Analysis of rectangular spiral transformers for MMIC applications

Multidielectric planar structures such as transformers and triformers are analyzed by cascading multidimensional chain matrices. The distributed-line model facilitates the use of these elements in microwave monolithic integrated circuits (MMIC) applications as wideband transformers and baluns. High-speed routines suitable for inclusion in computer-aided design packages for desktop PCs are implemented and used to calculate S parameters. Wideband MMIC triformers are fabricated and measured, showing good agreement between theory and measurement over the frequency range 1-10 GHz