The primary sensor of the modern fighter remains the radar. Up until the 1980s operating a radar effectively required a great degree of skill; today’s digital radars are simple to use, long-ranged and harder to jam than ever. As well as detection, modern sets can be used to jam, communicate and collect information about enemy sensors and communications. In the future AESAs will even be able to ‘fry’ enemy radars by overloading them with radio energy. That aircraft like the Rafale and Super Hornet are equally adept at the air superiority and ground attack missions has a great deal to do with the extreme versatility of the contemporary radar, which can simultaneously scan the air for fighters as it looks for ground targets. There are two types of fighter radar, mechanical- and electronically scanning. The latter can be divided into three categories: passive scanning, active scanning and ‘hybrid tilters’. The passive electronically scanning array radar (PESA) have a single radio source that sends energy to multiple receive/transmit modules. The PESA is relatively simple to create, but not as versatile as the AESA. The first PESA fighter radar was carried by the MiG-31, which entered service in 1981. The active electronically scanned array (AESA) also uses multiple modules but each can send a different radio signal (different in frequency or direction) allowing a greater degree of versatility, and making the radar harder to jam. The first frontline fighter to carry an AESA was the Mitsubishi F-2, though the Raytheon APG-63(V)2 for the US’ F-15C beat the type into full operational service in 2000. One of the limitations of AESA in the fighter role is that the signal is weaker at extreme fields of regard – a AESA can only see well at up to 60 degrees to the side. This issue will be addressed in the new hybrid tilting radars for the Typhoon and Gripen E/F which are AESAs mounted on tiltable plates. Russia’s PAK FA will also address the ‘field of regard’ issue with cheek-mounted arrays (additional to the AESA in the nose). However- neither the new Gripen E/F, Typhoon or PAK FA radar have entered service so do not make this list.
Radar performance is an extremely sensitive subject with security implications, so most of the important data is classified- but a broad understanding of capabilities can be described from open sources. The order is meaningful, but certainly not definitive: adhering to the top 10 format always requires a simplification. Much is open to interpretation so I am happy to receive corrections and additional information from reputable sources