2-V-OPERATION DELTA-DOPED POWER HEMTS FOR PERSONAL HANDY-PHONE SYSTEMS

A high-efficiency and high-power-density delta-doped AIGaAs/InGaAs HEM T with low adjacent channel leakage has been developed for the digital wireless personal handy-phone system (PHS). When qualified by 1.9-GHz pi/4-shifted quadrature phase shift keying (QPSK) modulated PHS stand ard signals, the 2.0-V-operation HEMT with a 1-mm gate width demonstra ted a power-added efficiency of 45.3% and an output power density of 1 05 mW/mm. This is the highest power density ever reported by the power transistors for the PHS. The state-of-the-art results for the PHS ope rating at 2.0 V were achieved by the delta-doped power HEMT for the fi rst time.