Russian PAK FA Stealth Fighter Jet

The PAK FA SH121 radar complex includes three X-Band AESA radars located on the front and sides of the aircraft. These will be accompanied by L-Band radars on the wing leading edges. L-Band radars are proven to have increased effectiveness against very low observable (VLO) targets which are optimized only against X-Band frequencies, but their longer wavelengths reduce their resolution. However the initial prototypes will use legacy passive electronically scanned array radar.