| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-frequency power amplifier with low amplification distortion using SiGe HBT, and a communication apparatus which uses the same. SOLUTION: Bias resistors R11-R1N, having high-resistance values of three to five times those of ballast resistors, added to the base of each transistor in the conventional high frequency power amplifier, are added to a base bias path of each transistor (SiGe HBT) Q1-QN. A coil LB is provided in parallel with the bias resistors, as a means of compensating the voltage drop produced by a direct current I<SB>DC</SB>flowing in these bias resistors. Since the addition of the bias resistors restrains the non-linearity in low frequency variations of the output current, and addition of the coil compensates for the voltage drop, the maximum linear output can be improved. As a result, the power amplifier having low amplification distortion in a broad output range can be obtained. COPYRIGHT: (C)2004,JPO&NCIPI
|
