A novel printed folded dipole antenna used for modern RFID system

For the minimization of RFID tag antenna, we designed a printed folded dipole antenna working at 2.4 GHz. And a mirror compensation technology was introduced to improve the radiation feature of antenna with better return loss characteristic and directivity. The simulated results show that when VSWR (vertical standing wave ratio) is less than 2, the antenna bandwidth is up to 0.39 GHz absolutely and to 15.48% relatively. Considering engineering processes, the influences of dielectric constant, board thickness, folding degree and other parameters on the properties of this antenna are particularly studied. On the basis, a dual-frequency folded dipole antenna is proposed, which can work in two main frequency for RFID system, i.e. 915 MHz and 2.4 GHz. Moreover, an antenna sample made on this novel structure has been tested and the results show that the bandwidth of antenna is improved in further, along with hemisphere directional radiation characteristics.