Design of a PIFA-Driven Compact Yagi-Type Pattern Diversity Antenna for Handheld Devices

摘要

This letter presents a compact folded-strip printed inverted-F antenna (FS-PIFA) having dipole-like radiation pattern. The designed antenna operates at 2.45-GHz band and offers 5.75% bandwidth. A parametric study of the FS-PIFA is presented to show the effect of symmetry on the quality factor. Next, an FS-PIFA-driven compact Yagi–Uda antenna is designed by using folded strips as passive elements. The dimension of the Yagi antenna is optimized using mutated particle swarm optimization (PSO) algorithm. The designed Yagi–Uda antenna operates in the 2.45-GHz band with front-to-back (F/B) ratio of 17 dB and gain of 4.6 dBi. Finally, a pattern diversity antenna is realized by placing two such Yagi–Uda antennas back to back with a common reflector. The diversity antenna is very compact, and it occupies approximately volume. The port isolation is about 24 dB. The signal envelope correlation coefficient of the diversity antenna is found to be as low as 0.074.