Electromagnetic heating apparatus having decoupled excitations

This paper demonstrates improved electromagnetic heating of a load by increasing the isolation (or decoupling) factor between two electromagnetic feed elements. The efficiency of the heating process is measured by the ratio of power absorbed by the heated load to total power delivered by the radio frequency or microwave sources. Intuitively, the use of multiple feeds increases the total power delivered to the load; however, coupling between sources tends to reduce the heating efficiency. The use of filtering techniques, applied between the source and feed elements in a two-port system, is shown to increase isolation between the ports and overall heating efficiency. Measurements with a Vector Network Analyzer (VNA) are presented to verify and quantify the improvement.