Within Wide Beam
When A Wide Beam Becomes A Problem
The same broad effect that helps THOR against dense swarms can complicate selectivity, safety boundaries and friendly electronics protection.
On this page
- Why spread out swarms reduce the payoff
- Selectivity limits near friendly electronics
- Why microwave defence still needs other layers
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Introduction
The same characteristic that makes THOR and similar high-power microwave (HPM) systems attractive against drone swarms can also become a limitation. A wide microwave beam allows one pulse to affect multiple drones at once, helping defenders cope with saturation attacks that would overwhelm one-target-at-a-time weapons. However, area effects inevitably create trade-offs in selectivity, safety management and electromagnetic compatibility. The challenge is not simply whether the beam can disable hostile drones, but whether it can do so without disrupting friendly systems operating in the same environment. As a result, wide-beam microwave weapons are often viewed as powerful counter-swarm tools rather than universal replacements for more precise defensive systems. Air Force Research Laboratory+2Air Force Research Laboratory [afrl.af.mil]afrl.af.milAir Force Research Laboratory AFRL conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — THOR, a high-powered microwave coun…
Why Spread-Out Swarms Reduce the Payoff
The strongest case for a wide microwave beam occurs when many drones occupy the same volume of airspace. THOR was specifically designed around this “one-to-many” engagement concept, allowing a single pulse to influence multiple targets simultaneously. Air Force Research Laboratory+2Air Force Research Laboratory [afrl.af.mil]afrl.af.milAir Force Research Laboratory AFRL conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — THOR, a high-powered microwave coun…
The advantage becomes less dramatic when a swarm changes its geometry. If drones are dispersed across a wider area, separated by altitude, approach from multiple bearings, or arrive in staggered waves, fewer targets may fall within the effective engagement zone at any given moment. The defender may still need multiple shots, multiple systems, or repositioning to maintain coverage.
This creates a fundamental operational tension:
- Concentrated swarms favour microwave weapons. [techradar.com]techradar.comOperating at distances beyond 3 km, it surpasses the range of similar systems like the U.S. Army's Epirus-developed Leonidas. The Hurrica…
- Dispersed swarms reduce the number of drones affected per pulse.
- Highly manoeuvrable or geographically distributed attacks can dilute the efficiency of area-effect engagement.
Modern counter-drone developers continue to highlight large multi-drone kills as proof of effectiveness because the economics improve dramatically when many targets occupy the same beam volume. Demonstrations by THOR and the Leonidas family of systems repeatedly focus on dense swarm scenarios for exactly this reason. Tom’s Hardware+3Air Force Research Laboratory+3Air & Space Forces Magazine [afrl.af.mil]afrl.af.milAir Force Research Laboratory AFRL conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — THOR, a high-powered microwave coun…
The implication is that a wide beam is not automatically superior in every engagement. Its value depends heavily on target density. As the swarm spreads out, the “one pulse, many kills” proposition becomes harder to achieve.
Selectivity Limits Near Friendly Electronics
The Area-Effect Dilemma
High-power microwave weapons work by coupling electromagnetic energy into electronic systems. Their purpose is to disrupt, degrade or damage electronics rather than physically strike a target. That mechanism creates an inherent selectivity challenge: electronics do not carry visible markings identifying friend from foe. [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…
A missile or laser can often be directed at a specific drone. A microwave effect, by design, covers a broader area. Any vulnerable electronics located within the relevant exposure zone may require consideration during planning and employment.
For this reason, military users typically establish safety procedures, exclusion areas and electromagnetic compatibility assessments before deploying HPM systems. Research on HPM counter-UAS design routinely incorporates safety-zone calculations and exposure boundaries as part of system planning. [arXiv]arxiv.orgA Multi-physics Simulation Framework for High-power Microwave Counter-unmanned Aerial System Design and Performance EvaluationFebrua…
Risks to Friendly Systems
The most obvious concern is interference with friendly electronics operating near the engagement area.
Potentially affected systems can include:
- Communications equipment.
- Sensors and radar components.
- Uncrewed aircraft operating on the defender’s side.
- Networked command-and-control systems.
- Civilian electronic infrastructure located near defended facilities.
Operational discussions of HPM systems frequently identify interference with nearby friendly electronics as a constraint that must be managed through doctrine, placement and beam control. [Norsk luftvern+2Facebook]norskluftvern.comepirus leonidas counter drone system usNorsk luftvernEpirus Leonidas Counter-Drone System (US)31 Mar 2025 — Limited effectiveness against hardened, shielded UAVs Requires a dir…
The issue becomes particularly important around airports, critical infrastructure, military headquarters and densely instrumented bases where large numbers of electronic systems coexist. A weapon designed to disable electronics can be highly effective against hostile drones while simultaneously demanding careful separation from the electronic assets it is supposed to protect.
Hardening Creates an Uneven Battlefield
Another selectivity problem arises because not all electronics respond equally to microwave exposure.
Some drones may incorporate shielding, hardened components or more resilient architectures. Industry and defence analyses routinely identify electromagnetic hardening as a likely countermeasure against future HPM systems. [Norsk luftvern]norskluftvern.comepirus leonidas counter drone system usNorsk luftvernEpirus Leonidas Counter-Drone System (US)31 Mar 2025 — Limited effectiveness against hardened, shielded UAVs Requires a dir…
This means that a broad pulse does not necessarily produce a uniform outcome. Within the same engagement area:
- Some drones may fail immediately.
- Others may suffer degraded performance.
- Hardened systems may continue operating.
- Friendly electronics may need protection despite not being the intended target.
The result is an engagement environment that can be less predictable than a purely kinetic intercept.
Why Microwave Defence Still Needs Other Layers
The limitations of wide-beam engagement help explain why military organisations increasingly discuss microwave weapons as one layer within a broader air-defence architecture rather than a complete solution.
A microwave system excels when numerous drones enter a defended zone simultaneously. Yet other threats may demand different tools:
- Precision weapons remain valuable when a single drone must be engaged without affecting nearby systems.
- Electronic warfare tools may be preferable when disruption is sufficient and physical damage is unnecessary.
- Lasers offer highly selective engagement against individual targets.
- Conventional interceptors may still be required against hardened or high-value threats. [Epirus+2TechRadar]epirusinc.comOur software-defined, long-pulse HPM systems, either fixed or semi-fixed, can integrate with other sensors and weapons…Read more…
This layered approach appears repeatedly in contemporary counter-drone planning. New HPM programmes are often presented as complements to existing sensors, command systems and other defensive weapons rather than replacements for them. [Epirus]epirusinc.comOur software-defined, long-pulse HPM systems, either fixed or semi-fixed, can integrate with other sensors and weapons…Read more…
The broad microwave beam therefore creates both the principal strength and the principal weakness of systems such as THOR. It enables efficient engagement of dense drone formations, but the same area effect imposes limits on precision, increases the need to protect friendly electronics, and makes operational context critical. The more crowded and electronically complex the environment becomes, the more important those trade-offs are in determining when a wide beam is the right tool for the job. Office of Naval Research+2Air Force Research Laboratory [onr.navy.mil]onr.navy.milOffice of Naval ResearchDirected Energy Weapons: High Power MicrowavesHPM weapons create beams of electromagnetic energy over a broad spe…
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Endnotes
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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: facebook.com
Link: https://www.facebook.com/unboxfactory/posts/the-us-military-has-successfully-tested-a-next-generation-high-power-microwave-h/944338644583853/Source snippet
iendly electronics, limiting its use near civilian infrastructure...
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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-sight-and-proximitySource snippet
Operating at distances beyond 3 km, it surpasses the range of similar systems like the U.S. Army's Epirus-developed Leonidas. The Hurrica...
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Source: facebook.com
Link: https://www.facebook.com/interestingengineering/posts/unlike-laser-based-systems-the-microwave-based-approach-can-engage-multiple-targ/1389544029883697/Source snippet
n exposed to high-power [microwaves]({{ 'microwaves/' | relative_url }}), potentially...
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Source: facebook.com
Link: https://www.facebook.com/AFResearchLab/videos/afrls-tactical-high-power-operational-responder-or-thor-system-%EF%B8%8F-is-swarming-int/1138955837220051/ -
Source: facebook.com
Title: Meet THOR, the Air Force Research Laboratory
Link: https://www.facebook.com/ArmedWithScience/videos/meet-thor-a-counter-drone-weapon/907504010708144/Source snippet
AFRL's...Thor is a high-power microwave counter drone weapon that the Air Force Research Lab has demonstrated for effectiveness against...
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Source: facebook.com
Link: https://www.facebook.com/AFResearchLab/posts/for-this-techtuesday-we-look-back-at-the-power-of-thor-and-what-that-means-for-n/3271349919568312/Source snippet
For this #TechTuesday, we look back at the power of THOR...A high-power microwave counter-drone system, the containerized THOR is design...
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Source: afrl.af.mil
Title: Air Force Research Laboratory AFRL conducts swarm technology demonstration
Link: https://www.afrl.af.mil/News/Article-Display/Article/3396995/afrl-conducts-swarm-technology-demonstration/Source snippet
Air Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — THOR, a high-powered microwave coun...
Published: May 16, 2023
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Source: afresearchlab.com
Link: https://afresearchlab.com/counter-swarm-high-power-weapon/Source snippet
uses high power microwaves to cause a counter...
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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: afrl.af.mil
Title: army partners with air forces thor for base defense
Link: https://www.afrl.af.mil/News/Article/2512426/army-partners-with-air-forces-thor-for-base-defense/Source snippet
Air Force Research LaboratoryArmy partners with Air Force's THOR for base defense23 Feb 2021 — THOR is a prototype directed energy weapon...
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Source: airandspaceforces.com
Title: air forces thor [drone swarm]({{ ‘swarm-limits/’ | relative_url }}) demo
Link: https://www.airandspaceforces.com/air-forces-thor-drone-swarm-demo/Source snippet
Air & Space Forces MagazineTHOR Hammers Drone Swarm with High-Power Microwaves19 May 2023 — THOR uses bursts of high-power microwave ener...
Published: May 2023
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Source: epirusinc.com
Title: Tap to unmute.Read more
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
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: norskluftvern.com
Title: epirus leonidas counter drone system us
Link: https://norskluftvern.com/2025/03/31/epirus-leonidas-counter-drone-system-us/Source snippet
Norsk luftvernEpirus Leonidas Counter-Drone System (US)31 Mar 2025 — Limited effectiveness against hardened, shielded UAVs Requires a dir...
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Source: epirusinc.com
Link: https://www.epirusinc.com/Source snippet
Our software-defined, long-pulse HPM systems, either fixed or semi-fixed, can integrate with other sensors and weapons...Read more...
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Source: epirusinc.com
Link: https://www.epirusinc.com/electronic-warfare -
Source: Wikipedia
Title: Air Force Research Laboratory
Link: https://en.wikipedia.org/wiki/Air_Force_Research_LaboratorySource snippet
Air Force Research LaboratoryThe Air Force Research Laboratory (AFRL) is a scientific research and development detachment of the Unite...
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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/press-releases/epirus-leonidas-demonstrates-successful-use-of-high-power-microwave-to-defeat-[fiber-opticSource snippet
Epirus' Leonidas Demonstrates Successful Use of High-...13 Jan 2026 — Leonidas is the first EW-based counter-UAS technology to demonstra...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=na0pGfopahM -
Source: afrl.af.mil
Link: https://www.afrl.af.mil/News/Photos/igphoto/2003223867/Source snippet
High-power Operational ResponderA high-powered microwave counter drone weapon, stands ready to demonstrate its effectiveness against a sw...
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Source: linkedin.com
Link: https://www.linkedin.com/posts/epirus_epirus-leonidas-high-power-microwave-defeats-activity-7371575751776608256-i0zZSource snippet
tic interference. “We believe showcasing our weaponized...
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Source: jpost.com
Title: article 884657
Link: https://www.jpost.com/defense-and-tech/article-884657Source snippet
Epirus: Bringing high-power microwave defense to the front27 Jan 2026 — Epirus' flagship system, Leonidas, is a high-power microwave (HPM...
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Source: defence-blog.com
Title: epirus confirms leonidas microwave system integration with dft platform
Link: https://defence-blog.com/epirus-confirms-leonidas-microwave-system-integration-with-dft-platform/Source snippet
Epirus confirms Leonidas microwave system integration...25 Feb 2026 — The system emits controlled bursts of high-power microwave energy...
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Source: nightdragon.com
Link: https://www.nightdragon.com/portfolio/epirus/Source snippet
Securing our world for tomorrow.Its flagship product, Leonidas, is a software-defined high-power microwave (HPM) system des...
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Source: calibredefence.co.uk
Title: epirus zaps fibre optic fpv with leonidas microwave weapon
Link: https://www.calibredefence.co.uk/epirus-zaps-fibre-optic-fpv-with-leonidas-microwave-weapon/Source snippet
Epirus zaps fibre-optic FPV with Leonidas microwave...28 Jan 2026 — Epirus has developed a microwave weapon called Leonidas that has dem...
Additional References
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Source: dvidshub.net
Link: https://www.dvidshub.net/video/904353/afrls-thor-tracks-and-disables-drone-swarmSource snippet
AFRL's THOR Tracks and Disables Drone Swarm"Numerous drones were flown to simulate a swarm attack, and using its wide beam, high peak pow...
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Source: ft.com
Link: https://www.ft.com/content/41703199-201e-4702-b34a-a0a633cdfcf5Source snippet
This weapon emits a wide beam of radio frequency energy designed to disable or destroy drones by damaging their electronic systems. Durin...
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Source: jedonline.com
Title: high power microwave systems getting much much closer to operational status
Link: https://www.jedonline.com/2023/01/24/high-power-microwave-systems-getting-much-much-closer-to-operational-status/Source snippet
Journal of Electromagnetic DominanceHigh-Power Microwave Systems – Getting (Much...24 Jan 2023 — HPM weapons can generate a range of eff...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=QjHGxKb6W1cSource snippet
THOR (Tactical High-power Operational Responder) Destroys...AFRL's THOR (Tactical High-power Operational Responder) is a prototype Direc...
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Source: defensescoop.com
Title: marines microwave weapon hpm epirus leonidas [expeditionary]({{ ‘marine-variant/’ | relative_url }})
Link: https://defensescoop.com/2024/09/23/marines-microwave-weapon-hpm-epirus-leonidas-expeditionary/Source snippet
Marines to get new drone-killing microwave weapon...23 Sept 2024 — The high-power microwave weapon prototype, known as Leonidas Expediti...
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Source: twz.com
Title: thor microwave anti drone system downs swarms in test
Link: https://www.twz.com/thor-microwave-anti-drone-system-downs-swarms-in-testSource snippet
THOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwave THOR syste...
Published: May 2023
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Source: airuniversity.af.edu
Title: army partners with air forces thor for base defense
Link: https://www.airuniversity.af.edu/News/Display/Article/2511792/army-partners-with-air-forces-thor-for-base-defense/Source snippet
partners with Air Force's THOR for base defense23 Feb 2021 — THOR is a prototype directed energy weapon used to disable the electronics i...
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Source: inzpire.com
Title: high power microwaves more than just a hot lunch
Link: https://www.inzpire.com/news/high-power-microwaves-more-than-just-a-hot-lunchSource snippet
High power microwaves – more than just a hot lunch!3 Mar 2025 — It is easy to imagine how these high-power levels can induce failures in...
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Source: taskandpurpose.com
Title: air force thor directed energy drone swarm test
Link: https://taskandpurpose.com/tech-tactics/air-force-thor-directed-energy-drone-swarm-test/Source snippet
Air Force's THOR directed energy weapon ready for drone...19 May 2023 — The Air Force has successfully employed its primary directed ene...
Published: May 2023
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Source: airforcetechconnect.org
Title: thor hammers drone swarm high power microwaves
Link: https://airforcetechconnect.org/news/thor-hammers-drone-swarm-high-power-microwavesSource snippet
THOR Hammers Drone Swarm with High-Power Microwaves24 May 2023 — An experimental directed energy weapon developed by the Air Force Resear...
Published: May 2023
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