On small antenna impedance in weakly dissipative media

Based on antenna modeling theory, a simple formula is established relating antenna impedance in a dissipative medium to that in free space. The approximation is shown to be valid for small losses (
\alpha/\beta \leq 0.1
) and is restricted to bare perfectly conducting small antennas. An application to a conical unipole is presented, and a simple graphical construction is proposed to derive the required impedance curve in the complex plane from that in free space.