The high-frequency power amplifiers for 2 band and the terminal null 1st frequency band

摘要

PROBLEM TO BE SOLVED: To stabilize a system and to make it highly efficient with simple circuit constitution by using a 1/4 wavelength line in the stabilization circuit of a high frequency power amplifier for two bands. ;SOLUTION: The signal wave of a first frequency band is inputted from an input terminal 201 and it is amplified. The signal wave of a second frequency band is inputted to an input terminal 202 and is amplified. Then, it is outputted from output terminals 203 and 204. At that time, the synthesized resistance value of first and second resistors 101 and 111 decides the stability of the high frequency power amplifier for two bands. A connection point 113 is grounded by a capacitor 103 in terms of high frequency. The 1/4 wavelength line 112 inverts the impedance of the second frequency band. The impedance of a connection point 114 is approximated to open and the resistance value of the first resistor 101 decides stability. On the other hand, the 1/4 wavelength line 112 does not invert the impedance of the first frequency band and therefore the impedance of the connection point 114 is not approximated to open. Then, the synthesized resistance value of the first and third resistors 101 and 111 decides stability.;COPYRIGHT: (C)1999,JPO