The present disclosure relates to electromagnetic marker devices for locating hidden or buried objects. One embodiment includes an antenna having a plurality of conductive windings enclosed in a housing made of a low dielectric constant material and an electronic circuit including a circuit board having circuit elements disposed thereon and electrically coupled to the conductive windings through a connector. The circuit elements receive an input signal having a first frequency from an above-ground transmitter, convert the input signal to a power supply to power up the electronic circuit, generate, in response to the input signal, an output signal having a second frequency different from the first frequency, and provide the output signal, via the antenna element, to an above-ground receiver.