Flehr Hohbach Test Albritton & Herbert LLP
Unbalanced FET mixer
 A unbalanced mixer capable of operation in the absence of DC bias is disclosed herein. The mixer includes an input or local oscillator (LO) port for receiving an input signal. A first transistor has a control terminal coupled to the mixer input port, and an output terminal coupled to a first signal port of the mixer. The mixer further includes a resonator circuit, connected between the transistor control and output terminals, for providing signal isolation between the mixer input port and the first signal port. In a preferred implementation the resonator circuit comprises an inductive element in parallel with a first intrinsic capacitance of the transistor. The mixer may also include a diplexer circuit for coupling signal energy of a first frequency between the output terminal and the first signal port, and for coupling signal energy of a second frequency between the output terminal and a second signal port. A series resonant circuit, connected between the input or LO port and the transistor control terminal, may also be provided for amplifying the input signal. In a preferred implementation the series resonant circuit comprises an input inductive element and an input intrinsic capacitance of the first transistor. 
Watkins Johnson Company
H H
H03D H04B
inventional additional
Michael Wendell Xiaohui
Vice Li