Turning Radar from Threat to Resource
For decades, military aircraft have relied on stealth technology to evade detection by enemy radar. The basic principle involves shaping the aircraft fuselage and applying special radar-absorbing materials to scatter or soak up incoming radio waves, preventing them from bouncing back to the receiver. Now, researchers in China have proposed a radical evolution of this concept. Instead of merely deflecting or dissipating radar energy, their new technology aims to capture it and convert it into usable electrical power. This development, rooted in advanced electromagnetic engineering, could fundamentally alter the dynamics of electronic warfare and the future of wireless communications.
The research, led by a team at Xidian University, focuses on a self-sustaining electronic system that merges wireless information transfer with energy harvesting. In practical military scenarios, this could allow a stealth jet to absorb the radar beam locking onto it and use that energy to power onboard propulsion, sensors, or communication systems. This creates a scenario where the act of detection by an enemy inadvertently provides the target with the energy needed to operate or evade.
The Science Behind Reconfigurable Intelligent Surfaces
At the core of this innovation is a technology known as a reconfigurable intelligent surface, or RIS. While traditional stealth relies on passive materials fixed during manufacturing, an RIS is a dynamic, two-dimensional structure composed of hundreds or thousands of tiny, programmable elements. These elements can manipulate electromagnetic waves in real-time, altering properties like phase and amplitude to control how the signal reflects or absorbs.
Researchers describe this RIS architecture as a low-cost and highly programmable solution for future wireless networks. Unlike standard antennas that require significant power and hardware to generate signals, an RIS primarily modifies existing signals in the environment. By drawing power from radar or other environmental signals, the surface can operate without the need for traditional batteries. Current prototypes demonstrate the ability to perform beam steering up to plus or minus 45 degrees with low side lobes. This precision allows the system to improve signal coverage in scenarios where a direct line-of-sight is obstructed by physical barriers, a common challenge in urban environments and complex terrain.
Simultaneous Information and Power Transfer
The researchers introduce a concept described as RIS-assisted simultaneous information and power transfer. In simple terms, this means the same electromagnetic signal can be used for both communication and energy harvesting. Radar signals, satellite links and communications transmissions already saturate military and civilian airspace. Rather than treating this electromagnetic environment purely as interference or a threat, the study argues it could be treated as a valuable resource.
In the proposed model, an intelligent surface captures incoming signals and routes part of the energy to an internal harvesting circuit. The remaining signal is then manipulated for communication or signal control purposes. The paper stresses that this process is passive in nature. The surface itself does not emit detectable signals, an important consideration for low-observable platforms trying to remain hidden from electronic support measures.
Electromagnetic Cooperative Stealth
The research outlines a vision for what the team calls electromagnetic cooperative stealth. This concept moves beyond the idea of a single aircraft hiding in isolation. Instead, it involves multiple networked platforms working in coordination to reduce their overall radar cross-section and visibility to sensors. By sharing data and dynamically adjusting their RIS coatings, a formation of drones or aircraft could theoretically create blind spots or confuse enemy tracking systems more effectively than they could individually.
In the case studies, by jointly optimizing parameters such as transceiver beamforming, robot trajectories, and RIS coefficients, solutions based on multi-agent deep reinforcement learning and multi-objective optimization are proposed to solve problems such as beamforming design, path planning, target sensing, and data aggregation, said the researchers in their paper.
This cooperative approach extends to multi-asset formations, enhancing collective invisibility across the radio frequency spectrum. The team suggests that this architecture will eventually enable environment-adaptive integrated sensing systems, where the platform reacts intelligently to the specific threats it encounters in real-time.
Implications for 6G Telecommunications
While the military applications capture the imagination, the researchers emphasize that the technology has profound implications for civilian infrastructure, particularly in the development of 6G networks. Many scientists believe the biggest leap in next-generation wireless communication will come not just from faster chips, but from rethinking how signals travel through the environment. A major focus of 6G research is precisely these reconfigurable intelligent surfaces.
For telecommunications, the surface promises 6G breakthroughs like integrated sensing and powering for satellites or base stations. The hardware platform integrates data transmission and radar-like functionality to optimize the use of spectrum and hardware resources. By jointly manipulating scattered electromagnetic waves and actively radiated signals, the system reduces the physical space and hardware costs typically required for such multifunctionality. This could lead to micro base stations that are easier to deploy and more energy-efficient than current cellular towers.
Supporters of the technology say 6G could blur the line between the physical and digital worlds, enabling applications such as holograms, digital twins and large-scale Internet of Things networks. In such an environment, devices fitted with intelligent surfaces could continuously collect small but meaningful amounts of power from ambient transmissions, potentially extending battery life or enabling entirely self-powered sensors.
Security and Anti-Jamming Capabilities
Beyond energy harvesting, the versatile nature of RIS technology offers significant advantages in network security. The surface can be configured to create intentional radio dead zones, a feature that helps mitigate signal interference and reduces the risk of electronic eavesdropping. By selectively blocking signals in specific areas, secure facilities could prevent data from leaking out or unauthorized signals from penetrating in.
Previous research cited in the study indicates RIS could also be used in anti-jamming technology, unmanned aerial vehicle communication and radio surveillance. These are areas where older optimization tools often struggle. The European Space Agency has further highlighted RIS as a candidate technology for satellite-to-ground communications, where controllable reflection and redirection of signals could help route links around physical obstacles like mountains or tall buildings.
Researchers from Fudan University, the University of Sydney and the Commonwealth Scientific and Industrial Research Organization note that, when combined with artificial intelligence, this technology could significantly enhance the security of air-to-ground Internet of Things links. This makes the technology relevant not just for stealth fighters, but for the vast ecosystem of connected devices expected to populate the smart cities of the future.
Challenges and Limitations
Despite the promising potential, the researchers are explicit about the current limitations of the technology. The study primarily presents a theoretical and experimental framework rather than a deployed weapon system. Significant challenges remain in materials science, durability, control electronics and the complexity of real-world electromagnetic environments.
Harvested power levels are currently modest. While the concept of powering a jet engine solely from radar beams remains science fiction for now, the energy could be sufficient for low-power avionics, sensors or communication buffers. Integrating such systems onto fast-moving platforms like jets or missiles would require further breakthroughs to withstand extreme aerodynamic forces and temperature variations.
Furthermore, the efficiency of energy conversion depends heavily on the frequency and intensity of the incoming signal. While higher-frequency 6G signals carry more concentrated energy, current radar systems operate at varying bands that may not be optimal for harvesting. The researchers are careful not to overstate the effect, noting that radar illumination becoming counterproductive is a conceptual shift rather than a near-term operational reality.
Global Race for 6G Dominance
The development of this technology occurs against the backdrop of an intense global race to define and dominate 6G standards. The United States and China are competing fiercely to build space-based data centres and advanced wireless infrastructures that could support artificial intelligence and future connectivity. China’s lead in RIS research could accelerate its ability to deploy reconfigurable networks, improving coverage in non-line-of-sight scenarios where traditional 5G networks struggle.
By including sensing, communication and power into one hardware platform, the device could allow for a range of advanced applications while reducing eavesdropping and interference. If successful, this technology could strengthen China’s position in the global tech race while also reshaping how future stealth and communication systems interact with the electromagnetic world.
The Bottom Line
- Chinese researchers developed a smart electromagnetic surface capable of converting ambient radar waves into electrical power.
- The technology uses reconfigurable intelligent surfaces (RIS) to manipulate waves in real-time without traditional batteries.
- Applications include powering stealth aircraft systems using enemy radar beams and enhancing 6G telecommunications.
- The system supports electromagnetic cooperative stealth, allowing multiple platforms to reduce their detectability together.
- Prototypes can perform beam steering up to plus or minus 45 degrees and create intentional radio dead zones for security.
- Challenges remain regarding power efficiency, materials durability and integration into fast-moving military platforms.
