Abstract: A module equipped with a non-radiative dielectric waveguide in accordance with this invention comprises a pair of parallel flat conductors arranged at a space of 1/2 or below of a high frequency signal wavelength .lambda. and a dielectric strip extending between these parallel flat conductors. This dielectric strip is formed from a cordierite ceramic having a dielectric constant of 4.5 to 8, especially 4.5 to 6. Conversion of an electromagnetic wave of LSM mode to an electromagnetic wave of LSE is minimal. When the module has a dielectric strip having a steep curved portion having a small radius of curvature, the transmission is possible with a low loss, and the band width of a high frequency signal is broad.

Abstract: A variable absorptive/reflective high power attenuator for attenuating microwave signals in a communication system is formed from a circulator connected to a section transmission line such as a waveguide, having at least one adjustable tuning element connected thereto. The transmission line itself is terminated with a microwave energy absorbing load. A signal injected into the circulator is partially reflected by the tuning element(s), and partially absorbed in the load. The reflected portion is routed to an output port of the circulator. The non-reflected portion is dissipated as heat by the load. The amount of output of signal attenuation is selectively controlled by the location and penetration of the tuning elements. In another embodiment, a latching type circulator is utilized to allow selective switching of the attenuation level insitu. More than one such switching type attenuator can be cascade connected to form a single customizable and variable attenuator design.

Abstract: The attenuator is applicable to the art of identification, interrogation and communication equipment. The attenuator has particular application to equipment used in conjunction with smart cards, tags and like apparatus and including, in one form, an RF based technology, which has found a use in electronic ticketing, monitoring passenger movement and the identification and sorting of airline baggage and/or other items, such as containers or mail items. The attenuator, in one form, is predicated on the principle of creating a substantially opposing field, and applying this proximate the interrogator to substantially reduce stray field emissions. The attenuator, in another form, combines the physics of conducting tubes and self-cancelling fields and applies them to a tunnel interrogator. The attenuator thus applies a conducting tube which confines the field and the property of a loop generating a self-cancelling field to an interrogator. This combination may be called a "loop tube".

Abstract: An opto-electronically controlled waveguide includes a waveguide; a finline mounted in the waveguide; a photovoltaic switch operably electrically cected to the finline; and a light source for generating an optical signal for modulating the photovoltaic switch. Modulation of the photovoltaic switch by intensity modulating the optical signal allows modulation of the insertion loss of the waveguide without the need for a DC bias.

Abstract: A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

Abstract: The present invention relates to a device for attenuating unwanted waves appearing in an electron tube which includes at least two coaxial cylindrical electrodes (2, 3). The electrodes (2, 3) contribute to forming the walls of a coaxial resonator. The unwanted waves to be attentuated generate surface currents in the walls of the coaxial resonator. The attenuation device includes several electrically conducting resistive elements (10) inserted into at least one wall of the resonator and arranged so as to cut the surface currents.

Abstract: A compact high-power RF load comprises a series of very low Q resonators, or chokes ?16!, in a circular waveguide ?10!. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer ?12! at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications.

Abstract: A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power.

Abstract: A waveguide evanescent mode filter is integrated with a monolithic microwave integrated circuit (MMIC) by forming both the MMIC circuitry and the waveguide filter on a single substrate that forms a common ground plane for both elements. The waveguide has a superstructure with an interior recess that is contoured to provide a desired cutoff frequency. The underlying portion of the ground plane can form the lower portion of the waveguide itself, and can also be contoured to define the cutoff frequency. Adjustable attenuation is provided by a resistive card that can be inserted by different amounts into the waveguide.

Abstract: A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.

Abstract: A waveguide absorber which withstands high mechanical and thermal loads is typified in that a member (4) exhibiting absorber material is clamped between waveguide walls (5, 6) in such a way that at least one wall region (5) adjoining the member (4) is constructed flexibly, and that a force acting on the flexible wall region (5) presses the latter against the member (4).

Abstract: A dielectric waveguide has a pair of parallel flat metallic plates spaced from each other, a dielectric strip sandwiched between the parallel flat metallic plates, and a wave absorber sandwiched between the parallel flat metallic plates and extending parallel to the dielectric strip. The wave absorber has a tapered portion which is progressively closer to the dielectric strip in a direction away from an inlet end of the wave absorber. The wave absorber has a side surface which may be held in contact with a side surface of the dielectric strip to provide a termination for eliminating reflections of input electromagnetic waves applied to the nonradiative dielectric waveguide, or may be spaced from a side surface of the dielectric strip to provide an attenuator for attenuating the power of input electromagnetic waves applied to the nonradiative dielectric waveguide.

Abstract: A circuit element for microwave and millimeter-wave bands and a method of producing the same. A dielectric line is made of a pure dielectric resin. A high-frequency wave absorbing member is made of a pure dielectric resin containing at least one of first, second and third powders dispersed therein. The first powder having a high specific inductive capacity, the second powder having a high magnetic permeability, and the third powder having a high specific resistance. A compression molding technique is used to fusion bond the high-frequency wave absorbing member to the dielectric line.

Abstract: A data processing system and housing are disclosed having reduced electromagnetic energy emissions. A central processor is mounted within a generally rectangular conductive outer case which includes one or more apertures for receiving and mounting electronic subassemblies such as: diskette drives; fixed disk drives; tape drives; and, optical disk readers. A conductive waveguide assembly having at least one waveguide is then mounted within the conductive outer case with one end of the waveguide mated conductively to the aperture within the conductive outer case. Electromagnetic energy from the electronic subassembly or from within the conductive outer case must then traverse the conductive waveguide prior to emission from the data processing system housing through the aperture therein. The shielding effect of requiring electromagnetic emissions to traverse an internal waveguide will provide substantial attenuation of electromagnetic interference.

Abstract: A liquid cooled adjustable waveguide termination for use in high power applications is described. The liquid cooled adjustable termination includes a waveguide housing having a shorting plate disposed at an end portion of the housing and an electromagnetic energy absorbent element disposed within the waveguide. The absorbent element includes a hollow tube disposed within a bore of the element for providing the liquid coolant to an inner portion of the element. The termination further includes a flow header assembly for providing coolant to the absorbent element via the hollow tube and for directing the heated coolant out of the termination assembly, and an adjustable seal plate disposed between the flow header assembly and the shorting plate for adjusting the position of the electromagnetic energy absorbent element within the waveguide.

Abstract: A microwave vector modulator (4) of the reflective type is used to match a microwave load. The adjustable reflection of the vector modulator is obtained by semiconducting surfaces (18, 19, 20, 21), illuminated by light-emitting means (24, 25, 26, 27).

Abstract: An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

Abstract: A waveguide having walls defining an opening. An optically transmissive aperture in one wall allows light from an optical illumination source such as a laser diode array to illuminate the opening in which is located a semiconductor slab positioned to be illuminated. When the array illuminates the slab, the propagation characteristics (phase velocity and attenuation constant) of the waveguide changes. A continuous wave signal passing through the waveguide is thus attenuated and phase shifted. The laser array may be pulsed on and off while still maintaining the altered propagation constant.

Abstract: The present invention discloses an apparatus that shields electronic equipment from electromagnetic interference. The apparatus is a partially enclosed box having a substantially enclosed cavity. Disposed within the cavity is electronic equipment that is either sensitive to or responsible for generating unwanted EMI radiation. Within each apparatus are cooling air openings. Within each opening is a heat sink device, dimensioned to provide a level of EMI filtering. The heat sink device has a dual function. First, as an EMI filter, it attenuates EMI radiation in the range of frequencies generated by or disruptive to the electronic equipment. Secondly, as a heat sink device, it transfers heat away from the apparatus. In this way, the apparatus of the present invention successfully provides an EMI filter that doubles as a heat sink.

Abstract: A plurality of waveguide elements are arranged to form an electromagnetic wave absorbing lattice in opposed relation to the advancing wave surface of the incident electromagnetic wave. Each waveguide element has a front opening on the lattice receptive of a part of the incident electromagnetic wave, a rear end portion spaced rearwardly from the front opening, and an inner peripheral surface portion extending between the front opening and the rear end portion to define a cavity effective to wave-guide the received electromagnetic wave. The inner peripheral surface portion has a given electric resistivity to effect absorption of the received electromagnetic wave during the wave-guiding thereof without substantial reflection thereof.

Abstract: A process for making attenuating circuits from a waveguide, in which the guide is made from two metal parts (A, B) of elongated shape, at least one of which comprises a groove (1) over the entire length of the part or parts, the two parts (A, B) being intended to be joined to close the groove and to constitute the actual waveguide. Before assembly of the two parts, an attack is performed on the surfaces of the two parts intended to constitute the walls of the guide to roughen them. The roughness is provided, for example, by projection of a jet of sand on these walls.

Abstract: An insert for non-reciprocal waveguide device comprises a layer of ferrite and a layer of energy absorbing material with a spacer layer between them. The device works by reason of asymmetrical interaction of the microwave energy and the ferrite whereby energy is preferentially absorbed in the reverse direction. The spacer layer affects the distribution of electromagnetic fields so that there is a relatively low attenuation associated with one direction and a relatively high attenuation associated with the reverse direction.

Abstract: The nonlinearity of the frequency response of a solid state power amplifier (SSPA) is obviated by effectively operating the SSPA at the 1 dB compression point, where the nonlinearity does not exist, and controllably reducing, downstream of the SSPA, the power output produced by the SSPA to the level required by the link. In particular, the output is reduced by controllably inserting a relatively thin tapered blade of ferrite material into a waveguide coupling section downstream of the SSPA. Preferably the ferrite material is comprised of a robust carbonyl steel of sufficient thickness to withstand the heat induced in the course of its absorbing microwave energy at the SSPA output, while being of a narrow or thin configuration and oriented for insertion into the absorbing section of waveguide so as to not effectively alter the characteristics of the signal profile of the electromagnetic wave.

Abstract: A linear microwave attenuator has an absorbing element which is selectively shaped to provide reduced capacitive coupling and increased attenuation by segmenting the absorber into at least two members. The selective shaping reduces both the surface area and mass of the absorber while maximizing the attenuation of possible from the absorber. In this way, reduced size, linear performance, and increased attenuation over those of the prior art are provided by the present invention.

Abstract: A waveguide device for producing absorption or attenuation includes a waveguide section which is provided with an external absorber material. For allowing a transfer of the high-frequency power into the absorber material, the wave section is provided with coupling apertures via which the absorber material is in connection with the interior of the waveguide section.

Abstract: A finline structure comprises a dielectric substrate-mounted circuit disposed within a waveguide having on the substrate integrated distributed capacitance elements at least partially formed by laterally separated metallization layers. Thin-film construction techniques may be employed in construction. In general, the distributed capacitance elements permit the biasing of a plurality of circuit elements in a finline transmission medium. In selected structures, r.f. continuity is effected between traces and metallization layers while maintaining d.c. isolation. Examples are described of circuits which can incorporate an integrated capacitor, including but not limited to detectors, r.f. modulators, r.f. attenuators, amplifiers, and multipliers. According to the invention, a plurality of elements, as well as multiple port elements, may be selectively biased while retaining d.c. isolation and r.f. continuity.

Abstract: A microwave absorber composed of dense silicon carbide having an electrical resistivity of one ohm-centimeter or more. In an electron linear accelerator, it is necessary to provide a microwave absorber to absorb excess energy used to accelerate electrons and discharge this excess energy in the form of heat in order for the accelerator to operate safely. The important characteristics are high-frequency wave absorption, good heat resistance, good thermal conductivity, and stability in a vacuum. The invention meets these requirements with a microwave absorber composed of dense silicon carbide. In an electron linear accelerator the absorber is attached to the end portion of an accelerator guide or a branch portion of a power divider to absorb unnecessary wave energy. Such a microwave absorber is found to have characteristics rendering it highly suitable for this application as well as others.

Abstract: A "Spacercore" design is used to provide the cores of the electromagnets which are used to bias ferrite slabs in phase shifters of a high power RF attenuator. The phase shifters require a given flux to provide a phase shift from zero to 90.degree.. With laminations of high permeability silicon steel, the core weight may be substantially reduced by including a filler comprising spacers of non-magnetic material (such as lightweight transformer pressboard. With 14-mil silicon steel laminations and 64-mil spacers, this construction provides a core which weighs 25 percent of a full ferrite core for the same flux density.

Abstract: A waveguide usable as absorber or as attenuator for high radio-frequency powers up to highest frequencies includes a tube with a dissipative material at whose inside a metallized layer is applied. The thickness of the metallized layer changes along the length of the tube with its initial thickness and end thickness determined in such a manner that a constant power density is obtained along the waveguide.

Abstract: An electrically controlled radio frequency tuner used in conjunction with an antenna. The antenna used both as a transmitter and a receiver. The tuner eliminating waveform reflection and circulator feedthrough of transmitted signals which heretofore reflected back into the receiver creating a noise threshold that decreased the sensitivity of the receiver.

Abstract: An electrically controlled radio frequency attenuator for electrically and magnetically controlling the attenuation transmitted power in a waveguide.

Abstract: A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

Abstract: A gyrotron traveling-wave device including quarter wavelength anti-reflece dielectric layers to enhance microwave absorption. A drift tube made from a hollow waveguide is positioned within the gyrotron to surround an electron beam passing from an electron gun to a cavity. A plurality of parallel highly lossy dielectric suppressor rings are interspaced with a plurality of conductive rings positioned to surround the electron beam and located within the waveguide. An anti-reflective layer is formed on the suppressor rings to enhance the absorption by the rings of radiation due to parasitic oscillations by reducing reflections of incident radiation from the suppressor rings. In an alternate embodiment, one or more suppressor rings including an anti-reflecting layer are located within the cavity.

Abstract: A cell changes conductivity by electrodeposition of a metal in response to an applied voltage pulse. The cell can be used as a variable resistance device to provide a broad frequency switching or modulating device that operates to switch dc as well as microwave energy. The cell also functions as a variable reactance device.

Abstract: An arrangement for suppressing interference waves and harmonic waves in traveling wave tubes has a short circuit slide in an output wave guide in which the slide has a groove in the form of a .lambda./4 or .lambda./2 wave guide element in its frontal surface which is the effective short circuit plane. The groove has an attenuation element arranged therein.

Abstract: The disclosure concerns an HF attenuator for a hollow waveguide or a coaxial conductor. A rod of dissipative ceramic material is disposed along the length of the attenuator, so that moving along the length of the attenuator, the ceramic material increasingly defines or replaces at least one wall of the hollow waveguide or at least one of the two opposite sides of the coaxial conductor. A coolant passage may be provided along the rods of ceramic material. The ceramic material may take other forms, such as leaves and annular rings. In another embodiment for use in a waveguide, at least one wall of the longitudinal opening through the waveguide is defined by ceramic leaves, whose extent of projection into the opening is varied for HF attenuation.

Abstract: Films of epitaxially deposited hexagonal ferrite material backed with metal and inserted into waveguides in single and multiple stages are used to form band-pass and band-stop filters, variable attenuators and modulators. The films have body resonance modes with resonant frequencies which are essentially fixed as an externally applied magnetic field is varied. Thin films of hexagonal ferrite material have resonant frequencies in the high microwave and millimeter wavelength frequency ranges. Since hexagonal ferrites have a high magnetic anisotropy and accompanying high internal magnetic field, little or no external magnetic bias may be required once the film is magnetized.

Abstract: A microwave low pass harmonic absorber having a main waveguide which passes a desired fundamental frequency. A plurality of shunt waveguides are disposed on the walls of the main waveguide for providing an absorptive path for the harmonic energy. Each of the shunt waveguides includes at least one ridge for lowering the cutoff frequency of the shunt waveguide. In another embodiment, the shunt waveguides include two ridges disposed opposite each other.

Abstract: A transmission line is disclosed which comprises a conductive layer, a resistive semiconductor layer disposed on the conductive layer and a blocking electrode disposed on the resistive semiconductor layer. By applying a biasing voltage between the blocking electrode and the conductive layer, a depletion layer is produced in the resistive semiconductor layer, the depletion layer formed in the semiconductor layer being used as a medium for transmission of electromagnetic wave.

Abstract: A delay line for traveling-wave tubes, particularly a wideband low-reflection attenuated line for millimeter waves, in the form of a hollow guide having successive transverse walls which define successive line cells, each of such walls having a central opening for the passage of the electron beam and at least one coupling opening, elongated attentuating members being disposed in the respective cells with their longitudinal axes extending parallel to the longitudinal axis of the delay line. The attenuating members are of like effective length and the matching cell lying immediately ahead of and/or behind the attenuating section of the tube contains, in each case, at least one matching member.

Abstract: A waveguide matched load device comprising a short-circuited rectangular tion with an energy absorbing material located approximately 1/4 of a wavelength from the short-circuited end.

Abstract: A coupler capable of correctly coupling a microwave source into a resonant avity in a cryogenic environment. The coupler utilizes a rotary mechanical means to adjust the energy through the waveguide-beyond-cutoff into the cavity and control the reflections thereby.

Abstract: A waveguide opening for moving paper in and/or out of a data printer employing wave attenuators and reflectors to suppress electromagnetic wave radiation generated within said printer from escaping through the paper opening.

Abstract: A pair of conductive circular plates are positioned in a parallel spaced relationship. A conductive ring-like band extending about the periphery of the plates forms an enclosed parallel plate transmission line. A coupling member is located at the center of this enclosed transmission line. A plurality of peripheral coupling members to the transmission line are spaced radially from and in a ring-like pattern about the center coupling member. A plurality of radio frequency (RF) power absorption members are coupled to the transmission line at the regions between the peripheral coupling members to reduce radio frequency signal coupling between the peripheral coupling members.

Abstract: A miniature waveguide attenuator which may be used in a dominant-mode (TEb.10) waveguide to maintain a low VSWR over a 20% frequency band comprising a short section of waveguide with an E- or an H-plane tee whose width is selected to set the cutoff frequency of the branch line of the tee at the design frequency F.sub.o. The branch line of the tee is terminated in a lossy material followed by a short circuit for absorbing energy propagating down the waveguide at frequencies higher than the design frequency in accordance with a controlled attenuation characteristic.

Abstract: Hyperfrequency band-cut filter enabling the transmitting of a first lower frequency band and cancelling a second frequency band which is absorbed. It is constituted by a compact assembly comprising two blocks fixed to each other and forming a rectangular wave guide whose upper and lower walls are drilled with slots connected to resonant cavities at the second frequency band, hollowed out in the faces opposite to the faces of the rectangular wave guide and comprising, moreover, two plates which are screwed onto said blocks overlying said cavities.

Abstract: A microwave reflector device of small size, making it possible to deliver a predetermined quantity of the power generated by a high-power microwave generator, comprises a unidirectional element which imposes an appropriate constant load on the generator, and a reflector system constituted by a waveguide D tapped into the output waveguide T of the unidirectional element, said waveguide D being terminated at its free end by a metal plate carrying three quartz rods 10, 11, 12 designed to slide, parallel to the axis of the waveguide D, respectively in three metallic sleeves 13, 14, 15 having a circular shape and dimensioins such that they form cut-off waveguides at the operating frequency of the generator. The free end of each of the sleeves 13, 14, 15 provided with three respective rings 16, 17, 18 of absorber material.

Abstract: A quasi-optical integrated circuit which makes use of a high resistivity k single crystal intrinsic semiconductor as a low loss quasi-optical wave transmission medium for millimeter and submillimeter waves having one or more circuit elements or devices disposed either at or near the surface of a portion of the semiconductor, or formed within a portion of either the semiconductor transmission medium or a portion of a high resistivity single crystal intrinsic semiconductor appendage to said semiconductor transmission medium. By varying the potential applied to said elements or devices, one can control either the phase or the amplitude of quasi-optical wave propagation along the semiconductor waveguide; moreover, solid state devices such as quasi-optical generators, mixers and detectors can be formed within the semiconductor wave transmission medium itself.

Abstract: An electromagnetic energy dissipative load or attenuator is provided having a lossy section of waveguide transmission line of sufficient length to provide substantial loss and a transition section for adaption to other waveguide configurations. The transmission line is short circuited as a terminating load, and cooling means may be circulated adjacent to the waveguide for removal of the heat energy generated in the waveguide walls. A second transition section in place of the short circuit provides for a high power attenuator. The lossy waveguide section is coiled in either a flat spiral or concentric helical configuration. A fluid coolant may be circulated adjacent to or inside the lossy section coils.