3D simulation of superconducting microwave devices with an electromagnetic-field simulator

High-frequency microwave applications, such as filters, delay lines, and resonators, are quite important for superconducting electronic devices. In order to design the superconducting microwave devices, circuit parameters should be precisely extracted from the physical structure of the devices. A 3-dimensional electromagnetic-field simulator is very useful for designing microwave devices. However, designing of superconducting microwave devices using a conventional 3D electromagnetic-field simulator is difficult because most of commercially available 3D electromagnetic-field simulators can not exactly characterize electromagnetic phenomena of superconductors. In this study, a novel calculation method of superconducting microwave devices, which can be applicable to a conventional 3D electromagnetic-field simulator, has been proposed. Calculation results of characteristic impedance of superconducting microstrip lines show very good agreements with the theoretically calculated vales. The frequency response of a superconducting Nb microwave filter designed by the proposed calculation method agrees well with the experimental results. This calculation method enables us to precisely estimate microwave characteristics of superconducting devices.