Before dawn on Feb. 28, the United States and Israel launched Operation Epic Fury, a large-scale air campaign against Iranian territory. One of the central tasks in the opening phase was neutralizing Iran's layered air defense network, which included Russian-built S-300 systems. What drew attention was not only the destructive power of missiles and bombs. It was the unseen domain of Electromagnetic Spectrum Operations (EMSO) and the role of the stealth fighters and electronic warfare assets capable of carrying them out. U.S. forces committed a range of electronic warfare and intelligence, surveillance and reconnaissance assets to the operation, including the F-35, the EA-18G electronic warfare aircraft, the EC-130H and the E-2D airborne early warning and control aircraft.
The true value of the F-35 lies not simply in a stealth airframe that reduces radar cross section (RCS). The key is that its high-performance AN/APG-81 AESA radar and AN/ASQ-239 integrated electronic warfare system operate within a single sensor-fusion architecture. The AN/ASQ-239 is designed to detect, identify and track enemy radar signals, analyze threat data and carry out electronic countermeasures and jamming. The U.S. F-35 Joint Program Office likewise describes the system as integrating radar warning, targeting support, threat detection, and electronic countermeasures and jamming.
The AN/APG-81 AESA radar carries 1,676 transmit/receive (T/R) modules. Because AESA designs steer the beam rapidly through electronic control of each module, they allow faster and more flexible detection and electronic warfare than mechanically scanned antennas. What matters is that this radar is not merely a target-detection device but is combined with electronic warfare functions. In other words, the F-35 does not operate its radar and electronic warfare equipment as separate systems. It is a platform that fuses information gathered from multiple sensors to build a picture of the battlefield and execute the electronic responses required.
When small air-launched decoy systems such as the ADM-160 are combined with various intelligence and surveillance assets, the result is a composite electromagnetic spectrum operation that lures enemy air defense radars, maps the location and operating characteristics of those systems, and improves the survivability of strike packages. Debris that appears to be from an ADM-160 MALD was recently identified in Iran, prompting analysis that such decoy systems may have been used during Epic Fury. The precise origin of the debris and the manner of its use, however, have not been publicly confirmed.
More important is the combination of stealth and passive sensing. The F-35 can detect the surrounding electromagnetic environment and identify enemy emitters through its electronic warfare system and various sensors without continuously radiating with its own radar. This allows it to secure situational awareness while reducing the chance of revealing its presence to the enemy. The F-35's electronic warfare system is designed to support the detection, identification and geolocation of threat signals, as well as sensor fusion.
Electrical power and cooling capacity are also important variables in advancing these electronic warfare and sensor capabilities. The F135 engine provides the power and thermal management the F-35 requires, and an Engine Core Upgrade (ECU) is underway to expand that power and thermal management capacity in order to accommodate the new sensors, weapons and electronic warfare capabilities coming with Block 4.
Once the AN/APG-85 radar is established as a core component of Block 4 modernization, the F-35's sensor and electronic warfare capabilities are expected to grow further. Much of the APG-85's detailed performance and semiconductor configuration has not been disclosed, however, so it is reasonable to treat specific output, detection range or electronic attack capability as a prospect for future improvement rather than to state them as fact. U.S. military documents also present the APG-85 as a major component of the Block 4 upgrade.
How, then, should South Korea — which is developing the 4.5-generation KF-21 fighter and already operates the fifth-generation F-35A — respond to this shift in the battlefield paradigm?
The South Korean military currently faces several challenges: the continuing upgrades and cost burden of the F-35A, dependence on foreign sources for core technologies, and the increasingly sophisticated AESA radar networks of neighboring countries. Four core strategies are needed to break through.
First, the country must secure its own electromagnetic spectrum intelligence and databases. An independent intelligence system must come first — one that continuously collects and analyzes signals from the radar and communications systems of neighboring countries and that can rapidly feed newly identified threat data into operational assets.
Second, South Korea must develop a layered concept of electromagnetic spectrum operations that links a domestically built electronic warfare aircraft, responsible for long-range wide-area electronic attack, with KF-21 variants and the F-35A capable of penetrating deep into enemy territory. What is required goes beyond electronic warfare aircraft and fighters each carrying out their own missions: a network-centric operational system that shares sensor and electronic warfare data in real time.
Third, "AI-based cognitive electronic warfare" technology — in which artificial intelligence analyzes enemy radar and electromagnetic signals as they change in real time and rapidly translates the results into electronic countermeasures — must be aggressively applied to domestic weapons systems. In the electronic warfare to come, relying solely on a pre-loaded threat database will not be enough to counter evolving threats.
Fourth, to spread risk now concentrated in expensive manned fighters, South Korea must strengthen the ability of low-cost unmanned systems to work with manned aircraft. It needs to advance manned-unmanned teaming (MUM-T) tactics, in which drones carrying electronic warfare pods or decoy systems lure and disrupt enemy radars while manned fighters strike key targets from a safer distance.
Victory on the modern battlefield no longer rests solely on who fires more missiles from farther away. Who first detects the invisible space of the electromagnetic spectrum, and who controls it more effectively, can decide the outcome of a fight.
Combining a hard shell of stealth with superior sensors and electronic warfare capability is the core of future air combat. Securing independent technology and operational capability to dominate the electromagnetic spectrum is the critical task South Korea must solve to maintain stable air operations among the great powers that surround it.
