Quad-Band CPW-Fed Monopole Antenna Based on Flexible Pentangle-Loop Radiator

A novel low-profile monopole antenna fabricated on flexible substrate based on a pentangle-loop radiator is presented and investigated in this letter. The proposed antenna is designed to operate at GPS L2/Bluetooth/WiMAX/wireless local-area network frequency bands. To maintain the small size of the antenna element, an improved pentangle loop is adopted and the higher order modes are also utilized. Also, a pair of symmetrical V-shaped parasitic radiators and a modified rectangular ground plane of the coplanar-waveguide feeding structure are used to improve impedance matching at higher bands. The proposed antenna is fabricated on flexible substrate which can be easy to integrate in wireless systems. Its experimental results shows good agreement with the simulated results.