Spin wave resonance (SWR) spectrum of an ensemble of permalloy ferromagnetic nanostripes (thickness T = 100 nm, width w = 300 nm, and length L = 100 μm): bottom curve in red: derivative spectrum, as measured at Q band (f = 34 GHz) with a magnetic field applied in the plane of the nanostripes, along the width w; top curve inblue: absorption spectrum, as numerically simulated without any free parameter (and without considering the differentoscillator strengths of the various SWR).