Abstract: Several embodiments include a cooking instrument. The cooking instrument can include a heating system. The heating system can include one or more heating elements capable of emitting wireless energy into the cooking chamber. The cooking instrument can also include a control system. The control system can determine a heating sequence (e.g., logical instructions) to drive the heating system. The control system can then execute the heating sequence. The heating sequence can include an instruction to adjust, based on a trigger event detectable by the control system, the spectral power distribution of wireless waves emitted from a heating element in the heating system.

Abstract: A coupling device is provided for coupling microwave radiation from a first microwave structure, in particular a microwave waveguide, into a second microwave structure, in particular a microwave resonant cavity, wherein the first and second microwave structures share a common wall, through an iris opening in said wall in front of which the coupling device is positioned on the side of the first microwave structure, in particular wherein the coupling device is of a basically cylindrical shape, characterized in that the coupling device comprises N electrically conducting conductor loops, with N?3, preferably 3?N?20, that the conductor loops are arranged coaxially in an array along a z-axis, and that axially neighboring conductor loops are separated by a dielectric. The inventive coupling device allows for a larger coupling coefficient, and in particular allows for a larger dynamic range.

Abstract: A transformer for power line reactance injection that can be adapted in manufacturing to different operating current ranges by interchanging primary windings having one, two, three, four or more laminar turns. Through its use of gaps in the magnetic circuit that are filled with high temperature, high thermal conductivity dielectrics, this transformer has tolerance to very high fault currents, and it can be passively cooled by the use of fins on the exterior walls of the core.

Abstract: An apparatus and method for creating nanometric delta doped layers in epitaxial diamond includes providing a dummy gas load with gas impedance equivalent to the reactor, and switching gas supplied between the reactor and the gas dummy load without stopping either flow, thereby enabling rapid flow and rapid gas switching without turbulence. An atomically smooth, undamaged substrate can be prepared, preferably in the (100) plane, by etching the surface after polishing to remove subsurface damage. A gas phase chemical getter reactant such as hydrogen disulfide can be used to suppress incorporation of residual boron into the intrinsic layers. Embodiments can produce interfaces between doped and mobile layers that provide at least 100 cm2/Vsec carrier mobility and 1013 cm?2 sheet carrier concentration.

Abstract: A system and method for holding and warming food held in pans or trays having a low relative magnetic permeability, such as 300-series stainless steel, using induction heating.

Abstract: An enclosed resonator includes a generally planar plate having a top side and a bottom side wherein a pocket is recessed into the bottom side to produce a bottom surface and a periphery around the rectangular pocket including a first pair of parallel sides and a second pair of parallel sides, a plurality of generally parallel channels formed into the top side each channel extending generally in a direction of the second pair of parallel sides, a first plurality of holes extending along a first side of the first pair of parallel sides each hole extending from the bottom side to one of the plurality of generally parallel channels, a second plurality of holes extending along a second side of the first pair of parallel sides each hole extending from the bottom side to one of the plurality of generally parallel channels.

Abstract: A highly-reliable electronic frequency tuning magnetron comprises an anode for forming a resonant cavity which is segmented into a plurality of spaces in an inner periphery side of a cylindrical anode shell, a cathode provided at the center of the anode shell along its cylindrical axial direction and an exhausted structure having a coaxial central conductor which is connected to the inside of the cavity of the anode shell and is coupled thereto in a high-frequency manner, wherein the coaxial central conductor is externally led through a wall of the exhausted structure via a through-hole and the through-hole is covered by a dielectric portion placed between an external conductor for constituting the coaxial central conductor and the central conductor, wherein a portion of the led coaxial central conductor is conductively connected to a switching element.

Abstract: A nano-oscillator magnetic wave propagation system has a group of aggregated spin-torque nano-oscillators (ASTNOs), which share a magnetic propagation material. Each of the group of ASTNOs is disposed about an emanating point in the magnetic propagation material. During a non-wave propagation state of the nano-oscillator magnetic wave propagation system, the magnetic propagation material receives a polarizing magnetic field. During a wave propagation state of the nano-oscillator magnetic wave propagation system, each of the group of ASTNOs initiates spin waves through the magnetic propagation material, such that a portion of the spin waves initiated from each of the group of ASTNOs combine to produce an aggregation of spin waves emanating from the emanating point. The aggregation of spin waves may provide a sharper wave front than wave fronts of the individual spin waves initiated from each of the group of ASTNOs.

Abstract: The present invention is, in one aspect, a radio frequency source, comprising a gyromagnetic precession oscillator. In a second aspect, the gyromagnetic precession oscillator comprises a closed, non-magnetic, cylindrical outer conductor defining a cavity therein; an axial field solenoid wound about the outer conductor; a non-magnetic, cylindrical inner conductor disposed within the cavity and coaxially aligned with the outer conductor; a plurality of cylindrical ferrite precessors, each defining a respective bore through which the inner conductor runs; a plurality of dividers disposed within and defining a resonant chamber in the cavity; and a dielectric material filling the cavity. In a third aspect, the radio frequency source is actively tunable. In a fourth aspect, the radio frequency source that is tunable pulse-to-pulse.

Abstract: It is an object to provide a magnetron for a small-sized microwave oven which takes safety standards and a noise into consideration, in a magnetron 10 for a microwave oven, a pair of choke coils 16 and 17 are provided in a filter case 11, and a height H1 of the internal surface of the filter case 11 is set to be 35 to 45 mm, an outside diameter d3 of an air-core type inductance 25 is set to be 5.5 to 7.5 mm and a sectional area S of a high frequency absorbing member 27 is set to be 5 to 16 mm2. In the magnetron 10 for a microwave oven, an electrostatic capacity between capacitor terminals 15A and 15B and the filter case 11 is increased to be 500 to 700 pF.

Abstract: A magnetron having a cathode 1 and an anode 2 with vanes 3, has an insulating surface 4 in it which faces the cathode and receives material from it due to sputtering at the cathode. A conductor 7 enables the resistance of the film so deposited to be measured, giving an indication of the thickness of the film and the lifetime of the magnetron.

Abstract: A magnetron (2), a launcher (4) which extracts the output power of the magnetron (2), an impedance generator (5) having one terminal connected to the output terminal of the launcher (4), and a reference signal supplier (6) connected to the other terminal of the impedance generator (5) are included. The reference signal supplier (6) supplies, to the magnetron (2), a reference signal lower in electric power and stabler in frequency than the output from the magnetron (2). The oscillation frequency of the magnetron (2) is locked to the frequency of the reference signal by injection of the reference signal. The impedance generator (5) can reduce the change width of the oscillation frequency of the magnetron (2) by adjusting the load impedance of the magnetron (2). This implements a magnetron oscillator (1) which has high frequency stability and does not fluctuate the frequency even when the output power is changed.

Abstract: The object to the present invention is to provide a magnetron which can reduce spurious oscillation such as the ??1 mode which presents a problem particularly in magnetrons and can reduce spurious radiations without placing filters. The magnetron of the present invention includes an anode 1 formed by plural vanes 12 in such a manner that inner ends 12 are radially extended toward the center of the anode shell 11 from the inner wall of a cylindrical anode shell, and a cathode 2 provided at the center of the anode 1. The magnetron of the present invention further includes a pair of pole pieces 4 provided in such a manner that a magnetic field can be applied on the interaction space 2 where the inner ends 12a of the vanes 12 and the cathode 2 face with each other.

Abstract: A safety apparatus for an output level-adjustable microwave oven includes a fuse disposed in a power supply line that connects a high power relay or a low power relay with a primary coil of a high voltage transformer of the microwave oven. Where a wrong operation occurs due to defects in the relays, such as a melting of any one of the relays, the fuse disposed in the power supply line connected to the primary coil of the high voltage transformer is cut off. Accordingly, a potential fire resulting from the wrong operation is prevented.

Abstract: A magnetron includes a positive polar cylinder, a plurality of vanes, a filament, upper and lower shields, and upper and lower pole pieces. The vanes are disposed in the positive polar cylinder to constitute a positive polar section along with the positive polar cylinder. The filament is disposed on an axis of the positive polar cylinder to form an activating space together with front end surfaces of the vanes and emit thermions. The upper and lower shields cover a top and bottom of the filament, respectively. The upper and lower pole pieces are spaced apart from the upper and lower shields, respectively, to induce magnetic flux in the activating space. In the present invention, the upper shield has a bottom surface formed to be entirely protruded downwardly, and the lower shield has a top surface formed to be entirely protruded upwardly.

Abstract: A magnetron has an output comprising a coaxial line 15 which transmits energy from a wanted oscillator mode as a first coaxial waveguide mode and energy from an unwanted oscillator mode as a second cylindrical waveguide mode. Energy in the cylindrical waveguide mode is intercepted by slots 17, 18 in the coaxial line 15 and absorbed by material 19. This enables the modes to be separated. Preferably, the output is taken from the axis of the magnetron and the wanted oscillator mode in the &pgr;-1 mode.

Abstract: A microwave oscillator with an M-type interdigital slow wave resonator structure is disclosed. In the above oscillator, the anode has top, middle and bottom resonance discs. The top disc has downward extending vanes and defines an upper resonance chamber, while the bottom disc has upward extending vanes and defines a lower resonance chamber. The upper and lower resonance chambers is separated from each other by a middle resonance disc that has upward and downward extending vanes. An emitter is placed between the filament and the anode and emits thermions into the actuating space when it is heated by the filament. The upward extending vanes of the middle disc engage with the vanes of the top disc in the type of interdigital engagement like clasped hands. The downward extending vanes of the middle disc engage with the vanes of the bottom disc in the same manner.

Abstract: There is provided a magnetron comprising a cold cathode having an electron emitting member which is formed linearly or as a plane on a substrate to emit electrons a subdivided anode disposed oppositely in parallel with the electron emitting member, the subdivided anode having cavity resonators formed therein at the side of the cold cathode, and a magnet which producing a magnetic field lying at right angles to an electric field applied between the cold cathode and the subdivided anode. There is also provided a microwave oven for dielectric-heating a substance to be heated by using the magnetron as a microwave supply source.

Abstract: A cascaded magnetron device has an elongate cathode shank extending along its axis and a series of tubular anode elements placed end to end in a linear cascade surrounding the cathode shank along at least part of its length. Each adjacent pair of anode elements is separated by a conductive, annular pin down disc, and the cathode shank has a series of spaced bands of field emitting material separated by non-emitting regions, each band being located within a respective one of the anode elements and spaced inwardly from the ends of that element. Suitable power inputs and magnetic field generators are provided for generating electron emission and oscillation in the interaction zone between each emitting band and the anode element surrounding that band, and suitable extraction devices are provided for extracting power from each of the interaction zones, the arrangement producing phase-locking of the cascaded magnetron bodies.

Abstract: A relativistic magnetron device comprising an elongate cathode shank extending along the axis of the device and a cylindrical anode surrounding the cathode shank along at least part of its length to define an annular interaction area. The anode has an even number of resonator cavities facing the cathode, and microwave extraction devices are connected to alternate resonator cavities to extract power from the device. The cathode has a central, emission band extending from the center of the interaction area in opposite directions and terminating short of the ends of the anode, while the remainder of the cathode is non-emitting.

Abstract: A microwave generator that uses an electron beam and the phenomenon of the oscillating virtual cathode, but makes it possible to obtain energy with improved spectral quality and conversion efficiency as compared with standard vircator generators. This is achieved by the separate use of the electrons coming from the virtual cathode (80), that is, transmitted electrons (80) or reflected electrons (81) to convert their kinetic energy into microwave energy (4).

Abstract: A high impedance circuit has radially disposed first vanes and radially disposed second vanes interdigitating between the first vanes. The first vanes and the second vanes are each interconnected by a first toroidal strap and a second toroidal strap, respectively. The first strap and the second strap are dipsosed co-axially on opposite sides of the vane structure. The vanes and straps are dimensioned so that the circuit has a single cavity impedance commensurate with a predetermined interaction impedance for the oscillator which is sufficient to sustain oscillation for a preselected injection locking bandwidth of the oscillator.

Abstract: A magnetron is powered via an output transformer TR whose primary winding (a) is connected in series with a resonant converter oscillator circuit comprising an inductor (L) and a capacitor (C3) and switching transistors (T.sub.1, T.sub.2) which are connected to positive and negative power supply terminals and are switched by respective current transformers (CT1, CT2). The switching points of the switching transistors are varied so as to vary the output of the circuit by varying the positive and negative flux excursions in the cores of the transformers (CT1, CT2) such that the net flux excursions are sufficient to saturate the transformers and switch off the switching transistors at a predetermined point in each half cycle. The relative positive and negative flux excursions in the transformer cores are controlled by providing additional windings (g) which are connected to a control circuit whcih rectifies the output of these windings and controls the rectified DC voltage appearing across them.

Abstract: A magnetron in which a choke for preventing leakage of harmonic components of leaking microwaves to the outside of the tube is formed by a metal piece with slots that is placed within the tube or a conductive film that is placed on an insulating area of the stem.

Abstract: In a peniotron, a hollow electron beam is generated from a cathode gun assembly and a DC magnetic field is applied to the electron beam from solenoid coils. Thus, each electron of the electron beam is gyrated into a resonant cavity and into propagating waveguide sections which are maintained in auto-resonant conditions so that the electrons interact with an electromagnetic waves of TE mode not only in the resonant cavity section but also in a waveguide section. Accordingly, the electromagnetic wave is oscillated in the resonant waveguide section and amplified in the propagating waveguide section in such a manner that the level of the electromagnetic wave in the resonant cavity section is far less than the output power from said propagating waveguide.

Abstract: A microwave oven uses a full wave full bridge inverter for supplying energy to a cooking magnetron by way of a power transformer. The inverter is controlled by a microprocessor which acts upon a control circuit having an oscillator. Two feedback loops are provided for controlling the operation of the magnetron. A relatively slow feedback loop uses the microprocessor to adjust inverter operation in order to stabilize the magnetron power output. A relatively fast feedback loop senses current passing through a primary of a power transformer. A signal based on the sensed current is provided to a comparator and compared to a reference. If the signal from the current sensor indicates that the current has become excessive, the comparator generates a shutdown signal which will stop the generation of gating pulses to the transistor switches of the inverter.

Abstract: Microwave oscillators and amplifiers which utilize a superconducting slow-wave circuit. The slow circuit is made from materials which exhibit superconductivity at relatively high critical temperatures. The slow wave circuit is integral with the device's vacuum housing. Coolant exterior to the vacuum housing maintains the circuit in the superconducting state. The slow-wave circuit, which protrudes into the vacuum housing provides modulation of an electron beam which traverses the interior of the vacuum housing. Output power is ultimately extracted from the slow wave circuit.

Abstract: A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.

Abstract: A magnetron with a filter case housing a through-type capacitor and a choke coil wherein a mounting plate for the capacitor is fixed in intimate contact with the wall of the filter case along a line encircling a through-hole drilled in the wall of the filter case for drawing out the terminals of the capacitor.

Abstract: A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit therethrough effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators.

Abstract: A crossed-field microwave power tube. Electrons are emitted from a tubular lectrode at ground potential. The electrons are accelerated by an electric field toward a high voltage anode located within the tubular electrode. A magnetic field is oriented along the axis of the tube; the magnetic field is perpendicular to the electric field. The electrons follow curved paths in the space between the tubular electrode and the anode, while producing electromagnetic radiation in a TEM mode. The TEM radiation is easily coupled from the tube.

Abstract: A push-pull current-fed parallel resonant oscillator includes a parallel resonant LC tank circuit with one end coupled to one terminal of a DC current source via a serially connected first diode and first switching transistor and the other end of the tank circuit coupled to said one terminal via a serially connected second diode and second switching transistor. Respective capacitors (17, 21) shunt the series connections. The tank circuit inductor includes the primary of a transformer whose secondary is part of the transistor drive circuit. The circuit parameters are chosen to provide a duty cycle less than 50% and a high voltage gain of the AC tank voltage. The transistors are controlled to delay the turn-off time of the on-transistor thereby allowing a negative voltage to develop on the opposite capacitor which in turn delays turn-off of its parallel connected transistor so as to provide a dead-time (.DELTA.t.sub.2) during the switching interval in which both transistors are simultaneously off.

Abstract: A coaxial magnetron has a high-Q resonant cavity surrounding a multiple-resonator anode circuit and coupled by slots to alternate anode resonators. The cavity is resonant in the TE.sub.111 mode, having two zero points of electric field on its periphery. The anode circuit is correspondingly resonant in its N/2-1 mode.Mode suppression means damp out the degenerate TE.sub.111 mode which is not coupled to the output iris.The size and weight of the magnetron are much less than conventional tubes using a cavity resonant in the TE.sub.011 mode with circular electric field.

Abstract: A resonant-cavity type electronic tube having mechanically-operable tuning vanes associated with its resonant-cavity structure and disposed within an evacuable envelope. A support member is provided within the envelope for adjusting the tuning vanes relative to the resonant-cavity structure, so as to tune the frequency of resonance of the structure step-wise in accordance with a predetermined program. The tuning is carried out with a step motor, having a stator and armature with the envelope having a portion extending between the stator and armature for enclosing the armature within the evacuable space containing the tuning vanes and the resonant cavity structure. The armature is coupled to the tuning vanes for altering the position thereof relative to the resonant-cavity structure in fixed relation to the displacement of the armature relative to the stator. Electrical signals are coupled to the stator for establishing a programmable series of displacements of the armature relative to the stator.

Abstract: A heating device for use in laboratories and the like comprising an oven housing having a magnetron tube, power control circuitry for the magnetron tube, a timer for determining an amount of pulse power for the magnetron tube, a settable heating time switch with display, a settable venting time switch and display, and magnetron tube resistance heating structure directly, physically attached thereto with thermostatic control therefore for accurately, and by a predetermined amount, heating the magnetron tube prior to operation of the overall heating device. Because the temperature of the magnetron tube is very accurately maintained all of the changeable operating controls for the magnetron respond predictably and with a high degree of accuracy, and therefore when the heating device is used in laboratory applications for heating and drying a plurality of samples individually, each sample can be predeterminedly heated and dryed in a predicable manner like the previous samples.

Abstract: In a magnetron of the type wherein a gasket member in the form of a fine metal wire net is disposed between a cup shaped sealing member on the output side, and a magnetic yoke providing a magnetic flux passage for permanent magnets contained in the magnetic yoke, a portion of the yoke is provided with an annular projection for snugly receiving the gasket member and a flat edge integral with the projection is provided between the annular projection and the cup shaped sealing member for supporting the gasket member.

Abstract: A method of controlling the power output of a magnetron tube, and an electric power supply for supplying power to the tube. According to the method, power is continuously supplied to the magnetron heater. At the same time, a voltage is continuously applied across the anode and the cathode of the tube. This voltage across the anode and the cathode varies in cycles between a first value, which is substantially at or below the threshold voltage of the magnetron tube, and a second value, which is above the threshold voltage. The average magnetron power output is determined by the proportion of each cycle during which the voltage across the anode and the cathode is above the threshold voltage.

Abstract: A gyrotron backward wave oscillator device is described which can be operated in a controlled and predictable manner. The device includes an evacuated waveguide section, an electron source at one end providing a spiral electron beam, a collector at the opposite end, means for producing a magnetic field parallel to the longitudinal axis of the waveguide section, and an output window, the parameters of the device being such as to support backward wave oscillation therein and to output same through the window.

Abstract: A magnetron has a filter circuit inserted in a feeder line to a cathode electrode included in a high frequency generator and comprised of choke coils and a capacitor connected in series, in order to suppress leakage of unwanted high frequency components from the cathode electrode. At least one of the choke coils has an air-core coarse coil winding close to the cathode electrode which has at least two turns and a remainder of fine coil winding wound about a ferrite core, so that burning of the choke coil and overheating of the ferrite core can readily be prevented without imparing the function to suppress unwanted high frequency component leakage.

Abstract: Microwave oven with a self-regulating circuit operated from a low voltage a.c. source based upon a substantially constant current transformer and condenser series combination and having a return path for current on alternate half cycles. For defrosting food the magnetron is operated at partial power which is achieved by decreasing the voltage applied to the magnetron. This is done either by increasing the capacitive reactance in series with the secondary of the transformer or by decreasing the secondary voltage. Switching problems are solved by providing the arrangement of the invention at the grounded end of the transformer secondary. The self-regulating circuit is required to be of the type which has one end of the secondary winding grounded.

Abstract: An SCR circuit is provided in a high-voltage supply for energizing a magnetron that is assembled in a microwave oven. The high-voltage supply circuit includes a voltage step-up transformer. This transformer is arranged with a low-voltage secondary winding which is connected across the heater-cathode electrode of the magnetron and a high-voltage secondary winding which is coupled in series with a capacitor. The series combination of the capacitor and the high-voltage secondary is connected across the cathode and anode electrodes of the magnetron; and importantly, the high-voltage SCR circuit includes a number of series-connected SCR's electrically in shunt of the magnetron. A triggering circuit gates the high-voltage SCR circuit to the current-conducting state during a selected phase portion of an applied AC potential, in order to control the amount of power being supplied to the magnetron.

Abstract: A microwave magnetron-type device comprises an anode assembly or block in the form of a multistage two-dimensional periodic retarding system, including cavities with vanes, each having a lumped inductance portion defined by the vane sidewalls near the vane bases, and straps. The straps are arranged on each stage of the retarding system and pass through windows made in the vanes. Provided in the inductive portion of the cavities of the retarding system is at least one duct with the following ratios:d.sub.1 >d.sub.2 >d.sub.3,d.sub.3 >d.sub.4 >d.sub.5,h.sub.1 .ltoreq.h.sub.2,where d.sub.1 is the distance between the vane ends and the outer surface of the anode assembly, d.sub.2 is the distance between the vane ends and the duct wall adjacent to the outer surface of the anode assembly, d.sub.3 is the distance between the vane ends and the wall of the inductive portion of the cavities, remotest from the vane ends, d.sub.4 is the distance between the vane ends and the opposite duct wall, d.sub.

Abstract: A circuit for controlling power consumption of a load, by controlling the flow of current thereto, utilizes at least one parallel combination of non-linear resistance elements, such as a varistor and the like, and a gateable semiconductor switching device, such as a triac and the like, to substantially reduce or prevent current flow when the semiconductor switching device is gated to an "off" condition and to enable normal current flow to a load when the semiconductor switching device is gated to an "on" condition. Embodiments of the power circuits for control of magnetron power, in a microwave oven, are illustrated.

Abstract: A magnetron energizing circuit preferably uses two transformers of the high leakage reactance type having isolated secondaries with an end terminal of each secondary connected to a common point which is at ground potential. The secondaries are connected to series condensers in two loops which provide leading current flowing in the secondaries at all times while both are connected in the circuit to produce saturation in the respective cores of the secondaries whereby to achieve substantially constant current and good regulation for variations in the primary voltage. A single magnetron is served by the circuit and variations in the loading of the magnetron are also compensated for by virtue of the substantially constant current circuit. The secondaries are connected in opposite phase with respect to the respective capacitors which they serve to charge to obtain a full wave doubler operation when the transformers are both in circuit but with low peak current.

Abstract: A magnetron device emits through the filament terminals electromagnetic waves of a broad frequency band which act as noises to other electronic devices. The magnetron device comprises a filament or heater circuit for supplying heater voltage to the filament to emit thermal electrons from the cathode and an anode circuit for applying a required voltage across the filament and anode. The filament circuit is connected to one secondary winding of a power supply transformer and the anode circuit to the other secondary winding thereof. Connected to the anode power supply line is a filter device comprising a capacitor and a choking element having a sufficient inductance to reduce a relatively low frequency of the broad frequency band. This filter device is intended to reduce or suppress a large amount of the noise transmitted to the anode circuit out of a magnetron through filament terminals.

Abstract: Apparatus for varying microwave power level is included in a microwave oven. The microwave oven includes a magnetron for producing microwaves used for heating and a half-wave voltage doubler for supplying half-wave pulsating DC voltage to the magnetron. In order to vary voltage and thus power output of the magnetron, the charging of the capacitor in the half-wave voltage doubler is controlled by a variable resistance connected in series with the rectifier in the otherwise conventional half-wave voltage doubler.

Abstract: A power supply for a microwave magnetron includes a transformer having a secondary winding, a capacitor connected to one end of the winding, a magnetron connected in between the remaining end of the capacitor and the winding so as to form a first unidirectional current conducting path capable of conducting current in one direction and a second circuit connected in shunt of the magnetron having unidirectional current conduction characteristics and being switchable to an On or Off condition, said second circuit being electrically poled opposite to the polarity of the magnetron and means for controlling the switching of the second circuit to its current conducting condition as a function of the magnitude of current through the magnetron.

Abstract: A microwave magnetron operating circuit includes a high leakage reactance transformer having a secondary winding a capacitor connected in series with the secondary winding and means connecting the series combination of capacitor and secondary winding across heater cathode and anode terminals of a magnetron. A controlled semi-conductor switch such as a triac is connected electrically in shunt of the magnetron. Control means are provided to operate the triac to its current conducting state so as to conduct current in shunt of the magnetron. The control means includes a positionable control member, accessible to the user, for varying the time at which the controlled semi-conductor device is placed in its electrically conductive state so as to permit the user to adjust or set the power supplied to the magnetron to various different power levels.

Abstract: A crossed-field device having a plurality of slow wave energy propagating structures, each with an associated cathode, requires relatively low voltage for operation to provide a high power output. Electron beam current control is achieved by means of RF drive signals. Periodic permanent magnet focusing is utilized.

Abstract: A high impedance circuit has radially disposed first vanes and radially disposed second vanes interdigitating between the first vanes. The first vanes and the second vanes are each interconnected by a first toroidal strap and a second toroidal strap, respectively. The first strap and the second strap are disposed co-axially on opposite sides of the vane structure. The vanes and straps are dimensioned so that the circuit has a single cavity impedance commensurate with a predetermined interaction impedance for the oscillator which is sufficient to sustain oscillation for a preselected injection locking band-width of the oscillator.