Last month Japan’s Acquisition, Technology & Logistics Agency (ATLA) released a new conceptual image of its prospective “high-power microwave (HPM) radiation device” capable of disabling unmanned aerial systems (UAS), currently in the research and development (R&D) stage.
The image, released as part of ATLA’s latest R&D pamphlet published on 31 January, includes a caption from the agency’s Future Capabilities Development Center. It explains that to counter swarms of unmanned aerial vehicles (UAVs), the agency envisions using HPM radiation technology instead of live ammunition or missile-based systems.
The key advantage of an HPM-based system is that it does not run out of ammunition as long as it has a power supply operating. The HPM-based approach is also seen as a cost-effective countermeasure for disabling drones, which are relatively inexpensive, and aligns with the Japan Ministry of Defense’s (JMOD) strategy to enhance labor efficiency in the Japan Self-Defense Forces (JSDF) while prioritizing the use of unmanned assets [1].
JMOD views the HPM system, which uses high-powered microwaves to disable multiple enemy drones and other targets by irradiating a wide area, disrupting their electronic circuits, and causing them to malfunction, as a potential “game changer.” JMOD has allocated 800 million yen (approximately 5.2 million USD) in fiscal 2025 to support ongoing HPM system development for drone neutralization [2].
According to ATLA, joint research with the U.S. is now underway following a Project Arrangement signed by JMOD with the U.S. Department of Defense (DoD) in July last year. Concrete plans include conducting outdoor irradiation tests at U.S. test centers to realize a HPM system for both Air and Maritime defense [3].
Since 2014, JMOD has been researching HPM technology. A prototype HPM generator has been developed for countering drones, with ongoing experiments successfully testing a 10-kilowatt system to down drones. The technology is already adaptable for land and vehicle deployment, with future plans to enhance output, miniaturize systems, and integrate them into ships, and aircraft, and even drones [4].
Japan’s Development of Counter-UAS Infrastructure
JMOD recognizes the need to invest in the R&D of an array of counter-UAS technologies, noting in particular the harm that aerial drones could cause to Japan’s defense facilities [5].
Last year, JMOD highlighted how Russia’s use of relatively inexpensive Iranian-made “HESA Shahed 131/13”6 suicide UAVs has severely impacted Ukraine’s defense industry and critical infrastructure [6].
To counter drone swarms effectively, JMOD plans to pair the HPM radiation device with a high-power laser system, using HPM for distant threats and lasers for closer targets.
JMOD is envisioning both a vehicle-mounted and shipboard applications for the laser system. ATLA has been developing a vehicle-mounted high-energy laser, showcased at the JSDF’s 70th anniversary ceremony last year. This is alongside a more powerful 100kW-class laser, in development since 2018, to counter both small UAVs and mortar shells.
Development History of Japan’s Drone-Disabling “HPM Radiation Device” (2014-2021)
In 2013, JMOD announced plans to develop an HPM-based air defense system to counter missile threats. The first phase (2014–2017) focused on advancing high-energy air defense technology using radio waves. This included the development of an active phased array system to electronically control antenna directionality, as well as high-power microwave technology capable of emitting high-energy bursts. Additionally, this phase aimed to gather technical data on a new type of miniaturizable electron tubes to support these systems [7].
In-house tests from 2016 to 2018 aimed to evaluate the feasibility and performance of the HPM technology. The research focused on ultimately creating a compact, high-power, wide-bandwidth X-band Microwave Power Module (MPM) energy beam management system. Advancements in HPM applications were also expected to reduce labor and material costs [8].
The 2014–2018 research phase shifted the focus of HPM technology toward countering UAVs and lead to the development of a prototype generator with the following specifications [9]:
- Transmitting Antenna Array
- Frequency Range: X-band
- Effective Radiated Power: 40MW or more
- Beam Scanning Coverage: ±45°
- Transmitting radio wave: Pulsed CW
In 2019, ATLA planned to conduct drone irradiation tests to determine an optimal beam pattern and effective radiated power. In 2020, additional irradiation tests on electronic devices targeted as threats were scheduled. These efforts were to support work from 2021 onward to miniaturize the HPM module, increase its output, and gather further technical data [10].
Current Development Phase and Future Prospects (2022-Present)
In August 2021, ATLA announced that the current phase of the HPM device, scheduled to run from 2022 to 2026, is now in the prototype development phase. This will be followed by in-house testing from 2026 to 2027 [11].
The ongoing project aims to further develop HPM technology using a phased array system, to establish a heat dissipation and cooling system, to advance HPM control technology, and to enhance HPM performance for countering multiple UAVs.
Given the alignment of the HPM with national defense policies, ATLA highlighted that experts recommend Japan to consider an accelerated development approach, as the HPM could become a potential defense export. Meanwhile, while previous research had demonstrated the HPM’s effectiveness in controlled environments, outdoor testing would now be required to validate its operational feasibility.
Conclusion
In conclusion, pairing ATLA’s domestic R&D coupled with U.S. cooperation ongoing July 2024 will be crucial for both validating the operational feasibility of the HPM device and maximizing its export potential. Notably, collaboration can take advantage of the U.S.’s vast land area, enabling outdoor irradiation tests that are difficult to conduct in Japan.
Looking ahead, the partnership could pave the way for collaboration between Japanese companies with cutting-edge technologies in the maritime defense sector and U.S. firms currently developing land-based HPM systems, such as Raytheon’s “CHIMERA” Counter-Electronic High-Power Microwave Extended-Range Air Base Defense system. There is significant potential for expanding the applications of these systems beyond air bases.
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Notes:
[1] Acquisition, Technology & Logistics Agency, 研究開発パンフレット, (Research and Development Pamphlet), February 14, 2025, https://www.mod.go.jp/atla/research/rnd_files/rnd_brochure_jpn2025.pdf
[2] Japan Ministry of Defense, “防衛力抜本的強化の進捗と予算－令和７年度予算案の概要－（令和6年12月27日掲載）”, (Progress and Budget in Fundamental Reinforcement of Defense Capabilities – Overview of FY2025 Budget Request (Published December 27, 2024)), https://www.mod.go.jp/j/budget/yosan_gaiyo/fy2025/yosan_20241227.pdf
[3] Japan Ministry of Defense, “Japan MoD and United States DoD sign a Project Arrangement concerning Cooperative Research on Directed Energy High-Power Microwave (HPM) systems”, July 16, 2024 https://www.mod.go.jp/atla/pinup/pinup_r060716_01.pdf
[4] Yahoo Japan, 高出力マイクロ波照射で無力化…防衛省、“迎撃ドローン”研究, (Ministry of Defense researches “interceptor drones” that can be neutralize other UAVs by irradiating them with high-power microwaves), December 5, 2024, https://news.yahoo.co.jp/articles/223100eb555b551415659fc2c039b786ccd11e4e; Norimono News, 自衛隊に「驚愕の新兵器」導入か!? ドローンの大群“まとめて無力化 ” 新たなイメージが公開(Will a “shocking new weapon” be introduced for the Japan Self-Defense Forces? New images showing drone swarms being “collectively neutralized” released), February 10, 2025, https://trafficnews.jp/post/518543
[5] Japan Ministry of Defense, 防衛力抜本的強化の進捗と予算－令和７年度予算案の概要－（令和6年12月27日掲載）, (Progress and Budget in Fundamental Reinforcement of Defense Capabilities – Overview of FY2025 Budget Request (Published December 27, 2024)), https://www.mod.go.jp/j/budget/yosan_gaiyo/fy2025/yosan_20241227.pdf
[6] Japan Ministry of Defense, 日本の安全保障政策：防衛力抜本的強化の全体像（7本柱）無人アセット防衛能力/領域横断作戦能力, (Japan’s Security Policy: Overall Picture of the Fundamental Reinforcement of Defense Capabilities (7 Pillars) Unmanned Asset Defense Capability/Cross-Domain Operation Capability), November 8, 2024 https://www.mod.go.jp/j/policy/agenda/meeting/drastic-reinforcement/pdf/bukai_siryo02_01.pdf
[7] Japan Ministry of Defense, 高出力マイクロ波技術に関する研究（要旨）, (Research on High Power Microwave Technology (Summary)), 2013, https://warp.da.ndl.go.jp/info:ndljp/pid/11339364/www.mod.go.jp/j/approach/hyouka/seisaku/results/25/pdf/jizen_09_youshi.pdf
[8] Ibid.
[9] Acquisition, Technology & Logistics Agency, ドローン・UAS対処にも適用可能な高出力マイクロ波技術の研究 (Research into High-Power Microwave Technology Applicable to Combating drones and UAS), 2019, https://www.mod.go.jp/atla/research/ats2019/doc/nishioka.pdf
[10] Ibid.
[11] Acquisition, Technology & Logistics Agency, 高出力マイクロ波技術に関する研究（要旨）, (Research on High Power Microwave Technology (Summary)), 2021, https://www.mod.go.jp/j/approach/hyouka/seisaku/2021/pdf/jizen_05_youshi.pdf
This article was originally posted on NSBT Japan, the first defense and security industry network in Japan. The publication provides the latest information on security business trends both within Japan and overseas. Asian Military Review began exchanging articles with NSBT Japan in April 2024.
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