The invention provides a sterically hindered polymer that comprises a water-soluble and non-peptidic polymer backbone having at least one terminus covalently bonded to an alkanoic acid or alkanoic acid derivative, wherein the carbon adjacent to the carbonyl group of the acid or acid derivative group has an alkyl or aryl group pendent thereto. The communication transformer is arranged by that a half way portion of the additional winding 4 along a length direction thereof is electrically connected to a constant potential. The information includes a font type, a recognition assurance level, character code and so on. The surface portion of the top protective layer includes electrical contact pads that are electrically connected with electrical contact pad extensions and with the integrated circuit.