A thin film spiral microstrip transmission-line using CoZrNb soft magnetic thin film for a quarter wavelength transformer

In order to miniaturize the quarter wavelength transmission-line transformer for high frequency impedance matching, a possibility of a spiral microstrip-line structure with a magnetic/dielectric hybrid structure was investigated. For this purpose, the CoZrNb/polyimide hybrid spiral microstrip-lines with various spiral turns were fabricated and evaluated. From the results, the spiral transmission-line structure enabled to miniaturize the quarter wavelength transformer, whose insertion loss was comparable with that of a straight-line structure.