PESA
Passive Electronically Scanned Array
Passive Electronically Scanned Array is a radar that uses a single transmitter and steers its beam electronically through phase shifters, offering faster scanning than mechanical radars but less flexibility than AESA.
A Passive Electronically Scanned Array (PESA) radar uses a single high-power transmitter to generate the radar signal, which is then distributed across the antenna array through a network of phase shifters that electronically steer the beam. This provides significantly faster beam steering than a mechanically scanned antenna, allowing the radar to track multiple targets and switch between modes more quickly.
PESA represented an important step between mechanically scanned radars and modern AESA systems. Notable PESA radars include the AN/APG-63 originally fitted to the F-15 Eagle, the Zaslon radar on Russia's MiG-31 interceptor (the first fighter PESA), and the Irbis-E radar on the Su-35 Flanker-E. These radars offered improved performance over mechanical systems but retained a single point of failure in their central transmitter.
PESA has largely been superseded by AESA technology in new-build aircraft, as AESA's distributed architecture of individual transmit/receive modules provides greater reliability (no single transmitter to fail), better electronic protection against jamming, lower sidelobe emissions, and the ability to simultaneously perform radar and electronic warfare functions. However, PESA radars remain in service on many older aircraft and some newer Russian and Chinese platforms.
Related Terms
AESA(Active Electronically Scanned Array)
Active Electronically Scanned Array is a type of radar that uses thousands of individual transmit/receive modules to steer its beam electronically, enabling simultaneous tracking and jamming across multiple frequencies.
RCS(Radar Cross Section)
Radar Cross Section is a measure of how detectable an object is by radar, expressed in square meters. A smaller RCS means the object is harder to detect.
EW(Electronic Warfare)
Electronic Warfare encompasses all military actions that use electromagnetic energy to control the electromagnetic spectrum, including jamming, deception, and electronic intelligence gathering.
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