Patent ID: 7122772

Claim:
A microwave resonator for the thermal processing of materials by means of microwaves, comprising a high mode resonator with an even number convex polygonal cross-section having wall segments and planar front sides and longitudinal edges formed between two immediately adjacent wall sections and extending parallel to the longitudinal axis of the resonator, at least two in-coupling structures arranged on said wall segments at opposite sides of, and along, at least one longitudinal wall edge, each in-coupling structure being arranged along a straight guide line which extends parallel to the longitudinal wall edge of the resonator wall, the straight guide line being disposed in spaced relationship to the associated longitudinal wall edge such that the microwave beam coupled thereby into the resonator is reflected with the first reflection by two adjacent wall area segments and divided into two beam parts, wherein: each in-coupling structure is connected to the end of a rectangular hollow conductor which is associated with a microwave source and carries a microwave in a TE 01 -mode, and the in-coupling structure into the wall area segment consists of a series of non-overlapping equidistant openings in the resonator wall, which are arranged alternately at opposite sides of the respective straight guide line extending parallel to the longitudinal wall edge, the incoupling openings being spaced so as to provide for a phase-constant out-coupling into the resonator of the microwave present in the rectangular hollow conductor in the base mode TE 01 , and the width of the opening being determined approximately from the condition for small refraction angles Θ with predetermined microwave length λ from tan Θ=λ/ d and for very small refraction angles Θ from Θ=λ/ d.