A particle scattering field was an energy field that, when projected into a planet's ionosphere, caused a hyperionization that disrupted all electromagnetic and subspace carriers, effectively rendering communications and transporter use through impossible. If the scattering field was thin, it may be possible to boost the annular confinement beam to allow transport through.
In 2368, the Tamarians induced a particle scattering field above the planet El-Adrel IV, where they had beamed Captain Jean-Luc Picard and Captain Dathon. This ensured that the both captains were trapped on the surface, though the Tamarians left the sensor channels clear so that the situation could be monitored. (TNG: "Darmok")
In 2377, a group of freed Hirogen prey holograms led by Iden used a scattering field to hide their ship from Hirogen hunting parties. However, their ship still produced a polarized EM signature detectable to sensors. (VOY: "Flesh and Blood")