Equivalent isotropic relative permittivity of microstrip on multilayer anisotropic substrate

A closed-form model to obtain the equivalent isotropic relative permittivity of the multilayer microstrip line on the anisotropic substrate for 0 w/h10, anisotropic ratio 0.5n3 for both low and high permittivity substrates is reported. The model has accuracy 0.5% against the full-wave method. It computes effective relative permittivity and characteristic impedance of microstrip on composite anisotropic substrates with deviations 5.3% and 1.78%, respectively against the EM-software Empire. It is used to obtain dispersion in multilayer anisotropic substrate microstrip up to millimetre wave range with high accuracy against the results of HFSS.