On October 22nd the U.S. Air Force tested CHAMP (Counter-electronics High-powered Microwave Advanced Missile Project), which is an air launched cruise missile equipped with a device that can be aimed at a ground target and hit it with a burst of microwave energy that disables (by damaging many microelectronics components) computers, radios, GPS, and any electronic equipment that is not “hardened” (built with casings that keep out the microwave radiation). For the CHAMP test the missile aimed its beam at seven different ground targets (buildings containing various types of military and civilian electronic equipment) and disabled nearly all the electronic items. After attacking all these targets, the missile crashed. A combat version would contain some explosives that would destroy the microwave device sufficiently so that it could not be easily duplicated. This is not a major issue, since this technology is already widespread. China is believed to be developing microwave devices that can attack American aircraft and ships. This is a difficult task because military equipment is built to withstand such microwave attacks. But if the microwave beam is strong enough, something might get hurt. There is also the possibility that some hardened military equipment had a component or two that was not hardened enough
The air force did not give out a lot of details but devices like this have been around for a while. All this is done using high-powered microwave (HPM) devices to create something like the EMP (Electromagnetic Pulse) put out by nuclear weapons, which damaged or destroys microelectronics. There are several ways to do this.
The most commonly mentioned devise to generate HPM is the AESA (Active Electronically Scanned Array) radars that are becoming standard equipment in modern warplanes. AESA is more reliable and, increasingly, no more expensive than the older mechanical (a small dish that moves around inside a dome) radar. AESA is also easier and cheaper to maintain, which makes a more expensive AESA cheaper, over its lifetime, than a cheaper (to buy) mechanically scanned radar.
AESA type radars have been around a long time, popular mainly for their ability deal with lots of targets simultaneously and produce a more accurate picture of what is out there. AESA radar consists of thousands of tiny radars that can be independently aimed in different directions. An AESA radar made the U.S. E-8 JSTARS aircraft possible, as it enabled it to locate vehicles moving on the ground. An innovative and much smaller MP-RTIP AESA radar for the RQ-4 Global Hawk UAV can also spot smaller objects on the ground. Alas this AESA radar is used at high altitude (over 10 kilometers/31,000 feet), too far for a high-energy (electronics destroying) signal. But other UAVs, like Reaper, are cheaper and fly lower, low enough to zap ground targets with the electronics-destroying beam. For heavily defended or very distant targets the cruise missile approach, while more expensive, would get the job done.
While AESA makes fighters much more effective, it's the many other uses of AESA that make this technology so attractive to warplane designers. For example, the U.S. Air Force has been equipping some of its fighters with the ability to focus the high-powered microwave (HPM) effects found in AESA radar technology. AESA is able to focus a concentrated beam of radio energy that could damage electronic components of a distant target. The air force won’t, for obvious reasons, discuss the exact “kill range” of the various models of AESA radars on American warplanes (the F-35 and F-22 have them). However, it is known that “range” in this case is an elastic thing. Depending on how well the target electronics are hardened against EMP, more electrical power will be required to do damage. Moreover, the electrical power of the various AESA radars in service varies as well. The air force has said that the larger AESA radars it is developing would be able to zap cruise missile guidance systems up to 180 kilometers away. CHAMP solves the distance problem by flying low and slow, thus getting close enough to do some real damage to electronics below. Moreover, cruise missiles like the Tomahawk weight 1.4 tons and have a half ton payload, which is sufficient for the generator and HPM device. The latest version of Tomahawk already has the ability to be controlled after launch.
A decade ago a British military research team announced that they had duplicated the rumored Russian device and produced an EMP bomb that can fit in a 155mm artillery shell, small rockets, or bombs. Such a device was supposed to be inexpensive and could be used to destroy civilian electronics that might be useful to nearby enemy troops. CHAMP appears to be a further development of these 1990s ideas.
What is particularly worrisome about this new development is that, in the hands of terrorists, it could do a new kind of damage. While not killing people directly, the destruction of all electronics within an urban area could cause casualties and much economic loss. Except for CHAMP none of these EMP bombs or similar weapons have ever reached the stage where they were actually ready to use. There was always some kind of flaw discovered in testing. The revelations about CHAMP indicate that progress is continuing.