Abstract: A bandpass filter having 4-degrees of freedom includes a plurality of resonant cavities having respective Qs where at least one of the Qs is different. A plurality of main couplings couple successive resonant cavities to establish a main signal path that provides a first degree of freedom for controlling the shape of the filter's frequency response over its passband. A plurality of bridge couplings couple pairs of the resonant cavities so that the cavities are connected in a canonical circuit topology. The bridge couplings provide second and third degrees of freedom for controlling the sharpness of the frequency response 's transition between its passband and stopband and controlling the linearity of its phase, respectively. The cavities' non-uniform Qs provide a fourth degree of freedom for controlling the amplitude of the filter's frequency response in the passband so that the amplitude is within a predetermined tolerance of a desired passband shape.

Abstract: An adjustable coupler for coupling electromagnetic energy into or out of a resonant cavity has an input/output line connected to a loop or conductor. A base of the coupler has a passageway into which a bolt is inserted. Threads on a bolt engage threads on a nut attached to the conductor. A head of the bolt is held in place on the outside of the base so that rotation of the head moves the nut and conductor.

Abstract: Dual-mode cavity of waveguide bandpass filters, which allow the realization of narrow-band filters with very limited transition band and extremely low losses, without tuning or coupling screws or smooth edges. The dual mode cavity is composed of three coaxial sections of waveguide arranged in cascade and provided with irises, of which the two end sections are suited to support two modes with orthogonal polarizations and the intermediate section, consisting of a rectangular waveguide, has its side tilted with respect to the plane on which the irises lie. The whole filter composed of these cavities can be entirely designed by means of a computer and requires no tuning operation.

Abstract: A magnetic device couples a main conductor of a TEM line and a waveguide forming a .lambda.g/2 resonator and procuring the propagation of an electromagnetic wave. The main conductor is fixed to a wall of the waveguide and extended by a pin inside the waveguide. The device comprises a tuning screw penetrating into the waveguide near the free end of the pin and perpendicular to the pin and an iris around and centered on the pin. The iris is closed on the side on the wall and its interior volume forms a zone in which the wave of the associated magnetic field is evanescent. The median axis of the tuning screw is in the plane of the aperture of the iris.

Abstract: A power microwave band-pass filter having very high quality factor (i.e., very low insertion loss) and selectivity, includes a cover and a body with dielectric resonator containing cavities. Non-adjacent cavities are cross-coupled by trapezoidal shaped bridging elements, at least one of which is associated with the cover and at least one of which is associated with the filter body. Each bridging element is penetrated in a slit of an electrically insulating holder placed in a knot of two non-adjacent cavities. The bridge element associated with the cover is grounded and acts inductively while the bridge element associated with the filter body is not grounded and acts capacitively.

Abstract: The invention relates to a resonator shell construction, comprising at least two metallic shell modules (41-44) connected to each other to form a modular shell construction, each module enclosing at least one resonator cavity (42-52). The modules comprise wall portions (41a-41c, 42a-42c, 43a-43c, 44a-44c) projecting from the modules, said wall portions being connected to one or more modules, whereby one or more new resonator cavities (61-68) are formed between the modules.

Abstract: A coupling device for use in a resonator has a loop electrically connected at one end to a central conductor and at the other end to an electrically conductive ring wherein the loop may be rotated independently of the coupling device connector and mounting plate thereby allowing the loaded Q of the resonator to be varied without complete disengagement of the coupling device from the resonator.

Abstract: A bandpass microwave filter (32) is constructed by use of a right cylindrical cavity resonator (10) wherein end regions (22, 24) of the resonator are tapered. The tapering is accomplished by replacing end portions of a right cylindrical sidewall with frusto-conic sections (22, 24) of side wall. Each frusto-conic section joins a central cylindrical section (26) of the sidewall with a planar end wall (14, 16). Each of the end walls is provided with a coupling slot (28, 30) having dimensions substantially smaller than a half wavelength of the center resonant frequency of the resonator so as to be a nonresonant slot. The slots in the end walls may be coupled to rectangular waveguides (34, 36) which form input and output ports by which electromagnetic signals are applied to and extracted from the resonator.

Abstract: The invention relates to a single mode multi-cavity microwave filter that includes a housing formed with a plurality of walls which define at least two rows of side-by-side dielectric loaded cavities, wherein sequential cavities are coupled to one another via slots formed in the walls therebetween and at least one pair of non-sequential adjacent cavities are coupled via a probe. The coupling via the slots is defined mathematically as positive coupling. The probe is selectively configurable to provide positive or negative coupling relative to the sign of the slot coupling. Further, at least one non-adjacent, non-sequential pair of cavities is coupled via a second probe that may be configured to provide either positive or negative coupling relative to the sign of the slot coupling. The filter housing supports a plurality of adjustable fins which extend into the slots, one fin to each slot, to selectively adjust the size of the slot.

Abstract: An electron beam tube arrangement in an inductive output tetrode. The arrangement comprises a resonant cavity circuit having two cavities, and includes an element for coupling high frequency energy between the two cavities. The coupling element includes a coupling dome projecting into one of the two cavities from a wall thereof. The coupling dome has a base portion which is adapted to be connected to a dome completion member selected from a set comprising at least one dome completion member for adjusting a coupling level between the two cavities.

Abstract: A dielectric resonator is provided which includes a dielectric block, an inner conductor formed on an outer surface of the dielectric block, and another outer conductor formed on an outer surface of the dielectric block. The inner conductor is so geometrically modified as to change the characteristic impedance in a manner wherein the shape of either the inner conductor or the dielectric block is changed.

Abstract: An input transformer for a coaxial transmission line is provided which allows continuously variable amplitude and phase of an RF signal conducted on the transmission line. The transformer comprises a housing having a longitudinal axis. A center conductor of the coaxial line extends along the axis through the housing. A first sleeve is axially movable within the housing, and has contact points on an outer surface thereof to provide electrical conductivity between the first sleeve and the housing. The ability of the first sleeve to move axially enables variability in the location of the transformer along the transmission line. The first sleeve has an inner wall that is eccentric relative to the longitudinal axis of the center conductor. A second sleeve having a cylindrical outer wall is disposed within the first sleeve. The second sleeve is rotationally movable within the first sleeve, and has contact points on the outer wall to provide electrical conductivity between the first sleeve and second sleeve.

Abstract: A plurality of dual mode, dielectric resonator loaded cavity filters may be coupled to respective ones of a plurality of radiators of an array antenna, such as a phased array antenna. Each of the filters is provided with a thin annular, electrically conductive ring disposed on a resonator surface facing the corresponding radiator of the antenna. The ring greatly increases the coupling of electromagnetic power for circularly and linearly polarized waves between the filter and the radiator for radiation of the power from the radiator into space, as well as during reception of radiation from outer space. The filter is operative also, if desired, to provide such coupling of electromagnetic power to a waveguide, as well as directly into the external environment. The ring may be located at the opening of the cavity through which the power is coupled between the filter and the radiator or the waveguide or the empty space.

Abstract: A dual-mode dielectric-resonator-loaded cavity filter comprises a generally cylindrical cavity, at least two longitudinally-spaced dielectric resonator elements coaxially aligned within the cavity, and at least one coupling obstacle disposed between the resonators and extending a distance from the cavity wall. The coupling obstacles are preferably conductive and are electrically connected to the cavity wall. However, the obstacles may be constructed of a dielectric material in some applications. Each obstacle may be aligned with one of the reference planes corresponding to a resonant mode of the resonators to effectively control or reduce the coupling between the parallel resonant modes of adjacent resonators. The reduction in coupling between resonant modes of adjacent resonators allows large coupling differentials to be produced, allowing a filter designer to implement a wide variety of high-performance filters without expensive irises.

Abstract: The radio frequency ferrite system for modulating, phase shifting, or attenuating radio frequency energy has a resonator, a ferrite polarizer, and coupling devices. The coupling devices are used to couple radio frequency signals to and from an interior of the resonator. The ferrite polarizer generates magnetic fields corresponding to an applied voltage or current. To produce phase modulation the ferrite polarizer may be used to detune the cavity from resonance by changing the orientation of the radio frequency signal with respect to a protrusion in the resonator. The ferrite system may be used for phase modulation, switching radio frequency signals, and amplitude modulation by arranging the coupling devices in various orientations and by simultaneously changing the polarization of radio frequency signals with the ferrite polarizer.

Abstract: A high Q microwave filter is disclosed. Coupling bar structures are included in a cylindrical resonator, extending substantially the entire length of the resonator for coupling orthogonal modes. The coupling bars have a lower profile than conventional tuning screws. The symmetry of the filter structure is improved over the prior art coupling devices which relied entirely on tuning screws for coupling E fields of one mode to the other mode. The coupling bar structure has a lower profile penetrating less into the supported E fields while obtaining the desired coupling. Increased bandwidth may be obtained at improved symmetries over the prior art devices. Fine tuning may be provided by inserting tuning screws into the cylindrical cavity. The tuning screws require less penetration as substantially most of the coupling occurs by virtue of the coupling bars.

Abstract: An assembly and a method is provided for coupling a microstrip circuit to a cavity resonator. The assembly includes a substrate, a microstrip circuit fabricated on one side of the substrate plate, a ground plane fabricated on the other side of the substrate plate and a cavity resonator. The microstrip is coupled to the cavity resonator by a slot fabricated in the ground plane and a planar radiator disposed between the ground plane and the cavity resonator. The assembly produces a resonator that can operate for frequencies in the range of 1-100 GHz in a simplified and less expensive manufacturing process.

Abstract: A structure of a reception frequency converting portion of a multi-band microwave detector, and including a microwave circuit comprises a horn antenna, two-port cavity integrally formed with the horn antenna and having one port communicated with a throat portion of the horn antenna, one-port cavity integrally formed with the two-port cavity and communicated with the other port of the two-port cavity, a mixer diode located at the throat portion of the horn antenna, a first local oscillator arranged within the two-port cavity, and a second local oscillator arranged within the one-port cavity.

Abstract: A highly sensitive, direct-contact, in situ sensor for nondestructively measuring or monitoring the complex dielectric and conductive properties of solids, liquids, or gasses at microwave frequencies. A metal microstrip dipole resonator (11) is etched on the surface of a dielectric substrate (12) which is bonded to a copper ground plane (14). The dipole resonator is electromagnetically driven by mutual inductive coupling to a short nonresonant feed slot (13) formed in the ground plane (14). The slot (13) is driven by a coaxial feed line (7) or a microstrip feed line (16) extending from a swept microwave frequency source (2) which excites the incident wave (17). Alternatively, the metal resonator is omitted and the length of the slot (15) is increased so that it becomes the resonator. In use, the sensor is placed in close physical contact with the test material (9) having complex dielectric constant .epsilon.* (=.epsilon.'-j.epsilon.") or conductivity .sigma..

Abstract: An accelerator includes a beam tube having a cavity with a central axis along which particles can be accelerated. A radio frequency power coupling device couples the cavity to a high frequency power source. The coupling device includes a coaxial waveguide having a central axis, an outer conductor and an inner conductor. The outer conductor is fixed relative to the cavity defining an angle between the central axis of the cavity and the central axis of the coaxial waveguide. An external drive moves the inner conductor along the central axis of the coaxial waveguide.

Abstract: A super-power, high voltage klystron includes an output cavity operating in the TM.sub.01x mode, where x is greater than zero.

Abstract: An arrangement for coupling microwave energy with a reaction chamber, including electrically stable tuning and being, within limits, tolerant against changes in critical dimensions and power fluctuations. A coaxial line between a hollow waveguide and the reaction chamber is of such a structure that it forms, at least together with the reaction chamber, a loss resonator for the microwave frequency employed. The coaxial line can comprise an absorber or, alternatively, can be made of a poorly conductive material. There is also the possibility of downgrading the quality of the resonator by leaving an annular gap between a metal plate and an outer conductor section.

Abstract: The invention relates to a device for coupling microwave power out of a first chamber (21) into a second chamber (22). For this purpose a primary antenna (2) and a secondary antenna (3) are provided, the primary antenna (2) reaching into the first chamber (21), while the secondary antenna (3) reaches into the second chamber (22). Between the first chamber (21) and the second chamber (22) there is provided a dividing wall (20) through which a current-carrying means (11) is brought, which joins together the primary antenna (2) and the secondary antenna (3).

Abstract: A method and system for controlling the transmission of radio frequency energy through an imperforate multi-layer fiber and resin composite structure. Multiple segments of conductive mesh are embedded between layers of fiber and resin in at least partially overlapping positions. Apertures within the conductive mesh are limited to diameters substantially smaller than the wavelengths of the radio frequency energy utilized; however, the apertures are large enough to permit resin to flow into those apertures during the cure process, thereby limiting the possibility of delamination during loading of the resultant composite structure. By utilizing nonconductive materials, such as glass fibers and a resin material having an appropriate dielectric constant, it is possible to create a radio frequency energy guide or capacitive structure which permits the controlled transmission of radio frequency energy through an imperforate composite structure.

Abstract: A power coupler that is held in place at two different points along its length to substantially eliminate any movement thereof due to vibration of the environment. One of these holding means comprises a piece of dielectric which snugly encloses the coupler to prevent side-to-side movement while still allowing a vertical adjustment of the coupler element through the holding means. A constant impedance equal to that of an electrically connected circuit is maintained along a portion of the coupler by varying passageway opening sizes. The electrical connection to the circuit, which has a threaded terminal comprising a part of the adjustment means and the other holding means eliminates connector insertion loss and signal reflections inherent in prior art signal interfaces between the coupler and an electrical signal receiving circuit.

Abstract: An electron beam tube arrangement has an output cavity resonator circuit which includes a first output cavity, a second output cavity being coupled thereto by means of a coupling loop. The coupling loop is located in the first cavity and connected to said second cavity. In one embodiment of the invention, the second cavity also contains a coupling loop which is electrically connected to that in the first output cavity.

Abstract: A system for coupling two resonating cavities, where the coupling system provides a form of bandpass or bandstop filtering about the desired frequency mode and helps suppress undesired modes about the desired frequency mode and higher order modes. The system for coupling the two resonating cavities includes a tuned evanescent iris, where the tunability of the iris is provided by at least one tunable resonating capacitance element embedded in the iris.

Abstract: A vacuum concentrator uses microwave heating to enhance the rapid drying of a liquid specimen. Microwave heating without excessive arcing is made possible in a vacuum chamber by controlling the power of a microwave generator, by modifying antenna-like objects, and by interposing air in a direct path between opposing edges of microwave injection slots, while maintaining the vacuum condition in the vacuum chamber. This can be accomplished by using air filled plastic bosses passing through, and substantially filling the microwave injection slots. An alternate to the air filled bosses can be a non-metallic closure plate that excludes the microwave injection slots from the vacuum chamber, while allowing energy to be injected freely into the chamber. The microwave heating energy is absorbed by a vacuum chamber cover and dissipated to the atmosphere as heat.

Abstract: An output of a magnetron operating in the TM.sub.01 /mode has a ceramic output window which is planar. As ceramic material may have a higher dielectric constant than glass a longer output probe can be used which, combined with the fact that the window is planar, gives good mode purity thus reducing heating and arcing in the window. Ceramic also has a higher melting point than glass which means that cooling of the window is less critical.

Abstract: A switchable dual mode directional filter system includes two identical filters coupled to input and output waveguides at the same plane in phase quadrature. Each waveguide has two ports through which the signal enters and exists. One of the filters has a switching device incorporated therein for selecting the desired output port. One embodiment of the switching device includes a pair of coupling members that extend radially inward within the cavity of the filter toward a central axis. These coupling members define two coupling positions for the system. Solenoids move the two coupling members into and out of the cavity of the filters. Only one coupling member is used at a given time. This switching device is designed to change the polarity of one of the components of the signal wave to change its wave characteristics in the output waveguide. As a result, the desired port of the output waveguide can be selected easily.

Abstract: An iris for an electromagnetic structure, such as a resonator assembly, is provided with a set of grooves introducing relief to thermally induced stresses, this allowing the iris to be fabricated of a metal having a greater coefficient of thermal expansion than the material of a sidewall and end walls of the resonator assembly. The grooves are arranged spaced apart from the central coupling aperture, and are disposed in an annular region of the iris plate composing the central coupling aperture. The grooves may be cut into the iris plate from both sides of the plate to extend partway into the plate, typically, approximately three-quarters of the distance through the plate. Alternatively, the grooves may pass completely through the plate, whereupon annular disks are soldered to the opposite sides of the iris plate to close off the grooves to ensure that coupling of electromagnetic power between opposite sides of the iris takes place only through the coupling aperture.

Abstract: A rectangular microwave resonant cavity applicator comprising two spaced-apart, cavity-containing sections is disclosed for heating a product web. Each section has a planar peripheral lip which faces the other and the sections are spaced apart by a distance "d". The lips have arrays of ferrite segments mounted on their surfaces which serve to limit radiation of microwave energy from the open space between the sections, through which the product web passes.

Abstract: In a quasi-optical gyrotron which exhibits a quasi-optical resonator having two mirrors (4a, 4b) which opposite one another on a resonator axis (5), the required electromagnetic radiation is coupled out by means of a hologram. In this arrangement, at least one of the two mirrors (4b) of the resonator exhibits a reflective surface (8b) provided with a hologram. The hologram is constructed in such a manner that the radiation to be coupled out is scattered in the direction of at least exactly one coupling-out axis (10), the at least exactly one coupling-out axis (10) enclosing a predetermined angle .alpha. not equal to zero with the resonator axis (5). The angle .alpha. is preferably as small as possible.

Abstract: Modular resonant cavities particularly for use in applications associated with high frequency electromagnetic energy each comprise a shell defining an aperture formed therethrough, and either end plates and/or divider closure plates, each having stepped-down regions for interfitting at perimeter ends of adjacent shells so as to form a resonant cavity. The modular resonant cavities include support rods passing through the corner regions of each closure plate. Fastening means at each end of the rods mechanically secure the modular resonant cavities together.

Abstract: A waveguide filter switch, including a waveguide transmission path for electromagnetic energy. At least one series resonator filter positioned in shunt with the transmission path. At least one coupling aperture in the waveguide for coupling the at least one series resonator to the waveguide. A switching positioned across the coupling aperture and having an open state wherein the coupling aperture is electrically open to provide for coupling the series resonator to the waveguide and having a closed state wherein the coupling aperture is electrically shorted to prevent coupling of the series resonator to the waveguide. The switch including a sliding member physically located to have an open retracted position wherein the coupling aperture is physically unencumbered to produce the open state for the switch and to have a closed extended position wherein the coupling aperture is physically encumbered to produce the closed state for the switch.

Abstract: A coupling-out window for linearly polarized high-power microwaves exhibits at least one plate transparent to microwaves and cooling fins. The cooling fins are situated together with the plate in a plate plane and are aligned perpendicular to a direction of polarization of the microwaves. They are in heat-conducting and pressure-locking contact with the plate.

Abstract: Dielectric-filled longitudinal slots in the common wall of concentric circular and coaxial dielectric-lined waveguides allow microwave energy to be efficiently coupled therethrough. Such couplers are used with megawatt level gyrotrons for varied applications. One application provides a double seal waveguide vacuum window with low reflections over a wideband of frequencies. Another application provides an output coupler and window for quasi-optical gyrotrons. Still another application provides a waveguide mode converter for converting high order microwave modes, as are commonly found in waveguide cavities of high power gyrotrons, to lower-order modes suitable for low-loss transmission, such as the HE.sub.11 mode.

Abstract: A combiner arrangement in a radio base station including a number of waveguide cavity resonators operating as channel filters in known manner. According to the invention, each resonator is divided into two substantially equal cavity resonsator parts. One base station transmitter is connected to one of the resonator parts and another transmitter is connected to the other resonator part. The decoupling of a resonator consists of two clamp-like elements situated in the center of the resonator. The coaxial connection to the antenna consists of coaxial pieces between the resonators and all the resonators are connected in series to the antenna.

Abstract: An open resonator comprises two concave spherical reflectors or one spherical and one plane reflectors positioned so as to form a resonant structure and each being provided at an electromagnetic coupling region thereof with a large number of conductor stripes disposed in parallel at a spacing sufficiently small in comparison with the wavelength of an incident electromagnetic wave. The diameter of the circular coupling region can be made very large in comparison with the wavelength. An ultra-high Q value can be obtained with the open resonator with very high excitation efficiency to a resonator mode. The Q value of the open resonator can be varied with the angle between the directions of the conductor stripes of the two reflecting mirrors.

Abstract: A multiplexed microwave filter comprising at least two elementary filters (10, 11) provided with respective coupling antennas of crankshaft or any other shape, and including a common access (14), which access is provided with a crankshaft-shaped coupling antenna which is rotatable about its axis in order to adjust coupling between the antenna and the corresponding elementary filter, in which the common access is situated astride the various elementary filters and includes as many crankshaft-shaped antennas (22, 23) as there are elementary filters (10, 11).

Abstract: There is provided a high performance extended interaction output circuit [EIOC] having two cavities. The EIOC of the present invention has an image impedance which is twice the magnitude of its output load resistance. The EIOC of the present invention also includes a three cavity EIOC which has two image impedances, the second image impedance being one half the magnitude of the first image impedance while the output load impedance of the three cavity EIOC is one third the magnitude of the first image impedance.

Abstract: A dielectric notch resonator particularly suitable for use in a band reject filter operable at ultra-high frequencies comprises a dielectric resonator and an associated housing which results in a reactance having an imaginary component effectively nulled by a coupling reactance mechanism forming part of the dielectric notch resonator so as to present a relatively low resistive impedance load at a given center frequency and frequencies in a narrow bandwidth thereabout. The coupling reactive mechanism comprises an inductive wire and a serially connected variable capacitor so as to null the reactive component of the dielectric resonator at a particular center frequency and to modify the symmetry of the rejected frequency bandwidth by adjusting the capacitance of the variable capacitor.

Abstract: A diplexer having receive and transmit sections connected to a common port comprises square-cross section cavities arranged in rows and columns. At least three adjacent cavities form a triangular group in which the non-adjacent cavities are cross-coupled. The cross coupling means comprises an inductive loop or a capacitative probe. Adjacent cavities in each section are also coupled, on folded paths, by irises. Cavity wall thickness is reduced where possible. The antenna port is diplexed to both sections by a T-branch connector having wire sections which are tapped into central resonators at a predetermined distance above electrical ground. Low pass filters with non-overlapping peak responses provide further isolation between the sections.

Abstract: The structure includes a conductive path and a ground plane applied to opposite faces of an insulating support. The ground plane has parallel slots placed under the conductive path and transversely thereto.

Abstract: An iris is located in a common wall separating two microwave enclosures such as waveguides and cavities for coupling electromagnetic power between the two enclosures. The iris is formed of an aperture elongated in one direction to define a longitudinal axis of the aperture with opposed first and second sides parallel to the axis. Portions of the common wall at peripheral regions of the aperture are extended from the first and second sides towards the iris and perpendicularly thereto to form teeth, there being an array of teeth extending from the first side and an array of teeth extending from the second side. The teeth are readily polarized as magnetic dipoles by surface currents induced in the wall by electromagnetic waves for increased coefficient of coupling of electromagnetic field components through the iris.

Abstract: An apparatus 10 with gears (22a, 22b, 22c, 25) for adjusting the position of a plate (13) in a cavity (12) and a rack (51) and gear (53) for moving a probe (15) into and out of the cavity is described. The apparatus includes knobs (34, 55) for controlling the movement of the plate and probe. Micrometers (37, 52) measure the precise position of the plate and probe in the cavity. The apparatus allows very precise tuning for selection of a mode of radiofrequency wave in the cavity and fine tuning within the mode.

Abstract: A microwave multiplexer has a set of independently tuneable signal channels coupled to a common waveguide. Each of the channels has input and output 3 dB couplers which are joined by cylindrical radiators carrying circularly polarized waves. Both TE and TM waves are propagated within a plurality of resonant cavities within each of the filters. Coupling between the cavities is provided by an array of slots and an array of probes wherein the slots couple TE waves and the probes couple TM waves. Adjustment of the slots and the probes provides for independent coupling coefficients for the two propagation modes. A set of coaxial line probe structures connect between the input and output couplers to end cavities of a filter for the launching of TM waves, there being discs in the end cavities adjacent the probes for converting energy of a TM wave to a TE wave, thereby providing both the TM and the TE wave propagation.

Abstract: A microwave filter composed of a plurality of cylindrical cavity resonators each having a side wall extending parallel to the direction of wave propagation in the resonator, wherein the cavity resonators are disposed with their side walls in contact with one another in a compact cylinder pack arrangement so that the side wall of each cavity resonator is in contact with the side wall of the maximum number of other mutually adjacent resonators, and coupling structures connecting resonators whose side walls are in contact, via the contacting side walls, for coupling electromagnetic energy between the resonators.

Abstract: A microwave oven the rectanguloid heating chamber 6 of which has at least two dimensions less than a wavelength of the energy supply thereto and capable of heating between 60-100 grams of food to an edible temperature in 30 seconds or less is provided. The oven comprises a housing 1 coupled to an energy source 2 by way of a coaxial cable 3 and a waveguide 4. The waveguide 4 has a horn 5 providing the transition to the chamber 6 encased by the housing 1. The larger end of the horn 5 feeds into the chamber 6 while the smaller end is connected to the waveguide 4. A lens essentially comprising a laminate assembly of dielectric material plates 11,12 carrying a prism 11 directed into the waveguide 4 is positioned between the horn 5 and the chamber 6. The chamber 6 has a volume of about 0.00168 cubic meters and the power input of the oven is between 600 and 1200 watts.

Abstract: A microwave resonating cavity including a hollow cylindrical body shaped in the form of a parallelepiped and consisting of a dielectric material coated by a metallic layer, said dielectric material having a high dielectric constant having a value greater than 30, and wherein said hollow body includes an upper base, a lower base, an external surface and an internal surface, and further includes a non-metallized area defining a metallized coupling line onto the external surface of the said hollow cylinder and wherein said hollow cylinder has an inner diameter ranging between 3 and 5 mm, an outer diameter ranging between 6 and 15 mm and a height ranging between 5 and 10 mm, and further including a metallic cap welded to the upper base of said hollow body, and further including an adjusting screw for fine adjustment of the resonating frequency.