Patent ID: 7425872
Filing Date: 2008-09-16
Classification: H03F

Abstract:
1. A radio frequency power amplifier for power amplification of a radio frequency signal, comprising: n transistors connected in parallel, wherein n is an integer of 2 or more and emitters thereof are grounded; n resistances each having a first terminal and a second terminal, wherein a direct-current bias voltage are connected in common to the first terminals of the n resistances, and the second terminals of the n resistances are connected to bases of the n transistors, respectively; m capacitors each having a first electrode and a second electrode, wherein m is an integer of 1≦m≦n, the radio frequency signal is input in common to the first electrodes of the m capacitors, and the second electrodes of the m capacitors are connected to the bases of m transistors of the n transistors, respectively; and at least one band rejection filter provided between the bases of the m transistors connected to the m capacitors and the bases of the n-m transistors not connected to the m capacitors, wherein the at least one band rejection filter passes substantially only radio frequency components.