On Circuits with Coupled Thick Microstrips

A method for calculation af coupled thick microstrip parameters is presented. The method is employed in analysis- and synthesis procedures (programs) for circuits with multiple coupled strips with arbitrary dimensions on arbitrary isotropic substrates. It is thus possible to analyze and synthesize e.g. interdigital microstrip filters with thick microstrips. The method takes into account losses due to conductor losses, these beeing the most important at practical frequencies. Measured and calculated insertion losses are in agreement, which has made it possible to present an empirical formula for the insertion loss for interdigital microstrip filters of almost any order and type, thus making it possible to find out in advance whether a certain filter is worth making.