A Fully Integrated Triple-Band CMOS Class-E Power Amplifier With a Power Cell Resizing Technique and a Multi-Tap Transformer

This letter presents a fully integrated triple-band CMOS class-E power amplifier (PA) for the 0.8/1.9/2.4 GHz frequencies. The operating frequency band is tuned by a power cell resizing technique and by changing the supply bias position with a multi-tap transformer for the required capacitance and inductance values for optimum class-E operation. The PA achieves output powers of 28/29.6/26.5 dBm and power-added efficiency of 40/45/37% at each frequency band. The PA is implemented in a 0.18 μm CMOS process without multiple transformers or input/output matching networks. The total chip size is 1.5 × 1.5 mm
²
.