Abstract: An RF power system, includes, in part, a power generating and a controller. The power generating unit, includes, in part, a first power detector adapted to detect a first amount of RF power radiated by the RF power generating unit and reflected off a living organism. The controller is adapted to reduce the radiated RF power if the first amount of RF power reflected by the living organism is detected as being greater than a predefined amount. The power generating unit may further include a Doppler radar to detect the living organism. The RF power system may further include a power recovery unit that, in turn, includes a second power detector adapted to detect a second amount of RF power radiated by the RF power generating unit and reflected off the living organism.

Abstract: A wireless power generating unit, includes, in part, a multitude of transmitting elements transmitting a multitude of RF signals to a wireless device, a backscatter RF receiver configured to receive the backscattered RF signal from the wireless device in response to the transmission of the RF signals, and a processor adapted to change the phases of the multitude of RF signals values in accordance with the strength of the received backscattered signal. The phases are changed to maximize the strength of the backscattered signal which may be modulated by varying a resistive load at the wireless device. The modulated backscattered signal may be encoded to carry information. The modulation frequency may be representative of the identity of the wireless device. The information may define the amount of RF power received by the wireless device.