Turning an enemy beam into onboard electricity
In a laboratory in Xi’an, researchers at Xidian University have published a design for a thin, reconfigurable metasurface that can both manipulate radar echoes and, in a different operating mode, harvest wireless energy—effectively turning incoming radar beams into usable electricity. The paper, published in National Science Review on 3 November 2025, describes an "all‑in‑one radiation‑scattering reconfigurable intelligent metasurface" whose individual meta‑atoms combine radiating patches, a 3‑dB coupler and switchable diodes to select radiation, scattering or energy‑harvesting modes.
All‑in‑one reconfigurable metasurface
The core idea is deceptively simple: rather than treat a surface as either reflective (to hide from radar) or transmissive (to communicate), the Xidian team constructs a single programmable layer that can be reconfigured electronically. Each meta‑atom in their prototype carries a small radiating patch and a coupler loaded with PIN diodes or varactors. By changing diode states, the surface switches between producing controlled radiation patterns (useful for phased‑array transmission), scattering incoming waves to create desired echoes, or closing the path to route energy into rectifiers for wireless energy harvesting. The authors demonstrate a 12×12 array in the paper to show proof‑of‑concept performance in both communication and harvesting modes.
How radar becomes power and a communications channel
In the energy‑harvesting mode, the metasurface operates like a rectenna array: it intercepts incident electromagnetic energy, rectifies the alternating current induced in the patches, and delivers direct current to onboard systems or to recharge batteries. The National Science Review article explicitly describes how the design integrates wireless information transfer and energy harvesting (WEH), and reports laboratory measurements that confirm the surface can collect and rectify parts of an incident waveform while still functioning as a controllable scatterer in other states. That duality—simultaneous or switchable sensing, communication and WEH—is what the authors call the hardware basis for "electromagnetic cooperative stealth."
Why this matters for stealth and 6G
At stake is a conceptual reversal of a long‑standing trade‑off: stealth aircraft have been designed to avoid enemy radar energy, because that energy both reveals the platform and can overwhelm internal systems. If a surface can instead capture a portion of that energy and use it to power low‑energy payloads—sensors, communications relays, or small actuators—an attacker’s emissions suddenly become a resource rather than only a hazard. Journalists who covered the work argue the idea could reshape electronic warfare and also contribute to next‑generation 6G hardware, where reconfigurable intelligent surfaces are already being explored to improve coverage and spectral efficiency.
Laboratory result versus airborne reality
Despite the dramatic headlines, the Xidian paper and subsequent reporting are careful to note the gap between tabletop demonstrations and integration into an operational fighter. The prototype array used by the researchers is a laboratory‑scale 12×12 element surface; scaling to square metres of conformal aircraft skin, surviving high temperatures, aerodynamic strain, and maintenance cycles—while keeping weight, reliability and stealth characteristics acceptable—presents a suite of engineering challenges. The energy densities available from radar emissions at operational standoff ranges are low; harvested power drops quickly with distance and depends on the emitter’s frequency, beam focus and duty cycle. The authors present a framework and hardware building blocks, not a ready‑to‑fly power system.
Practical constraints and tactical trade‑offs
Two immediate technical realities temper the near‑term threat. First, power conversion efficiency for rectennas is highly frequency and input‑power dependent: when incident power is weak or intermittent, rectifiers and matching networks struggle to deliver useful DC without large, heavy capture areas. Second, actively manipulating scattering and radiating behavior risks producing signatures that counter‑radar systems can exploit—switching into a transmit‑oriented state could betray an aircraft’s presence or direction if done improperly. In short, exploitation of enemy radar requires careful control logic and robust countermeasures against adversary detection and spoofing. These trade‑offs are intrinsic to any system that seeks to balance concealment, exploitation and communication.
Where this fits in a broader Chinese research push
The Xidian work arrives amid multiple, parallel Chinese research threads in electronic warfare and stealth technologies. Recent reporting has highlighted Chinese teams working on plasma‑based stealth, ultra‑thin radar‑absorbing coatings, and single‑photon detectors suited to quantum radar concepts—each of which aims to change the balance between hiding and sensing in different ways. Those projects illustrate a broader strategic effort to master both sides of the radar problem: stealth to reduce detectability, and new sensing and counter‑sensing tools to defeat adversary stealth. The metasurface concept is distinctive because it attempts to combine sensing, communications and power in a single surface, rather than treating them as separate subsystems.
Implications for policy and procurement
From a defence‑policy angle, the paper underlines why electronic warfare and radio‑frequency research deserve sustained attention and funding. If adversaries field metasurfaces that can opportunistically harvest energy from radar, doctrine and tactics will have to adapt: sensors will need to discriminate between innocent, benign returns and adversary surfaces actively exploiting emissions, and rules of engagement for emissions control may change. On procurement, aircraft integrators will weigh whether to embed reconfigurable skins that provide communications and energy advantages—but only if they meet strict reliability, signature and survivability requirements. That evaluation will be long and multidisciplinary, combining RF engineering, materials science, thermal management and systems‑level safety analysis.
Next steps and the research horizon
The Xidian team suggests several follow‑on directions in the paper: larger arrays, integration with phase‑change materials for more robust control, and tighter co‑design of the electronic control layer with antenna physics to suppress undesirable grating lobes. Independent verification and airborne demonstrations would be the next hard milestones industry and defence observers will watch for; until then, the work should be read as an important, credible laboratory advance that maps a new set of possibilities rather than an immediate battlefield capability.
Sources
- National Science Review (research paper: "Electromagnetic all‑in‑one radiation‑scattering reconfigurable intelligent metasurface")
- Xidian University (Key Laboratory of High‑Speed Circuit Design and EMC of Ministry of Education)
- South China Morning Post (reporting on Chinese smart surface and related EW developments)
