ABSTRACT
A 3.3V operating GaAs power metal semiconductor field effect transistor for digital/analog dual-mode hand-held phones has been developed with state-of-the-art performance using a high-low doped structure grown by molecular beam epitaxy (MBE). For analog mode, the MESFET tested at a 3.3 V drain bias and a 900 MHz operation frequency displays power-added efficiency of 68% with output power of 32.5 dBm. For digital mode, the device shows that 3rd-order inter-modulation and power-added efficiency at an output power of 28 dBm were 32 dBc and 41%, respectively. A power amplifier operating at 3.3V for the dual-mode hand-held phones are developed by using the high-low MESFET. The amplifier shows an output power of 31.5 dBm and a power-added efficiency of 61% for AMPS mode. The third order intermodulation and the fifth order one are measured to be -32 dBc and -45 dBc at an output power of 26 dBm for CDMA mode. These are good enough for dual-mode requirements.
