The Navy’s New Secret Sauce for Drone Swarms ? Microwaves !

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The Navy’s New Secret Sauce for Drone Swarms ? Microwaves !
It’s not just for your Hungry Man TV dinner anymore…
By Wes O'Donnell
20 May 2025

Leonidas H20, courtesy Epirus
Let’s face it: If Ukraine has taught the West anything, it’s that battlefield drones have become a real pain in the ass.
As drone swarms become more ubiquitous, nations around the world will start to discover what Ukraine figured out years ago: that kinetic effectors are often too slow, too expensive, or too limited to deal with the swarm-era battlefield.
But the US Navy may have just found its silver bullet, or rather, its electromagnetic wave. Meet Leonidas H2O, the latest iteration of the US military’s high-power microwave (HPM) arsenal developed by California-based defense firm Epirus.
This isn’t theoretical. It has already been tested. And it’s already changing how the Navy thinks about boat-stopping, drone-zapping, and swarm-breaking technologies. Spoiler: it does all three at once.
Zap Boats and Drones in the Same Shot
In the never-ending race between defense systems and the threats they’re designed to counter, the US Navy may have just leaped ahead a generation.
It pains me to say that — as an Army and Air Force vet, I never like to give the Navy more credit than they deserve.
But at the heart of this advance is Leonidas H2O, a high-power microwave weapon that doesn’t discriminate between threats above water and those buzzing in from the sky.
If it has a circuit board, it’s vulnerable.
If it has an engine, it is on borrowed time.
During recent live-fire trials under the Navy’s Advanced Naval Technology Exercise — Coastal Trident (ANTX-CT), Leonidas H2O demonstrated its ability to simultaneously disable multiple classes of unmanned systems.
Think drone swarms and unmanned surface vessels, neutralized in one blast of directed energy. It’s a first-of-its-kind capability. And it worked.
The tests, held off the California coast, targeted four different commercial outboard motors ranging from 40 to 90 horsepower, simulating the propulsion systems typically found in small attack boats and suicide drones, both known favorites of Iran’s IRGC and Russia’s Black Sea fleet.
Despite operating at only half of its maximum power output due to safety and range constraints, Leonidas H2O still fried every target.
All of them.
At what the Navy called “operationally relevant ranges.”
That phrase, “operationally relevant,” is key. It means this isn’t a lab experiment or a PowerPoint weapon . It’s a system that can realistically be deployed on warships or at forward operating bases today. No fantasy. No vaporware. The implications are massive.
In maritime environments, where traditional point-defense systems rely on missile interceptors or autocannons with finite ammunition and slow target reacquisition rates, Leonidas offers an unlimited magazine. That means no reloads and no delay between kills. Once powered on, it is always on standby, ready to instantly fry whatever flies or floats into its engagement zone.
More critically, Leonidas engages without warning. Unlike radar-guided interceptors, which can be detected by enemy sensors, HPM systems are silent assassins. The drone never knows it’s being cooked until its electronics seize up and it tumbles into the sea.
The unmanned boat doesn’t explode, it just dies mid-charge, engine frozen by a bath of microwave radiation.
This also gives US naval commanders a new gray-zone tool, a non-lethal but tactically decisive option to neutralize threats without triggering a shooting war.
If you disable an unmanned surface vessel without launching a missile, you avoid escalation (in theory).
That is a capability the Navy has never had before. And one it desperately needs in places like the South China Sea, the Red Sea, and the Strait of Hormuz.
In essence, Leonidas H2O is turning electromagnetic dominance into battlefield control. One pulse, multiple targets, zero missiles fired. And for adversaries hoping to overwhelm US ships with swarms of cheap drones or boat bombs? That tactic just became obsolete.
At its core, Leonidas is a software-defined, solid-state, high-energy microwave weapon that emits powerful pulses of non-ionizing radiation. These microwaves overload the circuits of electronics in their field of fire, essentially cooking them from the inside out, without the boom or the blast radius.
Unlike kinetic systems that rely on finite missile tubes or ammunition stocks, Leonidas has what Epirus calls an “unlimited magazine.” As long as there’s power, it keeps firing. The system can repeatedly engage multiple drones from multiple swarms, according to the company. That’s not just force projection, that’s area denial in the electromagnetic spectrum.
The Brains Behind the Beam: LRAM Architecture

Leonidas family, courtesy Epirus
At the heart of Leonidas H2O’s blistering performance is a system so deceptively modular it borders on sci-fi: the Line Replaceable Amplifier Module, or LRAM. Think of it as the neural network behind the microwave barrage, a grid of smart, swappable components that collectively power, aim, and control the weapon’s high-energy output with surgical precision.
Traditional high-power microwave systems have historically suffered from a fatal design flaw: single points of failure. Vacuum tubes, legacy cooling systems, and analog control nodes make them as brittle as they are powerful. One glitch, one overheated circuit, and the whole system collapses.
Not so with LRAM.
Each LRAM in the Leonidas platform is a self-contained solid-state amplifier, capable of independently producing high-energy pulses. They are hot-swappable, individually addressable, and smart.
These aren’t just amplifiers, they’re adaptive units that respond in real time to the battlefield environment. When you scale up Leonidas, whether you’re fitting it to a truck, a naval vessel, or a fixed installation, you’re not adding bulk. You’re adding intelligence and resilience.
If one module falters, the others reroute the power and pick up the slack. This kind of graceful degradation is what separates a field-ready system from a Pentagon white paper. It is what makes Leonidas a true warfighter’s tool.
When your ship is under attack from thirty drones, failure is not a troubleshooting scenario, it’s death. LRAM ensures Leonidas keeps firing.
Beyond survivability, LRAM is also the key to Leonidas’ scalability. Want a compact variant for a Humvee or a Stryker?
Use fewer modules.
Need a high-power array to protect a forward operating base?
Stack them. The same core building block powers every configuration, meaning the cost stays manageable, training stays consistent, and upgrades can be pushed across the entire platform family without redesigning the whole system.
Critically, this architecture also enables software-defined waveform control. That’s not just marketing jargon. It means Leonidas can be reprogrammed mid-mission to adjust its energy output, pulse frequency, and target parameters.
You can tailor it to zap a swarm of plastic-bodied quadcopters one minute and then dial in a new profile to scramble the electronics of hardened naval drones the next.
Epirus didn’t just build a microwave weapon. They built a plug-and-play ecosystem for electromagnetic warfare.
So while the beam may be invisible, its architecture is anything but. LRAM is the hidden backbone transforming Leonidas from an experimental showpiece into a combat-ready game-changer.
With drone swarms becoming cheaper, faster, and more autonomous, traditional point-defense systems, like CIWS guns or Stinger missiles, are struggling to keep up. Microwave weapons fill that gap. They’re non-kinetic, they’re relatively cheap to operate, and they don’t care how many drones are coming; they’ll fry as many as they can reach.
The implications are serious. If Leonidas works as advertised, the US Navy could field soft-kill systems that neutralize electronic threats before they become kinetic ones.
That changes naval doctrine from “intercept and destroy” to “deny and disable,” shifting the burden back onto adversaries like Iran, China, and Russia, who increasingly rely on drones and unmanned naval platforms to overwhelm American forces through saturation.
Bridging the Capability Gap

Leonidas Mobile, courtesy Epirus
Epirus CEO Andy Lowery pulled no punches: “The Department of Defense has poured tens of millions into developing a non-kinetic vessel stop solution. To date, no operational system has been deployed.”
That frustration is shared across a defense establishment long enamored with theoretical tech that never leaves the whiteboard. Leonidas H2O, by contrast, appears to be the first system that not only crossed the finish line but did it while casually turning off a boat engine from a football field away, without breaking a sweat or launching a single projectile.
But here’s the nuance. Leonidas is not merely filling a capability gap, it is rewriting what that gap even means. Traditionally, navies have operated in binary mode: launch or don’t launch. Kinetic weapons kill or they don’t. Missiles strike or they miss.
But high-power microwave systems introduce a third dimension, a kind of digital gray zone where you can disrupt instead of destroy, deny instead of detonate. It is escalation control in a box, with a dial that can be turned up or down depending on the mission.
This is where Leonidas starts to look less like a weapon and more like a strategic governor of conflict. You do not have to sink a vessel if you can blind it, jam it, or kill its propulsion mid-channel. You do not have to shoot down a drone swarm if you can erase its internal guidance software before the propellers even spin up. In an age where every headline screams about cost overmatch and the $20,000 missile taking out the $200 drone, Leonidas flips the script. Now, it’s the $20 beam neutralizing the $2 million threat before it ever becomes one.
And that shift has enormous implications. Militaries no longer have to choose between restraint and lethality. Leonidas gives commanders a new form of control to dominate the spectrum without triggering the smoke and fire of traditional escalation. In contested gray zones like the South China Sea or the Strait of Hormuz, that flexibility is not just convenient, it is decisive.
The future of warfare may still involve hypersonic interceptors and railguns that fire slugs at Mach 7, but in the shadows, systems like Leonidas will be quietly reshaping the battlespace — one fried circuit board at a time. Not with noise, but with silence. Not with steel, but with spectrum.
This is not your grandfather’s Navy. And the next war might not be won by who fires first, but by who quietly turns off the enemy’s ability to fire at all.
This becomes even more relevant as drone swarms evolve from experimental tech demo to frontline menace. In a future surface action group, it will not be enough to defend against a handful of precision-guided threats.
Fleets will face dozens, maybe hundreds, of autonomous platforms coming at them from the sea, the air, and even below the surface.
Traditional missile defense systems, with their limited magazines and costly interceptors, were never designed for that kind of saturation. But Leonidas, with its unlimited ‘shots’ and near-instant target reengagement, is purpose-built for that reality.
Think of it as a digital moat around every carrier battle group, corvette, or amphibious ready group. In that scenario, Leonidas does not just bridge the capability gap, it becomes the backbone of a future-proof fleet, one where supremacy is measured not just in tonnage or missiles launched, but in who controls the electromagnetic high ground.
All thanks to lessons learned in Ukraine.
Слава Україні! Crimea is Ukraine.