Note: Derivative divide, a method for the analysis of broadband ferromagnetic resonance in the frequency domain

Broadband ferromagnetic resonance (bbFMR) spectroscopy is an established experimental tool to quantify magnetic properties. Due to frequency-dependent transmission of the microwave setup, bbFMR measurements in the frequency domain require a suitable background removal method. Here, we present a measurement and data analysis protocol that allows to perform quantitative frequency-swept bbFMR measurements without the need for a calibration of the microwave setup. The method, its limitations and advantages are described in detail. Finally the method is applied to evaluate FMR spectra of a permalloy thin film. The extracted material parameters are in very good agreement with those obtained using a conventional analysis in field-space.