REMOTE COMMUNICATION SYSTEM

摘要

A remote communication device is provided that includes an antenna configured to receive a first signal and a second signal at different frequencies and to transmit a third signal; a power circuit coupled to the antenna and configured to provide a supply voltage from the first signal; and an identification circuit coupled to the antenna and the power circuit and configured to use the supply voltage to generate the third signal. Ideally, the first and second signals are received simultaneously through a single antenna, which may also be used to transmit the third signal. Alternatively, a first antenna is used to receive the first signal and a second antenna is used to receive the second signal and transmit the third signal. In one embodiment, an energy signal is transmitted at a first frequency to a tag where it is rectified and used by the tag to receive the second signal at a second frequency and to transform the second signal into the third signal for transmission at the second frequency or at a different frequency. The energy signal may be from a parasitic source, such as wall current, existing radio waves, or from natural or artificial light.