Patent attributes
An antenna useful in an antenna array of a man-portable buried utility locator includes a flexible bobbin made of copper foil. The bobbin has a plurality of axially spaced grooves and an axially extending gap formed therein. A layer of insulation surrounds an outer surface of the bobbin. A conductive wire is disposed in the grooves and wound around the bobbin over the layer of insulation to form a plurality of axially spaced sub-coils. A layer of copper-foil tape having an insulating backing is wound about the conductive wire and has a second gap aligned with the gap in the bobbin. A layer of a low dielectric material is wound about the copper-foil tape. The antenna provides more antenna wire surface for an equivalent coil cross-sectional area, compared to prior art antennas, thus yielding greater sensitivity. The construction of the antenna provides a series of Faraday-shielded sub-coils, which yield a greater useful antenna bandwidth by moving the inherent resonance of each coil to a higher frequency. The construction of the antenna also reduces inherent winding capacitance and provides a self-shielding effect that further improves sensitivity.
