Quasi-Isotropic Radiation Pattern Synthesis Using Triple Current Line Sources

This communication proposes a design method to synthesize a quasi-isotropic radiation pattern with a planar antenna structure. The proposed method is based on the combination of triple current line sources. As a demonstrated example, a pair of out-of-phase line sources is combined with another orthogonal line source for radiation pattern synthesis. By optimizing the spatial distance in the proposed triple current line source model, quasi-isotropic radiation performance can be realized with theoretical analyses, showing that the gain variation (i.e., the maximum gain minuses the minimum gain) of the proposed method is 0.53 dB. As a proof of concept, a folded dipole antenna is designed and fabricated to verify the proposed method. Full-wave simulation shows the gain variation of the folded dipole antenna is 1.37 dB and measured result is 3.62 dB.