Patent ID: 7038539

Claim:
A power amplifier adapted for amplifying an RF input signal, comprising: an input for receiving an RF input signal; an amplifier device coupled to the input and receiving the input signal and providing an amplified output signal; a dynamically varying output load coupled to the amplifier device, including a variable impedance device coupled to the amplifier device so as to vary the impedance across the amplifier device as a function of an input signal, wherein the impedance across a amplifier device is substantially constant through a first portion of the input signal power range corresponding to the lower major portion of the input signal power range and drops substantially for a second portion of the input signal power range having higher power than said first portion of the input signal power range, the variable impedance device having approximately zero impedance through said first portion of the input signal power range and a substantially greater impedance through said second portion of the input signal power range; and an output coupled to the output load for outputting the amplified output signal, wherein said second portion of the input signal power range comprises the input signal power range greater than about 6–10 dB below the amplifier device saturation region and wherein the impedance across the amplifier device in said second portion of the input signal power range is about 50% of the impedance across the amplifier device in said first portion of the input signal power range.