Theoretical dielectric loss effects in superconducting transmission lines

The author proposes a method based on a Fourier cosine Series approximation, using frequency as the variable. The series can fit the frequency-dependent resistance or conductance per unit length, automatically providing a sine series approximation to the frequency-dependent capacitive susceptance per unit length. The advantage of using a cosine series is that the coefficients are easily computed. The real and imaginary parts are easily determined numerically, and this model does not have poles, or other numerical singularities. An advantage of the proposed model over others is that it can be close to measured data with the frequency band of interest, although a wavefront is not very sensitive to the details of frequency dependence