US Marines ready to fry enemy drone swarms with new Epirus ExDECS microwave weapon system.

The US company Epirus announced on April 29, 2025, the delivery of an Expeditionary Directed Energy Counter-Swarm (ExDECS) system to the Naval Surface Warfare Center Dahlgren Division for evaluation by the U.S. Marine Corps. ExDECS is a high-power microwave (HPM) counter-drone system, developed as a derivative of the Leonidas Expeditionary system. The system was delivered following successful Factory Acceptance Testing, formalized via Department of Defense Form DD250, and subsequent Government Acceptance Testing. It was developed under a contract from the U.S. Navy’s Office of Naval Research (ONR) and additional testing and evaluation are funded through the Preliminary Evaluation of Ground-based Anti-Swarm UAS System (PEGASUS) program awarded in September 2024.
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The ExDECS system is a derivative of the Leonidas system, using high-power microwaves to disable drones through electromagnetic interference. (Picture source: Epirus)

The Expeditionary Directed Energy Counter-Swarm (ExDECS) is intended to support the Marine Corps’ Low Altitude Air Defense (LAAD) mission and Ground Based Air Defense (GBAD) capability development. The system is designed to integrate with light tactical vehicles, trailers, and other mobile platforms. It utilizes solid-state, gallium nitride (GaN) based, software-defined, long-pulse HPM technology, emphasizing modularity, scalability, and the ability to operate in expeditionary scenarios. Leonidas Expeditionary, introduced by Epirus in 2024, is part of a product line that also includes Leonidas Pod, Leonidas IFPC-HPM (fixed or relocatable variant), and Leonidas Maneuver SHORAD systems. AirPower 2.0 reported that ExDECS is the fourth form factor developed by Epirus for the U.S. services, with future developments including an Extended Range (ER) 10-kilometer HPM system.

The ExDECS system is a derivative of the Leonidas system, using high-power microwaves to disable drones through electromagnetic interference. Andy Lowery, CEO of Epirus, stated that systems like ExDECS provide a "one-to-many" capability by disrupting the electronics of multiple drones simultaneously. In comments to Inside Defense, Lowery compared the effect to an electromagnetic version of the Phalanx Close-In Weapon System, emphasizing that instead of physically damaging drones, ExDECS overloads their circuits by creating an intense electromagnetic environment. This concept allows the disruption of swarm communications without kinetic engagement.

Epirus’ approach to high-power microwave technology involves several claimed operational advantages: size, weight, and power (SWaP) efficiencies compared to traditional HPM systems; the use of solid-state components without ionizing radiation; software-defined adaptability to increase range or optimize waveforms without hardware modifications; modularity using Line Replaceable Amplifier Modules (LRAMs); and integration with existing command and control systems through open API architectures, including FAAD C2. The company also states that Leonidas addresses cost challenges, providing engagements at a significantly lower cost-per-shot compared to kinetic defenses.

Leonidas systems have been validated through extensive testing and were selected for the U.S. Army's Indirect Fire Protection Capability–High-Power Microwave (IFPC-HPM) initiative. Four Leonidas IFPC-HPM prototypes were delivered in May 2024, as previously announced. Army Chief of Staff Gen. Randy George testified before Congress that the systems would be deployed to the U.S. Central Command (CENTCOM) area for operational testing. The goal is to enable soldiers, developers, and testers to adjust capabilities in real-world environments. Army acquisition head Doug Bush highlighted the challenges of directed-energy system integration, especially with high-energy lasers at 50-kilowatt power levels, while emphasizing that lower-power directed-energy systems like 20-kilowatt Palletized High Energy Lasers (P-HEL) are proving more viable for certain fixed-site applications.

Directed-energy weapons have become a focus across the US Department of Defense as inexpensive, mass-produced drone and missile threats proliferate globally. (Picture source: Epirus)

The IFPC-HPM systems developed by Epirus were tested against both single drone targets and drone swarms, demonstrating the claimed ability to neutralize multiple threats. After engineering development testing and new equipment training, the Army confirmed that these systems are bound for operational deployment pending final approvals. Military leaders including Vice Adm. Brendan McClane and Gen. Michael "Erik" Kurilla have expressed the need for accelerated adoption of directed-energy weapons, including HPM systems, as part of layered defenses against drones, missiles, and other distributed aerial threats.

In May 2024, Epirus CEO Andy Lowery indicated that the company plans demonstrations of scaled Leonidas systems with the U.S. Navy at Advanced Naval Technology Exercises (ANTX), and that deployments to PACOM and Ukraine were possible depending on test outcomes. Lowery explained that Epirus had incorporated design features to mitigate electromagnetic interference effects and built flexibility into system architecture to adapt to evolving threats.

In the broader context, the operational need for systems like ExDECS has been reinforced by the evolution of drone warfare, particularly evident in the Ukraine conflict. Reports have described the large-scale use of cheap drones by both sides, creating challenges for traditional air defense systems. According to Epirus, systems such as ExDECS can provide a lower-cost and more scalable response, avoiding the high financial and logistical burdens associated with kinetic interceptors. Forbes reporting from September 2024 detailed that ExDECS emits a wide-area pulse that affects drones almost instantaneously, offering an alternative to lasers or projectile-based defenses, with a per-shot cost described as being approximately five cents.

Epirus emphasizes that ExDECS, because of its wide-area effect, avoids the risks associated with friendly fire incidents, which can occur when engaging low-flying drones with traditional weapons. The system’s compact, solid-state construction is intended to support highly mobile Marine Corps operations under the Expeditionary Advanced Base Operations (EABO) concept. This aligns with the Marine Corps’ need for mobile, lightweight, and rapidly deployable counter-UAS capabilities. The first ExDECS unit will be integrated with the Marine Corps' Common Aviation Command and Control System (CAC2S) for field experimentation and multi-platform testing later in 2025.

The ExDECS system emits a wide-area pulse that affects drones almost instantaneously, offering an alternative to lasers or projectile-based defenses, with a per-shot cost described as being approximately five cents. (Picture source: Epirus)

Previous reports indicated that Epirus mounted its Leonidas system onto a Stryker vehicle under an earlier $66 million prototyping contract with the U.S. Army's Rapid Capabilities and Critical Technologies Office (RCCTO) to explore mobile applications of high-power microwave technology. Field demonstrations in late 2023 showed successful engagements of single drones and swarms. The Stryker Leonidas platform, developed in under one year, was publicly exhibited at the Association of the U.S. Army conference.

Directed-energy weapons have become a focus across the Department of Defense as inexpensive, mass-produced drone and missile threats proliferate globally. According to a 2023 Congressional Research Service report, high-powered microwaves are particularly suited to engaging large swarms over wide areas. Defense contractors including Raytheon are also developing microwave systems for shipboard applications under Navy programs such as METEOR, with first shipboard tests anticipated by fiscal year 2026.

Beyond near-term operational tests at CENTCOM and other theaters, Epirus plans to open a large-scale simulation center in Oklahoma in Q3 2025, adjacent to Fort Sill and the Joint Counter-Small UAS University at the Fires Center of Excellence. The center will feature immersive, modular training environments for directed-energy operations. Additional expansions of U.S. manufacturing and production facilities are planned throughout 2025 to meet anticipated demand from U.S. and allied customers.

Since its founding in 2018, Epirus has positioned itself among the emerging class of "neo-primes" — nontraditional defense companies combining Silicon Valley methods with defense sector requirements. The company's approach emphasizes rapid prototyping, modular architectures, and adaptability, aiming to support U.S. and allied forces facing evolving aerial and electronic threats. Epirus has stated that its solid-state, software-defined Leonidas systems can be upgraded through software alone to adapt to new threat frequencies without hardware changes, contributing to scalability across various operational domains.