Patent ID: 7260371

Claim:
An RF transponder comprising an antenna system characterized by: a programmable load connected to the antenna system for transmission modulation; and a power supply and level shifters connected to the programmable load, wherein voltage changes in the power supply dynamically vary a magnitude of the programmable load according to power available in the transponder; and the programmable load comprises: a plurality of first output stage transistors connected to a first terminal of the antenna system; a corresponding plurality of second output stage transistors connected to a second terminal of the antenna system; and control logic for determining which ones of the first output stage transistors and which ones of the second output stage transistors are used to modulate the antenna system, the control logic connected for modulating the programmable load, wherein the control logic has a control signal input formed in a gate by logically combining a system clock signal and a data stream; and a sync delay circuit for delaying the system clock signal in order to synchronize the system clock signal with the data stream.