An apparatus that includes two non-coinciding arrangements disposed in an two axes Cartesian coordinate system such that each arrangement having a non-zero projection on a respective axis from among the two axes. Each one of the arrangements includes a pair of oppositely directed, spaced apart, co-axial radiating-capable elements, each of the elements being hollow with internal space, and being slotted throughout its entire extent. A first circuitry coupled to the arrangement and being configured to sense an electric field projection along the axis and to convey it to a first feeding terminal. A second circuitry coupled to a slot of the arrangement and being configured to sense a magnetic field's projection along said axis and to convey it to a first feeding terminal.