A Low Complexity and Accurate Battery-Less Trackable Device

In this work, a low complexity battery-less device able to feedback the transmitter with its Received Signal Strength (RSS) is proposed. The system operates at 5.8 GHz for wireless power transfer and 3.45 GHz for a pilot signal that is modulated and backscattered from the device back to the transmitter. This device is intended to operate with any controllable scanning array by adding to it a pilot signal generation and monitoring system. It will be shown that a conventional low cost ring oscillator, attached to the device, will convert some of the rectified energy into a backscattered pilot signal with a certain frequency modulation. Experimental results on a prototyped device are reported indicating good tracking accuracy and power consumptions below 16% of the available input power.