Stanford University researchers have demonstrated how thermal noise, the background static generated by electron vibrations in electrical conductors, can be harnessed to transmit data without an actively generated signal. The findings, published in the Proceedings of the National Academy of Sciences and reported on October 19, 2026, explain the fundamental working principles of thermal noise communication, a technology that could enable energy-efficient wireless systems for applications requiring small amounts of data.
The research team sought to develop low-power communication methods for applications such as agricultural sensing, where devices need to transmit information such as soil moisture levels. Senior author Zerina Kapetanovic, an assistant professor of electrical engineering at Stanford, was inspired by radio-frequency identification (RFID) tags used for highway toll collection and explored whether similar functionality could be achieved without an energy-intensive radio signal.
Thermal noise is produced by the vibrations of electrons in electrical conductors, with particle movement varying according to temperature. Although Kapetanovic’s initial experiment successfully transmitted information from a transmitter to a receiver, the system worked even when both devices and their surroundings were at room temperature. This raised the question of how the system could generate distinguishable noise patterns without temperature differences.
At Stanford, Kapetanovic worked with graduate students Geneva Ecola and Jida Zhang, co-first authors of the study, and Professor Joseph Kahn of electrical engineering to investigate the mechanism. The researchers constructed a densely insulated chamber to block external signals and placed a transmitter and receiver on a testbed that allowed them to adjust the distance between the devices.
The transmitter, equipped with an antenna, switched between two types of electrical circuits—an open circuit and a short circuit—representing the binary values one and zero. The receiver amplified the thermal noise reflected by the antenna to detect the transmitted information.
The team found that switching between the circuits created noise frequencies that appeared “hotter” or “colder” to the receiver, allowing the system to distinguish between binary values without actual temperature changes. At the receiver, an amplifier acts like an electron refrigerator, slowing electrons and making the thermal noise appear colder. Meanwhile, the transmitter alternates between absorbent and reflective states, changing the apparent temperature of the reflected noise.
Professor Kahn explained that the transmitter modulates the signal between hotter and colder states without physically cooling anything, functioning simply as a reflector. He compared the process to a castaway using a hand mirror to reflect sunlight as a means of communication.
Using their experimental results, the researchers developed a channel model defining the fundamental variables governing the system. Such models are essential for designing and optimizing wireless communication networks. Based on the model, the team refined its experimental setup and improved the data transfer rate by 100 times.
The researchers are now investigating how to connect multiple transmitters into a network and prevent signals from being lost in noisier environments outside the insulated chamber.
Thermal noise communication could be useful in applications where power is limited and only small amounts of data need to be transmitted. According to the researchers, conventional radio-frequency transmitters can consume up to 1,000 times more energy to send information than transmitters using thermal noise. The approach could also reduce interference from actively generated signals, making it potentially suitable for use alongside equipment sensitive to electromagnetic radiation, including medical devices and astronomy observatories, as well as environmental sensing systems.
Ecola said: The team hopes the unconventional communication system will enable wireless communication in settings where existing approaches have been difficult to use. The findings provide a foundation for further improving the technology and exploring its practical applications.