South Korea's KF-21 with self-produced phased array radar
On March 4, 2022, South Korea's Defense Acquisition Program Administration (DAPA) announced that the KF-21 Falcon Fighter Aircraft No. 003 prototype took off from the Air Force's 3rd Flight Training Wing base in Sacheon, located about 300 kilometers south of Seoul, at 10:00 a.m., completing an 84-minute flight, which was the first time that the Korea's domestically produced active electrosweep phased array (AESA) radar was tested on the KF-21, and the flight test met all requirements.
The Koreans themselves have no active phased array radar development capability, so after the KF-X program was proposed, the Koreans' first thought was to ask for help from U.S. companies.
Because the South Korean Air Force has purchased 40 F-35As under a 2014 contract signed by the two Koreas, one of the main terms of the contract includes technology transfer, with four of the items categorized as "core technologies" required for the development of the KF-21, including the active electronically scanned (AESA) radar, AESA radar, radar (RF) jammer, electro-optical targeting pod (EO-TGP) and infrared search and tracking (IRST) system.
Lockheed Martin, an official partner in the KF-X program, had promised to transfer these technologies, but the U.S. Congress banned them as too sensitive. The South Koreans in this case will have to rely on indigenous research and development or acquire advanced radars through partnerships with international partners.
Development of the AESA radar for the KF-21 (formerly KFX/IFX) began in 2016 by Hanwha and the Defense Development Agency, a research and development agency under the South Korean Ministry of National Defense, with the South Koreans opting to import the technology and partner with Israeli company Elbit Systems, which was involved in the production of the radar prototype, as well as the airborne testing phase. The first AESA radar prototype was displayed on August 7, 2020 and sent to Israel for ground and flight testing.
Hanwha then used a Boeing 737-55S narrowbody (registration ZS-TFJ, serial number MSN26541) airplane using South Africa's Paramount Aerospace Systems as a flight test bed. The aircraft is actually a Boeing 737-500 with a KF-21 radome modified in the nose, containing a radar prototype, ancillary equipment, test equipment, etc., and is capable of sustained flights of 4-5 hours.The test budget is estimated to be approximately 60.1 billion won ($50 million) and will involve evaluating the radar's air-to-air, air-to-surface, and air-to-surface modes.10 flights were conducted in November and December 2021 through the flights overseas to complete the radar's function and performance tests.
In March 2022, DAPA announced that the ZS-TFJ had undergone localized performance test trials in South Korea, as well as multiple flights over the Yellow Sea, and 18 flight tests between November 2022 and February 2023, focusing on 25 tests in air-to-air mode.
The South Korean domestic trials, which will continue until April 2023, have tested some 62 items through a total of ***50 flights, testing detection and tracking functions in air-to-air mode, as well as synthetic aperture radar (SAR) functions to identify/avoid unforeseen operational risks through software optimization.
In 2023, the radar will be fitted to the KF-21 fighter jet, and through 90 flights from March 2023 to February 2026, it will be geared towards testing 34 items such as maximum detection range, tracking range and accuracy in air-to-air mode, conducting developmental and operational test evaluations to ensure operational performance validation, checking that it meets the requirements of military operations and the force's deployment of security elements The practicality of the
The phased-array radar for the KF-21 fighter, developed by South Korea's Hanwha, is X-band, with an aperture guessed at 700 millimeters, carries about 1,000 transmitting/receiving gallium nitride (GaN) components, and electronically controls the beams by adjusting the phase of the radar waves, which are cooled by a radar demonstrator at 7.7 kilowatts.
The radar is powered by Hanwha Systems for the hardware and LIGNex1 for the software, notably the AESA radar's antenna, semiconductor transmitter/receiver module, and other key components can be reused 100% for MFR radars with the same frequency bands, which helps to reduce costs. The Koreans claim that its radar metrics are better than the AN/APG-83.
To develop this radar, a lot of domestic efforts have been made, such as the establishment of South Korea's first AESA radar rooftop lab and near-field test site, which verifies the radar's performance under the antenna cover by setting up a test environment, as well as the ability to perform simulated or actual target surveillance and tracking and OFP verification, and its radar is equipped with six Degree of Freedom Swing Test Bed as a way to simulate different angles of a fighter jet.
South Korea is producing six prototypes, which will undergo some 2,241 test flights. The ROK Air Force (ROKAF) 52 Test and Evaluation Team will select 17 pilots and 10 ground crew members to work at Sacheon Air Base, where KAI is headquartered.
The main reason why the South Koreans have continued to release information throughout the test flights is to show off their technical prowess and attract foreign trade orders.
After all, competition for fighters in the KF-21 class is still fierce. What's more, 65 percent of the KF-21's total **** components are made in South Korea, and the breakthrough mission and flight control computers, AESA radar, electronic warfare equipment, infrared search and tracking sensors, and electro-optical targeting pod production technology will also benefit South Korea's defense industry, and its mass production will also create 10,000 new jobs, with many benefits!