Abstract: A microwave window for transmitting microwave radiation includes a solid body and a flange. The solid body includes a first surface and a second surface spaced apart from each other in a first direction thereby defining a thickness of the solid body in the first direction. The flange is disposed at a periphery of the solid body such that a peripheral portion of the solid body extends a length into the flange in a second direction perpendicular to the first direction. The thickness and the length are selected such that the power of reflections of microwave radiation by the microwave window are no more than about ten times the power of reflections at the minimum value.

Abstract: A plurality of slots are provided so as to be located between a thin plate flexible opening section screen member and a heating chamber wall surface 1 for allowing insertion of the opening section screen member. A gently-curved bulging surface exists in an area where the heating chamber wall surface 1 and the opening section screen member 5 are mated together. As a result, residual warpage which would otherwise remain when the opening section screen member is warped for attachment becomes invisible, thereby preventing occurrence of clearance, which would cause sparking or the like.

Abstract: A device for efficient transmission of electromagnetic waves comprising two layers of dielectric separated by a gap or space. The layers may be uniform or laminar, orthogonal or non-orthogonal to the direction of wave propagation, and made of Teflon, quartz, polypropylene, and the like. The preferred distance between layers is an odd multiple of quarter wavelength in the environment between the layers. The preferred thickness of the layers is an odd multiple of half of the effective wavelength for the layer. The device allows over 95% efficiency for transmission into a pressurized vessel for evaporation under high pressure and temperature and does not require a cooling system. The separating space may be connected with a pressure-sensing subsystem to monitor the device's integrity and shut down the system in the event of a breach. A sleeve connecting the device to the vessel may be coated with conductive material for improved efficiency.

Abstract: A device for efficient transmission of electromagnetic waves comprising two layers of dielectric separated by a gap or space. The layers may be uniform or laminar, orthogonal or non-orthogonal to the direction of wave propagation, and made of Teflon, quartz, polypropylene, and the like. The preferred distance between layers is an odd multiple of quarter wavelength in the environment between the layers. The preferred thickness of the layers is an odd multiple of half of the effective wavelength for the layer. The device allows over 95% efficiency for transmission into a pressurized vessel for evaporation under high pressure and temperature and does not require a cooling system. The separating space may be connected with a pressure-sensing subsystem to monitor the device's integrity and shut down the system in the event of a breach. A sleeve connecting the device to the vessel may be coated with conductive material for improved efficiency.

Abstract: The invention relates to microwave windows used for providing a vacuum seal and for transmitting the electromagnetic energy output by a high-power microwave tube.

Abstract: A measuring device for determining the level of material in a container including a process seal comprising: a substantially conical portion including a narrow end and a wide end, the conical portion terminating at the wide end in a substantially cylindrical outer surface; and a flange portion extending outwardly from the substantially cylindrical outer surface. The process seal minimizes reflection and attenuation of measuring device energy, seals the connection to the container, and meets sanitary standards.

Abstract: A millimeter-wave window is constructed from a high conductivity metal plate. The metallic plate is made transparent over a range of frequencies by perforating it with a periodic array of slots. In one embodiment, the millimeter-wave window is used in a gyrotron as the output window. In such a case, one suitable periodic array of slots comprises an equilateral triangular array of slots for operation at 95 GHz. By proper choice of the hole spacing and diameter, the window can be made transparent at any desired frequency. In addition to being transparent, however, the window must also be vacuum tight, as the pressure inside a gyrotron is on the order of 10−9 torr. The present invention solves this problem by covering the surface of the window with a thin layer of a suitable dielectric material, such as fused quartz.

Abstract: A measuring device for determining the level of material in a container including a process seal comprising: a substantially conical portion including a narrow end and a wide end, the conical portion terminating at the wide end in a substantially cylindrical outer surface; and a flange portion extending outwardly from the substantially cylindrical outer surface. The process seal minimizes reflection and attenuation of measuring device energy, seals the connection to the container, and meets sanitary standards.

Abstract: A window assembly for use with electromagnetic waveguides includes a window 3 and a housing 4. The window 3 has impermeable layers 33 and 34 which are bridged by a reticulum 35 of ceramic material with internal spaces which form a continuous flow path for coolant. The window is received in an opening in the housing 4 which is surrounded by an inwardly-directed flange having a peripheral recess opposed to the window 3 to improve the microwave performance of the window.

Abstract: A millimeter-wave window is constructed from a high conductivity metal plate. The metallic plate is made transparent over a range of frequencies by perforating it with a periodic array of slots. In one embodiment, the millimeter-wave window is used in a gyrotron as the output window. In such a case, one suitable periodic array of slots comprises an equilateral triangular array of slots for operation at 95 GHz. By proper choice of the hole spacing and diameter, the window can be made transparent at any desired frequency. In addition to being transparent, however, the window must also be vacuum tight, as the pressure inside a gyrotron is on the order of 10−9 torr. The present invention solves this problem by covering the surface of the window with a thin layer of a suitable dielectric material, such as fused quartz.

Abstract: A window for a waveguide for a beam of electromagnetic radiation. The window includes a layer of a material capable of allowing electromagnetic radiation to pass therethrough and a support on each side of the layer. Each support defines a passage for electromagnetic radiation. Further, the layer is provided with at least one recess formed in the periphery thereof.

Abstract: The invention concerns an assembly for the pressure-tight separation of a first waveguide (12) from a second waveguide (16), having a pressure-resistant conductor body (22) and a first adaptor (26), which is arranged between the first waveguide (12) and the end of the conductor body (22) facing the latter, and a second adaptor (30), which is arranged between the second waveguide (16) and the end of the conductor body (22) facing the latter, the dielectric constants of the first and second adaptors (26, 30) lying between those of the conductor body (22) and the waveguides (12, 16). An assembly of this kind can be used in particular for an electronic device with a contact pin (10) and an antenna (18), the contact pin (10) radiating into a first waveguide (12) and the antenna (18) being connected to a second waveguide (16) and a pressure-tight bushing for microwave radiation being required between the first and second waveguides (12, 16).

Abstract: A crossed-field device such as a crossed-field amplifier or magnetron has a cathode body portion and an anode which cooperates with a crossed magnetic field to maintain emitted electrons on cycloidal paths and amplify an input signal or develop a microwave or millimeter wave output signal in an interaction space. The device is switched to shut down between working cycles, and delayed and secondary emissions are reduced to allow low noise operation and reduce multipactor for dependable operation at lower magnetic field strengths. Ceramic windows cover the output transformer (and input transformer in an amplifier device), and at least one window is grooved to reduce its secondary electron yield while maintaining its rf aperture. In addition, one or more walls within the device are physically structured or chemically treated or arranged to further address multipactor, allowing operation at reduced magnetic field strengths.

Abstract: A description is given of a filling level measuring device operating with microwaves, having a housing and an insert composed of a dielectric, and of a process for producing the dielectric, in which the dielectric constant of the insert is adjustable and in which the insert has a high chemical resistance and a mechanical strength adequate for industrial applications. The dielectric is a composite material composed of a fluoroplastic, in particular polytetrafluoroethylene, and ceramic and is produced by mixing powdered ceramic and powdered fluoroplastic, drying the mixture, pressing the mixture and sintering the pressed mixture.

Abstract: Illustrated and described is a microwave window for the spatial separation and microwave-transmitting connection between an external microwave conductor and an internal microwave conductor or a horn radiator, with a microwave-permeable transmissive window plate and with a metal fixture for mounting said window plate.

Abstract: The invention concerns a microwave level measuring device for measuring of material levels in containers, suitable for operation at extreme container conditions, comprising high temperatures, high pressures, and/or chemically aggressive substances.

Abstract: This level measuring instrument which operates with microwaves, has a radiation characteristic with a pronounced forward lobe and can be used to transmit and/or receive microwaves with a large frequency bandwidth. A housing section is designed as a waveguide short-circuited at one side and one end by a rear wall, and is virtually completely filled with an insert made of a dielectric. An exciter element, projects into the housing section and is connected to a microwave source. An antenna adjoins the housing section, for transmitting and/or receiving microwaves. A gap is arranged in the insert between the exciter element and the antenna. The gap forms a filter which is essentially non-transparent to higher modes of the waveguide.

Abstract: A high average-power microwave window is provided whose thermal conductivity has been enhanced to enable it to transmit higher average RF power levels than conventional windows of the same size. Such a window is suitable for use with high-average power RF sources such as klystrons and magnetrons. The window comprises a ceramic substrate, typically a low-loss ceramic such as alumina or quartz, to which narrow strips of a high thermal conductivity material have been bonded. One such high thermal conductivity material is synthetic polycrystalline diamond, which can be bonded to the surface of a dielectric substrate using a high-temperature cement or can be directly deposited on the surface by a process such as chemical vapor deposition (CVD). High-purity alumina, a commonly-used material for high-power RF windows, has a thermal conductivity of 26.4 W/m.multidot..degree. C., while synthetic diamond has a thermal conductivity of 1000 W/m.multidot..degree. C., 2.6 times that of copper and 38 times that of alumina.

Abstract: The invention relates to a method for producing low cost hermetic Integrated Module Assembly (IMA) packaging, where an aluminum coating (24) is deposited on a poly-tetrafluoral-ethaline substrate (20), the aluminum coating (24) is selectively etched to form a waveguide window (26) and the substrate (20) is selectively treated over the waveguide window (26) to produce a non-conductive hermetic seal. The substrate (20) is then joined to a metal carrier (28) containing the waveguide (30). As a result of using selectively treated low cost substrates to produce hermetic seals, more expensive substrates are not required to form hermetic seals over substrate to waveguide interconnections.

Abstract: Inexpensive and reliable apparatus for blanking the signal path between an antenna and a transmitter or a receiver to protect them from harmful radiation in the absence of power forms supplied thereto. The apparatus is preferably formed as a printed circuit waveguide switch window having a plurality of parallel conductors, such as metal wires or printed circuit traces, disposed on a dielectric substrate. The waveguide switch window is secured between two sections of waveguide. The conductors have a predetermined separation and width that are designed to appear as a solid metal surface that rejects radiation over a wide bandwidth. A bias terminal is coupled to the plurality of conductors, and insulating material is disposed between the bias terminal and the conductors to insulate the top portion of the grid array from the adjacent waveguide. The lower portion of the grid array is grounded to the adjacent waveguide.

Abstract: The waveguide window assembly disclosed herein is particularly adapted for use in conjunction with a waveguide housing of a high expansion material such as aluminum. The window is formed of a glassy material having a relatively low coefficient of thermal expansion and is provided with a frame of a material having a matching coefficient. The housing is provided with an opening for receiving the frame with substantial clearance. A wall member is interposed between the frame and the edges of the opening with solder filling the space between the wall member and the frame and also the space between the wall member and the edges of the opening, the wall member being constructed of a material having a coefficient of thermal expansion which is intermediate those of the housing material and the frame material.

Abstract: A waveguide for microwave radar level gages that includes a process sealed barrier in the waveguide that is impedance matched with bore transition sections of the waveguide at opposite ends thereof. The impedance matching results in positioning of the tapered end of the barrier offset from the ends of the bore transition sections.

Abstract: A microwave window is made as a flat layer of dielectric material having opposite first and second surfaces. Between these surfaces, the window is formed with a plurality of parallel coolant channels which, in cross-section, have racetrack configurations with flat sides and curved ends. The channels are distanced from each other in the window to establish parallel plate waveguides between the flat sides of adjacent channels. A plurality of cylindrical lenses are formed on the first surface of the dielectric layer to focus incident microwaves into convergence in a respective waveguide. Additionally, a plurality of cylindrical lenses are formed on the second surface of the dielectric layer to refocus microwaves emerging from the parallel plate waveguides back into a substantially parallel relationship as the microwaves radiate from the window.

Abstract: A process sealed waveguide is formed in a flange mounted on a tank, and is used for transmitting microwave energy from a source of microwave energy to an aperture of an antenna on the interior of the tank. The process sealed waveguide includes a mechanical barrier to prevent escape of fluid under pressure or liquid from the interior of the tank, and also serves to reduce impedance mismatch between the air, vapor, or liquid filled waveguide or antenna apertures. The flange is mated to the microwave source through an electronic housing to flange adapter that interfaces with the flange in a manner to provide a vent in case the mechanical barrier fails so pressure is released, and to provide flame quenching if flames are present. The adapter includes a second waveguide having a process sealed mechanical barrier mounted coaxially with the mechanical barrier in the waveguide in the flange.

Abstract: A waveguide assembly for a process sealed level gage includes first and second waveguide portions, a process sealing cavity and a mechanical barrier. The first waveguide portion has a first waveguide bore. The second waveguide portion is fastened to the first waveguide portion and has a second waveguide bore which is axially aligned with the first waveguide bore for communicating microwave signals at a waveguide wavelength .lambda..sub.G between the waveguide bores. The process sealing cavity is formed at an interface between the first and second waveguide portions. The mechanical barrier includes a first shaft section positioned within the first waveguide portion, a second shaft section positioned within the second waveguide portion and a raised annular shoulder positioned at the interface, within the process sealing cavity. The raised annular shoulder has a width, which is measured radially outward from an outside diameter of the shaft sections, of approximately 1/2 .lambda..sub.

Abstract: In a high frequency transmission arrangement such as that used to deliver microwave energy from a magnetron to a waveguide, a ceramic probe is covered with a non-ceramic dielectric material such as PTFE. This allows the magnetron to operate satisfactorily at low Pressures where arcing would otherwise be expected to occur.

Abstract: A distributed microwave window (12) couples microwave power in the HE11 mode between a first large diameter waveguide (32) and a second large diameter waveguide (34), while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric (14) and hollow metallic (16) strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips (14). A suitable coolant flows through a coolant channel (18) that passes through the metallic strips (16).

Abstract: A microwave window includes a transparent disk made of glass or ceramic that lets microwaves through and an attachment device made of metal that is used to attach the transparent disk. This microwave window is characterized by the fact that the transparent disk of glass is sealed into the attachment device or the transparent disk of ceramic is sintered into the attachment device.

Abstract: An improved housing assembly is used for a microwave level sensing instrument for sensing level of a process fluid in a vessel. The process vessel includes a vessel flange defining an opening into a storage space in the vessel. The housing assembly includes a flange assembly including a housing flange having a distal gasket face sealingly mateable with the vessel flange in use. The housing flange is connected to a window housing for housing a window spaced from the gasket face and providing a process seal. An electronics housing is mounted to the window housing. The electronics housing supports a microwave antenna proximate the window for focusing energy through the window to the process fluid.

Abstract: A first circular waveguide or an elliptical waveguide has an inner circumferential surface tapered such that its inside dimension is gradually reduced continuously toward an end thereof. The elliptical waveguide comprises an antenna waveguide connected to an antenna device. Another circular waveguide has an end joined to the end of the first circular waveguide or the elliptical waveguide. Both waveguides have different inside dimensions at the joined ends. A hermetic seal is sandwiched between the joined ends of both the waveguides. The tapered inner circumferential surface is effective to cancel out a susceptance produced by the hermetic seal. The first waveguide with the tapered inner circumferential surface can easily be manufactured by die casting.

Abstract: The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided.

Abstract: A hermetically sealed electromagnetic window is formed by butt end brazing an overhanging dielectric window between first and second waveguide segments. The waveguide segments have opposed knife edges with a dielectric insert positioned between the knife edges. A pair of brazing forms are inserted between the insert and the two knife edges. The window is heated, causing the brazing material to reflow and provide a hermetic seal between the insert and the waveguide segments, and a conductive path between the waveguide segments.

Abstract: A fluid-cooled dielectric window for a microwave plasma system which uses microwave absorbing fluids is described. The window includes a dielectric window and a cooling member in contact with an outer surface of the window which defines a channel and a medium adjacent to the channel. The channel transports a microwave absorbing cooling fluid over the outer surface of the window. The medium allows an electric field to enter through the window and sustain a plasma in a chamber while the fluid is flowing through the channel.

Abstract: A vacuum output window comprises a planar dielectric material with identical systems of parallel ridges and valleys formed in opposite surfaces. The valleys in each surface neck together along parallel lines in the bulk of the dielectric. Liquid-coolant conduits are disposed linearly along such lines of necking and have water or even liquid nitrogen pumped through to remove heat. The dielectric material can be alumina, or its crystalline form, sapphire. The electric-field of a broadband incident megawatt millimeter-wave radio frequency energy is oriented perpendicular to the system of ridges and valleys. The ridges, about one wavelength tall and with a period of about one wavelength, focus the incident energy through in ribbons that squeeze between the liquid-coolant conduits without significant losses over very broad bands of the radio spectrum. In an alternative embodiment, the liquid-coolant conduits are encased in metal within the bulk of the dielectric.

Abstract: A microwave waveguide is presented which includes a gas tight seal which provides pressure isolation between two portions of the waveguide. In accordance with an important feature of this invention, an upper flange includes a threaded axial opening for receiving and retaining a threadably mated dielectric filling material. If the thread pitch is small relative to the signal wavelength, the threaded section has essentially the same electrical characteristics as a smooth waveguide. The resulting structure provides an economical and practical method of retaining a solid dielectric filling material in a waveguide against high pressure without changing the effective diameter of the waveguide. In accordance with another feature of this invention, a novel high pressure seal is provided between the upper and lower flanges in the area surrounding the threaded axial opening.

Abstract: A broad passband pressure barrier arrangement is provided for insertion in circular waveguide between a source and a receiver of radio frequency (RF) energy with a spatially circumferential electric field characteristic of the TE.sub.01 mode. At least two cylindrical barrier regions are coaxially aligned and arranged symmetrically in mirror image fashion about a radial plane of the circular waveguide. The cylindrical barrier regions include at least one solid cylindrical plug region sealed in a cross-section of the circular waveguide and having a longitudinal thickness sufficient to withstand a predetermined pressure load. Each of the cylindrical barrier regions are defined by a characteristic impedance at opposing end faces thereof and a by characteristic impedance between the opposing end faces. A region-by-region impedance analysis process begins with an end face of the arrangement that is furthest from the source and is completed with an end face of the arrangement that is nearest the source.

Abstract: A broad passband pressure barrier arrangement is provided for insertion in circular waveguide between a source and a receiver of radio frequency (RF) energy with a spatially circumferential electric field characteristic of the TE.sub.01 mode. At least three abutting cylindrical barrier regions are coaxially aligned a arranged symmetrically in mirror image fashion about a radial plane of the circular waveguide. The cylindrical barrier regions include: at least one solid cylindrical plug region sealed in a cross-section of the circular waveguide and having a longitudinal thickness sufficient to withstand a predetermined pressure load, and at least one solid cylindrical tuning region having a radius less than that of the circular waveguide and further having a longitudinal thickness. Each of the cylindrical barrier regions are defined by a characteristic impedance at opposing end faces thereof and a by characteristic impedance between the opposing end faces.

Abstract: A plurality of magnetized elements form a continuous surface proximate to a waveguide opening, sufficient to satisfy electron cyclotron resonance plasma generation. With the elements similarly magnetized in a direction perpendicular to their central axis and parallel to the plane in which they are situated, a continuous resonance surface may be formed without the need for an externally applied magnetic field. Other magnetization orientations, such as perpendicular to the plane of the elements, may require an external magnetic field, such as that derived from solenoidal coils, but of a magnitude substantially reduced due to the combined field supplied by the elements.

Abstract: A window has two plates of radiation-propagative material, such as two plates of glass or two films of transparent dimensionally-stable plastic which serve as window panes through which electromagnetic radiation can propagate. The panes are spaced apart by one quarter wavelength of the radiation by a spacer block to provide for cancellation of any reflected wave. The window is readily disassembled to permit replacement of the spacer block to increase or to decrease the spacing as may be required to adjust the window for a different frequency band of radiation. Also, the construction of the window permits its mounting within the aperture of a wall, and to serve for joining two waveguides, thereby, to facilitate use of the window in the conduct of tests in a laboratory. The spacer block with the transparent plates thereon are positioned between a base and a cap, both of which are configured for attachment to waveguides.

Abstract: An improved waveguide window (10) for use in high power waveguide applications. The window (10) preferably includes a thin sheet (12) of dielectric material having a first planar face (14), a second (16) face, and a support structure (18) attached to the first face (14) to provide mechanical support for the sheet (12). The support structure (18) preferably includes a plurality of parallel conductive support bars (20), each bar having an inner portion (22) attached to the first face (14) and an outer portion (24) extending away from the sheet (12), the outer portion (24) being tapered to minimize wave reflection. At least one bar (20) also has a channel (28) bored therethrough to allow a coolant to flow through the bar (20) to remove heat generated within the dielectric sheet (12). Together, the sheet (12) and the support structure (18) form a waveguide window (10) which may be used to environmentally separate one waveguide section (32) from another (34).

Abstract: A distributed microwave window couples microwave power in the HE.sub.11 mode between a first large diameter waveguide and a second large diameter waveguide, while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric and hollow metallic strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. A suitable coolant flows through the metallic strips. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips. The surfaces of the dielectric strips fronting the microwave power may be corrugated in a specified manner to reduce losses.

Abstract: A distributed microwave window couples microwave power in the HE.sub.11 mode between a first large diameter waveguide and a second large diameter waveguide, while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric and hollow metallic strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. A suitable coolant flows through the metallic strips. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips.

Abstract: A distance measuring device for measuring the fill level in industrial tanks, which includes electronic transmitting- and receiving elements for short wave electromagnetic waves, such as microwaves, and a cylindrical waveguide which extends through a separating wall and inside of which is a waveguide window separating the two spaces and made of a material, such as quartz glass, which is transmissive with respect to electromagnetic waves. The waveguide and the waveguide window (3) have conically-shaped sections (5) to provide axial support. To protect the waveguide window against destruction due to thermal expansions and pressure fluctuations, the conical section (5) of the waveguide window (3) is in a correspondingly formed conical socket (8). The socket is mounted with play in a cylindrical bore (9) of the waveguide window (3) and is supported by a shoulder (10) of the waveguide in the axial direction.

Abstract: A microwave process seal and method is provided for use, for example, in the detection of ullage level and flow in a vessel or conduit by detecting the presence of a solid or liquid material in proximity to a microwave detector. Particularly, a horn design is provided in conjunction with, the microwave process seal of the present invention which fits in the mouth of the horn. The microwave process seal is kept as thin as possible to meet pressure requirements. The surface of the seal is oriented at or near the Brewster angle. The Brewster angle is that angle for which there is total transmission across a dielectric boundary for energy that strikes the boundary with a linear polarization.

Abstract: A window for transmitting radiation of 20 microns or longer comprises a layer supported around its periphery by a frame. The layer comprises a first major surface on one side capable of receiving the radiation and a second major surface on the opposite side to the first major surface. The layer comprises a plurality of diamonds and a bonding polymeric resin capable of transmitting the radiation. The diamonds can, in one embodiment, be diamond plates located edge-on relative to neighbouring diamond plates.

Abstract: A microwave transmitting window for a plasma processing device. The window is a body of one or more pieces of the same or different dielectric materials. A surface of the window facing a microwave transmitting horn or waveguide is planar and extends perpendicularly to an axial direction. An opposite surface of the window is recessed such that the body has a non-uniform thickness between the two surfaces. The recessed surface can have various shapes and the overall size of the window can be equal to the size of a plasma formation chamber of the plasma processing device. The outlet of the plasma formation chamber can be formed in an end wall or the outlet can be formed by the inner periphery of the plasma formation chamber.

Abstract: A microwave window assembly for transmitting high power microwave energy from microwave propagating means into the interior of a chamber and including first and second windows formed of a dielectric material substantially transparent to microwave energy with the first window sealed in a wall of the chamber and the second window spaced rearwardly from the first window to define a space therebetween. A cooling fluid is circulated in the space between the windows to cool the window positioned in the wall of the vacuum chamber and a waveguide tube extends from the microwave propagating means to the rear surface of the second window to define a waveguide surface extending from the microwave source to the rear surface of the second window.

Abstract: A gyrotron microwave output window made of a pair of centrally coupled dielectric disks in which the displacement between the windows is tunable by adjusting means external to the waveguide and in which the window central coupling automatically compensates for such adjustments and for coolant pressure changes.

Abstract: The process of the invention consists in co-sintering a fine-grain alumina (8,9,10) with a metallizable alumina (11,12). The component obtained has dielectric properties which are homogeneous in its useful part (8,9,10) and its metallizable parts (11,12) permitting the assembly thereof very solidly with metallic components (1).

Abstract: A window assembly for transmitting relatively high power microwave energy from a waveguide, held at substantially atmospheric pressure levels, into a microwave reaction chamber at sub-atmospheric pressure levels. The window assembly provides for the transmission of microwave energy to generate a glow discharge plasma without suffering from catastrophic failure as a result of excessive temperature and pressure conditions.