Hybrid-Mode Analysis of Coupled Microstrip-Slot Resonators

An advanced microwave and millimeter-wave integrated circuit element, that is, a coupled microstrip resonator with a tuning slot, or a coupled microstrip-slot resonator, has been developed. As speciaf cases, a microstrip-slot resonator, coupled microstrip resonator, and microstrip resonator have been investigated. A hybrid-mode analysis is presented for obtaining resonant frequencies. It is based upon Galerkin´s method in the Forier transform domain. The Green functions in this domain, which are versatile and applicable to other microstrip-slot structures, are shown in simple form. Computed resonant frequencies and measured resonant values are compared for aluminum substrates in the 3-7-GHz frequency range.