The deflector grid is an important part of Federation starships like the USS Enterprise-D. It is a part of the deflector system.

In 2369, Geordi La Forge devised a technique, called warp-power transfer, to channel additional energy generated by the warp drive through the EPS mains to the deflector grid, thereby increasing the sensor capacity of the Enterprise-D by twenty-six percent. (TNG: "Schisms")

The runabout used by Kira Nerys and Julian Bashir in 2370 had a damaged deflector grid. (DS9: "Crossover")