THE INFLUENCE OF FINITE CONDUCTOR THICKNESS AND CONDUCTIVITY ON FUNDAMENTAL AND HIGHER-ORDER MODES IN MINIATURE HYBRID MICS (MHMICS) AND MMICS

This paper presents a rigorous analysis of the effect of finite metall ization thickness and finite conductivity on the propagation character istics of conductor-backed CPW on thin substrate. A self-consistent ap proach is used together with the method of lines (MoL) to determine th e propagation constant, losses and field distribution of the fundament al and first two higher-order modes in CPW's with finite metallization thickness and lossy backmetallization. The method used is general and can be applied to miniature MIC's (MHMIC) and MMIC's including lossy semiconductor substrate. It is shown that the onset of higher order mo des limits the usable frequency range of conductor backed CPW. The ana lysis includes also microstrip transmission lines on thin substrate ma terial. It is demonstrated that a resistive strip embedded into the mi crostrip groundplane may potentially be useful in the design of integr ated planar attenuators.