A room-temperature microwave platform uses correlated radio-frequency signals to strengthen secure communications while opening new possibilities for radar, sensing, and quantum electronics.
MIT researchers have developed a compact electronic platform that can generate strongly correlated microwave signals at room temperature, potentially removing a major barrier to practical quantum-inspired wireless communication, radar, and sensing systems.
The technique replaces the cryogenically cooled superconducting circuits traditionally used to generate correlated microwave signals with a hybrid system built around a magnetic film and a microwave resonator. The device can split an incoming microwave signal into two synchronized outputs with different frequencies. Because the signals remain strongly correlated despite appearing random individually, one can act as a transmission signal while its partner serves as a decoding key.
Conventional approaches often rely on Josephson junctions integrated into superconducting circuits. Such systems can generate tightly correlated microwave photons, but they require extremely low temperatures and bulky cryogenic equipment, increasing system complexity, energy requirements, and cost. MIT’s approach instead exploits magnetic excitations known as magnons, allowing the correlated signals to be generated without cryogenic cooling.
At the heart of the new device is a magnetic film placed inside a metal microwave cavity. By controlling the energy supplied to the system, the researchers created hybrid magnon-photon waves. This interaction separates the otherwise overlapping pair of correlated magnons into distinct microwave frequencies. The resulting signals remain synchronized while their individual frequencies vary randomly.
The researchers demonstrated the security concept by encoding a small image into one microwave signal. The information could be recovered only by using its correlated partner, effectively making the second signal function as a key. The architecture could therefore support communication systems designed to resist noise and unauthorized interception.
Beyond secure wireless links, the technology could enable high-precision radar capable of detecting faint signals, quantum-limited sensing, hardware random-number generation, and correlation-based signal processing. Room-temperature operation could also make quantum simulators more scalable and less expensive. The researchers now aim to develop a scalable architecture and investigate additional applications of correlated microwave signals.
