| 摘要 |
<p>A high efficiency harmonic injection power amplifier has a power amplifier circuit (10) and at least a second-harmonic termination circuit which is coupled in parallel with the power amplifier circuit so as to sample a small portion of the input signal and to inject into the power output signal an amplified harmonic signal which is phase-shifted for proper harmonic termination. The second-harmonic termination circuit includes a frequency multiplier (2) for multiplying the frequency of the sampled input signal to twice the fundamental frequency, i.e., to 2fo, an amplifier (20) for amplifying the 2fo signal to the level of the corresponding harmonic component of the power amplifier output signal, and a phase shifter (23) for shifting the phase of the second-harmonic signal for proper harmonic termination. Additional harmonic termination circuits may be provided for terminating third- and higher-order harmonics.</p> |
