Near-field RF charging pad with adaptive loading to efficiently charge an electronic device at any position on the pad

A method of charging an electronic device through radio frequency (RF) power transmission, the method comprising:

• providing a charging pad that includes a transmitter comprising at least one RF antenna, wherein the at least one RF antenna comprises:
• a conductive line forming a meandered line pattern;
• a first terminal at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by the at least one processor;
• and
• a second terminal, distinct from the first terminal, at a second end of the conductive line, the second terminal coupled to a component controlled by the at least one processor, the component configured to modify an impedance value at the second terminal;
• transmitting, via the at least one RF antenna, one or more RF signals;
• monitoring an amount of energy that is transferred via the one or more RF signals from the at least one RF antenna to an RF receiver;
• and
• adaptively adjusting a characteristic of the transmitter to optimize the amount of energy that is transferred from the at least one RF antenna to the RF receiver, wherein the characteristic is selected from a group consisting of (i) a frequency of the one or more RF signals, (ii) an impedance of the transmitter, and (iii) a combination of (i) and (ii).