OPTIMIZATION OF SLOTTED WAVEGUIDE FEEDING FOR 2.45 GHz APPLICATORS USING NEW SLOT SHAPE

Sebastijan Stanculovic^1,2, Lambert Feher² and Manfred Thumm^1,2

University of Karlsruhe, Institute for Highfrequency Techniques and Electronics, Kaiserstr. 12,

76128 Karlsruhe, Germany

Forschungszentrum Karlsruhe, Institute for Pulsed Power and Microwave Technology,

Hermann-von-Helmholtz-Platz-1, 76344 Eggenstein-Leopoldshafen, Germany

Abstract

High temperature microwave processing of materials shows shorter processing time and reduced energy consumption and gives economic benefits with respect to conventional material processing technology. Analysis of high efficient microwave heating systems for industrial applications at 2.45 GHz frequency suggests further optimization of the energy feeding elements. Slotted waveguide radiators are very desirable for this process, because their parameters like shape, length, width and position of the slots, have a strong influence on the applicator properties. They determine the amount of coupled energy from the feeding waveguide into the applicator and also effect the uniformity of heating. Using commercial numerical solvers for 3D electromagntic field calculations, the influence of novel slot shapes on the system characteristic is investigated and compared with characteristics of the conventional systems having common rectangular narrow slots. Magnitude of the S₁₁ parameter of the systems and Poynting vector patterns for different loads are numerically determined. It is shown that the new slot shape is more appropriate for the design of microwave applicators than the conventional one. Measurements of reflection coefficients with a vector network analyzer and determination of heating patterns using an infrared camera will be performed to verify the computationally obtained results.