A highly-linear radio-frequency envelope detector for multi-standard operation

A highly-linear RF envelope detector for amplitude modulation of multiple wireless standards is presented. The RF envelope detector employs a differential voltage-to-current converter and a current-mode full-wave rectifier to enhance linearity of output envelope signal. It is shown that the proposed RF envelope detector linearly tracks 5-MHz sine-wave envelope at 1.9-GHz RF carrier as well as WCDMA and WiMAX envelopes at 1.95 GHz and 2.4 GHz, respectively. The RF envelope detector was fabricated in a standard 0.18 mum CMOS technology. The active area is 0.12 by 0.12 mm 2 , and it consumes 1.8 mW of power at 1.8-V power supply.