A Generalized Spectral Domain Analysis for Coupled Suspended Microstriplines with Tuning Septums

An efficient computation method is developed for solving the microstrip-type structures in which a number of conducting strips are located on several interfaces of dielectric layers. The method is applied to the coupled suspended microstripline with tuning septums on the underside of the suspending dielectric layer. The numerical solutions obtained by the new method are compared with available data. The method is believed useful in the design of tightly coupled structures such as the 3-dB hybrid as well as of transitions between different transmission lines for microwave and millimeter-wave integrated circuit application.