A new ultra-low-power method of communication at first glance seems to violate the laws of physics. It is possible to wirelessly transmit information simply by opening and closing a switch that connects a resistor to an antenna. No need to send power to the antenna.

 Our system, combined with techniques for harvesting energy from the environment, could lead to all manner of devices that transmit data, including and implanted , without needing batteries or other power sources. These include sensors for smart agriculture, electronics implanted in the body that never need battery changes, better contactless credit cards and maybe even new ways for satellites to communicate.
 

Apart from the energy needed to flip the switch, no other energy is needed to transmit the information. In our case, the switch is a transistor, an electrically controlled switch with no moving parts that consumes a minuscule amount of power.

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