I am pretty sure we have at least one topic related to spawn camping where I posted info, that there is no valid and fair way of block spawn camping. I asked for ideas and AFAIK no one bring solution that will be fair and would not be abused by one side (spawn camper, or players who camp on own spawn).
If enemy manage to spawn camp you, it means (in 99% case) that you and your team failed to protect your spawn point(s).
In majority of maps, you have 2 spawn points. Select safe one if other is under enemy fire. Do not allow enemy to flank you and camp your spawn. If you die on spawn, inform your team that there is someone who camp. Give them intel where he is, so they can get rid of him. After spawn, you have few seconds when you are invincible - use it to destroy spawn camper.
We cannot give you force field. Such "bonus" will create waves of spawn campers who will sit on own spawn and try to get points waiting for enemy, by itself being unreachable by opponents.
I cannot recall one multiplayer game that manage to solve spawn camping in fair way. If you know any, point an example and submit adjusted to WT setting idea in Suggestion Section on our forum.