Browsing by Author "Lee, DH"

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A 1.2-V operation power pseudomorphic high electron mobility transistor for personal handy phone handset application
(2000-10-15)
Chang, EY
;
Lee, DH
;
Chen, SH
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A 1.2 V GaAs power pseudomorphic high electron mobility transistors (PHEMT's) for personal handy phone system (PHS) handset application was developed. The power PHEMT has a dual delta doped AlGaAs/InGaAs/GaAs based structure with compact device layout. The 6.72 mm device exhibits maximum power added efficiency (PAE) of 43.62% at 1.2V drain bias with an output power of 22.18 dBm. Under 1.9 GHz pi /4-shifted quadrature phase shift keying (QPSK) modulated PHS signal, the device shows an adjacent channel leakage power (P-adj) Of -56.86 dBc at 600 kHz apart from the center frequency and a linear efficiency of 41.31%. This is the first report on the 1.2-V operation power PHEMT for PHS handset application so far.
Power PHEMT with compact device layout for low voltage CDMA application
(2000-03-16)
Chang, EY
;
Lee, DH
;
Chen, SH
;
Chang, HC
;
材料科學與工程學系
A high efficiency low voltage operation dual delta-doped AlGaAs/ InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) for low voltage code division multiple access (CDMA) application has been developed. When tested at 2.4V and 1.9GHz under IS-95 CDMA modulation, the 20.16mm PHEMT device was found to have a linear output power of 28dBm with a power added efficiency of 30.2%. The device also has a saturation power of 30.0dBm with a power added efficiency of 61.5%. The high efficiency and linearity of the PHEMT at low bias voltage is attributed to the use of the dual delta-doped PHEMT structure and to the reduction of the size of the device layout. The device is suitable for low voltage CDMA applications.