Formation of hotspots in partially filled ferrite-loaded rectangular waveguides

We theoretically investigate the formation of hotspots at microwave frequencies in a partially filled, ferrite-loaded rectangular waveguide. When the unidirectional mode of this waveguide approaches an impenetrable conducting barrier, its magnetic field rises sharply due to the absence of reflection. To study this phenomenon, we use the magnetostatic approximation and derive a surface integral equation for the normal component of magnetic flux density on the surface of the ferrite layer. For a half-filled waveguide, an analytic solution is found, which shows the magnetic field to diverge near the barrier as vertical bar x vertical bar(-q), where vertical bar x vertical bar is the distance from the barrier edge and q is slightly less than unity. For filling factors other than one-half, the numerical solution of the surface integral equation again confirms the appearance of a hotspot near the barrier edge. Published by AIP Publishing.