Sokymat S.a.

Martin Miehling

Reinhard Jurisch

Peter Peitsch

Egon Konopitzky

Philippe Held

A transponder unit which can be integrated in a transport unit or a card or the like. The transponder unit includes, in addition to an encapsulated transponder of an integrated circuit, an aerial winding having a resistance Rand a capacitor parallel thereto and having a capacitance C. A closed coupling circuit of secondary winding is coupled with the aerial winding by a mutual inductance Mand a substantially larger primary winding in series with the secondary winding and having fewer turns, for example only one turn. To achieve almost optimum energy transfer between a reading device and the transponder and to increase the permissible reading distance, the mutual inductance Mis adjusted to comply with the relationship M=&#x221a;{square root over ( )}[R/&#x3c9;) (L+L+2M)], where &#x3c9;=1/(LC) is true for the receiving frequency &#x3c9; of the transponder and Land Lare the inductances of the primary winding and of the secondary winding and Mis their mutual inductance.

Transponder unit and transport unit and card

A transponder contains an integrated circuit, a power transmitting component (antenna) and a capsule made of a thermoplastic resin (hot glue) that surrounds the circuit continuously at least on one surface of the circuit. The glue preferably is a polyamide and surrounds the circuit protectively, ensuring a mechanical connection between the circuit and the antenna. The encapsulation with the hot glue is conducted at pressures and temperatures that are below the pressures and temperatures encountered during conventional injection molding. The transponder can be integrated into an injection molded part, for example a coin, by being placed in an injection mold in which it is supported by feet and then surrounded by molding material in a conventional injection molding process so that it develops a more resistant sheath.

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Granges, Switzerland

Martin Miehling