Abstract: The present invention relates to an apparatus for heating a sample, such as chemical reaction mixtures, whose dielectric properties varies during the heating process. In particular, the present invention relates to a microwave heating apparatus comprising a microwave generator, a waveguide for guiding the generated microwaves to an applicator, and a deflector formed by a closed loop defining a plane, said deflector having an inherent resonance frequency and a thickness in a direction normal to said plane, the deflector being rotatable around an axis being at least substantially parallel to said plane, the deflector being positioned in the waveguide so as to form a resonant cavity with the sample and the waveguide applicator. The resonance conditions of the resonant cavity and the coupling factor of radiation from the waveguide to the cavity are easily adjustable by rotation of the deflector.

Abstract: A source provides an electromagnetic wave that has a range of frequencies. The source sweeps the frequency of the electromagnetic wave between a cutoff frequency and double the cutoff frequency. The location, angle, or effective angle of an opening is adjusted by an opening adjuster. A path for an electromagnetic wave has a short for creating a standing wave. The path has a movable surface that can push and pull the peaks and valleys of the standing wave so as to achieve more uniform heating of the material. A dielectric wheel pushes and pulls the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A dielectric structure has a surface that has a short side and a long side. A motor rotates the dielectric structure to push and pull the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A path has a first choke flange that has a width w1 and a second choke flange that has a width w2.

Abstract: In a microwave oven system comprising at least one magnetron of a given operating frequency and a mains unit for the at least one magnetron, the at least one magnetron of a given operating frequency is replaceable by a magnetron of another operating frequency. The magnetrons of the different operating frequencies have at least approximately the same mechanical dimensions so that they can be easily replaced quickly. The mains unit can be used for the different magnetrons in unchanged form or in a form involving minor modifications, without any change in the electrical parameters or with a slight change therein, thereby affording interchangeability of the various magnetrons.

Abstract: The microwave applicator for microwaves outputs from a guide (1) comprises an envelope (3) that forces microwaves to converge towards a focal point (16) by means of a complementary central reflector (4). A fraction of the waves reaches this point after reflection on two facets (11, 13), usually curved and concave, of the reflector (4) and the envelope (3), while the other fraction is reflected three times on three facets (10, 12 and 14), the last two facets of which form part of the envelope and one of which is concave for focussing. These devices can be used for removing a concrete surface, because the microwaves cause vaporisation at the focal point (16).

Abstract: A microwave applicator for heating a moving fluid includes a heating chamber having a fluid inlet and a fluid outlet and through which the fluid to be heated flows. The applicator also includes a microwave energy source and a microwave circuit having at least one wave-guide element. The microwave circuit transforms microwave energy from the microwave source into a cylindrical wave-guide mode within the heating chamber for uniformly heating fluid flowing through the heating chamber. This technology is also applied as a method for applying microwave energy for heating a moving fluid. This method includes passing a fluid from a fluid inlet, through a heating chamber, and out a fluid outlet; and applying a microwave energy source through a microwave circuit including at least one wave-guide element to transform microwave energy from the microwave energy source into a cylindrical wave-guide mode within the heating chamber to uniformly heat the fluid flowing through the heating chamber.

Abstract: A compact and highly controllable impedance-varying-unit, a microwave device using the same unit, and a high-frequency-heating appliance using the same unit are provided. The impedance varying unit includes a rectangular waveguide-section as a main body made of metallic material, an open end of waveguide-section working on microwave in a microwave cavity, a terminal end of waveguide-section closed by metallic material, a rotary movable body made of non-metallic material, and a driver for the movable body. A rotating angle or a position of the movable body is controlled, so that an impedance at the open end is varied and transmission status of microwave is changed, thereby variably controlling a standing wave distribution. Controlling the standing wave distribution allows an object in the cavity to be selectively heated or uniformly heated. Further, the standing wave produced in the microwave cavity is sequentially varied, so that the object can be selectively heated or uniformly heated.

Abstract: A method and a furnace are provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.

Abstract: A path for a material passes through an opening and along a segment through an off-peak region of an electric field. An E-plane bend delivers an electromagnetic wave to the segment. A standing wave is used to heat the material. The peaks or valleys are pushed or pulled by a movable surface or by changing the frequency of the electromagnetic wave. A rectangular choke flange is used at the opening to the segment. A curved segment connects the segment to another segment for heating the material. According to another aspect of the invention, a segment is used to heat just the edge of a planar material.

Abstract: The invention provides a dielectric heating device. The device includes a plurality of electrically conductive side walls which are electrically interconnected in use and arranged in series to define a heating cavity. At least one pair of adjacent side walls has its walls inclined to each other at a corner having an included angle selected from the group consisting of acute angles and obtuse angles. At least one electromagnetic power source capable of emitting electromagnetic radiation suitable for dielectric heating is arranged to feed waves of such radiation into the cavity with circular polarization of the waves, to cause the cavity to act as a multimode resonant heating cavity.

Abstract: Embodiments include a process including providing a microwave radiation source and a processing chamber. The process includes generating a region of pure magnetic field from the microwave radiation in the processing chamber. A region of pure electric field from the microwave radiation is also generated. A material is positioned in the region of pure magnetic field while no portion of the material is positioned in the region of pure electric field, and the material is heated in the region of pure magnetic field. The heating may be conducted to sinter the material. The material may includes a metal.

Abstract: A microwave heating apparatus is used for heating a chromatographic column assembly containing a microwave absorbing material. The microwave heating apparatus includes an antenna transmitting a microwave signal and a resonant cavity containing the chromatographic column assembly. The chromatographic column assembly extends relative to predetermined electromagnetic field strength contours within the resonant cavity to provide a predetermined heating profile along the length of the chromatographic column assembly. For example, a single-mode chromatographic column microwave oven can be used to heat a coiled chromatography column to a desired temperature gradient along its length. Oven design embodiments utilizing coaxial transmission line structures, coaxial resonators, and cylindrical resonators are described. Oven designs are provided to achieve more suitable oven size for fixed operating frequencies. Apparatuses for impedance matching an oven to a microwave source are described.

Abstract: A feed that provides circularly polarized microwave energy such as for energizing a microwave oven cavity. The feed includes a transformer to match a linearly polarized rectangular waveguide to a polarization waveguide section which may be circular or square in cross section. The polarization waveguide section contains an asymmetrical element that provides symmetry about a plane only. The asymmetrical element therefore introduces a difference in microwave electrical phase for polarizations which are respectively parallel to and perpendicular to the symmetry plane. A second waveguide section having a bend is also used in the feed assembly. The second waveguide section, which may for example be a bent section of circular waveguide, also presents an electromagnetic symmetry about a plane only. As a result, the two waveguide sections operating together provide circularly polarized energy at constant magnitude but continually rotating phase.

Abstract: A method and apparatus for the removing solvents from coated materials while capturing evaporated vapors in a confined space and maintaining non-explosive conditions within the space. Microwave energy may be applied to a coated material as the coated material passes through a cavity configured to produce an electromagnetic resonance mode. The application of microwaves to the coated material causes rapid evaporation of the solvents. The cavity is also configured to confine the evaporated vapors in a small volume and control the inflow of air into the volume so as to produce an effluent waste stream which includes a relatively high concentration of solvent molecules while maintaining a non-explosive atmosphere within the cavity. The method and apparatus are particularly suited for treating coated web materials, especially continuous webs.

Abstract: A source provides an electromagnetic wave that has a range of frequencies. The source sweeps the frequency of the electromagnetic wave between a cutoff frequency and double the cutoff frequency. The location, angle, or effective angle of an opening is adjusted by an opening adjuster. A path for an electromagnetic wave has a short for creating a standing wave. The path has a movable surface that can push and pull the peaks and valleys of the standing wave so as to achieve more uniform heating of the material. A dielectric wheel pushes and pulls the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A dielectric structure has a surface that has a short side and a long side. A motor rotates the dielectric structure to push and pull the peaks and valleys of a standing wave so as to achieve more uniform heating of a material. A path has a first choke flange that has a width w1, and a second choke flange that has a width w2.

Abstract: A microwave heating apparatus is used for heating a chromatographic column assembly containing a microwave absorbing material. The microwave heating apparatus includes an antenna transmitting a microwave signal and a resonant cavity containing the chromatographic column assembly. The chromatographic column assembly extends relative to predetermined electromagnetic field strength contours within the resonant cavity to provide a predetermined heating profile along the length of the chromatographic column assembly. For example, a single-mode chromatographic column microwave oven can be used to heat a coiled chromatography column to a desired temperature gradient along its length. Oven design embodiments utilizing coaxial transmission line structures, coaxial resonators, and cylindrical resonators are described. Oven designs are provided to achieve more suitable oven size for fixed operating frequencies. Apparatuses for impedance matching an oven to a microwave source are described.

Abstract: A microwave heating apparatus is used for heating a chromatographic column assembly containing a microwave absorbing material. The microwave heating apparatus includes an antenna transmitting a microwave signal and a resonant cavity containing the chromatographic column assembly and the antenna. The chromatographic column assembly extends relative to predetermined electromagnetic field strength contours within the resonant cavity to provide a predetermined heating profile along the length of the chromatographic column assembly. For example, a single-mode chromatographic column microwave oven can be used to heat a coiled chromatography column to a desired temperature gradient along its length. Oven design embodiments utilizing coaxial transmission line structures, coaxial resonators, and cylindrical resonators are described. To control the electromagnetic field gradient in the axial direction, the oven designs provide for varying some part of the oven geometry in the axial direction.

Abstract: A device for applying microwaves particularly for cooking products on a metallic support, includes at least one microwave generator (G) and a metallic waveguide, particularly of rectangular cross section (1, 11, 11', 11", 11"'). The waveguide forms a cooking chamber whose floor is constituted by a removable flat metallic support (5, T), on which are disposed the products to be cooked (6).

Abstract: A microwave applicator that provides a substantially uniform microwave field distribution over a large area, includes an elongated chamber, preferably operating in the length independent mode. A microwave source generates a microwave field at an output frequency. A waveguide or coaxial cable directs the microwave field from the microwave source into the elongated chamber, either through a side launch, end launch or multi launch. A frequency of the microwave field in the elongated chamber and the output frequency of the microwave source are matched through the use of controlled feedback of critical material and process parameters.

Abstract: A microwave heating apparatus includes a magnetron (6) mounted on a top surface of a wave guide (7). A bottom surface of wave guide (7) is inclined towards the bottom of the wave guide opening. A metal plate (9) is provided with a predetermined clearance above the bottom surface of wave guide (7). The microwaves are irradiated from an antenna (10) of magnetron (6) and travel along the bottom surface of wave guide (7). The microwaves are guided to an opening (8) under regulation by a metal plate (9) dispersion, and thus the microwaves reach the opening without suffering from the loss of energy. An object of heating (1) is irradiated directly by the microwaves with an improved heating efficiency.

Abstract: An apparatus for generating uniform heating in material contained in a cylindrical vessel is described. TE.sub.10 -mode microwave radiation is coupled into a cylindrical microwave transition such that microwave radiation having TE.sub.11 -, TE.sub.01 - and TM.sub.01 -cylindrical modes is excited therein. By adjusting the intensities of these modes, substantially uniform heating of materials contained in a cylindrical drum which is coupled to the microwave transition through a rotatable choke can be achieved. The use of a poor microwave absorbing insulating cylindrical insert, such as aluminum oxide, for separating the material in the container from the container walls and for providing a volume through which air is circulated is expected to maintain the container walls at room temperature. The use of layer of highly microwave absorbing material, such as SiC, inside of the insulating insert and facing the material to be heated is calculated to improve the heating pattern of the present apparatus.

Abstract: A control system for a blind microwave radiation tool a workpiece is described. The controlled system automatically tunes the cavity containing the workpiece. The control system automatically controls the temperature of the workpiece according to a predetermined temperature versus time schedule. Control system automatically determines when the workpiece has reached a particular predetermined physical condition. To achieve these results the control system automatically monitors applied power, reflected power or current temperature and automatically controls the microwave cavity volume and shape and launch structure including antennae location, cavity short location, cavity diameter, coupling loop position, etc. in order to maintain the cavity in resonance and to determine when to exit without operator intervention.

Abstract: A microwave oven includes a magnetron for generating electromagnetic wave energy, a waveguide for guiding and directing the electromagnetic wave energy into a cavity body defining a cooking chamber, and an antenna for radiating the electromagnetic wave energy generated by the magnetron into the waveguide. The waveguide includes a first opening for uniformly dispersing the electromagnetic wave energy into the cooking chamber, a second opening for uniformly dispersing the electromagnetic wave energy into the cooking chamber, and a short circuit for providing a short surface to the antenna. The first opening is formed on a portion of the waveguide which contacts the cavity body and extends along a longitudinal direction. The second opening is spaced away from and having a predetermined angle with respect to the first opening.

Abstract: A microwave heating apparatus is used for heating a chromatographic column assembly containing a microwave absorbing material. The microwave heating apparatus includes an antenna transmitting a microwave signal and a resonant cavity containing the chromatographic column assembly and the antenna. The chromatographic column assembly extends relative to predetermined electromagnetic field strength contours within the resonant cavity to provide a predetermined heating profile along the length of the chromatographic column assembly. For example, a single-mode chromatographic column microwave oven can be used to heat a coiled chromatography column to a desired temperature gradient along its length. Oven design embodiments utilizing coaxial transmission line structures, coaxial resonators, and cylindrical resonators are described. To control the electromagnetic field gradient in the axial direction, the oven designs provide for varying some part of the oven geometry in the axial direction.

Abstract: A device and method for elimination of contamination during transfer of materials either into or from bioreactors, food containers, or other microbially vulnerable systems. Using microwave power, thermal sterilizations of mating fixtures are achieved simply, reliably, and quickly by the volatilization of small quantities of water to produce superheated steam which contacts all exposed surfaces.

Abstract: A microwave applicator including a cylindrical elongated chamber used to process materials therein; a microwave power source capable of producing microwave power having an electric field; a waveguide connected to the chamber couples microwave power into the microwave chamber. The applicator provides microwave energy having a substantially uniform field distribution over a large area for processing materials such as a web or sheet-like product. The uniformity of the applicator is enhanced by the use of matching devices within the applicator to match the regions of the applicator with no load to regions where the load is present in a continuous manner.

Abstract: An electric cooking oven comprising a cooking vessel (1), a microwave energy source and a waveguide (2') substantially parallelepiped in shape delimited transversally by two substantially rectangular surfaces (20', 21') located in two parallel planes separated by a predefined distance (d), the output of guided waves occurring in at least two zones (230, 231) located in an outlet plane (23') perpendicular to the two surfaces and delimited by two parallel edges (b'.sub.1, b'.sub.4) connecting the two surfaces. The length (1) of the edges is greater than the distance (d) separating the two surfaces (20', 21') so as to optimize the number of excited transversal electric and/or transversal magnetic modes inside the cooking vessel in excitation planes parallel to the outlet plane.

Abstract: A microwave processing system comprising a microwave applicator and a microwave source. A microwave source generates a microwave field at an output frequency. A frequency of the microwave field in the elongated chamber and the output frequency of the microwave source are matched through the use of controlled feedback of critical material and process parameters.

Abstract: A microwave oven and microwave heating method generates microwaves within a cavity in a predetermined mode such that there is a known region of uniform microwave field. Samples placed in the region will then be heated in a relatively identical manner. Where perturbations induced by the samples are significant, samples are arranged in a symmetrical distribution so that the cumulative perturbation at each sample location is the same.

Abstract: A feed that provides circularly polarized microwave energy such as for energizing a cavity in a microwave oven. The feed includes a transformer to match a linearly polarized rectangular waveguide to an exit waveguide which may be circular or square in cross section. The exit waveguide contains an asymmetrical element that provides symmetry about a plane only. The asymmetrical element therefore introduces a difference in microwave electrical phase of 90 degrees for polarizations which are respectively parallel to and perpendicular to the symmetry plane. The two components add to provide circularly polarized energy at constant magnitude but continually rotating phase. An extension may be used to modify the spread and matching of the energy from the exit waveguide into the enclosure.

Abstract: A microwave applicator includes an elongated chamber, preferably having a cylindrical shape, for processing materials therein. A waveguide, connected to the elongated chamber, couples microwave power into the elongated chamber. The cross-sectional area of the elongated chamber can be mechanically adjusted to control and maintain the microwave field uniformity and resonant mode, preferably the length independent mode TM.sub.010, during the processing of the material. The applicator can thus provide microwave energy having a substantially uniform field distribution over a large area for processing materials, for example, a web or sheet like product, plywood and pre-impregnated cloth, in a continuous manner.

Abstract: A microwave applicator includes an elongated chamber, preferably having a cylindrical shape, for processing materials therein. A waveguide, connected to the elongated chamber, couples microwave power into the elongated chamber. The cross-sectional area of the elongated chamber can be mechanically adjusted to control and maintain the microwave field uniformity and resonant mode, preferably the length independent mode TM.sub.010, during the processing of the material. The applicator can thus provide microwave energy having a substantially uniform field distribution over a large area for processing materials in a non-continuous, semi-continuous or fully continuous manner.

Abstract: The invention relates to a device for heat treating products by microwave radiation with a heating chamber to take the products in which the microwaves (16) can be coupled to a device (12) in the heating chamber (2) and the heating chamber (2) has at least one wall (13) which reflects the microwaves (16).

Abstract: The present invention overcomes many of the problems associated with electromagnetic exposure of planar materials. A diagonal slot compensates for the effects of signal attenuation along the propagation path. Adjustably variable path lengths allow peaks and valleys of the electromagnetic field in one exposure segment to compensate for peaks and valleys in another exposure segment. Dielectric slabs may be used to extend the peak field region between top and bottom conducting surfaces to allow for more uniform exposure of planar materials that have a significant thickness. Specialized choke flanges prevent the escape of electromagnetic energy. One or more rollers between exposure segments may be enclosed by an outer surface to prevent the escape of electromagnetic energy.

Abstract: A method of dispensing the material that is heated by microwave energy immediately before the material is dispensed. The method comprises a series of steps including conveying the material through a pressurized passage through a dispensing tube that has radial boundaries transparent to microwave energy. The dispensing tube is located within a microwave resonant chamber. The microwave energy is channeled from a microwave generating source along a waveguide to the microwave resonant chamber. Material within the passage is heated by the microwave energy and produces a TM.sub.020 heating profile with negligible heating at the radial boundaries of the dispensing tube. The material is dispensed onto a component along a path. The dispensing step requires a measure of time to define a dispensing cycle. The output of the microwave generating source is varied. The amount of microwave heating that occurs within the material is dependent upon the output of the microwave generating source.

Abstract: A microwave oven for radiating microwaves generated from a magnetron into a cavity to heat and cook foodstuff disposed therein, the microwave oven comprising an antenna disposed between a magnetron and the cavity for converting the microwaves to circularly polarized waves to radiate same into the cavity, the microwave oven having the advantage in that the foodstuff in the cavity is heated by radiation of the circularly polarized waves, thereby enabling a uniform heating of the foodstuff and improving an absorption efficiency of microwave energy.

Abstract: A waveguide of a microwave oven is provided to keep constant output and electric field distribution at a cavity regardless of food load by minimizing change in impedance of waveguides depending on food load for cooking, the waveguide comprising radiating holes of first and second output waveguides formed at top and bottom parts of a lateral wall of the cavity centering the power supply hole of the input waveguide to spray microwaves having the electric fields of opposite phases, whereby change in impedance of the waveguide depending on the change in food load is minimized to keep the output from the microwave oven and the electric field distribution constant regardless of food load.

Abstract: A microwave oven is disclosed in which the structure of the wave guiding tube is improved such that the variation of the impedance is minimized in spite of the variation of the load of the food, thereby making it possible to maintain the output of the microwave oven at a constant level regardless of the load of the food. The microwaves are divided into a plurality of wave streams, and the wave streams are made to have different phases. The microwave oven includes an input wave guiding tube coupled with a magnetron, for receiving microwaves from the magnetron. A first output wave guiding tube communicates to the input wave guiding tube, for receiving the microwaves from the input wave guiding tube to diffusely irradiate the microwaves into a cavity. A second wave guiding tube communicates to the input wave guiding tube, for converting the microwaves to a phase different from that of the first wave guiding tube to irradiate them into the cavity.

Abstract: An apparatus, system, and method, for using circular mode magnetic microwave energy to heat the interior regions of a work piece of wood fiber and glue. The microwaves are generated and transmitted as rectangular waveguide mode microwave energy, and are converted by mode converter to circular magnetic mode microwave energy. As circular magnetic mode microwave energy, the microwave energy passes through a work piece or billet of material is reflected on the other side, and travels through the billet a second time. Reflected microwave energy from the main reflected wave as well as reflections from other structures, surfaces and layers in the system travel back toward the microwave source. They are sensed, and a computer tuning system causes capacitive probes to generate offsetting microwave reflections, which are opposite in phase and equal in magnitude to the sum of all of the reflected waves.

Abstract: An assembly for applying microwave irradiation to a load having a generally circular cross-section. The applicator supports a dominant TM.sub.120 mode and the load is aligned with a central axis in the applicator, with each aperture of a pair of feed apertures diametrically opposed (for the circular cross sectional case) or located on parallel opposed walls (for the polygonal cross sectional case) with one of the pair of feed apertures positioned at 90 degrees with respect to the other pair about the axis. The applicator may be formed as a cylinder or as a polygonal prism of the type having parallel opposed sides, such as those having a square, hexagonal or octagonal cross-section. Means such as a microwave transparent tube or conveyor provide for positioning of the load in the applicator. In an alternative embodiment, two cavities are used, with one cavity associated with each of the two feed systems, and a means for conveying the load from the first cavity to the second cavity is provided.

Abstract: A microwave applicator of microwave reflective material having a closed first end, four side walls and, in a first embodiment, an open second end spaced apart from and facing a ground plate, the ground plate extending in a pair of transverse directions and having a longitudinal direction perpendicular thereto, and in a second embodiment, a closed second end, the applicator forming a cavity containing a desired hybrid mode having a low wave impedance in the longitudinal direction and an absence of an E field component in one of the transverse directions.

Abstract: Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Abstract: Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Abstract: 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.

Abstract: Disclosed is a wave guide used in a microwave oven, by which superimposed high-frequency microwaves are radiated towards food to be heated, and distorted waves included in the high-frequency microwaves are removed. The wave guide has a housing provided with a magnetron, a mode transducer disposed in the housing so as to superimpose and distribute a high-frequency microwave radiated from the magnetron, and a differential mode absorber for absorbing a distorted wave included in the high-frequency microwave which has been passed through the mode transducer. The mode transducer includes a first hollow-frustuconical member welded to an inner wall of the housing, a second hollow-frustuconical member accommodated in the first hollow-frustuconical member, and a transmission line attached to an inner wall of the second hollow-frustuconical member.

Abstract: An apparatus, system, and method, for using circular mode magnetic microwave energy to heat the interior regions of a work piece of wood fiber and glue. The microwaves are generated and transmitted as rectangular waveguide mode microwave energy, and are converted by mode converter to circular magnetic mode microwave energy. As circular magnetic mode microwave energy, the microwave energy passes through a work piece or billet of material is reflected on the other side, and travels through the billet a second time. Reflected microwave energy from the main reflected wave as well as reflections from other structures, surfaces and layers in the system travel back toward the microwave source. They are sensed, and a computer tuning system causes capacitive probes to generate offsetting microwave reflections, which are opposite in phase and equal in magnitude to the sum of all of the reflected waves.

Abstract: There is provided a microwave waste sterilizer comprising an upper outer shell, a lower outer shell, an upper means for guiding microwave energy, a lower means for guiding microwave energy, an upper means for dispersing microwave energy, and a lower means for dispersing microwave energy. There is also provided a method for sterilizing waste materials with dual sources of microwave energy. Further there is provided a method for dispersing microwave energy into a chamber such that the dispersed microwave energy creates a flux field of substantially uniform flux.

Abstract: A microwave applicator including a generally cylindrical microwave containment chamber, a microwave energy source, and a feed structure connecting the microwave energy source to the containment chamber. The diameter of the containment chamber is designed according to a process that need only take into account supporting a microwave pattern having substantially only two transverse magnetic modes, each with a characteristic guide wavelength, where the guide wavelength of one mode is substantially equal to twice the guide wavelength of the other mode. Additionally, the interior diameter can be sized to minimize the index subscript numbers of the transverse magnetic modes. The feed structure of the applicator includes at least two feed apertures spaced physically apart around the cylindrical axis of the applicator by a physical angle equal to an electrical phase shift angle of the microwaves introduced through the respective apertures, which in a preferred embodiment is 90 degrees.

Abstract: A wave guide system of a microwave oven is provided, comprising a cavity containing a food to be cooked and having a pair of microwave feed openings formed in one wall thereof; a magnetron having an antenna and positioned between the microwave feed openings in spaced apart relation to the wall having the feed openings, to generate microwaves having a wavelength of .lambda..sub.g ; and a waveguide provided to cover the feed openings, support thereon the magnetron and guide the microwave through the feed openings into the cavity and having a short circuited surface which is spaced apart from the antenna by a distance of .lambda..sub.g /4 and parallel to the antenna. With this arrangement, the microwave generated in the magnetron produce standing waves in the waveguide, and then are emitted into the cavity through the microwave feed openings of the cavity, thereby uniformly heating a food in the cavity.

Abstract: A microwave applicator device for continuous heat treatment of elongate products comprises an applicator housing that defines a generally rectangular waveguide cavity and at least one excitation system for exciting the cavity with microwaves propagating in TE.sub.01 transverse electric mode, the system including at least one microwave generator associated with a feed waveguide connected to the cavity via a window formed through a wall of the cavity. The front and rear walls of the feed waveguide are respectively connected to the front and rear edges of the window, and the feed waveguide is associated with a guide flap extending in the cavity in the vicinity of the rear edge of the window, and with a guide member provided substantially facing the window.

Abstract: A microwave processing system is provided wherein the material to be processed is in the form of a web type quantity configuration with a thickness that is small in relation to the wavelength of a particular microwave frequency. The material is passed through the field associated with a plurality of microwave standing waves of the particular frequency, each adjacent standing wave being offset 1/4 wavelength along the direction of movement of the web. A carrier gas removes volatile solvents from the material surfaces. Control is provided for the interrelationship of temperature, rate of movement, flow of carrier gas, and microwave power.