Microwave heating device and method

A method of converting microwave radiation to heat

• placing a microwave reflective member into an area to be irradiated with microwave radiation;
• placing a lossy magnetic ferrite containing material of a type having a Curie temperature, said ferrite being in heat transfer relationship with a surface of said member with said ferrite containing material having thickness (d) in a direction generally normal to said surface such that at the Curie temperature the ferrite containing material will reflect at least about 65% of the impinging microwave radiation in the frequency range of about 300 MHZ to about 10.sup.5 MHZ, said ferrite containing material having a volume resistivity (R) in ohm cm of greater than about a value where Log R=(Tc/100)+2 (where Tc=the Curie temperature in .degree.C. of the ferrite material) at room temperature;
• and
• irradiating said member and said ferrite containing material with microwave radiation thereby causing said ferrite containing material to convert microwave radiation to heat and thereby heat said member.