On the equivalence between normal mode helical and coated wire antennas

Both normal mode helical and coated wire antennas are widely designed for many applications due to their smaller physical size while exhibiting the similar radiation pattern compared to bare dipole antennas. Sometimes these two kinds of antennas have the identical performance properties. The purpose is to investigate the equivalence between normal mode helical and coated wire antennas and derive the equivalent relationship. Different antenna configurations are analyzed using a full-wave modeling code to confirm the validity of this equivalent relationship. Radiation properties including input admittance over a wide frequency range and radian pattern near the resonance are considered. Good agreements are obtained for each set of normal mode helical and coated wire antenna under the equivalent conditions, which can be used by engineers to flexibly choose different structures, coated wire or helix, for miniaturization in practical design cases.