Abstract: A power amplifying apparatus includes a Doherty amplifier having a carrier amplifier and a peaking amplifier connected in parallel, each having an input/output matching circuit and an asymmetric power driver for driving the carrier amplifier and the peaking amplifier using an asymmetric power driver.

Abstract: A base station power amplifier for minimizing memory effect is provided. The power amplifier includes a bias circuit which supplies a direct current (DC) power to a transistor; the transistor which amplifies the DC power provided from the bias circuit; a matching circuit which transfers maximum power to a load by reducing loss of the power amplified by the transistor; and a large capacitor which lies between the matching circuit and the transistor, reduces a low-frequency second harmonic voltage by electrically connecting directly to the matching circuit, and has a preset capacitance value.

Abstract: A power amplifying apparatus includes a Doherty amplifier having a carrier amplifier and a peaking amplifier connected in parallel, each having an input/output matching circuit and an asymmetric power driver for driving the carrier amplifier and the peaking amplifier using an asymmetric power driver.

Abstract: A microwave Doherty amplifier employs a way-extension in which N ways (N?2, N is a natural number) are established, and envelope tracking for high efficiency and linearity of the power amplifier of a mobile communications base station or of a handset with improved reliability. The Doherty amplifier includes N ways, where N?2 and N is a natural number; a carrier amplifier which is placed on one of the N ways; peak amplifiers which are placed on respective ways of the (N?1) ways excluding the way on which the carrier amplifier is placed; a power distribution unit which distributes power to each of the N ways; and a quarter wave impedance transformer at which the N ways meet.

Abstract: An amplifier circuit using an adaptive bias control comprises an envelope detector for detecting an envelope of an input signal from a coupler, envelope shaping circuits for transforming of the envelope voltage from the envelope detector. The one transformed envelope voltage is applied to a drain bias for the peaking amplifier and the other is add by VDC to be applied to a gate bias for the carrier amplifier. In the Doherty amplifier, the gate voltage of the peaking amplifier and the drain voltage of the peaking amplifier are controlled in accordance with the input signal envelope to maximize efficiency with a desired linearity.

Abstract: A so-called microwave Doherty amplifier is provided. The microwave Doherty amplifier employs a way-extension method by which N ways (N≧2 N is a natural number) are established, and an envelope tracking method so that high efficiency and linearity of the power amplifier of a mobile communications base station or a handset can be achieved and price competitiveness and reliability of an apparatus employing the Doherty amplifier can be improved. The Doherty amplifier comprises N ways, where N≧2 and N is a natural number; a carrier amplifier which is placed on one of the N ways; peak amplifiers which are placed on respective ways of the (N−1 ways excluding the way on which the carrier amplifier is placed; a power distribution unit which distributes power to each of the N ways; and a quarter wave impedance transformer at which the N ways meet.