Dual-band loop-loaded printed dipole array with a corporate balun/feed structure

A novel loop-loaded printed dipole (LLPD) antenna array is introduced for a dual-band operation at 3.0/5.5 GHz bands. As the loop elements placed on the dipole aperture provide the dual-band operation, a new corporate balun/feed structure is employed to achieve balanced and matched excitation for the array. The simulation and measurement results for 1 x 1, 2 x 2 and 4 x 4 LLPD array designs are presented, demonstrating quite well agreement. In particular, the 4 x 4 design offers better than 17% impedance bandwidth and a realised gain of at least 15 dBi with tolerable side-lobe levels at the designated frequency bands.