Far-Field RF-Powered Variable Duty Cycle Wireless Sensor Platform

This brief discusses a low-power wireless sensor based on commercial components for sensing and data transmission. The sensor is wirelessly powered from the far field through an integrated single or dual-polarization antenna, rectifier, and power management module. Since the unit is intended for mobile use, the variable available power is monitored, and the duty cycle for wireless data transmission adaptively adjusted through the use of a low-power microcontroller and a custom power management circuit. In sleep mode, the circuit consumes 1 μA at 2.5 V.