Network representation of planar microwave discontinuities: potential and limitation

A novel deterministic quasi-static space-spectral domain approach is introduced to analyze capacitive planar circuit discontinuities. Capacitance parameters for a wide range of planar circuit discontinuities, including CPW (coplanar waveguide) air bridges, can be calculated using this deterministic quasi-static method. It was found that, for miniature line dimensions, the proposed approach is effective at frequencies higher than 40 GHz. Line dimensions with the potential of noticeable dispersion can only be characterized up to 20 GHz. A comparison with full-wave techniques shows that, as long as low-dispersive planar transmission lines are used, results obtained from quasi-static methods are very useful for fast CAD (computer-aided design) of miniature hybrid microwave integrated circuits (MHMICs) and monolithic MICs.<>