Patent ID: 8810313

Claim:
A power amplifier for operation in at least a first frequency band and a second frequency band, the power amplifier comprising: a transistor for amplifying an input signal of the power amplifier; and an output coupling network operatively connected to an output terminal of the transistor and having its own output terminal for connecting the power amplifier to a resistive load; wherein the output coupling network is configured such that, when the power amplifier is connected to the resistive load, the power amplifier is configured to: operate in class F for frequencies in one of the first frequency band and the second frequency band; and operate in inverse class F for frequencies in the other of the first frequency band and the second frequency band; wherein a center frequency f 2 of the second frequency band is higher than a center frequency f 1 of the first frequency band; and wherein a ratio between f 2 and f 1 is 1.5.