TRANSISTOR-BASED POWER AMPLIFIER OF RADIO TRANSMITTER Russian patent published in 2012 - IPC H03F3/20 

FIELD: radio engineering.

SUBSTANCE: amplifier consists of a driver stage with a parallel oscillatory circuit at its output with a secondary coil, tuned in resonance to the first harmonic of the input signal, and an output stage with a parallel oscillatory circuit at its output, also tuned in resonance to the first harmonic of the input signal. There is an additional varactor, a capacitor and two parallel oscillatory circuits tuned in resonance to the third harmonic of the input signal, one of which has a secondary coil shunted by the additional capacitor, and connected through a varicap in parallel to the output oscillatory circuit of the driver stage, one end of the secondary coil of which is earthed, and the other end is connected to one end of the secondary coil of the additional circuit, the second end of which is connected to the input of the output stage of the transmitter; and the second additional circuit is connected in series to the circuit at the output of the output stage of the transmitter.

EFFECT: high efficiency due to the third harmonic of the input signal.

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