Design of a magnetization gradient ferrite substrate integrated waveguide isolator to mitigate higher order mode effects

We demonstrate a new magnetization gradient ferrite approach to mitigate the insertion loss degradation effects of higher order modes in a substrate integrated waveguide isolator. Using a layered gradient magnetization ferrite structure to form a saturation magnetization profile, insertion losses were decreased. Measured insertion losses of the gradient isolator were ~0.1-1 dB compared to 2-4 dB of insertion loss using the nominal isolator. Both simulated and measured results are shown.