Northrop Grumman Systems Corporation

Manouchehr Ghanevati

Timothy R LaRocca

John M Trippett

Mansoor K Siddiqui

Michael Herndon

David J Miller

An RF amplifier utilizes first and second main amplifiers in a balanced amplifier configuration with first and second auxiliary amplifiers connected in parallel across the first and second main amplifiers, respectively. The main and the auxiliary amplifiers are biased such that the third-order nonlinearity components in the combined output current are reduced. A common or independent bias control circuit(s) control(s) the DC operating bias of the auxiliary amplifiers and establishes DC operating points on curves representing third-order nonlinear components within the drain current having a positive slope (opposite to the corresponding slope of the main amplifiers). This results in reduction of overall third-order nonlinear components in combined currents at the output. In another embodiment, a phase shift of an input to one auxiliary amplifier is used to provide a peak in minimization at a frequency associated with the phase shift.

Balanced amplifiers with wideband linearization

An exemplary embodiment of a low noise amplifier has integral noise cancellation to provide a low noise figure and operation over a frequency range of 40 GHz-60 GHz. An amplifier amplifies an input signal as well as noise present with the amplified signal and amplified noise being out of phase and in phase, respectively, with the corresponding inputs. An auxiliary amplifier amplifies the same inputs and generates an amplified signal and amplified noise both being out of phase relative to the inputs. A summation circuit combines all of these amplified signals with the noise being cancelled since the auxiliary amplifier provides the same amount of amplification as the amplifier and the amplified noise signals being summed are 180 degrees out of phase to each other. Preferably, the amplifier, auxiliary amplifier and the summation device utilize CMOS transistors disposed on an SOI substrate with impedance stabilization over the frequency range.

Low noise amplifier with noise cancellation

A low noise amplifier has integral noise cancellation to provide a low noise figure and operation over a frequency range of 0.5 GHz-50 GHz. An amplifier amplifies an input signal as well as noise present with the amplified signal and amplified noise being out of phase and in phase, respectively, with the corresponding inputs. A feedback circuit that is non-linear with frequency enables a constant amplification. A summation circuit combines amplified signals with the noise being cancelled since two combined noise signals being summed are 180 degrees out of phase to each other. An optional secondary amplification stage provides additional amplification. Preferably, the amplifier, auxiliary amplifier and the summation device utilize CMOS transistors disposed on an SOI substrate with impedance stabilization over the frequency range.

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Laguna Niguel, CA, United States of America

Manouchehr Ghanevati