Leonidas is a high-power microwave (HPM) directed energy weapon system developed by the U.S. technology company Epirus to counter unmanned aerial systems (C-UAS). Introduced in 2020, with a third-generation variant unveiled in April 2022, Leonidas utilizes solid-state HPM technology, employing Gallium Nitride (GaN) semiconductors to deliver counter-electronics effects. This design minimizes size and weight while enhancing maneuverability and operator control. 
The system can be mounted on various platforms, including the U.S. Army’s Stryker armored vehicle, providing a mobile solution for countering drone threats.
in September 2024, the U.S. Marine Corps received a new drone-killing microwave weapon prototype known as Leonidas Expeditionary.
Epirus has secured a contract modification worth nearly $17 million from the U.S. Army’s Rapid Capabilities. This contract modification builds upon the initial $66 million awarded to Epirus in January 2023 for rapid prototyping of HPM systems.
Leonidas offers rapid firing capabilities with near-instant effects without overheating, eliminating the need for traditional ammunition and enabling effective defense against multiple drone threats simultaneously.