Technologies are generally described for transmitting electric power using electromagnetic waves. An example device may include a transmitting unit, a dielectric waveguide, and a receiving unit. The transmitting unit can be configured to transmit the electromagnetic wave through a first waveguide. The dielectric waveguide can be configured to direct the electromagnetic wave from the first waveguide to a second waveguide. Further, the receiving unit can be configured to receive the electromagnetic wave from the dielectric waveguide through the second waveguide. An example borehole radar system may generate an electromagnetic wave from a DC power supply and provide the electromagnetic wave to a power transmitting unit. The power transmitting unit can be configured to transmit the electromagnetic wave through a dielectric waveguide. The electromagnetic wave can be rectified to generate a DC voltage signal, by which a transmitting antenna may be powered to generate a radar signal.