FEM analysis of MMIC microstrip structures up to 40GHz for studying effects of dispersion and physical dimensions on effective dielectric constant and characteristic impedance behaviour

This paper presents a behavioural study of the microstrip´s electrical parameters viz. effective dielectric constant (ε_eff) and characteristic impedance (Z_o) in a multi-layered dielectric medium (MMIC) on a GaAs substrate with a conducting strip of finite thickness. The effects of variation of microstrip width, substrate height and frequency on ε_eff and Z_o have been evaluated up to 40 GHz with the help of a High Frequency Structure Simulator (HFSS) which employs Finite Element Method for solving electromagnetic fields associated with 3D MMIC structures.