Abstract: The present invention is primarily related to the composition of an aqueous etchant containing a precursor of oxidant and patterning methods for conductive circuits, in which the chemical structure of the precursor contains chlorine and can produce oxidants through various reactions. And, the patterned conductive circuits can be used for electronic devices, including printed electronics, sensors, displays, organic light emitting diodes (OLED), touch panels, electronic circuit boards, electrodes, electroluminescent (EL) films, antennas, and solar cells.

Abstract: The present invention is an antenna structure of a radio frequency identification system transponder, especially an antenna structure wherein an insulation layer and a foldback circuit, an opening of which faces toward a coupling part, are provided at corresponding positions of an antenna body which is provided with the coupling part. The foldback circuit is provided with a radio frequency integrated circuit, such that radio signals can be transmitted by induction by the foldback circuit and the coupling part. By this foldback circuit, an issue of directivity of the radio signals can be reduced, an effective read range of the radio signals can be increased, as well as a near field induction function and a far field induction function can be provided at a same time. Therefore, when manufacturing an RFID transponder, a production speed can be increased and production cost can be reduced.