A recent issue of Aviation Week had some articles on high-power-microwave weapons. There's a blurred photo of a BAE-developed switching gadget that looks like a coffee-stirrer-sized slab of white ceramic with some dark strips deposited on top. The strips may be something like GaAs or possibly amorphous diamond. It's the heart of a 4x4 inch "tile" emitter.
Each tile apparently has a dc/dc converter and a storage capacitor. The cap is charged to 9KV and the strip thing is blasted by a diode-pumped yag laser. It switches on in picoseconds, dumping 30,000 amps (270 megawatts) into a wideband antenna built into the surface of the tile. A plane can be covered with these to form an electronically-steered transmit antenna capable of beam-forming something like 10 GW of impulse RF, with much higher powers expected in a few years. This will illuminate a stealth aircraft 100 miles away, or fry the electronics of an enemy plane or incoming missile. Navy versions could hit terawatts, enough to shut down everything on an enemy ship. There's talk of using these against roadside munitions, too.
google has a lot of hits.
John