This is a conceptual design for an
EMP gun. The first question to ask is, what is an
EMP, in simple terms? It is a sharp
pulse of
electromagnetic energy across a wide band of
frequencies. Its effect is to
induce destructive oscillations in
electronic equipment.
It should be possible to generate a sufficiently large EMP by directing a short, noisy electrical pulse into some type of broadband antenna. It should be directional, so it can be targeted and not just be an EMP bomb. This will also improve the range of the weapon.
So, our conceptual design now consists of a pulse generator and a broadband directional antenna capable of handling its output and being pointed. The antenna is likely to be high impedance, so the pulse generator should generate a high voltage pulse as well. Ideally, the whole device should be easy to transport, aim, and fire, but that's secondary at this point. A pulse generator that fits the bill is relatively easy to build; a bank of capacitors and an impulse transformer will do the trick nicely. However, a capacitor bank of sufficient energy density is likely to be expensive.
The antenna is trickier. It not only must be efficient over a broad band, it must be directional, preferably with a relatively high gain, and fairly compact. It must also be a good impedance match with the pulse generator output or you risk blowing the pulse generator to hell with the reflected power and not transmitting sufficient forward power through the antenna, rendering it ineffective. I would love it some other noders came and brainstormed possible antenna configurations.
See Also: electromagnetic pulse gun, EMP bomb