In this paper, a folded slot active tag antenna for 5.8 GHz radio frequency identification (RFID) applications is presented. It consists of an inverted U-shaped monopole radiator fed by a coplanar waveguide (CPW) feed line and extended ground planes. A 10 dB return loss bandwidth of 5.65-6.55 GHz is achieved. The overall volume of the presented antenna is 10.7 × 11 × 1.6 mm 3. A good agreement between the simulated and measured results is observed. The antenna has an omnidirectional radiation pattern at 5.8 GHz which makes it suitable for RFID applications. It has advantages of compact dimensions and wider bandwidth than previously reported structures.

A double printed rotated quadrilateral dipole UWB antenna for wireless communication is presented. The rotation of quadrilateral and modification of integrated balun structure is employed to enhance bandwidth and impedance matching. The proposed antenna shows impedance bandwidth of 3.8-18.1 GHz which covers the entire C, X and Ku bands. The radiation patterns of the designed antenna structure are relatively stable and omnidirectional over the entire obtained bandwidth with an average gain of 3.6 dB. A good agreement is found between the simulated and experimental results. The proposed antenna has a simple design, comparatively compact size and more bandwidth than previous reported double rhombus antenna.