Disclosed is an antenna device having a substrate, an antenna element for transceiving a wireless signal, an antenna signal feeding line for feeding the wireless signal, and an ion-implanted resonant pattern, which includes a first coupling pattern implanted in the substrate by an Ion-implantation process and a second coupling pattern formed at a position corresponding to the first coupling pattern with a predetermined distance therebetween, formed at an adjacent position with respect to the antenna element. As the antenna element transceives the wireless signal of the predetermined radiation frequency and generates an induction voltage, the first coupling pattern and the second coupling pattern each generates a coupled induction voltage and a capacitance therebetween, hence forming a resonance with the antenna element.