Physics-based optimization design of broadband folded dipole antennas through manipulations on Smith chart

A printed folded-dipole antenna of length l and radius a can be made optimally broadband (≈ 40%) with just a few steps of manual manipulation in the Smith chart, on the frequency locus of the folded-dipole. The optimization design procedures are quite simple due to the physics-guided manipulations. During the manipulation steps, the structure changes of the printed folded-dipole is linked with the changes of locations of and speed along the frequency locus, around the Smith chart center. The results indicate the validity of the optimized design method.