Magnetically Tunable Ferrite-Loaded Half-Mode Substrate Integrated Waveguide

A magnetically tunable ferrite-loaded half-mode substrate integrated waveguide (HMSIW) is presented. To achieve the magnetic tuning, a planar Yttrium Iron Garnet (YIG) slab is loaded along the metalized wall of the HMSIW, where the concentration of the magnetic field is strongest. Static (DC) magnetic bias is applied on the ferrite slab transversely to the direction of propagation. Measured phases of forward and reverse transmission coefficients show the non-reciprocal behavior of this transmission line. Measured results illustrating the comparison between a single ferrite slab-loaded SIW and a HMSIW are presented. As an application example, a two-dimensionally tunable bandpass filter (BPF) operating at X-band is proposed and studied. By controlling the value of loaded lumped capacitors and the applied magnetic bias, a bandwidth tunable BPF is demonstrated.