Power amplifier with harmonically trapped heterojunction bipolar transistor

A power amplifier for operation within a narrow bandwidth regime, said power amplifier comprising:

• a heterojunction bipolar transistor having a base, a collector and an emitter for providing a non-linear gain;
• an input terminal connected to the base of said heterojunction bipolar transistor for providing an input electrical signal thereto;
• an output terminal connected to the collector of said heterojunction bipolar transistor for providing an amplified output electrical signal;
• harmonic input trap circuit means interposed in the connection between said input terminal and the base of said heterojunction bipolar transistor and being resonant at a harmonic of substantially band center frequency;
• and
• harmonic output trap circuit means interposed in the connection between the collector of said heterojunction bipolar transistor and said output terminal;
• said harmonic input and output trap circuit means increasing the efficiency of the power amplifier by dissipating energy resulting from harmonic generation by said heterojunction bipolar transistor during amplification of the electrical signal.