Current Distribution of a Cylindrical Antenna in a Warm Plasma

The current distribution of a center-fed dipole cylindrical antenna of arbitrary dimension immersed in unbounded lossless warm plasma is considered, taking into account the commonly neglected end-cap effect. The approximated solution of the integral equation for the current distribution is obtained with the aid of Fourier analysis, and the expression is derived for the current distribution I(z) as the function of position z along the cylindrical surface of the antenna. Sample calculations are made for a half-wavelength dipole antenna with different values of thickness parameter τ=(a/l)<0.25 and of the normalized plasma density parameter po=(ωp/ω)2 <1. Here a and l denote the radius and the half-length of the antenna, respectively. ωp and ω denote the plasma angular frequency and the radiation angular frequency. The variation of the amplitude and phase of the current with the position, and the variation of radiation resistance with po and τ are examined and discussed in detail.