Antenna protected from dielectric breakdown and sensor or switchgear apparatus including the same

A switchgear apparatus includes a switchgear device, such as a circuit breaker, having a power bus, and an antenna element including an antenna member and one or more antenna leads. A material encapsulates the antenna member and is adapted to suppress dielectric breakdown through the material to the encapsulated antenna member from the power bus. The circuit breaker also includes a conductive housing having an opening receiving the antenna leads. The conductive housing is mounted on or proximate to the power bus. A sensor circuit is disposed in the conductive housing and is adapted to output a radio frequency signal to the antenna leads or to input a radio frequency signal from the antenna leads.