Abstract: The present invention provides a radio frequency identification device comprising an antenna module and a substrate module. The antenna module has a flexible substrate having an antenna circuit forming thereon. A first surface of the flexible substrate further has a first and a second electrical connecting pads coupled to the antenna circuit, wherein the antenna circuit does not pass through a space between the first and second electrical connecting pads. The substrate module comprises a RFID chip and at least one passive element electrically coupled to a substrate having a pair of third electrical connecting pads. A conductive adhesive formed between the first and second electrical connecting pads and the third electrical connecting pads is utilized to couple the antenna module with the substrate module.