Abstract
To simultaneously cover multiple wireless services and protocols, the antenna in communication devices should operate over a wide and ultra-wide frequency band. The use of wide/ultrawideband antennas not only lessens the number of antennas necessary to cover multiple frequency bands but also decreases the system complexity, size, and costs. To operate over the ultrawide frequency band, in this paper a CPW-fed small antenna is reported for portable communication devices. The anticipated antenna comprises a bow-tie-shaped patch and two ground planes. One inverted L-shaped and one extended U-shaped ground plane are asymmetrically placed with the main radiator which helps the antenna prototype to realize a functional band of 3.05 - 11.25 GHz (VSWR <= 2). In the functional band, the studied antenna accomplished a maximum peak gain of 4.98 dBi and maximum efficiency of 94.4%. Moreover, it exhibits symmetric omnidirectional radiation patterns and good time-domain behavior. The lucrative characteristics such as simple design, very small size (24.5 x 20 mm2), ultra-wide operating band, good gain and efficiency, stable radiation characteristics, and good time-domain characteristics make it a potential candidate to be used in portable communication devices.