PURPOSE: To provide a high efficiency power amplifier which has a simple higher harmonic processing circuit by connecting a resonator which resonates to an optional higher harmonic of the output of an amplifier to the transmission line of the output of the amplifier.
CONSTITUTION: The resonator 3 which has line length 1/4 as long as the wavelength λnf of an optional object high frequency nf of the output of the amplifier (FET) 1 and has its one end grounded to resonate to the higher harmonic is provided and connected to the transmission line 2, which has impedance matching the fundamental wave (f) of the output of the amplifier 1 and outputs it, in parallel while a gap (d) is left. The impedance of the higher harmonic nf when the transmission line 2 for the output of the amplifier 1 where the resonator 3 is coupled is viewed from the amplifier 1 is in a zero short-circuit state, and the object higher harmonic nf of the output of the amplifier 1 is reflected to the input-side amplifier 1 of the transmission line 2. Therefore, the output efficiency of the fundamental wave (f) of the output of the amplifier 1 is improved and the power amplifier with high efficiency is actualized with the simple circuit constitution.
SUZUKI HIROSHI
WATANABE TOMINAGA
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