Clearly an AESA derived from the experience that Elta had with the 2052 AESA radar. However, this one is a GaN based AESA.
ADD, Hanwha Close To Testing KF-X Radar Prototype
Bradley Perrett Kim Minseok March 23, 2020
SEOUL, BEIJING—Radar development for the Korea Aerospace Industries (KAI) KF-X is moving toward production of a prototype, following evaluation of a technology demonstrator in Israel and South Korea.
The program, led by the government’s Agency for Defense Development (ADD), is planning to ground test the production-representative prototype by the end of May, manufacturing subcontractor Hanwha said.
Since Elta worked on the technology-demonstration phase, that company may also be supporting full-scale development, which appears to have begun in May 2019 when the intended production sensor passed its critical design review. Hanwha is also contributing to development.
A terrain-following mode, formerly a notable omission from the sensor’s capabilities, is reportedly being added. No name for the radar has been published.
Radar development is 50% complete, Hanwha researcher Hong Yoon-Sung told the Chosun Ilbo newspaper, adding that the prototype would be tested within months.
A prototype radar is due to be fitted in a KF-X for flight tests in 2023. Development is scheduled for completion in 2026, the year in which deliveries of the fighter are supposed to begin.
Software for air-to-air and air-to-surface modes is due to be developed by October 2021.
The design includes an active electronically scanned array (AESA) and, according to a government research institute statement in 2014, gallium-nitride components. In several countries the latter are superseding gallium-arsenide technology, formerly the standard for AESAs. The demonstrator also uses gallium-nitride technology, according to the South Korean news outlet Today Defense.
Cooling power provided to the demonstrator radar is 7.7 kW, Hanwha said. This is a hint at its maximum average output power, which is related to cooling power according to the overall efficiency of the system—though guessing that efficiency requires several difficult assumptions. Analyzing the gallium-arsenide Northrop Grumman APG-83 radar, Hellenic Air Force researchers last year worked on the basis of 5.6 kW cooling and found an average antenna output of up to 1 kW. So the South Korean demonstrator should exceed that figure.
Hanwha said in November that evaluation of demonstrator hardware had been completed. This leaves open the possibility that demonstrator software is still being worked on.
The demonstrator radar was installed in an Elta-owned Boeing 737 testbed and flew 10 times in Israel and six times in South Korea, the ADD said in October. Elta was chosen in 2017 to support the demonstration phase. The demonstrator includes an antenna and software from the ADD and Hanwha and signal processors and software from Elta.
But South Korean officials and industry leaders have a strong tendency to play up the role of indigenous engineering work and downplay the extent of foreign support. It would not be surprising, therefore, if Elta helped in design or at least refinement of the demonstrator. Similarly, the Israeli company may be quietly helping, or standing by to help, with development of the production sensor.
South Korea has not developed a fighter radar of any sort before, let alone one with an AESA and gallium-nitride technology.
In December the ADD announced a contract with Hanwha to add the terrain-following function. Pictures and models of the KF-X have previously shown it with a navigation pod, like the U.S. AAQ-13, implying that the radar lacked terrain following, which is used for low-altitude flight.
Using the pod brought significant disadvantages: loading the aircraft with additional weight and drag; and transmitting at a higher, and therefore more detectable, power level than would be necessary if the much larger nose array were used.
A video presentation made by Hanwha shows the demonstrator radar was tested in three air-to-air modes: all-aspect search and track, nose aspect search and track, and air combat maneuvering. Tested air-to-surface modes were stationary and moving target indication, synthetic aperture, ranging and air-to-sea.
The demonstrator also has no known name.
In winning KF-X radar work, Hanwha beat LIG Nex1, which had done preliminary development at its own expense and had worked on fitting foreign radars to aircraft of the Republic of Korea Air Force. Despite the setback, LIG Nex1 is persisting with developing a radar at company expense for other aircraft.