Microwave weapons: US, Japan's answer to defend against swarms of combat drones

Amid concerns over China conducting surveillance missions using drones against Taiwan, North Korea deploying large numbers of drones in swarm attacks and a general sense that most of the wars will be fought with the help of drones, Japan and the US are collaborating for the joint development of high-power microwave weapons designed to protect military personnel and equipment from attacks by drones.

According to a South China Morning Post report, Tokyo is particularly keen to develop countermeasures against swarms of drones that are expected to accompany any contingency involving Chinese forces in areas off southern Japan.

“Drones are now being used as weapons as well as in intelligence-gathering, monitoring and communications roles, and it is fair to say that from now on, no war will be fought without drones,” South China Morning Post report quoted Kazuto Suzuki, a professor of science and technology policy at Tokyo University, as saying.

“They have already proved to be very useful and very effective on the battlefield and there are many benefits to using drones, including not incurring casualties on the user’s side and having a relatively inexpensive drone being able to target and destroy enemy weapons systems that can be worth many millions of dollars,” he added.

The recent developments in Ukraine and the brief resurgence of hostilities between Armenia and Azerbaijan over Nagorno-Karabakh in late 2023 underscored for military strategists globally the critical significance of drones and the urgency to advance countermeasures.

What is microwave weapon?

Microwave weapon emits electromagnetic waves designed to disrupt the internal electronics of drones. While microwave technology itself isn’t new — microwave ovens have been household fixture in kitchens for decades — weaponising electromagnetic waves is a more recent development.

According to Yomiuri, quoting an official from the Japanese Defense Equipment Agency_,_ Japanese government has been researching the technology for several years and is adjusting the joint research period to about three years to lead US-Japanese joint research into specific gear development.

The Japan Defence Ministry expects weapons using microwaves to be a game changer that could transform the balance of military capabilities.

Microwave weapons offer a distinct advantage by “blanketing” a wide area to intercept approaching drones, unlike traditional ammunition and anti-aircraft missiles, which are more pinpoint weapons.

They are also just as effective against small drones, which might evade detection by radar or human vision, as larger unmanned vehicles, reported South China Morning Post report, citing analysts.

And as long as they have a power source, microwave weapons can keep up a constant barrage of waves instead of having to be reloaded. This also makes them a cheaper form of defence.

“A lot of countries are now working on how they can counter drones, with Japan beginning back in around 2015 under then-prime minister (Shinzo) Abe,” South China Morning Post report quoted Garren Mulloy, a professor of international relations at Daito Bunka University and a specialist in military issues, as saying.

What led to Japan’s interest in anti-drone capabilities?

The heightened interest in developing anti-drone capabilities stemmed from an incident on April 22, 2015, when a drone carrying mildly radioactive sand from Fukushima prefecture was discovered on the roof of the prime minister’s official residence in central Tokyo.

This incident, orchestrated by an anti-nuclear campaigner, underscored vulnerabilities in Japan’s security.

Concerns in Tokyo also revolved around potential drone threats during the postponed 2020 Olympic Games. However, attempts to use nets to capture drones proved ineffective.

“We have seen in Ukraine that a US$100 drone can knock out a multimillion-dollar weapon system, so the challenge now is to develop an asymmetric way of countering drones just as inexpensively,” Mulloy was quoted as saying.

While there is little information available on the joint research that Japan and the US are planning to carry out, collaborative efforts between the two countries are likely to focus on enhancing the efficiency of microwave weapons, developing portable versions, and integrating more potent systems onto agile platforms.

Security challenges

While joint research initiatives are underway, each country prioritises distinct security challenges.

“A key concern at the moment is North Korea using large numbers of drones in swarm attacks and there is already lots of evidence of Pyongyang using its new security relationship with Russia to obtain experience and know-how in the use of drones on the battlefield in Ukraine,” South China Morning Post quoted Tokyo University’s Suzuki as saying.

Suzuki noted North Korea’s growing drone capabilities and China’s significant role as a manufacturer of drones, which could be militarised in conflicts involving Taiwan or other regional tensions.

“In Japan, we know that China is conducting surveillance missions using drones against Taiwan and there is serious concern that Beijing will use large numbers of drones should it choose to attack,” Suzuki added.

Mulloy said Japan is also interested in expanding drone capabilities beyond aerial operations, including underwater and surface-based unmanned vehicles.

He underscored the rapid integration of drones into modern warfare, likening their impact to that of mortars in World War I, drastically reshaping battlefield dynamics.

“Drones are in many ways perfect because they do not expose soldiers to fire, they can operate as the eyes of the military to see what the enemy is doing, and they can also carry out attacks. In the last 15 years, hiding places on the battlefield have shrunk considerably, and now we need to find ways to counter the drones that provide that intelligence,” Mulloy was quoted as saying.