Wireless power transfer versus wireless information transfer

Currently, there is not only a great need for power harvesting but also in many cases it is necessary to send information along with power over the same channel like in a RFID scenario. The goal of this paper is to illustrate that these objectives of simultaneous power transfer and information transfer are contradictory and a balance must be reached for the optimum operation. A simple example of a set of dipole antennas as transmit and receive case is used to illustrate how one can optimize simultaneously the power transfer along with information transfer over the same channel. It is important to note that the meaning of information in the colloquial language is quite different from the implication of information in information transfer. We start with the expression for the Shannon Channel capacity and illustrate how the dual goal of power and information transfer can be achieved. It is demonstrated that an optimization need to be performed for simultaneous transmission of information and power as one is carried out at the expense of the other.