The Chinese will still need to overcome major hurdles in order to get the system out of the laboratory and onto the battlefield.
China claims to have revealed a prototype of an advanced quantum radar that is resistant to jamming and may be able to detect stealth aircraft. The system's operation is rooted in proven science and could be game-changing, but the Chinese still face significant development challenges in turning it into an operational capability.
The state-owned China Electronics Technology Group Corporation (CETC) brought a mockup of their quantum radar, which might have also been only a smaller scale model, to the biennial Zhuhai Airshow, which opened its doors on November 6, 2018, and has a wide array of military technology on display. CETC says that its 14th Research Institute has been working on the system for years and first tested it in 2015.
A quantum radar does essentially the same thing, but using photons that are “entangled” together after a single beam of light is split in half. One of the two new beams passes through a converter that sends the particles traveling onward at a microwave frequency to bounce off objects like a normal radar. The full system would convert the particles back into the visible frequency as they returned to the radar’s receiver.
The second beam doesn’t do much actively, but serves an immensely important purpose. A phenomenon called quantum entanglement means that the pairs of photons that appear at the point a beam of light is split otherwise have a tendency to operate identically regardless of how far they are apart.
What this means is that the quantum radar should be able to register the paired photons in both streams and record only the signals it gets back from particles that have a partner. This would make the system more accurate since it would be able to quickly eliminate signals from other sources, such as ground clutter when tracking targets at low altitude or operating in a maritime role.