Amplifier
A amplifier that obtains an output by power combining, comprising; a distribution circuit that distributes an input signal into two signals; a first amplifier circuit that amplifies one of the two signals distributed by the distribution circuit and operates in class AB mode; a second amplifier circuit that amplifies the other of the two signals distributed by the distribution circuit and operates in class B or C mode; a lumped constant circuit that connects outputs of the first and second amplifier circuits; a first impedance transformation circuit connected to an output of the first amplifier circuit; a second impedance transformation circuit connected to an output of the second amplifier circuit, and a quarter wavelength impedance transformation circuit with one end thereof connected to a combining point of output sides of the first and second impedance transformation circuits and with the other end thereof connected to a load (FIG. 1 ).
1. An amplifier that obtains an output by power combining, comprising:
a distribution circuit that distributes an input signal into two signals;
a first amplifier circuit that amplifies one of the two signals distributed by the distribution circuit and operates in class AB mode;
a second amplifier circuit that amplifies the other of the two signals distributed by the distribution circuit and operates in class B or C operation mode;
a lumped constant circuit that connects outputs of the first and second amplifier circuits and that performs impedance transformation;
a first impedance transformation circuit connected to an output of the first amplifier circuit;
a second impedance transformation circuit connected to an output of the second amplifier circuit; and
a quarter wavelength impedance transformation circuit with one end thereof connected to a combining point of output sides of the first and second impedance transformation circuits and with the other end thereof connected to a load.
2. The amplifier according to claim 1 , wherein
the lumped constant circuit comprises a capacitor, an inductor, and a resistor connected in parallel.
3. The amplifier according to claim 1 , wherein
the first and second impedance transformation circuits are constructed with a micro strip line of a one-eighth wavelength circuit.
4. The amplifier according to claim 1 , wherein
the distribution circuit includes for one of the first and second amplifier circuits a variable phase converter that converts a phase of the input signal.