As the form of warfare evolves, the operational environment changes, and new technologies advance, the electromagnetic spectrum—once a critical carrier for battlefield information acquisition and transmission—has gradually emerged as a new-type operational domain, following the traditional domains of land, sea, air, space, and cyberspace. As a novel operational concept for seizing electromagnetic dominance on the battlefield and effectively controlling the electromagnetic spectrum, electromagnetic spectrum warfare has garnered widespread attention and in-depth research.

Some views hold that electromagnetic spectrum warfare is an extension of electronic warfare. Certain experts have expanded traditional electronic offense and defense into "electronic warfare + electromagnetic spectrum control," elevating it to a comprehensive form of warfare in the electromagnetic spectrum domain.

In recent years, to gain an edge in electromagnetic spectrum warfare, major military powers worldwide have continuously advanced the development and application of electromagnetic spectrum technologies such as cognitive radio, artificial intelligence (AI), frequency agility, adaptive frequency selection, and dynamic spectrum access.

The concept of "electromagnetic spectrum warfare" was first proposed by the U.S. military in its 2015 report Winning the Airwaves: Regaining U.S. Dominance in the Electromagnetic Spectrum. However, military operations in the electromagnetic spectrum domain have a long history, dating back to the early days of the invention and application of radio stations—over a century ago.

Over the past 100-plus years, driven by the development of emerging technologies, the methods of electromagnetic spectrum warfare have undergone tremendous changes, which can be summarized into four key phases:

Shortly after the invention of radio stations, adversarial activities in the electromagnetic spectrum domain emerged. During the 1905 Russo-Japanese War, the Japanese deliberately used radio stations to jam Russian radio communications. This early form of electronic countermeasures was further applied in World War I. In 1930, Radio Detection and Ranging (radar) systems began to be deployed on the battlefield, using radio waves reflected by large targets such as warships and aircraft to determine target positions.

Electromagnetic spectrum warfare in this phase was primarily characterized by two competing approaches: the active use of active radio networks to coordinate troop movements and guide fire strikes, and the use of passive direction-finding equipment to locate or monitor enemy radio transmissions. This formed a rivalry between "active" means (represented by radio communications) and "passive" means (represented by communications reconnaissance).

With advancements in missile, aviation, and aerospace technologies, electronic jamming, electronic deception, and other active countermeasures were increasingly applied on aircraft and warships. While combatants intercepted and exploited enemy electromagnetic spectrum information transmissions, they also had an urgent need to block such transmissions. Active countermeasures—including long-range active sensors, short-range active self-defense countermeasure systems, and active infrared countermeasure systems—were fully developed to meet the growing demands of the battlefield.

This phase began in the late Cold War era, focusing on using stealth technology to reduce the radar cross-section (RCS) of platforms, and employing passive sensors as well as sensors with adjustable waveforms and power to minimize the electromagnetic signal radiation of stealth platforms. Since the 1980s, the U.S. military has successively developed stealth platforms such as the F-117 Nighthawk stealth attack aircraft, B-2 Spirit bomber, and F-22 fighter jet. Russia and other countries have also stepped up research on low-detectability platforms, advanced sensors, communication networks, and countermeasures targeting "stealth" and "low-power network" capabilities.

This phase began in 2015 with the proposal of the new operational concept of "low-zero power" electromagnetic spectrum warfare. It primarily uses passive operating modes or low probability of interception (LPI)/low probability of detection (LPD) technologies to reduce the probability of self-detection, maximize the effectiveness of its own detection capabilities, confuse or suppress enemy detection capabilities, and enhance friendly penetration and attack capabilities. The development and application of new technologies—such as passive sensors, electronic counter-countermeasures (ECCM), and anti-jamming and anti-destruction wireless communication networks—have provided support for improving "low-zero power" network capabilities.

For example, digital radio frequency memory (DRFM) jamming technology can digitize received signals, modify them slightly, and then transmit false signals to enemy sensors. The application of this technology has driven the development of radar countermeasures.

The rapid development of technology is the internal driving force behind the evolution of electromagnetic spectrum warfare. Reports indicate that countries such as Russia, the United States, and Israel are actively pursuing innovations in electromagnetic spectrum technology and continuously enhancing the military application of electromagnetic spectrum warfare equipment with networked, information-based, intelligent, and adaptive capabilities.

Currently, Russia’s electromagnetic spectrum warfare capabilities primarily rely on electronic warfare systems, which are used in military operations such as electromagnetic suppression, electromagnetic jamming, and battlefield reconnaissance. The "Krasukha" electronic warfare system is a typical example of Russian electromagnetic spectrum warfare equipment, with variants including the Krasukha, Krasukha-2, and Krasukha-4. These are highly mobile platforms with multi-functional capabilities such as electronic suppression, electromagnetic jamming, and electromagnetic protection, capable of delivering real-time electromagnetic effects while quickly evading attacks. In January of this year, the Russian Ministry of Defense officially commissioned the Su-57 stealth multi-role fighter jet. Equipped with low-detectability technology, an active electronically scanned array (AESA) integrated multi-functional radar system, optical sensor systems, and radio reconnaissance and countermeasure systems, the Su-57 can detect enemies and conduct jamming without activating its radar or exposing itself.

In recent years, the U.S. military has carried out research on technologies such as cognitive electronic warfare, AI, AESA, adaptive radar countermeasures, and dynamic spectrum access. It has mastered capabilities including electronic warfare planning and management, multi-functional electronic warfare, defensive electronic attack, electromagnetic command and control, and airborne electronic reconnaissance. The U.S. military also emphasizes the integration of electronic warfare systems and spectrum management tools to achieve joint electromagnetic spectrum operations based on electronic warfare and spectrum management.

As weaponry and equipment become increasingly dependent on the electromagnetic spectrum, spectrum management has become an increasingly complex yet critical element in electromagnetic spectrum warfare. To improve the efficiency of spectrum management, the U.S. military has added hardware or software modules to traditional radio stations to enable dynamic spectrum access capabilities. Additionally, in projects such as the Next-Generation Wireless Communications Program, the U.S. military has conducted in-depth research on the application of dynamic spectrum access technology, which allows equipment to automatically and quickly adjust frequencies through flexible selection of digital spectrum strategies, achieving autonomous and orderly spectrum usage.

Israel has also invested heavily in developing electromagnetic spectrum warfare capabilities. Researchers have upgraded the communication and control systems of F-35I fighter jets with the latest electronic warfare technology, equipped them with self-developed air-to-air and air-to-ground precision-guided weapons, and installed advanced electronic intelligence systems—significantly enhancing the aircraft’s original targeting, detection, and jamming capabilities.

As warfare evolves toward informatization and intelligentization, major military powers worldwide continue to pursue technological innovations in the electromagnetic spectrum domain. Next-generation electromagnetic spectrum warfare systems will become more precise, intelligent, and agile, supporting capability leaps in electromagnetic spectrum operations such as electromagnetic sensing, early warning and detection, navigation and positioning, electronic countermeasures, and spectrum control.

In electromagnetic spectrum domain operations, the integrated operation of various spectrum management and utilization systems in an ad-hoc network and autonomous frequency selection mode will facilitate the sharing of electromagnetic spectrum sensing information and enable efficient collaboration in electromagnetic space spectrum operations. The operational effectiveness of such a system will far exceed that of individual systems operating independently.

In recent years, unmanned combat swarms have attracted widespread attention, and the "Gremlin" electronic warfare drone swarm is a typical electromagnetic spectrum warfare system featuring networked autonomous spectrum collaboration. From a technical perspective, the "Gremlin" is an unmanned combat cluster composed of a large number of small, low-cost, heterogeneous drones with single functions. By overcoming key technologies such as AI, cognitive electronic warfare precision sensing and collaboration, adaptive electronic warfare behavior learning, and adaptive radar countermeasures, it is expected to achieve air launch, air recovery, distributed air operations, and multi-platform collaboration in the future—accomplishing combat missions through efficient group cooperation.

In the military electromagnetic spectrum domain, new concepts such as cognitive radio and cognitive electronic warfare continue to emerge. Among them, cognitive electronic warfare focuses on developing key technologies such as threat sensing based on target signals, cognitive-based jamming strategy optimization, and real-time evaluation of jamming effects. Through real-time sharing of electromagnetic spectrum sensing information, it enables efficient and flexible cognitive countermeasure capabilities of electromagnetic spectrum warfare systems.

Cognitive radio is an intelligent wireless communication technology based on software-defined radio (SDR) platforms. By integrating SDR, advanced sensors, and autonomous machine learning, it can evolve from simple spectrum sensing or adaptation to intelligent cognitive radio communication capabilities—thereby improving the utilization of spectrum resources and enhancing the operational effectiveness of equipment.

In essence, "cognition" refers to intelligence, and cognitive technologies will drive electromagnetic spectrum operations toward dynamic, autonomous, and intelligent development.

Future electromagnetic spectrum warfare systems need to adapt to complex electromagnetic environments with intense confrontation, adjusting spectrum usage parameters such as frequency, beam direction, and power level in a timely manner to achieve operational freedom in the electromagnetic spectrum domain and thus seize and maintain electromagnetic dominance. By introducing the concept of "tactical agility" and developing agile spectrum operation control technology, the efficiency of dynamic spectrum management can be improved, enabling autonomous and orderly spectrum usage to serve electromagnetic spectrum domain operations efficiently.

For enhancing electronic countermeasure capabilities, tactical agility not only enables agile countermeasures against enemy sensors or communication systems but also reduces the detection probability of enemy passive sensors. In the future, related technologies can be applied to missiles and small unmanned aerial vehicles (UAVs) to improve electromagnetic spectrum mobility.