relatively low impedance to said fifth frequency at said hybrid junction, and
m. said first, second, third, fourth and fifth signals are a set of signals composed of first and second input signals and related modulation product signals derived from combining the input signals in accordance with the heterodyne principle, the first, second, third, fourth and fifth signals respectively comprising a received signal, a local oscillator signal, an intermediate frequency signal, a sum frequency signal, and an image frequency signal.

10 more elements

Microwave mixer apparatus, comprising:

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. means for coupling a first signal at a first frequency into said slot line,
e. a coplanar strip line comprising said layer of conductor material forming a center strip aligned along said reference axis, and said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
f. means for coupling a second signal at a second frequency into said coplanar strip line,
g. said slot line and said coplanar strip line being disposed in end-to-end relationship and at their adjacent ends cooperating to form a hybrid junction,
h. heterodyne circuit means operatively associated with said hybrid junction to derive a third signal at a frequency different from either that of the first and second frequencies,
i. means cooperative with said coplanar strip line to suppress derivation of a fourth signal at a fourth frequency different from any of the first, second and third frequencies,
j. means cooperative with said slot line to suppress derivation of a fifth signal at a fifth frequency different from any of the first, second, third and fourth frequencies,
k. said means for coupling said second signal being operative to couple same into the coplanar strip line at the end thereof remote from its hybrid junction end, and
l. means for coupling said third signal from said coplanar strip line to a signal utilization means, said means for coupling said third signal being operative to couple same from said coplanar strip line at the end thereof remote from its hybrid junction end.

9 more elements

Microwave mixer apparatus, comprising:

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. means for coupling a first signal at a first frequency into said slot line,
e. a coplanar strip line comprising said layer of conductor material forming a center strip aligned along said reference axis, said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
f. means for coupling a second signal at a second frequency into said coplanar strip line,
g. said slot line and said coplanar strip line being disposed in end-to-end relationship and at their adjacent ends cooperating to form a hybrid junction,
h. heterodyne circuit means operatively associated with said hybrid junction to derive a third signal at a frequency different from either that of the first and second frequencies,
i. means cooperative with said coplanar strip line to suppress derivation of a fourth signal at a fourth frequency different from any of the first, second and third frequencies,
j. means cooperative with said slot line to suppress derivation of a fifth signal at a fifth frequency different from any of the first, second, third and fourth frequencies,
k. said hybrid junction being comprised of said adjacent ends of said slot line and said coplanar strip line cooperating to form first and second generally lateral gaps which at their inner ends intersect with one another and the slot line and which at their outer ends intersect respectively with said first and second longitudinal gaps,
l. a first d.c. bias pad formed in said layer of conductor material as a portion thereof isolated from all adjacent portions of said layer by a gap in conductor material, said first d.c. bias pad being disposed adjacent to said first lateral gap,
m. a second d.c. bias pad formed in said layer of conductor material as a portion thereof isolated from all adjacent portions of said layer by a gap in conductor material, said second d.c. bias pad being disposed adjacent to said second lateral gap,
n. said heterodyne means comprises first and second unidirectional current devices having nonlinear impedance characteristics, said first device being connected between the first d.c. bias pad and said center strip and said second device being connected between said second d.c. bias pad and said center strip, said devices being so connected to form a series circuit between the first and second d.c. bias pads with the devices poled to conduct in the same circuit direction,
o. first and second bias sources respectively operatively connected to said first d.c. bias pad to forward bias the first unidirectional current device, and operatively connected to said second d.c. bias pad to forward bias the second unidirectional current device, and
p. first and second a.c. short circuiting means respectively connected between said first d.c. bias pad and an adjacent nonisolated portion of the layer of conductor material, and connected between said second d.c. bias pad and an adjacent nonisolated portion of the layer of conductor material.

13 more elements

Microwave mixer apparatus, comprising:

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. means for coupling a first signal at a first frequency ratio into said slot line,
e. a coplanar strip line comprising said layer of conductor material forming a center strip aligned along said reference axis, and said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
f. means for coupling a second signal at a second frequency into said coplanar strip line,
g. said slot line and said coplanar strip line being disposed in end-to-end relationship with their adjacent ends cooperating to form first and second generally lateral gaps which at their inner ends intersect with one another and the slot line and which at their outer ends intersect respectively with said first and second longitudinal gaps,
h. a first unidirectional current device having nonlinear impedance characteristics connected between the center strip and one portion of the layer of conductor material which is disposed across said first lateral gap, and a second unidirectional device having nonlinear impedance characteristics connected between the center strip and another portion of the layer of conductor material which is disposed across said second lateral gap, said one and another portions of said layer of conductor material being on opposite sides of said slot line, said devices being so poled to provide heterodyne mixing of the first and second signals to derive a third signal at a third frequency,
i. means cooperative with said coplanar strip line to present a relatively low impedance to a fourth signal at an undesired fourth frequency in the region at which said slot line and said lateral gaps intersect and in shunt relation to both of said unidirectional current devices,
j. said means for coupling said second signal being operative to couple same into the coplanar strip line at the end thereof remote from the end adjacent to the slot line, and
k. means for coupling said third signal from said coplanar strip line to a signal utilization means, said means for coupling said third signal being operative to couple same from said coplanar strip line at the end thereof which is remote from the end adjacent to the slot line.

8 more elements

Microwave mixer apparatus, comprising:

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. means for coupling a received signal at a first frequency into said slot line,
e. a coplanar strip line comprising said layer of conductor material forming a center strip line aligned along said reference axis, and said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
f. means for coupling a local oscillator signal at a second frequency into said coplanar strip line,
g. said slot line and said coplanar strip line being disposed in end-to-end relationship with their adjacent ends cooperating to form first and second generally lateral gaps which at their inner ends intersect with one another and the slot line and which at their outer ends intersect respectively with said first and second longitudinal gaps,
h. a first unidirectional current device having nonlinear impedance characteristics connected between the center strip and one portion of the layer of conductor material which is disposed across said first lateral gap, and a second unidirectional current device having nonlinear impedance characteristics connected between the center strip and another portion of the layer of conductor material which is disposed across said second lateral gap, said one and another portions of said layer of conductor material being on opposite sides of said slot line, said devices being so connected to form a series circuit between the one and another portions of the layer of conductor material with the devices poled to conduct in the same direction of circuit current flow,
i. means cooperative with said slot line to present a relatively low impedance to an undesired image signal modulation product in the region at which said slot line and said lateral gaps intersect and in shunt relationship to said series circuit of unidirectional devices between the one and another portions of the layer of conductor material, said image signal modulation product being derived from the application of both the received signal and the local oscillator signal across each of the first unidirectional device and the second unidirectional device in accordance with the heterodyne principle,
j. said means for coupling said local oscillator signal being operative to couple same into the coplanar strip line at the end thereof remote from the end adjacent to the slot line, and
k. means for coupling the intermediate frequency signal modulation product from said coplanar strip line to a signal utilization means, said intermediate frequency signal being derived in accordance with the heterodyne principle from the application of both the received signal and the local oscillator signal across each of the first unidirectional current device and the second unidirectional current device said means for coupling said intermediate frequency being operative to couple same from said coplanar strip line at the end thereof which is remote from the end adjacent to the slot line.

8 more elements

Mixer apparatus, comprising:

a. a dielectric substrate,
b. a layer of conductor material affixed to one surface of said substrate,
c. a slot line formed in said layer of conductor material, the axis of said slot line establishing a longitudinal reference axis,
d. a coplanar strip line comprising said layer of conductor material forming a center strip aligned along said reference axis, and said layer of conductor material forming a first side conductor laterally spaced from one side of the center strip by a first longitudinal gap and forming a second side conductor laterally spaced from the other side of the center strip by a second longitudinal gap,
e. said slot line and said coplanar strip line being disposed in end-to-end relationship, and having their adjacent ends cooperating to form first and second generally lateral gaps which at their inner ends intersect with one another and the slot line and which at their outer ends intersect respectively with said first and second longitudinal gaps, forming a hybrid junction,
f. a first unidirectional current device having nonlinear impedance characteristics connected between the center strip and one portion of the layer of conductor material which is disposed across said first lateral gap, and a second unidirectional current device having nonlinear impedance characteristics connected between the center strip and another portion of the layer of conductor material which is disposed across said second lateral gap, said one and another portions of said layer of conductor material being on opposite sides of said slot line, said devices being so connected to form a series circuit between the one and another portions of the layer of conductor material with the devices poled to conduct in the same direction of circuit current flow,
g. means for coupling a received signal into said slot line to apply same across the series circuit of first and second unidirectional current devices, and
h. common coupling means electrically connected to said coplanar strip line, said common coupling means being operative to introduce a local oscillator signal into said coplanar strip line for propagation therealong to apply same across said first unidirectional current device and across said second unidirectional current device, and said common coupling means being operative to receive intermediate frequency signal energy which emanates from said first unidirectional current device and propagates along said coplanar strip line and which emanates from said second unidirectional current device and propagates along said coplanar strip line and operative to couple such intermediate frequency signal energy from the coplanar strip line to a signal utilization means.

5 more elements

Dependencies are inferred from the claim text.