A microwave radiator assembly comprising an oven cavity, an antenna chamber communicating with the oven cavity by radiation openings and an antenna structure energized by a microwave generator. The introduction of radiation into the oven cavity is effected by an arrangement comprising a metallic plate in which said radiation openings are carried out and a coupling pin mounted in a microwave-transparent plate projecting through each opening forming coaxial paths into the oven chamber.
An energy feed system for microwave ovens includes a substantially symmetrical planar conductor system of the microstrip-line type having a central feeding point where energy from a microwave source is applied to the conductor system. The feeding point is surrounded on all sides by a conducting plate from which a number, preferably four, radial plates extend. Openings are formed between the plates which widen outwardly. The radial plates are surrounded by at least one closed annular conductor which receives energy from the radial plates.
A combination microwave and electrically heated oven having a door with a high temperature seal which inhibits the escape of hot gases around the periphery of the door and which is isolated from the major portion of the electric fields of the microwave energy entering the space between the door and the oven aperture walls by a slotted choke microwave seal so that the vapor seal may be formed which high microwave energy absorption characteristics without either reducing the intensity of microwave energy in the oven or causing substantial heating of the vapor seal by microwave energy.
An excitation system for a microwave oven in which a rotating microwave field is established in a waveguide section prior to being propagated into the microwave oven cavity. A circular waveguide has an internal L-shaped rotating antenna excited from a coupling probe in an attached rectangular waveguide to establish in the waveguide a stationary TM01 and a TE11 mode. These modes interact in the waveguide to give an asymmetric rotating waveguide field which is then propagated into the oven to provide a rotating field pattern of desirable average uniformity. The excitation circular waveguide is located in a central position on the bottom wall of the oven.
A method for microwave assisted chemical processes is disclosed that comprises applying sufficient microwave radiation to a temperature-monitored mixture of reagents, with at least one of the reagents being thermally responsive to electromagnetic radiation in the microwave range, and based on the monitored temperature, to maintain the added reagents at or closely about a predetermined temperature while substantially avoiding thermal dilution (or before substantial thermal dilution can occur) that otherwise would have been caused by the addition of the reagents to one another.
A microwave processing system is disclosed. The system is particularly useful for concurrently controlling a plurality of chemical reactions from a single microwave source. The system comprises a source that produces electromagnetic radiation in the microwave range; a waveguide in communication with the source and into which the source propagates microwave radiation; a resonator in communication with the waveguide; and an adjustable dynamic moderating device between the waveguide and the resonator for moderating the wave energy passing from the waveguide to the resonator without substantially changing the propagated mode in the waveguide.
