Abstract
We studied on circularly polarized wave characteristics of a normal mode herical antenna. The normal mode herical antenna consists of a series connection structure of infinitesimal dipole antenna and infinitesimal circular loop antenna. Therefore it's expected to have circularly polarized wave when the magnitude of electric field of dipole and that of circular loop are equal and their phase difference is 90°. In this paper, with moment method, we exerimined the shape of the normal mode herical antenna with good axial ratio. As the results, parameters for the normal mode herical antenna with axial ratio less than 0.15dB in all directions in the vertical plane are as follows; at 1000MHz(wavelength λ=30cm), herical circumference radius r=1cm=λ/30, pitch p=0.6cm=λ/50, number of turn t=2.5turns.
