It really depends on how advanced the technology you want to make it

My instinct is if you wanted a repeatable shotgun I was thinking a phased array system but ultra high wattage and small enough to fit into a shotgun or shotgun-like form factor. (with supporting phased array antennas to clean up the wave that travels opposite and laterally to the shotgun direction I guess. Its going to have to be a very complicated song and dance but the closest tech we have is phased array radar)

down and dirty? Just have a emp coil shorting across a massive capacitor and hopefully a grounded shielding cone can eat some of the energy going in directions that weren't desired.

Granted this is conjecture and I will most likely be mistaken on how EMP's work.

It really depends on how advanced the technology you want to make it

My instinct is if you wanted a repeatable shotgun I was thinking a phased array system but ultra high wattage and small enough to fit into a shotgun or shotgun-like form factor. (with supporting phased array antennas to clean up the wave that travels opposite and laterally to the shotgun direction I guess. Its going to have to be a very complicated song and dance but the closest tech we have is phased array radar) Edit: Comms antenna, proximity radar, etc. -- anything that could have a phased array antenna in it

down and dirty? Just have a emp coil shorting across a massive capacitor and hopefully a grounded shielding cone can eat some of the energy going in directions that weren't desired.

Granted this is conjecture and I will most likely be mistaken on how EMP's work.