Title :
Self-linearizing technique for L-band HBT power amplifier: effect of source impedance on phase distortion
Author :
Yamada, Wiroshi ; Ohara, Shiro ; Iwai, Taisuke ; Yamaguchi, Yasuhiro ; Imanishi, Kenji ; Joshin, Kazukiyo
Author_Institution :
Appl. Syst. Lab., Fujitsu Labs. Ltd., Akashi, Japan
fDate :
12/1/1996 12:00:00 AM
Abstract :
L-band power amplifiers operating with high efficiency and high linearity at a single and low supply voltage are in strong demand for mobile communication systems. This paper presents a new self-linearizing technique for power heterojunction bipolar transistors (HBTs). Utilizing the nonlinear input conductance of the device itself and setting the source impedance to the self-linearizing impedance, the phase distortion and the adjacent channel leakage power (ACP) for π/4-shift QPSK modulated signal of our InGaP/GaAs power HBTs have been greatly improved. As a result, the HBT exhibited the ACP at 50 kHz offset frequency of -49.2 dBc with a power-added efficiency (PAE) of 56% at an output power (Pout) of 31 dBm under a supply voltage of 35 V
Keywords :
UHF power amplifiers; heterojunction bipolar transistors; mobile radio; quadrature phase shift keying; 3.5 V; 50 kHz; 56 percent; HBT power amplifier; InGaP-GaAs; L-band; QPSK modulated signal; adjacent channel leakage power; efficiency; linearity; mobile communication systems; nonlinear input conductance; output power; phase distortion; power-added efficiency; self-linearizing technique; source impedance; Heterojunction bipolar transistors; High power amplifiers; Impedance; L-band; Linearity; Low voltage; Mobile communication; Phase distortion; Power amplifiers; Quadrature phase shift keying;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
