Stealth aircraft, such as the F-22 Raptor or the F-35 Lightning II 5th generation jets are equipped with Luneburg (or Luneberg) lenses: radar reflectors used to make the LO (Low Observable) aircraft (consciously) visible to radars. In fact, tactical fighter-sized stealth aircraft are built to defeat radar operating at specific frequencies; usually high-frequency bands as C, X, Ku and S band where the radar accuracy is higher (in fact, the higher the frequency, the better is the accuracy of the radar system). However, once the frequency wavelength exceeds a certain threshold and causes a resonant effect, LO aircraft become increasingly detectable. For instance, ATC radars, that operate at lower-frequency bands are theoretically able to detect a tactical fighter-sized stealth plane whose shape features parts that can cause resonance. F-35s deployed abroad usually feature their typical four radar reflectors: to exaggerate their real RCS (Radar Cross Section) and negate the enemy the ability to collect any detail about their LO "signature".

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