Application of enhancement mode FET technology for wireless subscriber transmit/receive circuits

Single-supply power amplifers have become the new paradigm in portable phon e handsets due to the recent availability of heterojunction bipolar transis tor (HBT) and pseudo enhancement mode PHEMT technology. We have developed a true enhancement mode heterostructure insulated gate FET device (HIGFET) w hich is suitable for use in both saturated and linear power amplifiers, A t hree-stage power amplifier designed for 1900-MHz NADC application delivered +30-dBm output power and 41.7% power-added efficiency with an adjacent cha nnel power of -29.8 dBc and alternate adjacent channel power of -48.4 dBc, In addition to this, me have demonstrated excellent noise figure and linear ity performance for small-signal applications. At 900 MHz and bias conditio ns V-DS = 1.0 V and I-DSQ = 1 mA, a single-stage amplifier achieved a noise figure of 1.17 dB with an associated gain of 18.5 dB, These results make t he technology an ideal candidate for application in both transmitter and re ceiver circuits.