HIGH FREQUENCY POWER AMPLIFIER MODULE

摘要

PROBLEM TO BE SOLVED: To provide a small-sized high-frequency amplifier module that is operated at two different frequencies and optimum to a portable telephone set having provision for a dual band. SOLUTION: A DC bias circuit 30 of a high frequency power amplifier module is made up of transmission lines M11 and M12 and capacitive elements C11 and C12 . One terminal A of the transmission line M11 connects to a voltage source terminal Vdd and the other end connects to an output matching circuit 40. One end C of the transmission line M12 connects to a ground terminal and the other end D connects to the other end B via the capacitive element C11 . The capacitive element C12 connects between the voltage source terminal and the ground terminal. Length of lines L11 , L12 between the A and B and between the C and D are selected within a range of 0.106-0.178 wavelength or below with respect to the lower operating frequency f0 . The C11 is selected between 0.35/(2πf0 .Z0 ) and 0.5/(2πf0 .Z0 ), where Z0 is a characteristic impedance of each transmission line.