A Wideband Compact Filtering Array Antenna Using Two Sections L-CRLH Impedance Transformer

In this paper, a new two-elements wideband circular monopole array antenna is presented. The array is fed by a new compact two-sections wideband impedance transformer. The transformer is comprised of two unit cells of inductor loaded composite right/left handed (L-CRLH) transmission line. The L-CRLH transformer has a size of 9.3×15.3 mm
²
≡0.54× 1.07 λg
²
, at mid frequency; 80% miniaturized compared to conventional design. The simulation results confirm that the transformer has a return loss less than 10 dB and insertion loss less than 0.02 dB within the passband. Consequently, the array antenna has wideband 10 dB return loss bandwidth from 1.6 GHz – 3.3 GHz (70%) with 3 dB out of band at 0.95 GHz and 3.95 GHz.