Theory of Space-borne Linear Antennas Fed at Arbitrary Position in an Ionospheric Plasma

In this paper, the current distribution and input impedance of a very low frequency (VLF) antenna fed at the arbitrary position in an anisotropic ionosphere are determined. By considering the ionospheric anisotropy in the VLF band, we obtain the current along the antenna fed at the arbitrary position through the integral equation, with the contributions from both the ordinary and extraordinary waves. This work helps to improve the efficiency of space-borne antennas by analyzing their electrical characteristics.