Card Lamination

An RFID structure comprising:

• an antenna substrate including, on a first surface, an antenna assembly having an antenna track and at least two contact pads;
• an integrated circuit unit coupled to the at least two contact pads;
• a first stack layer positioned adjacent to the first surface of the antenna substrate;
• and
• an unheated unidirectional thermally expansive material separating the antenna substrate and the first stack layer, wherein gaps are defined between one or more portions of the antenna assembly and the thermally expansive material.

An RFID structure comprising:

• an antenna substrate including, on a first surface, an antenna assembly having an antenna track and at least two contact pads;
• an integrated circuit unit coupled to the at least two contact pads;
• a first stack layer positioned adjacent to the first surface of the antenna substrate;
• and
• a previously heated unidirectional thermally expansive material separating the antenna substrate and the first stack layer, wherein gaps formed between the antenna substrate and the first stack layer are at least partially filled by the thermally expansive material.