Synthesis of heating patterns by interference of microwaves

Synthesis of heating patterns by interference of microwaves and time averag ing of the resulting intensity fields is proposed as a novel approach to mi crowave heating. In the process multiple incident signals which are phase s hifted relative to each other are fed into an applicator inside which they result in interference patterns. The position of the field patterns' peaks and troughs is changed via the relative phase difference between the incide nt signals. An overall mean pattern is the result of time averaging individ ually weighted patterns. Carbon composite blocks located inside a slotted waveguide are exposed to s ignals from two coherent magnetron based sources to demonstrate the idea. T heir results clearly show that individual heating patterns are a function o f relative phase difference between sources as predicted by theory and that only a small number of instantaneous patterns is necessary to realize the desired and predetermined mean distribution pattern. Although the topology is not applicator specific it is limited by the requi rement of interference. This can be inhibited by excessive material losses.