Viasat, Inc.

Sirenza Microdevices, Inc.

Dean Muellenberg

Kenneth V Buer

Gaurav Menon

Gregg Alan Hollingsworth

Ramanamurthy V Darapu

Khalid Paul Shallal

Systems, devices and methods are disclosed for suppressing the 2LO frequency spur, output from a mixer. In various exemplary embodiments, a DC bias circuit is electrically connected to provide DC bias to one or more non-linear elements of the mixer. The biasing voltage is used to cause the current-voltage characteristics and/or junction capacitances between non-linear elements to be more symmetric and/or to suppress 2LO leakage currents that form 2LO frequency spurs at the output of the mixer. The non-linear elements may comprise one of: BJT's, diodes, and FET's. The mixer may be one of: a subharmonic mixer; a fundamental resistive mixer; a fundamental subharmonic transconductance mixer; and a fundamental transconductance mixer comprising an anti-parallel diode pair. The system may further be configured to automatically determine an appropriate DC bias voltage level that will improve one of the LO-IF isolation and the LO-RF isolation.

Systems, devices, and methods for suppressing frequency spurs in mixers

An apparatus for improving linearity of an RF signal comprising: (a) a splitter configured to receive an input RF signal, and configured to split the input RF signal into two RF signals comprising a first input RF signal, and a second input RF signal; (b) an over-biased non-linear RF power amplifier configured to receive the first input RF signal and configured to generate an over-biased non-linear output signal having an over-biased non-linear distortion component; (c) an under-biased non-linear RF power amplifier configured to receive the second input RF signal and configured to generate an under-biased non-linear output signal having an under-biased non-linear distortion component; and (d) a combiner configured to combine the over-biased non-linear output signal and the under-biased non-linear output signal, and configured to output the RF signal having substantially cancelled over-biased and under-biased distortion components. The over-biased non-linear RF power amplifier is configured to receive an over-biased DC signal being greater than an optimum bias DC voltage. The under-biased non-linear RF power amplifier is configured to receive an under-biased DC signal being lower than the optimum bias DC voltage.

Distortion cancellation for RF amplifiers using complementary biasing circuitry

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Tempe, AZ, United States of America

Dean Muellenberg