An Autonomous Wireless Sensor Node Incorporating a Solar Cell Antenna for Energy Harvesting

An autonomous 3-5 GHz UWB wireless sensor node uses a single 2 x 2 cm(2) solar cell to generate up to 20 mW-peak power outdoors. The solar cell behaves as a broadband monopole antenna in the 3-10 GHz range, thus miniaturizing the overall package size. The sensor node consumes an average power of 10 mu W when transmitting 1 kb/s every minute using OOK wideband FM data bursts. Storing 2.85 J of harvested energy on a supercapacitor from the solar cell in a single charge cycle ensures more than two days of packet data transmission.