Title :
The effect of source impedance on linearity in InGaP/GaAs power HBTs
Author :
Yamada, H. ; Ohara, S. ; Iwai, T. ; Yamaguchi, Y. ; Imanishi, K. ; Joshin, K.
Author_Institution :
Fujitsu Labs. Ltd., Atsugi, Japan
Abstract :
L-band power amplifiers operating with high efficiency and linearity at a single, low supply voltage are in strong demand in mobile communication systems. This paper reports the effect of source impedance on the phase distortion and the adjacent channel power (ACP) for a /spl pi//4-shift QPSK modulated signal in the InGaP/GaAs power heterojunction bipolar transistors (HBTs). Our results show that the phase distortion and the ACP of our HBTs are improved by adding a positive reactance to a gain-matched source impedance. The ACP for a 50 kHz offset is -49.2 dBc with a power-added efficiency (PAE) of 56% at a output power (P/sub out/) of 31 dBm under a supply voltage of 3.5 V.
Keywords :
III-V semiconductors; UHF bipolar transistors; UHF power amplifiers; electric distortion; electric impedance; gallium arsenide; gallium compounds; heterojunction bipolar transistors; impedance matching; indium compounds; land mobile radio; power bipolar transistors; quadrature phase shift keying; /spl pi//4-shift QPSK modulated signal; 3.5 V; 56 percent; InGaP-GaAs; L-band power amplifiers; UHF type; adjacent channel power; gain-matched source impedance; linearity; mobile communication systems; phase distortion; positive reactance; power HBTs; power heterojunction bipolar transistors; single low supply voltage; source impedance; Gallium arsenide; High power amplifiers; Impedance; L-band; Linearity; Low voltage; Mobile communication; Phase distortion; Phase modulation; Quadrature phase shift keying;
Conference_Titel :
Microwave Symposium Digest, 1996., IEEE MTT-S International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-3246-6
DOI :
10.1109/MWSYM.1996.510995
