This category of the DEW namely High Power Microwave (HPM) weapons have been a dream of military planners for many years, ever since electronic warfare proved that radar could be jammed. These weapons offer solutions in anti-sensor applications and non-lethal weapon category. However, HPM advancements have been limited by uncertainty about its effects and effectiveness. Hence, only a few developed states are investing in this category of weapons for many years and there are reports that the US has even used it in Yugoslavia (1999).
In this category of weapons, microwave and millimetre wave systems could be treated separately because there are certain differences in their physical properties. However, here this entire spectrum is being considered under HPM category only for simplicity. HPM weapons vary widely in their effectiveness and development, as their design characteristics are varied over a number of parameters. For that reason these weapons are often categorised first by band ratio on the following basis:
1. Narrowband/continuous wave (band ratio about 1 per cent)
2. Narrowband/pulsed (band ratio about per cent)
3. Wideband (band ratio < 100 per cent)
4. Ultrawide band (band ratio > 100 per cent)
In simple language, HPM could be called as capacitors aboard the missile that discharge an energy pulse which moves at the speed of light and make electronic gadgets in the close-by area unserviceable. Such pulse can destroy any electronics within 1,000 ft of the flash by short-circuiting internal electrical connections by producing powerful surge.
This leads to burning/stop functioning of the memory chips and other electronic components. Such types of weapons are called as e-bombs. Here, essentially a magnetic armature is driven by explosives through a coil, energised by a bank of capacitors and the resulting energy is directed through an antenna. Attack by such weapons may not remain restricted towards the destruction of command and control systems of the enemy but could also cause unintended problems like destroying hospital equipment and other household equipment in the nearby vicinity. Also, this particular property of the weapon could even limit selection of the delivery platform. Hence, it is envisaged that the best platform for delivery of such weapons could be the long-range cruise missiles (interestingly, it was reported that B-2 stealth bombers were used as a delivery platform over Yugoslavia).
However, even though the work on microwave is being carried out for almost four decades, the technology is far away from being weaponised fully for the operational purposes. There are various reasons to it. First, at very high-power levels, microwave energy creates plasma in air which in turn prevents the microwaves from propagating. Second, the wavelength of HPM is significantly higher than laser, thereby spreading it out ten thousand times more than the laser. Hence, in comparison to the laser (which can reach space without spreading) an HPM beam is not good for more than a km or so. And finally, reducing the size of the system is the real challenge.
In spite of such difficulties, the work on different types of microwave weapon is still under progress particularly in the US defence labs. However, no clear information is available in open sources because of the obvious secrecy maintained with such projects.
Two HPM weapons are claimed to be ready for full-scale development. The US Air Force (contractor Raytheon) started developing the active denial system (ADS) in the mid-1990s. This system is also known as the ‘pain ray’ and uses an HPM beam to heat the outer layer of human skin by producing an intolerable, but supposedly harmless, burning sensation. Another HPM weapon is the vigilant eagle anti-missile defence system. Based on a classified precursor, this system is intended to defend aircraft against man-portable air-defence systems (MANPADS). The system could work as an alternative or could complement to installing infra-red countermeasures on the aircraft themselves.
It has been reported that the US Air Force intends to put a high-power microwave weapon on an advanced version of its unmanned strike aircraft by 2012. Also, the US Air Force Research Lab is starting a new, long-term, USD 60–75 million project to develop high-powered microwave weapons, for both ‘airborne and mobile ground-based systems’. This would be in addition to its ‘near-term’ Air Armament Command effort to use microwaves ‘as a Counter Electronics payload that would cause physical damage to the buildings or harm to humans’.
The military technologists are working on a technique to multiply the speed and power of HPM pulses—powerful enough to destroy the enemy electronics without using explosives or huge electrical generators. They predict leaps of 10–100 times in power output within two years. This could push the beam-weapon technology far beyond the 1–10 GW (gigawatt) limits of current tactical-size HPM devices. The success in this field would boost the process of weapon development significantly because as per the estimates it would require a 100 GW pulse for a few nanoseconds to disable a cruise missile at a useful range.
The work is also under progress towards building distributed array radars that can produce air-to-air and surface-to-air HPM weapons effects. The F-22, F-35, F/A-18E/F and the latest F-15 radars are designed to accept modifications that would focus their beams to produce HPM energy spikes powerful enough to disable cruise, anti-aircraft, air-to-air and emitter-seeking missiles.
At present, major players from the US defence industry like BAE Systems, Northrop Grumman and Raytheon are involved in developing HPM technologies. It appears that the HPM weapons may be on the verge of a high-speed turn toward practical applications. Researchers in this fi led are even trying to combine both lasers and HPM devices to produce smaller, more powerful and cheaper non-kinetic weapons. Apart from the US, countries like Germany are also involved in developing devices like suitcase-size HPM devices. Such devices could be placed surreptitiously in a target building to damage electronics such as computers.
There are also reports that the HPM weapon technologies are also being developed by states like China and Russia. The Russians are believed to be developing radio-frequency microwave weapons for air defence, and the Chinese are developing HPM and electromagnetic pulse weapons for information warfare. Even countries like the UK and France also have interest in this field and some work to that extent is under progress.
The significance of microwave weapons is that they provide a range of strategic and operational capabilities in both offensive and defensive operations. Such weapons could be found useful in carrying out tasks like suppression of enemy air defences. A reasonable estimate is that a single high-power microwave weapon could destroy the entire air defence system. This could become a possibility because the footprint of a microwave munitions is at least 100 times greater than that of a conventional munitions. There could be several microwave weapons capable of accomplishing such tasks, such as, microwave precision guided munitions, microwave unmanned combat air vehicles (UCAVs) or microwave self-protection pods on the attacking fighter air-craft. Also, microwave weapons could be found useful in the destruction of enemy’s command and control function. They could also be used for the purposes like striking enemy supplies and troops. A microwave weapon could be used to attack and disable enemy air-fields. Here the weapons would essentially cause damage and destruction to the electronics in all flying and static air assets inclusive of air traffic control equipment, communications facilities, radars and ground defence systems.