A local coil unit for a magnetic resonance apparatus, which radiates a radio-frequency field into an examination subject, has a housing and at least a part of the housing is formed of an insulating dielectric material that passively compensates for an inhomogeneity in the high-frequency field in the subject. The material has a relative dielectric value _r of greater than 50, preferably greater than 100, and a dielectric loss factor tan of less than 2.510^-2, preferably less than 110^-3. In the dielectric material displacement currents are generated which create an additional magnetic field that compensates for the minima in the B1 field as a result of the eddy currents arising in the patient due to the radio-frequency radiation.