Microwave and millimeter were computer aided design (CAD) programs currently available do no include the effect of parastic coupling, that is unintended coupling between elements of the circuit not electrically connected. Such coupling can have a significant effect on a circuit's performance as packing densities and frequencies of operation are increased. In this Research Initiation Award, a new method of incorporating parasitic coupling into circuit modeling programs is investigated. The method takes advantage of the weak nature of the coupling (10 to 30 dB) by using a perturbational scheme in which the modifications to the currents in the isolated elements are calculated in a fast, efficient manner. The method promises to improve the speed of existing modeling algorithms significantly, and yet be at least as accurate when realistic roundoff limitations are considered. The algorithm is also speeded up by the development of a uniform, asymptotic expansion of the matrix elements which represent the parasitic coupling. The method will be tested on a number of simple, canonical structures and checked against experimental measurements and results from other available codes.
