Extremely high frequency in the context of "Brimstone missile"

Brimstone is a ground or air-launched ground attack missile developed by MBDA UK for the UK's Royal Air Force. It was originally intended for "fire-and-forget" use against mass formations of enemy armour, using a millimetre wave (mmW) active radar homing seeker to ensure accuracy even against moving targets. Experience in Afghanistan led to the addition of laser guidance in the dual-mode Brimstone missile, allowing a "spotter" to pick out specific and the highest priority targets, particularly useful to minimise collateral damage when friendly forces or civilians were in the area. The tandem shaped-charge warhead is much more effective against modern tanks than older similar weapons such as the AGM-65G Maverick missile. Three Brimstones are carried on a launcher that occupies a single weapon station, allowing a single aircraft to carry many missiles.

After a protracted development programme, single-mode or "millimetric" Brimstone entered service with RAF Tornado aircraft in 2005, and the dual-mode variant in 2008. The latter was used extensively in Afghanistan and Libya. An improved Brimstone 2 was expected to enter service in October 2012, but problems with the new warhead from TDW and the ROXEL rocket motor put back the planned date to November 2015. MBDA is studying the use of Brimstone on ships, attack helicopters, UAVs, and from surface launchers. However, it will not be integrated on the Lockheed Martin F-35 Lightning II. Germany, Qatar and Saudi Arabia have purchased the missile. The cost per missile has been quoted as £175,000 each in 2015, or "over £100,000".