Jeremy Reed

US Patent:

20070222512, Sep 27, 2007

Filed:

Feb 9, 2007

Appl. No.:

11/673422

Inventors:

Vikram Krishnamurthy - Smyrna GA, US
Tanveer Khanijoun - Atlanta GA, US
Kyle Hershberger - Atlanta GA, US
Jeremy Reed - Atlanta GA, US
Paul Pace - Acworth GA, US

Assignee:

VT SILICON, INC. - Atlanta GA

International Classification:

H03F 1/26

US Classification:

330149000

Abstract:

Sets of power amplifier branches (which comprise an RF/microwave amplifier stage) are power combined within each stage and each set of power amplifier branches are biased in different classes of operation by bias circuits possessing different impedance characteristics such that the fundamental frequency components present at the output are in-phase with one another and the IMD3 components are anti-phase over a broad range of power levels. The RF input signal is provided by the output of the previous stage of the RF/microwave amplifier. The output of each stage is formed by power combining sets of these power amplifier branches, each of which are separately biased, so the fundamental components are additive resulting in the maximum possible output power and the IM3 components cancel partially or completely. IM3 reduction or cancellation can be achieved over a large range of output powers with the use of a feed forward control loop monitoring the input power and appropriately adjusting the bias currents and impedance characteristics of the bias circuits feeding the individual power amplifier branches in each stage of the RF/microwave amplifier.

US Patent:

20100033242, Feb 11, 2010

Filed:

Aug 10, 2009

Appl. No.:

12/538428

Inventors:

Vikram Bidare Krishnamurthy - Smyrna GA, US
Tanveer Kaur Khanijoun - Smyrna GA, US
Kyle Mark Hershberger - Marietta GA, US
Jeremy Thomas Reed - Atlanta GA, US
Paul Erik Pace - Acworth GA, US

Assignee:

VT SILICON, INC. - Atlanta GA

International Classification:

H03F 3/68

US Classification:

330124 R, 330149, 330200

Abstract:

Sets of power amplifier branches (which comprise an RF/microwave amplifier stage) are power combined within each stage and each set of power amplifier branches are biased in different classes of operation by bias circuits possessing different impedance characteristics such that the fundamental frequency components present at the output are in-phase with one another and the IMD3 components are anti-phase over a broad range of power levels. The RF input signal is provided by the output of the previous stage of the RF/microwave amplifier. The output of each stage is formed by power combining sets of these power amplifier branches, each of which are separately biased, so the fundamental components are additive resulting in the maximum possible output power and the IM3 components cancel partially or completely. IM3 reduction or cancellation can be achieved over a large range of output powers with the use of a feed forward control loop monitoring the input power and appropriately adjusting the bias currents and impedance characteristics of the bias circuits feeding the individual power amplifier branches in each stage of the RF/microwave amplifier.