Pyrometric temperature control system for microwave processing of materials

Summary form only given. Accurate temperature measurements and uniform processing of a material with microwaves can be difficult with thermocouples that perturb the electromagnetic field. Arcing and field intensification is particularly a problem with low loss materials that do not couple well. Optical pyrometers offer a non-invasive alternative, but are generally restricted to surface temperature measurements and are usually non-linear over the temperature range of interest. Improved accuracy over the entire range of interest is possible with an integrated approach using a PC to calibrate the pyrometer against a thermocouple reference. A pyrometer-retrofitted microwave processing system that can measure and control from 40/spl deg/C to 1600/spl deg/C is presented.