Design of 2.4GHz 10dBm CMOS class-e power amplifier and pre-power amplifier buffer with high overall transmitter efficiency

Abstract

Wireless sensor network applications are being introduced to various fields and some applications intend to widen their coverage by extending communication range between sensor nodes. To satisfy these needs, trans-mitter is expected to perform with increased output power while still retaining high overall transmitter efficiency in order to prolong battery life. This dissertation provides insight on how to design power amplifier and pre-PA buffer that are optimal for such transmitter requirements. By using 65nm process and 0.6V low supply voltage, class-E power amplifier operating at 2.4GHz and with 10dBm output power is designed with adequate modifi-cations to maximize power efficiency. Key practices are adopting cascode structure to avoid transistor break-down and realizing LC filter which is required for harmonic suppression outside the chip. Two candidates for pre-PA buffer, which are inverter chain buffer and resonant buffer, are analyzed and compared giving useful insight on why resonant buffer outperforms its counterpart in many ways. Post-layout simulation results are included to show resonant buffer and class-E power amplifier satisfies target performance.