Abstract
In this framework, novel ultra wideband (UWB) small antennas based on the composite right/left-handed transmission lines structures are proposed and designed. The antennas are presented with best in size, bandwidth and radiation patterns. The physical size and the operational frequency of the antennas depend on the unit cell size and the equivalent transmission line model parameters of the CRLH-TL. To realize specifications of the proposed antennas, Q-shaped gaps, which are incised into rectangular radiation patches, are used. The first CRLH antenna is composed of two unit cells, each of which occupies only 10.8 mm × 8.6 mm. This antenna covers the bandwidth from about 2.7–9.3 GHz for VSWR <2. The antenna radiation gains and efficiencies, obtained by ADS, HFSS and CST Microwave Studio simulators, are more than 4 dBi and 25%, respectively. Moreover, second CRLH antenna with same in size and enhancement in bandwidth, gains and efficiencies than the first antenna with similar design procedure is designed. This antenna is constructed of four unit cells. The length, width and height of the antenna are 21.6 mm, 8.6 mm and 1.6 mm, respectively, and this antenna covers bandwidth from almost 4–11.7 GHz for VSWR <2, also radiation gains and efficiencies, achieved with mentioned simulators, are more than 6 dBi and 45%, respectively.