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Why the Microwave Is Only Half the System

A microwave weapon can only protect an airbase if detection, tracking and command systems place the swarm in front of it in time.

On this page

  • How drones must be detected before engagement
  • Command and control links around a defended base
  • Integration questions left by public THOR tests
Preview for Why the Microwave Is Only Half the System

Introduction

THOR’s microwave pulse is the most visible part of the system, but it is not the part that makes airbase defence possible. A high-power microwave weapon can disable multiple drones at once, yet it can only do so if the drones are detected, identified, tracked and placed within the weapon’s engagement area before they reach the base. In practice, THOR is only one component in a larger counter-unmanned aircraft system (C-UAS) network that includes sensors, command-and-control software, communications links and operators. Public information about THOR repeatedly refers to targets being identified, tracked and aimed at, while demonstrations have involved operators directing the system against simulated swarm attacks rather than the weapon acting independently. Air Force Research Laboratory+2Air Force Research Laboratory [afresearchlab.com]afresearchlab.comThere are several drone negating systems available; guns, nets and laser systems.Read more…

Sensor Chain illustration 1 For airbase defence planners, the key lesson is that defeating drone swarms is not simply a question of whether a microwave beam is powerful enough. It is a question of whether the wider defensive network can discover a threat early enough, understand what it is seeing and cue the weapon before the swarm reaches critical infrastructure. [Air University]airuniversity.af.eduAir University Army partners with Air Force's THOR for base defenseAir UniversityArmy partners with Air Force's THOR for base defense - Air UniversityFebruary 23, 2021 — THOR is a prototype directed energ…Published: February 23, 2021

How Drones Must Be Detected Before Engagement

A microwave weapon does not search the sky for threats. It affects targets that have already been found and brought into its field of fire. Public AFRL descriptions of THOR state that “a target is identified” before the weapon fires, implying reliance on external detection and tracking functions even if details remain classified. [Air Force Research Laboratory]afresearchlab.comThere are several drone negating systems available; guns, nets and laser systems.Read more…

This requirement becomes more demanding when defending an airbase against a swarm. Small drones often have limited radar signatures, can approach from multiple directions and may fly at low altitude among terrain features and buildings. Detecting a single drone is difficult enough; maintaining tracks on dozens of drones simultaneously is a broader sensing challenge. Research into drone detection radar systems shows that small UAVs present distinctive but often weak radar returns, making specialised surveillance systems valuable for reliable classification and tracking. [arXiv]arxiv.orgRadar Cross Section Based Statistical Recognition of UAVs at Microwave FrequenciesFebruary 23, 2021…Published: February 23, 2021

For THOR, sensor performance directly affects weapon effectiveness:

  • Early warning determines engagement time. The sooner a swarm is detected, the more opportunities operators have to position the microwave beam.
  • Tracking quality determines pointing accuracy. Even a wide microwave beam must be directed toward the threat axis.
  • Classification matters. Airbases routinely see friendly aircraft, birds and other airborne objects. Operators need confidence that a detected contact is genuinely hostile before firing.
  • Swarm assessment affects shot timing. The greatest advantage of a microwave weapon is engaging multiple drones at once, which requires understanding how the swarm is distributed in space. [Unmanned Airspace]unmannedairspace.infoUnmanned Airspace US Air Force Research Laboratory demonstrates anti- …He was responsible for aiming the THOR system at the swarm“THOR was exceptionally effective at disabling the swarm with its wide beam, high peak powers and …Read more

The practical consequence is that improvements in radar, electro-optical sensors and tracking software may increase overall defensive performance as much as improvements in the microwave emitter itself.

THOR (Tactical High-power Operational Responder) Destroys Swarms of Enemy Drones

Channel: AFResearchLab

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Why a Wide Beam Still Needs Precise Information

THOR is often described as having a wide microwave beam capable of affecting multiple drones simultaneously. AFRL officials have highlighted the system’s wide beam, high peak power and fast-moving gimbal during swarm demonstrations. [Unmanned Airspace]unmannedairspace.infoUnmanned Airspace US Air Force Research Laboratory demonstrates anti- …He was responsible for aiming the THOR system at the swarm“THOR was exceptionally effective at disabling the swarm with its wide beam, high peak powers and …Read more

That capability can create a misunderstanding. A wide-area effect does not eliminate the need for precise situational awareness.

A defended airbase is a crowded environment. Aircraft may be taking off and landing, helicopters may be operating nearby and friendly drones may be conducting reconnaissance or maintenance tasks. The wider the area affected by a microwave pulse, the more important it becomes to understand exactly what occupies that space before engagement.

In operational terms, sensors help answer questions that the microwave emitter cannot answer on its own:

  • Where is the swarm heading?
  • How large is it?
  • Is it splitting into multiple groups?
  • Are some drones decoys while others carry payloads?
  • Are friendly systems nearby?

Without those answers, the weapon becomes a powerful effect generator with limited ability to make informed engagement decisions.

Sensor Chain illustration 2

Airbase defence is fundamentally a command-and-control problem. Information from sensors must reach operators, be fused into a coherent picture and then be translated into engagement decisions quickly enough to matter.

Public reporting on THOR demonstrations consistently refers to operators aiming the system at incoming targets. During the 2023 swarm demonstration, AFRL noted that a test engineer was responsible for directing THOR against multiple drones, indicating that sensing, tracking and human decision-making remained central elements of the engagement chain. [The War Zone]twz.comthor microwave anti drone system downs swarms in testThe War ZoneTHOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwav…Published: May 2023

This highlights an important governance issue for future deployment. A transportable airbase-defence system may move between locations, but it still requires integration into local command networks. Questions include:

  • Which radar provides the initial warning?
  • Who authorises engagements?
  • How are tracks shared with other defensive systems?
  • How are friendly drones identified?
  • How is responsibility divided between base defenders and higher headquarters?

These are not engineering details. They determine whether THOR functions as an isolated prototype or as part of a coordinated defensive architecture.

The U.S. Army’s interest in combining high-power microwaves with other directed-energy systems reflects this broader layered-defence approach. Public statements have emphasised multiple methods of defeating incoming threats rather than relying on a single weapon type. [Air University]airuniversity.af.eduAir University Army partners with Air Force's THOR for base defenseAir UniversityArmy partners with Air Force's THOR for base defense - Air UniversityFebruary 23, 2021 — THOR is a prototype directed energ…Published: February 23, 2021

America’s “THOR” Shoots Drones With High-power Microwaves | Has US Found the Answer to Drone Swarms?

Channel: CRUX

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What Public THOR Tests Reveal—and What They Do Not

Public demonstrations have shown that THOR can disable multiple drones and engage realistic swarm scenarios. AFRL’s 2023 demonstration described the system as exceptionally effective against a swarm and highlighted its ability to track and disable targets. [Air Force Research Laboratory+2Unmanned Airspace]afrl.af.milrl conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstration16 May 2023 — “THOR was exceptionally effective at disabling the…Published: May 2023

However, the public record leaves important sensor-related questions unanswered.

Open sources provide little detail about:

  • The radar systems used to detect the drones.
  • Whether tracking came from dedicated sensors, integrated air-defence networks or local observers.
  • The range at which the swarm was first detected.
  • How sensor information was fused before engagement.
  • The degree of automation involved in target selection and engagement approval. [The War Zone]twz.comthor microwave anti drone system downs swarms in testThe War ZoneTHOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwav…Published: May 2023

This absence of information is significant because it means public demonstrations largely validate the microwave effect rather than the entire operational kill chain. Successfully disabling drones after they have been presented to the weapon is not identical to proving that a deployed airbase can discover, classify, track and engage a complex swarm under combat conditions.

For analysts and policymakers, that distinction matters. The most difficult part of counter-drone defence is often not generating an effect against a target. It is building a reliable chain that turns a distant, ambiguous radar contact into a timely engagement decision.

Sensor Chain illustration 3

The Real Measure of Airbase Defence Capability

THOR’s value lies in its ability to defeat multiple drones rapidly, something conventional guns and many laser systems struggle to achieve against dense swarms. Yet that advantage only becomes operationally meaningful when paired with a robust sensing and command architecture. [Air University]airuniversity.af.eduAir University Army partners with Air Force's THOR for base defenseAir UniversityArmy partners with Air Force's THOR for base defense - Air UniversityFebruary 23, 2021 — THOR is a prototype directed energ…Published: February 23, 2021

Seen from an airbase-defence perspective, the microwave emitter is therefore only half the system. The other half consists of the radars, electro-optical sensors, communications links, data fusion tools and command structures that provide warning, tracking and engagement authority. A swarm that is not detected in time cannot be defeated by THOR, regardless of how effective the microwave pulse may be once it is fired. [Air Force Research Laboratory+2Unmanned Airspace]afresearchlab.comThere are several drone negating systems available; guns, nets and laser systems.Read more…

Air Force Research Lab unleashed THOR on drone swarm

Channel: Straight Arrow

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Endnotes

  1. Source: afresearchlab.com
    Link: https://afresearchlab.com/counter-swarm-high-power-weapon/
    Source snippet

    There are several drone negating systems available; guns, nets and laser systems.Read more...

  2. Source: afrl.af.mil
    Link: https://www.afrl.af.mil/News/Article-Display/Article/2339175/enemy-drone-operators-may-soon-face-the-power-of-thor/
    Source snippet

    Air Force Research LaboratoryEnemy drone operators may soon face the power of THORSep 24, 2019 — The technology, which cost roughly $15 m...

  3. Source: unmannedairspace.info
    Link: https://www.unmannedairspace.info/counter-uas-systems-and-policies/us-air-force-research-laboratory-demonstrates-anti-[drone-swarm
    Source snippet

    “THOR was exceptionally effective at disabling the swarm with its wide beam, high peak powers and...Read more...

  4. Source: airuniversity.af.edu
    Title: Air University Army partners with Air Force’s 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

    Air UniversityArmy partners with Air Force's THOR for base defense - Air UniversityFebruary 23, 2021 — THOR is a prototype directed energ...

    Published: February 23, 2021

  5. Source: arxiv.org
    Link: https://arxiv.org/abs/2102.11954
    Source snippet

    Radar Cross Section Based Statistical Recognition of UAVs at Microwave FrequenciesFebruary 23, 2021...

    Published: February 23, 2021

  6. 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-test
    Source snippet

    The War ZoneTHOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwav...

    Published: May 2023

  7. Source: afrl.af.mil
    Title: rl 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 demonstration16 May 2023 — “THOR was exceptionally effective at disabling the...

    Published: May 2023

  8. Source: afrl.af.mil
    Title: mil Air Force Research Laboratory Video
    Link: https://www.afrl.af.mil/News/Video/?dvpTag=Thor&dvpmoduleid=69743
    Source snippet

    Force Research Laboratory VideoNovember 15, 2023 — Tactical, High-power, Operational Responder, known as THOR, is a high-power microwave...

    Published: November 15, 2023

  9. 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...

  10. Source: usfk.mil
    Link: https://www.usfk.mil/What-We-Do/Exercises/Freedom-Shield/?dvpTag=Thor&videoid=904340
    Source snippet

    Tactical High-power Operational Responder - Freedom ShieldTactical, High-power, Operational, Responder, known as THOR, is a high power mi...

  11. Source: afresearchlab.com
    Link: https://afresearchlab.com/thor/
    Source snippet

    by AFRL PA | Sep 16, 2019. Search. Search. Recent Posts. AFRL redesigns for strategic advantage, positions research enterprise to acceler...

Additional References

  1. Source: techbriefs.com
    Link: https://www.techbriefs.com/component/content/article/49907-meet-thor-afrls-counter-drone-that-tracks-and-disables-drone-swarm
    Source snippet

    Meet THOR: AFRL's Counter-Drone that Tracks and...THOR is a high-power microwave counter-drone weapon that the Air Force Research Lab ha...

  2. 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/

  3. 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

    counter-drone HPM system developed by Raytheon for AFRL. It is designed to take down drones either in single numbers or in swarms. AFRL p...

  4. Source: youtube.com
    Link: https://www.youtube.com/watch?v=QjHGxKb6W1c
    Source snippet

    THOR (Tactical High-power Operational Responder) Destroys...AFRL's THOR (Tactical High-power Operational Responder) is a prototype Direc...

  5. Source: potomacofficersclub.com
    Title: AFR L Demonstrates Microwave-Powered Defense System
    Link: https://www.potomacofficersclub.com/afrl-demonstrates-microwave-powered-defense-system-against-drone-swarms/
    Source snippet

    AFRL Demonstrates Microwave-Powered Defense System...May 23, 2023 — Tactical High-power Operational Responder, a counter-drone swarm tec...

    Published: May 23, 2023

  6. Source: facebook.com
    Link: https://www.facebook.com/DefenseNews/posts/the-pentagons-counter-drone-task-force-is-set-to-test-a-high-energy-laser-system/1337596991735690/
    Source snippet

    This capability will be an amazing asset to our...Read more...

  7. Source: facebook.com
    Title: Meet THOR, a Counter-Drone Weapon
    Link: https://www.facebook.com/ArmedWithScience/videos/meet-thor-a-counter-drone-weapon/907504010708144/
    Source snippet

    November 27, 2023 — Meet THOR, the Air Force Research Laboratory - AFRL's tactical high-power operational responder that's an ele...

    Published: November 27, 2023

  8. Source: airandspaceforces.com
    Title: air forces thor drone swarm 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 — The Air Force Research Laboratory's directed...

    Published: May 2023

  9. Source: popsci.com
    Title: thor weapon drone swarm test
    Link: https://www.popsci.com/technology/thor-weapon-drone-swarm-test/
    Source snippet

    Air Force uses THOR's energy to zap drones23 May 2023 — THOR, or the Tactical High-power Operational Responder, is designed to defend aga...

    Published: May 2023

  10. Source: droneshield.com
    Link: https://www.droneshield.com/blog/a-counter-to-drone-swarms-high-power-microwave-weapons
    Source snippet

    A Counter to Drone Swarms: High-Power Microwave...HPM weapons work by emitting directed bursts of electromagnetic energy, disabling the...

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Deployment Can THOR Fit Real Airbase Defence?

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