A counter to drone swarms: high-power microwave weapons

Military forces must prioritise a counter to drone swarming tactics with which inexpensive, mass-produced drones can overwhelm defences. What is needed is a layered defensive system that includes systems that can neutralise many threats within seconds. One such solution is now becoming available: the contemporary high-energy, high-power microwave (HPM) weapon.
The employment of lethal drones costing a few hundred dollars each is threatening the ability of forces to accomplish missions without suffering unacceptable casualties and equipment losses. And when drones appear in large numbers, conventional defences, such as automatic cannons, can’t neutralise them fast enough. Defensive systems that use interceptors or projectiles are not only too slow against a drone swarm; their shots can cost more than the drones they aim to defeat.
This is an urgent matter for all defence forces, including Australia’s.
HPM weapons work by emitting directed bursts of electromagnetic energy, disabling the electronics of drones in mid-flight. In the most basic sense, they do in fact work rather like your microwave oven at home and even use similar radio-energy frequencies, but they act over hundreds, or low thousands, of metres. Unlike traditional kinetic systems, which must intercept and physically destroy each target individually, high-energy HPMs can adjust their beam to incapacitate massive swarms of drones in a single engagement.
Importantly, modern high-energy HPM systems are software-defined, making rapid updates possible as threat technologies and tactics evolve. They are also more mobile, modular and scalable than earlier versions of directed energy technology, and focus on cumulative energy on a target, not the peak power of earlier generations of HPM weapons.
Addressing the cheap-drone threat is not a future concern; it is an immediate battlefield reality. First-person-view drones have become one of the deadliest weapons in the war in Ukraine. Battlefield casualties caused by drones currently outnumber those inflicted by artillery, with some estimations as high as 70-80 percent.
Beyond technological advances, tactics are evolving rapidly. The war in Ukraine has demonstrated a brisk cycle of countermeasures and counter-countermeasures. Battlefield adaptations are happening in weeks rather than years. For example, recent adaptations to counter the protection afforded by jammers includes the use of drones enabled by artificial intelligence and drones flown by fibre-optic cable.
The core challenge in countering a drone attack is one of detecting, tracking and then neutralising it before it can inflict damage. With swarms, this difficulty is multiplied, particularly for defensive systems that lack the speed or capacity to engage many threats simultaneously. With many existing counter-drone systems handling one target at a time, they are highly susceptible to being overwhelmed or defeated by drone swarms.
But HPM weapons can neutralise swarms of drones in a single, speed-of-light engagement. Traditional counter-drone measures, including kinetic defences like missiles and gun-based systems, are costly to re-supply, insufficiently scalable to defeat a multitude of drones, or simply incapable of adapting at the pace of evolving swarm technologies.
Large and small nations are working on the capability to conduct large, coordinated drone swarm attacks, including swarms by kamikaze drones, which are, in effect, guided missiles. The sheer volume of these drones overwhelms defensive systems and makes high-value assets increasingly vulnerable. Through programming or increasing autonomy, swarms can coordinate attacks from several directions, exploiting gaps in traditional air defence networks.
To counter this evolving drone swarm threat effectively, Australia should invest in systems that are scalable, adaptable and capable of integrating with a broader counter-small uncrewed aerial system capability. HPM weapons fit this requirement. Their rapid response time and ability to neutralise swarms of drones simultaneously make them an essential component in modern layered air defences.
The magazines of HPM systems are effectively endless, limited only by an energy source, which could be a generator or even mains electricity; in all these cases, the cost per engagement becomes trivial, just a few cents. This flips the cost equation: previously, expensive interceptor missiles or shells with none-too-cheap proximity fuses were needed. So were elaborate re-supply arrangements.
But HPM is not a silver bullet. It must be integrated into a layered approach that combines kinetic, electronic warfare and directed energy systems to maximise the adaptability of defences against evolving threats.
Maintaining an edge in counter-drone technology is not optional; it is imperative. Because failure to adapt to these rapid changes will leave military forces dangerously exposed, speed in acquiring, deploying and adapting counter-drone capabilities is now critical.
Collaboration with allies, particularly through AUKUS arrangements, will be essential. Developing advanced technologies and ensuring interoperability with key partners, such as the United States and Britain, will give Australia a competitive edge.
The question is no longer which counter-drone system Australia should acquire but how quickly it can establish the commercial and military partnerships to rapidly and effectively keep up with the changing threat.