Abstract: A marking tape comprising at least one resonant circuit, each resonant circuit comprising an inductive coil and a capacitor, forming a resonant circuit of a selected frequency, comprises inductive coils and capacitors formed by conductive material layers (2, 3, 4) on the surfaces of a dielectric plastic film (1) and is dimensioned to be wireless detected when positioned in a hidden location. Such marking tape can be produced with low cost and provide a wireless detection of the integrity of a marking tape in a hidden position, e.g. from the surface above a subterranean positioned marking tape.

Abstract: A resonance security tag (1) comprises a dielectric foil material (2) provided with conductive material layer patterns (3-7) on both sides. The conductive material layer patterns are formed to provide an inductor (3) and a capacitor (4, 6) positioned inside the inductor (3), and mutually connected to form a resonance circuit. By cutting (9) the capacitor (4, 6) free of the dielectric foil material (2) and folding the capacitor (4, 6) away from the position inside the inductor (3), this part is left free for the penetration of magnetic flux through the inductor (3), whereby the detection level is improved and a possibility of reducing the size of the resonance security tag is provided.

Abstract: A method for producing a deactivatable tag is described including first short circuiting two opposite conductive layers at a predetermined place by using a heated tool applied on one of the layers, thereby permanently deforming such layer to produce a short, checking the quality of the short, and if the quality of the short is satisfactory, then connecting the two conductive layers with a crimp to obtain the desired frequency and finally removing the short by electrically or mechanically removing the short circuit to thereby bring the tag in the desired form ready for use and deactivation.

Abstract: In order to produce labels incorporating electrical oscillating circuits, certain parts of the circuits are initially punched out of a center area of a metal web covered by an adhesive. Thereafter the center area is covered by an insulating material web for handling stability in order to thereafter punch out the part of the circuit to be located at the outer web area. A covering foil is laminated onto the metal web and the parts of the circuits to be located at the reverse side are applied onto the insulating material web and connected electrically to the remainder of the circuit. This allows an economical and yet precise mass production of labels, for instance for a use in article safeguarding and controlling systems.

Abstract: The most essential of this novel production method of planar circuit or oscillating circuits is that the most important steps for extricating the conduit tracts on at least one electrically conductive layers is performed by laser beams, whereby already the initial reference points for the plurality of circuits to be produced are practically simultaneously applied by lasers and the application of the laser technique allows, furthermore, an exact correcting of the elements of the circuit by a simple reworking and highly precise circuits are formed which are extremely economically produced.