Inversion field
An inversion field is an energy field that blocks subspace communications and short-range sensors.

In 2370, a T'Lani cruiser generated a broadband inversion field to prevent Benjamin Sisko and Jadzia Dax from calling Starfleet for help. ()

In 2371, the crew of the  encountered an inversion field while investigating a distortion ring in the Delta Quadrant. The field eventually enveloped Voyager when Lieutenant Tuvok flew the ship through the ring. ()

de:Breitbandinversion
Energy fields
Communications technology