An easy (albeit AIP-increasing) method of dealing with a gate wave is to park a Lightning Warhead on top of the wormhole the wave will appear on. Unless it's a pure Missile Frigate wave, you can count on 80-90% of the enemy ships evaporating without firing a shot.
This is a very powerful tactic that can nullify a wave, however it is a dangerous one also.
Because of the AIP increase warheads cause, using one of these to kill wave results in the next wave being larger, it is very possible to get into a spiral of death where you have to keep warheading waves because the AIP increase from the warheads means your defences never catch up.
So yes, in an emergency situation this can save you from death by killing off an entire AI wave, but if you are using this as a regular tactic the AIP increase will make the waves big enough that eventually even the warhead will not be enough to stop it.
Yes, I learned this the hard way, why do you ask?
Like everything else it is about the tradeoffs you are making while you play the game.
D.