2.45 GHz power and data transmission for a low-power autonomous sensors platform

This paper describes a power conversion and data recovery system for a microwave powered sensor platform. A patch microwave antenna, a matching filter and a rectifier make the system front-end and implement the RF-to-DC conversion of power carrier. The efficiency of the power conversion is as high as 47% with an input power level 250 /spl Omega/W at 2.45 GHz. Then, a 0.18 /spl Omega/m CMOS integrated circuit extracts the clock and the digital data. A modified pulse amplitude modulation scheme is used to modulate the data on the 2.45 GHz carrier frequency for combined data and power transmission; this scheme allows very low power consumption of the entire IC to be less than 10 /spl Omega/W and making the system suitable for an autonomous wireless connected sensor module.