Tunable metamaterial bandstop filter based on ferromagnetic resonance

Tunable wideband microwave bandstop filters have been investigated by experiments and simulations. The negative permeability is realized around the ferromagnetic resonance frequency which can be influenced by the demagnetization factor of the ferrite rods. For the filter composed of two ferrite rods with different size, it exhibits a -3 db stop bandwidth as large as 500 MHz, peak absorption of -40 db and an out-of-stopband insertion loss of -1.5 db. This work provides a new way to fabricate the microwave bandstop filters. (C) 2015 Author(s).