China’s new carrier based AWAC can detect stealth planes from over 200 miles away

China is building its first carrier-borne early-warning plane called the KJ-600.

Above is the KJ-600

The KJ-600 would be fitted with an advanced active electronically scanned array, or AESA, radar which could enable it to spot stealth aircraft such as US F-22s and F-35s. The new surveillance plane could also become a command center in the air.

It is very similar to the E-2 Hawkeye, the US’ all-weather, carrier-capable tactical airborne early-warning aircraft.

Advanced Hawkeye’s built by Northrop Grumman

China and Russia already have AESA (Active Electronically Scanned Array) radar, which emits separate radio waves on different frequencies, on Navy ships. By rapidly changing frequencies, the radar is more difficult to fool. The system are apparently capable of locating a stealth aircraft within 220 miles.

“It is the physics of longer wavelength and resonance that enables VHF and UHF radar to detect stealth aircraft,” Westra wrote in his article, titled “Radar vs. Stealth.”

operate at frequencies between 300 MHz and one GHz, which results in wavelengths that are between 10 centimeters and one meter long. Typically, due to the physical characteristics of fighter-sized stealth aircraft, they must be optimized to defeat higher frequencies in the Ka, Ku, X, C and parts of the S-bands.

There is a resonance effect that occurs when a feature on an aircraft — such as a tail-fin tip — is less than eight times the size of a particular frequency wavelength. That omnidirectional resonance effect produces a “step change” in an aircraft’s radar cross-section.

Effectively, what that means is that small stealth aircraft that do not have the size or weight allowances for two feet or more of radar absorbent material coatings on every surface are forced to make trades as to which frequency bands they are optimized for.