Flexible CPW-Fed Fishtail-Shaped Antenna for Dual-Band Applications

A flexible fishtail-shaped antenna for WiMAX and X-band applications is presented in this letter. The proposed antenna is fed by a coplanar waveguide (CPW). Stepped-impedance lines that can provide smooth transitional impedance for improved impedance matching and broadband characteristics are also introduced. The antenna is printed on a 0.127-mm polytetrafluoroethene (PTFE) substrate and occupies a size of 25 × 50 mm
²
. In the lower frequency band, the measured impedance bandwidth for | S11 | ≤ -10 dB is about 200 MHz from 3.4 to 3.6 GHz, while it is about 7 GHz from 7.4 to 14.4 GHz in the upper frequency band. In addition, the antenna demonstrates a low sensitivity to performance degradation due to bending effects, which makes it suitable for integration within portable devices.