N036 Byelka (Russian: Белка, literally Squirrel) is an advanced active electronically scanned array radar system developed by Tikhomirov NIIP for the fifth generation Sukhoi Su-57 fighter aircraft.

The radar is a part of Sh121 multifunctional integrated radio electronic system (MIRES) on board the Su-57. The N036 radar system is developed by Tikhomirov NIIP Institute and consists of a main nose-mounted X-band AESA radar with 1,552 T/R modules, designated the N036-1-01,^[1] and two smaller X-band AESA radars with 358 T/R modules mounted on the sides of the forward fuselage designated N036B-1-01. The suite also has two N036L-1-01 L-band arrays on the wing's leading edge extensions that are not only used for friend-or-foe identification but also for electronic warfare purposes. Computer processing of the X- and L-band signals enable the systems information to be significantly enhanced. It has the ability to track 60 targets and shoot 16 simultaneously, at the same time having the ability to engage 4 targets on land simultaneously altogether. The L402 "Himalayas" electronic countermeasures (ECM) suite made by the KNIRTI institute uses both its own arrays and that of the N036 radar.^[1]