Biased FET mixer
AssigneeWatkins-Johnson Company
InventorMichael W. Vice
Life of this patent
Estimating the term…
Abstract
A mixer including a "reflection" transmission line transformer having at least first and second ports. The ports are connected such that nearly complete coupling of energy between the ports relies on substantially complete reflection of energy at a reference plane of the transformer. In a preferred implementation there is produced at the first port an intermediate frequency (IF) signal and received a DC bias signal via an IF balun. At the second port there is inputted a radio frequency (RF) signal through an RF balun. The DC bias signal will preferably be provided to a set of phase-selecting GaAs MESFET transistors operatively connected between an LO balun and a third port of the reflection transformer. In the preferred implementation the MESFET transistors are realized using an MMIC.
Claims20
A DC-biased reflection transformer, comprising:
- a transmission line transformer having at least two ports, said ports connected such that nearly complete coupling of energy between said ports relies on substantially complete reflection of said energy at a reference plane of the transformer, said DC-biased reflection transformer further including phase selector switch means for inducing said substantially complete reflection of energy at said reference plane by switchably creating an impedance mismatch at a first end of a transmission line connected to at least one of said two ports, said reflection transformer being disposed to receive a DC bias signal through one of said ports from a DC bias network coupled thereto.
A DC-biased mixer, comprising:
- a first and a second FET transistor each having a gate and a first drain/source and a second drain/source, the first and second FET transistors having their gates tied to one another and said first drain/source of the first FET transistor connected to said first drain/source of the second FET transistor;
- a third and a fourth FET transistor each having a gate and a first drain/source and a second drain/source, the third and fourth FET transistors having their gates tied to one another and said first drain/source of the third FET transistor connected to said first drain/source of the fourth FET transistor;
- a DC bias network for providing DC bias to said second drain/source of the first, second, third, and fourth FET transistors;
- a local oscillator (LO) balun having a first output port in electrical communication with said gates belonging to the first and second FET transistors and a second output port in electrical communication with said gates belonging to the third and fourth FET transistors;
- and
- a reflection transformer coupled to said first, second, third, and fourth FET transistors, said reflection transformer comprising a transmission line transformer having at least two ports wherein said DC bias is applied to one of said two ports, said ports connected such that nearly complete coupling of energy between said ports relies on substantially complete reflection of said energy at a reference plane of the transformer, said substantially complete reflection of energy at said reference plane resulting from an impedance mismatch at a first end of a transmission line connected to at least one of said two ports wherein an RF signal and an intermediate-frequency (IF) signal each pass through a different one of said two ports.
A DC-biased reflection transformer, comprising:
- a transmission line transformer having at least two ports, said ports connected such that nearly complete coupling of energy between said ports relies on substantially complete reflection of said energy at a reference plane of the transformer, said DC-biased reflection transformer further including phase selector switch means for inducing said substantially complete reflection of energy at said reference plane by switchably creating an impedance mismatch at a first end of a transmission line connected to at least one of said two ports, said reflection transformer receiving a DC bias signal through a first of said ports from a DC bias network coupled thereto and said reflection transformer including means for providing an intermediate-frequency (IF) signal through a second of said ports.
Dependencies are inferred from the claim text.