Implement antimagic fields as a region. They are a static, possibly invisible region inside which magical effects cannot function, including all of the following effects:

• Completely disables spellcasting both for the player and for monsters.
• Monsters behave as if cancelled, as do you if you are polymorphed.
• Enchantments do not add to AC or weapon to-hit or damage.
• Magical extrinsics are suppressed.
• Potions have no magic effects (so non-magic potions like acid work the same, but e.g. drinking a potion of object detection would consume the potion and do nothing else).
• Scrolls do nothing; they won’t disintegrate when read but won’t do anything else either. “You pronounce the formula, but nothing happens.”
• Wands do nothing; they won’t consume a charge when zapped or engraved with, and can only engrave in the dust.
• Artifacts have no special powers.

The anti-magic field trap could be repurposed into casting one of these rather than draining energy, which could be split off into a different trap type.