Electromagnetic Pulse Grenades
There are rumors of a prototype:
Even the highly advanced US forces hadn’t been generally thought to have developed a successful pulse-bomb yet, with most reports indicating that such a capability remains a few years off (as has been the case for decades). Furthermore, the pulse ordnance has usually been seen as large and heavy, in the same league as an aircraft bomb or cruise missile warhead — or in the case of an HPM raygun, of a weapons-pod or aircraft payload size.
Now, however, it appears that in fact the US military has already managed to get the coveted pulse-bomb tech down to grenade size. Colonel Buckhout apparently envisages the Army electronic warfare troopers of tomorrow lobbing a pulse grenade through the window of an enemy command post or similar, so knocking out all their comms.