You can enable it, but there is a good reason why it is disabled. Before early game phase design, you could land troops anywhere on the map (like right up on your door step to your base), since they went to reinforcement points landing only, that made the Shutter Shield redundent and screws up gameplay.
Shutter Shield will stop ALL bombing runs by an invading enemy 100% all across the land map though.
Only human players MP can really build the shutter shield. The AI does not understand to build it would seem, and it screws up the biuld queue...it will not build any shield! Still not 100% sure on that.
The particle shield is just an upgrade option for the regular shield by clicking on it (cost 1800 credits IIRC). That is not obvious while playing.
You can modify the regular shield to include the 10000 range no bombing run ability of the shutter shield by simple increasing its range. The regular shield is set for 800. Just change to 10,000 like the shutter shield.