The invention relates to a bearing cage including a bearing cage main body made of a polymer material and having pockets for receiving at least one row of rolling elements of a bearing. The cage is provided with a passive resonant circuit including an antenna coil attached to the cage main body. It is proposed that the antenna coil is formed as a conductive layer directly attached to the cage material of the bearing cage main body and is designed so as to have a breaking point less than or equal to a breaking point of the cage material. Thus, a rupture in the cage main body ruptures the antenna coil, changing the resonance behaviour of the passive resonant circuit.