Miniature Four-Band CPW-Fed Antenna for RFID/WiMAX/WLAN Applications

A novel four-band coplanar waveguide (CPW)-fed antenna is designed for RFID/WiMAX/WLAN applications. The design is optimized to operate at 0.945, 2.50, 3.50, and 5.80 GHz using the finite element method. In this design, two U-shaped, two F-shaped, and four L-shaped branches are used as additional resonators to achieve multiband operation. Simulated results show that the 30 x 30-mm(2) antenna achieves less than -10 dB reflection coefficient at the targeted frequencies. Measured results are given to validate the antenna's performance. Although the proposed antenna attenuates a bit at some frequencies, measured S-11 is less than -6.5 dB at all frequencies, and it is less than -19 dB at 2.50 GHz.