Improved perturbation method of complex permittivity using correction charts for TM010 and TM020 modes of a circular cylindrical cavity

Correction charts to obtain the accurate complex permittivity (ε
_r
and tanδ
_r
) from approximate values ε
_p
and tanδ
_p
by perturbation method were made on the basis of the rigorous analysis for the TM
₀₁₀
and TM
₀₂₀
modes of a circular cavity. Usefulness of these charts is verified from the measured results for four rod samples (Bakelite, Polyethylene, PTFE, Silica glass).