In a breakthrough that could redefine modern warfare and wireless communication, Chinese scientists at Xidian University have developed a “smart surface” technology capable of converting enemy radar waves into usable electricity. This innovation, part of China’s aggressive push toward 6G networks, promises to make stealth aircraft self-powered by harvesting electromagnetic energy from the very signals designed to detect them. Reported widely on December 27, 2025, the development merges electromagnetic engineering with advanced communications, potentially shifting the balance in electronic warfare.
The Core Technology: Reconfigurable Intelligent Surfaces (RIS)
At the heart of this advancement lies Reconfigurable Intelligent Surface (RIS) technology—a two-dimensional array of programmable elements that dynamically manipulates electromagnetic waves in real time. Unlike traditional radar-absorbing materials that merely deflect or dissipate signals to achieve stealth, this RIS goes further by actively harvesting the energy from incoming radar beams, ambient signals, or even communication waves.
Researchers describe the surface as a “self-sustaining electronic system” that integrates three key functions: wireless information transmission, energy harvesting, and integrated sensing. In practical terms, it acts like a smart mirror for radio waves, capable of reflecting, scattering, or absorbing them while converting absorbed energy into direct current (DC) power via rectennas—rectifying antennas embedded in the surface. This all-in-one design minimizes hardware needs, slashing costs and physical space compared to separate batteries, sensors, and transceivers.
The Xidian team employed multi-agent deep reinforcement learning to optimize the RIS’s performance. AI algorithms fine-tune beamforming (directing waves precisely), robot trajectories for deployment, and RIS coefficients for wave control, enabling adaptive responses to dynamic environments like battlefields or urban 6G networks. Early simulations show efficiency rates high enough to power onboard avionics, propulsion aids, or even low-power communications without traditional fuel cells or solar panels.
Military Applications: Electromagnetic Cooperative Stealth
The most tantalizing prospect is for stealth platforms, such as China’s J-20 or J-35 fighters, which could coat their surfaces with this material to turn detection attempts into an advantage. Enemy radars, constantly probing for low-observable targets, would inadvertently supply power—fueling the jet’s systems while the RIS scatters residual waves to maintain invisibility.
This enables “electromagnetic cooperative stealth,” where multiple assets (jets, drones, satellites) network via RIS to create intentional radar dead zones. One platform absorbs and redirects waves, starving sensors downstream, while harvesting energy to sustain the group. No more bulky batteries that add weight and heat signatures; instead, perpetual operation as long as adversaries emit radar. In drone swarms or unmanned aerial vehicles (UAVs), this could extend mission durations indefinitely in contested airspace, countering jamming by self-powering anti-jam relays.
Beyond aircraft, naval vessels like China’s Type 055 destroyers could integrate RIS panels to power sensors amid electronic warfare barrages. Submarines might deploy buoyant RIS buoys that lurk near chokepoints, silently harvesting sonar-adjacent EM fields to relay intel or disrupt foes. The technology’s low profile—thin, lightweight, and deployable like wallpaper—makes it ideal for hypersonic missiles, where every gram counts.
Civilian and 6G Revolution: Powering the Wireless Future
Military uses grab headlines, but the researchers emphasize broader impacts on 6G, the Internet of Things (IoT), and smart cities. RIS could blanket urban areas as “smart walls,” harvesting stray Wi-Fi, cellular, or radar signals to power streetlights, cameras, or EV chargers—creating battery-free infrastructure.
In the Internet of Robotic Things (IoRT), robots navigate factories or disaster zones by tapping environmental EM waves for locomotion and sensing. Micro base stations, self-powered by ambient signals, extend coverage to remote areas without grid ties, vital for rural Asia or disaster response. Satellites could use orbital RIS to beam power from ground radars or solar-reflected waves, reducing launch weights and costs.
For 6G, which demands terahertz speeds and ultra-reliable low-latency, RIS solves propagation woes. It bends signals around obstacles, boosts weak links, and integrates sensing (radar-like detection) with communication—termed Integrated Sensing and Communication (ISAC). This “environment-adaptive” system adjusts in milliseconds via AI, outperforming 5G’s limitations.
| Application Area | Key Benefits | Potential Challenges |
|---|---|---|
| Stealth Aircraft | Harvests enemy radar for power; reduces RCS (Radar Cross Section) | High-power radar saturation could overload rectennas |
| 6G Networks | Self-powered relays; ISAC integration | Interference in dense urban EM environments |
| IoT/Robotics | Battery-free operation; extended range | Scalability for massive deployments |
| Smart Cities | Ambient energy for infrastructure | Regulatory hurdles for EM spectrum use |
Technical Deep Dive: How It Works
The RIS comprises thousands of meta-atoms—subwavelength patches tunable via diodes or liquid crystals. When a radar wave (microwave frequencies, typically 1-100 GHz) hits, part scatters coherently to mimic stealth, while the rest couples to rectenna circuits.
Rectification converts RF to DC: dipole antennas capture waves, Schottky diodes demodulate at high frequencies, and capacitors smooth output. Efficiency hits 50-70% in labs, per Xidian’s models, rivaling solar in bright EM fields. AI optimization uses deep learning agents: one for beam steering, another for energy allocation, coordinating via shared RIS states.
Deployment modes include:
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Passive Reflection: Standard stealth, minimal power draw.
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Active Radiation: Emits shaped beams for comms/jamming, powered internally.
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Harvesting Mode: Prioritizes energy, dims reflection for survival.
Power output scales with incident field strength— a 100 dBm/m² radar (typical search mode) yields watts per square meter, enough for a jet’s radar warning receiver. Cooling remains key, as rectification generates heat, but metamaterial designs dissipate passively.
China’s 6G Ambitions: A Strategic Edge
This emerges amid Beijing’s 6G race, where state funding pours billions into labs like Xidian, Southeast University, and Tsinghua. Unlike the U.S.’s DARPA-focused efforts or Europe’s ESA projects, China’s integrates civilian-military dual-use from inception—echoing hypersonic and quantum radar advances.
Xidian’s paper, published late December 2025, positions RIS as “optimal low-cost” for 6G, urging mass production. Prototypes reportedly tested on scale models, with field trials hinted for 2026. Globally, it pressures rivals: U.S. F-35s might need RIS countermeasures, while Qualcomm and Ericsson scramble for 6G patents.
Critics note lab-to-field gaps—real radars vary in polarization, frequency-hop, and power. Weather, angle-of-incidence, and multi-path interference could degrade harvesting. Yet, simulations using multi-agent RL show robustness, with 90%+ optimization in complex scenarios.
Global Reactions and Geopolitical Ripples
News rippled worldwide: South China Morning Post broke it, sparking defense analyses from Business Standard to Asia Times. U.S. think tanks like RAND likely reassess stealth doctrines, fearing “radar-powered” Chinese drones swarming carriers.
Europe eyes 6G civilian upsides, but NATO worries about export controls on meta-materials. India, with its own RIS research, accelerates amid border tensions. Ethical debates loom: weaponized EM harvesting could escalate arms races, blurring warfare’s energy lines.
Future Prospects and Challenges Ahead
Scaling production challenges persist—meta-atoms demand nanoscale fab, currently costly outside Huawei’s facilities. Standardization for 6G (ITU deadlines 2028-2030) requires international buy-in, tricky amid U.S. bans.
Optimistically, by 2030, RIS-coated EVs harvest road radars for range boosts; disaster robots thrive sans batteries. Militarily, it heralds “energy-dominant” warfare, where emitters feed foes.
Xidian’s team envisions “profound influence” on IoT, stealth, and 6G—propelling China ahead. As President Trump’s administration eyes Pacific deterrence, this smart surface underscores Beijing’s tech ascent.
