Within Electronics Risk
Where Friendly Gear Must Stay Out of the Beam
Commanders may need controlled no-go areas for friendly drones, vehicles and radios before firing a microwave counter-drone system.
On this page
- Why separation matters before firing
- How airspace and ground equipment shape safe zones
- Limits of exclusion zones in crowded battlespaces
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Introduction
Microwave counter-drone systems create a distinctive operational problem: before a commander can engage hostile drones, they may need to ensure that friendly electronics, vehicles, aircraft and communications systems are outside the area where intense electromagnetic energy could produce unwanted effects. Unlike a missile that follows a physical trajectory, a high-power microwave (HPM) weapon creates an electromagnetic effect volume. The result is a need for exclusion zones—temporary areas where friendly equipment is restricted, repositioned or protected before firing. These zones are not merely safety measures for personnel; they are a practical tool for preventing electromagnetic fratricide against friendly drones, radios and networked systems. The challenge becomes more acute because modern microwave defences are designed specifically to affect multiple targets across a broad beam rather than a single point target. [GAO+2Office of Naval Research]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave…
Why Separation Matters Before Firing
The purpose of an exclusion zone is to reduce the chance that friendly equipment experiences the same electromagnetic effects intended for hostile drones. High-power microwave weapons work by coupling energy into electronic systems, potentially causing disruption, malfunction or damage. That mechanism is valuable against drone swarms because many drones rely on vulnerable electronic components, but it also means nearby friendly systems may be exposed if they occupy the wrong location at the wrong time. [Office of Naval Research+2NATO Store]onr.navy.milOffice of Naval ResearchDirected Energy Weapons: High Power MicrowavesHPM weapons create beams of electromagnetic energy over a broad spe…
For commanders, the issue is not simply distance. Risk depends on several factors:
- The power and frequency of the microwave pulse.
- The shape and width of the beam.
- Whether equipment is directly illuminated or partially shielded.
- The susceptibility of individual electronic systems. [navysbir.com]navysbir.comNavy SBIRHigh-Power Microwave (HPM) Weapons' Effects and…12 Dec 2011 — OBJECTIVE: Develop a tool to model the vulnerability and suscep…
- The presence of antennas, cables and apertures that can act as coupling paths. [Office of Naval Research+2Navy SBIR]onr.navy.milOffice of Naval ResearchDirected Energy Weapons: High Power MicrowavesHPM weapons create beams of electromagnetic energy over a broad spe…
As a result, exclusion zones are often defined around the beam path rather than as a simple circular radius around the weapon. A friendly drone flying through the engagement sector may represent a greater concern than a vehicle parked elsewhere at a similar distance.
How Airspace and Ground Equipment Shape Safe Zones
In practice, exclusion zones are usually divided between airspace management and ground-system protection.
Airspace Restrictions
Friendly unmanned aircraft are often the first systems considered when establishing a microwave engagement zone. Modern military formations increasingly operate reconnaissance drones, relay drones, loitering systems and logistics aircraft simultaneously. A microwave pulse intended for hostile targets may not distinguish between friendly and hostile platforms if both occupy the same electromagnetic volume. Consequently, commanders may establish temporary no-fly corridors or require friendly drones to leave a designated sector before engagement. [GAO]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave…
The problem is amplified by the very feature that makes HPM systems attractive. Systems such as THOR, Leonidas and Phaser are designed to affect multiple drones within a wide engagement area rather than a single aircraft. That wider area effect increases the need for airspace coordination before firing. [AFRL+2RTX]afrl.af.milRLAFRL conducts swarm technology demonstrationRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm wit…
Ground-System Restrictions
Ground equipment can also influence exclusion-zone design. Tactical radios, command posts, radar systems, electronic warfare equipment and autonomous vehicles may all be considered when commanders determine whether a microwave engagement is acceptable.
Military research on HPM vulnerability repeatedly highlights the importance of antennas, wiring and electronic subsystems as pathways through which microwave energy can enter equipment. Consequently, exclusion zones may be tailored around the location of sensitive assets rather than applying a uniform rule across an entire force. [Navy SBIR]navysbir.comNavy SBIRHigh-Power Microwave (HPM) Weapons' Effects and…12 Dec 2011 — OBJECTIVE: Develop a tool to model the vulnerability and suscep…
In some circumstances, friendly systems may remain nearby if they possess sufficient hardening, shielding or electromagnetic protection. Exclusion zones therefore become part of a broader electromagnetic compatibility plan rather than a fixed-distance rule. [NATO Store]sto.nato.intNATO StoreHigh Power Microwaves: Threat to Infrastructure and…Over the past few decades, the potential threat from High Power Microwav…
Why Exclusion Zones Are Difficult to Standardise
Readers often assume that microwave weapons have a published “safe distance”. In reality, exclusion zones are highly system-specific.
Different microwave weapons employ different frequencies, power levels, pulse structures, antenna designs and beam geometries. A zone appropriate for one counter-drone system may be unsuitable for another. Defence organisations generally treat exact hazard distances as operationally sensitive information, making public discussion of precise military exclusion radii uncommon. [Office of Naval Research]onr.navy.milOffice of Naval ResearchDirected Energy Weapons: High Power MicrowavesHPM weapons create beams of electromagnetic energy over a broad spe…
Even environmental conditions matter. Terrain, buildings, metallic structures and reflections can alter how electromagnetic energy propagates through an operational area. A firing position that appears acceptable on a map may present different risks once local electromagnetic conditions are considered. Research into HPM modelling increasingly incorporates propagation, coupling and environmental effects precisely because outcomes can vary significantly across locations. [arXiv]arxiv.orgA Multi-physics Simulation Framework for High-power Microwave Counter-unmanned Aerial System Design and Performance EvaluationFebrua…
This means commanders typically rely on system-specific safety procedures, mission planning and electromagnetic risk assessments rather than a universal distance chart.
The Human-Safety Layer and the Electronics-Safety Layer
Exclusion zones around microwave defences usually serve two overlapping purposes.
The first concerns human exposure. High-power radio-frequency systems must operate within established electromagnetic safety frameworks, and designers often incorporate hazard calculations to ensure personnel are not exposed to unacceptable field strengths. Research into both military HPM systems and high-power RF applications demonstrates the importance of controlled operating areas when intense electromagnetic energy is present. [arXiv]arxiv.orgA Multi-physics Simulation Framework for High-power Microwave Counter-unmanned Aerial System Design and Performance EvaluationFebrua…
The second concerns equipment protection. A zone that is safe for personnel may still be unsuitable for sensitive electronics. Commanders therefore frequently have to manage two separate questions:
- Can personnel safely occupy the area?
- Can friendly electronics safely operate in the area?
The electronics question often drives operational restrictions because modern forces depend heavily on connected digital systems even when personnel themselves face little direct hazard. [NATO Store]sto.nato.intNATO StoreHigh Power Microwaves: Threat to Infrastructure and…Over the past few decades, the potential threat from High Power Microwav…
Limits of Exclusion Zones in Crowded Battlespaces
Exclusion zones solve only part of the problem. They work best when friendly forces can temporarily clear a sector before engagement. Modern battlefields increasingly make that difficult.
A brigade may have dozens of friendly drones airborne at once. Civil authorities protecting airports or critical infrastructure may have numerous legitimate wireless systems operating nearby. Naval vessels carry dense concentrations of sensors, antennas and communications equipment. In such environments, creating a completely clean electromagnetic engagement area may be impractical. [GAO]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave…
This creates an important operational trade-off. The larger the engagement volume, the more effective a microwave system may be against a drone swarm. Yet the larger the volume, the harder it becomes to guarantee that no friendly systems occupy it. The challenge is therefore not simply technical but organisational: commanders must coordinate airspace, communications plans, sensor usage and drone operations before firing. [GAO+2Office of Naval Research]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave…
Recent counter-drone demonstrations have shown the attractiveness of one-to-many engagements against swarms, including tests in which dozens of drones were disabled in a single event. Those same characteristics explain why exclusion-zone management remains central to operational employment. A weapon capable of affecting many drones simultaneously inherently requires confidence that friendly electronics are not occupying the same electromagnetic battlespace. [Epirus+2Tom's Hardware]epirusinc.comEpirusEpirus' Leonidas High-Power Microwave Defeats 49-Drone…10 Sept 2025 — Leonidas neutralized 61-of-61 drones, culminating in a 49…
Exclusion Zones as an Operational Control Measure
For microwave air-defence systems, exclusion zones should be understood less as static safety circles and more as a command-and-control tool. They allow operators to create temporary electromagnetic clear areas before firing, reducing the risk of interference with friendly drones, communications and other critical systems.
The effectiveness of these zones depends on accurate knowledge of friendly positions, reliable electromagnetic compatibility assessments and disciplined coordination across the force. As microwave counter-drone weapons become more common, managing who and what must stay out of the beam may prove nearly as important as aiming the beam itself. [GAO+2Office of Naval Research]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave…
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Endnotes
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Source: gao.gov
Title: gao 23 106717
Link: https://www.gao.gov/products/gao-23-106717Source snippet
Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — High power microwave weapons produce microwaves, which have longer wave...
Published: May 2023
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Source: onr.navy.mil
Link: https://www.onr.navy.mil/organization/departments/code-35/division-353/directed-energy-weapons-high-power-microwavesSource snippet
Office of Naval ResearchDirected Energy Weapons: High Power MicrowavesHPM weapons create beams of electromagnetic energy over a broad spe...
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Source: rtx.com
Link: https://www.rtx.com/raytheon/what-we-do/integrated-air-and-missile-defense/phaser-high-power-microwaveSource snippet
Phaser High-Power Microwave System | RaytheonOperators focus a wide, arcing energy beam on drones that sends out a short, high power burs...
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Source: sto.nato.int
Link: https://www.sto.nato.int/document/high-power-microwaves-threat-to-infrastructure-and-military-equipment/Source snippet
NATO StoreHigh Power Microwaves: Threat to Infrastructure and...Over the past few decades, the potential threat from High Power Microwav...
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Source: navysbir.com
Link: https://navysbir.com/n12_1/N121-008.htmSource snippet
Navy SBIRHigh-Power Microwave (HPM) Weapons' Effects and...12 Dec 2011 — OBJECTIVE: Develop a tool to model the vulnerability and suscep...
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Source: arxiv.org
Link: https://arxiv.org/abs/2602.08477Source snippet
A Multi-physics Simulation Framework for High-power Microwave Counter-unmanned Aerial System Design and Performance EvaluationFebrua...
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Source: arxiv.org
Link: https://arxiv.org/html/2602.08477v1Source snippet
A Multi-physics Simulation Framework for High-power...9 Feb 2026 — This paper has presented a multi-physics simulation framework for the...
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Source: arxiv.org
Link: https://arxiv.org/abs/2311.12809 -
Source: afrl.af.mil
Title: RLAFRL conducts swarm technology demonstration
Link: https://www.afrl.af.mil/News/Article-Display/Article/3396995/afrl-conducts-swarm-technology-demonstration/Source snippet
RL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm wit...
Published: May 16, 2023
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Source: epirusinc.com
Link: https://www.epirusinc.com/press-releases/epirus-leonidas-high-power-microwave-defeats-49-drone-swarm-100-of-drones-flown-at-live-fire-demonstrationSource snippet
EpirusEpirus' Leonidas High-Power Microwave Defeats 49-Drone...10 Sept 2025 — Leonidas neutralized 61-of-61 drones, culminating in a 49...
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Source: tomshardware.com
Title: Tom’s Hardware High-power microwave system downs 49 drones in [one shot]({{ ‘one-shot/’ | relative_url }})
Link: https://www.tomshardware.com/tech-industry/high-power-microwave-system-downs-49-drones-in-one-shot-weaponized-electromagnetic-interference-erases-drone-swarms-en-masseSource snippet
electronics warfare company, successfully demonstrated a major advancement in counter-drone technology with its Leonidas high-power micro...
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Source: Wikipedia
Title: Epirus Leonidas
Link: https://en.wikipedia.org/wiki/Epirus_LeonidasSource snippet
Epirus LeonidasThe Leonidas is a high-power microwave (HPM) weapon developed to disable unmanned aerial vehicle (UAV) swarms. It was n...
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Source: epirusinc.com
Link: https://www.epirusinc.com/electronic-warfareSource snippet
N) semiconductors for unmatched counter-electronics effects.Read more...
Additional References
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Source: lockheedmartin.com
Link: https://www.lockheedmartin.com/en-us/capabilities/directed-energy.htmlSource snippet
Directed Energy | Lockheed MartinExperience the potential of our laser weapons and directed energy weapon technologies, providing afforda...
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Source: techradar.com
Link: https://www.techradar.com/pro/forget-lasers-and-missiles-china-wants-to-kill-drones-using-a-common-tech-households-use-everyday-in-kitchens-all-around-the-world-invisible-microwave-weapons-can-fry-electronics-but-still-require-[line-of-sightSource snippet
China wants to counter drone swarms using high power...17 Jan 2026 — China has revealed new details about a high power microwave weapon...
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Source: euronews.com
Link: https://www.euronews.com/next/2025/04/18/what-is-the-uks-microwave-weapon-that-counters-drone-attacks-and-how-does-it-workSource snippet
What is the UK's 'microwave weapon' that counters drone...18 Apr 2025 — Called RapidDestroyer, the device uses the high-power frequency...
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Source: twz.com
Title: british high power microwave weapon successfully tested against drone swarms
Link: https://www.twz.com/news-features/british-high-power-microwave-weapon-successfully-tested-against-drone-swarmsSource snippet
British High-Power Microwave Weapon Successfully...17 Apr 2025 — The Radiofrequency Directed Energy Weapon demonstrator, or RF DEW, uses...
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Link: https://www.youtube.com/watch?v=aSM6q_TKcTsSource snippet
DRDO'S New Microwave Weapon ExplainedDRDO'S New Microwave Weapon Explained The DRDO High Power Microwave (HPM) Directed Energy Weapon sys...
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Source: incompliancemag.com
Title: air force unveils new microwave weapon named thor that can kill drones
Link: https://incompliancemag.com/air-force-unveils-new-microwave-weapon-named-thor-that-can-kill-drones/Source snippet
Air Force Unveils New Microwave Weapon Named 'Thor'...2 Jul 2019 — Using an inaudible and invisible magnetic wave, the high-powered devi...
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Source: afresearchlab.com
Link: https://afresearchlab.com/counter-swarm-high-power-weapon/Source snippet
A target is identified, the silent weapon discharges in a nanosecond and the...Read more...
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Source: jedonline.com
Link: https://www.jedonline.com/2023/01/24/high-power-microwave-systems-getting-much-much-closer-to-operational-status/Source snippet
High-Power Microwave Systems – Getting (Much...24 Jan 2023 — In this article, we're going to look at HPM technology, it's history and cu...
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Source: facebook.com
Link: https://www.facebook.com/unboxfactory/posts/the-us-military-has-successfully-tested-a-next-[generationSource snippet
rowave (HPM) weapon capable of disabling dozens of drones at once...
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Source: facebook.com
Link: https://www.facebook.com/themilitarychannelusa/posts/read-the-american-defense-technology-company-epirus-released-footage-confirming-/122182740638902462/Source snippet
mpleted initial government acceptance testing of its high...
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