Open-Circuit One-Port Network Analyzer Ferromagnetic Resonance

Broadband spectrometers based on transmission coplanar waveguides have recently found much success for extracting the frequency dependent magnetic permeability. Here, we describe a simpler instrument based on a coplanar waveguide terminated by an open-circuit. This geometry and the associated standing wave ensure that the permeability is measured in the low excitation regime. We demonstrate a scheme to transform reflexion parameters into permeability spectra, and compare our evaluation method to measurements performed using the standardized transmission geometry.