Imaginary part of antenna´s admittance from its real part using Bode´s integrals

The imaginary part of an antenna input admittance is calculated from its real part using Bode´s integrals. Since the real part is typically a smoother function of the frequency than the imaginary part, the procedure presented here requires computation at a smaller number of frequency points, thus saves time, and is ideal for systems whose input conductance exhibits sharp peaks. A numerical procedure to evaluate the singular Bode´s integral is also presented. Numerical examples using a wire antenna are used to illustrate the advantages of this approach compared to calculations involving a densely scanned frequency range. The noise stability and robustness of the algorithm are demonstrated through the successful prediction of the susceptance and the resonant frequencies of the antenna in the presence of random noise in the conductance