Impedance of a dipole antenna in a cold collisional plasma: theory and ionospheric measurements

Summary form only given, as follows. The impedance of a finite dipole antenna immersed into a cold collisional magnetoplasma is evaluated using a quasi-static theory. Different possible current distributions on the antenna surface are considered and their influence on the antenna impedance is studied. The closed form solution is obtained for a collisionless plasma. Conclusions about the significance of an assumed current distribution are drawn and results are compared with those of Balmain (1969) and others. Simple single quadrature formulas are obtained for a dipole with an exponential current distribution in a collisional plasma. The impedance behavior around the upper hybrid resonance and its application to an ionospheric plasma diagnostics is studied. This includes the upper hybrid frequency shift as a function of collision frequency and the appearance of additional resonances for a highly collisional ionospheric plasma. These theoretical results are compared with measurements from an antenna immersed in an ionospheric plasma flown from Puerto Rico in February of 1998.