Dielectric loss in hybrid integrated circuits

The dielectric loss is of importance in hybrid integrated circuits which require small attenuation. Such circuits are usually built with microstrip or suspended microstrip transmission lines. It is shown that the dielectric loss can be computed from the loss tangent tan δ of the dielectric substrate and the partial derivate δεeff/δεrwhere εeffis the effective dielectric constant and εrthe relative dielectric constant of the substrate. The effective loss tangent, the unloaded dielectric Q and the attenuation per unit length are given for microstrip and suspended microstrip transmission lines.