Abstract: A waveguide assembly comprising a first waveguide, and a second waveguide designed as a dielectric multimodal waveguide, and a waveguide transition for transmitting an electromagnetic wave between the first waveguide and the second waveguide, the waveguide transition having a dielectric waveguide piece which is between the first waveguide and the second waveguide. The dielectric waveguide piece is capable of guiding a smaller mode number than the second waveguide, at least in a front section, facing the first waveguide.

Abstract: The present disclosure provides an over-the-air measurement system for testing a device under test. The over-the-air measurement system includes a single measurement antenna and a rotary antenna positioner for the measurement antenna. The over-the-air measurement system further comprises a hardware trigger that is capable of triggering a measurement. The hardware trigger is associated with the rotary antenna positioner. The over-the-air measurement system comprises at least one rotary joint attached to the antenna positioner.

Abstract: A power combiner for combining a plurality of radio frequency signals into a combined output signal includes: a circular waveguide having a cross-section and three or more waveguides, each waveguide morphing to align with a common axis at a cross-section of the circular waveguide wherein each one of the three or more rectangular input waveguides gradually transitions from a rectangular cross-section to a cross-section resembling a pie slice of a composite circular cross section.

Abstract: Aspects of the subject disclosure may include a generator that facilitates generation of an electromagnetic wave, a core, and a waveguide that facilitates guiding the electromagnetic wave towards the core to induce a second electromagnetic wave that propagates along the core. The core and/or the waveguide can be configured to reduce radiation loss of the second electromagnetic wave, propagation loss of the second electromagnetic wave, or a combination thereof. Other embodiments are disclosed.

Abstract: A horn having folded axial corrugations is provided. The horn includes folded axial corrugations for a compact, low-profile, high-efficiency, and high power handling performance. The folded axial corrugations may include a plurality of grooves that are symmetric about a central axis, each groove including an axial portion that extends in a direction parallel to the central axis and a radial portion that extends from an end of the axial portion in a direction perpendicular to the central axis.

Abstract: Aspects of the subject disclosure may include, a generator that facilitates generation of an electromagnetic wave, a core, and a waveguide that facilitates guiding the electromagnetic wave towards the core to induce a second electromagnetic wave that propagates along the core. The core and/or the waveguide can be configured to reduce radiation loss of the second electromagnetic wave, propagation loss of the second electromagnetic wave, or a combination thereof. Other embodiments are disclosed.

Abstract: Techniques disclosed herein include an apparatus for treating substrates with plasma generated within a plasma processing chamber. In one embodiment, dielectric plates, of a plasma system can include structural features configured to assist in generating a uniform plasma. Such structural features define a surface shape, on a surface that faces the plasma. Such structural features can include a set of concentric rings having an approximately non-linear cross section, and protrude into the surface of the dielectric plate. Such structural features may include feature depth, width, and periodic patterns that may vary depth and width along the concentric rings.

Abstract: A parallel plate waveguide structure may be configured to suppress spurious propagating modes by including a lossy frequency selective surface (FSS) formed from a resistive film. The electromagnetic material properties of individual layers disposed between the conductive plates of the waveguide may be engineered to extend the suppression band of the fundamental TE mode up to the cutoff frequency of the second TE mode, and to simultaneously create a multi-octave TM mode suppression band. Applications include, for example, cavity mode suppression in microwave and millimeterwave assemblies at the board, package, and chip level.

Abstract: A radio frequency (RF) transmission-line structure includes a parallel-plate transmission line formed from a first conducting plate and a second conducting plate. The second conducting plate is spaced apart from the first conducting plate and substantially parallel to the first conducting plate. A support member is attached to the first and second plates and is operative to maintain a fixed mechanical spacing between the first conducting plate and the second conducting plate. The transmission-line structure further includes at least one feature configured to isolate or suppress RF interaction of the support member with RF fields within the parallel-plate transmission line.

Abstract: In a gap-mode waveguide embodiment, an interior gap in a tubular waveguide principally condenses a dominant gap mode near the interior gap, and an absorber dissipates electromagnetic energy away from the gap mode. In this manner, the gap mode may dissipate relatively little power in the absorber compared to other modes and propagate with lesser attenuation than all other modes. A gap mode launched into a gap-mode waveguide may provide for low-loss, low-dispersion propagation of signals over a bandwidth including a multimode range of the waveguide. Gap-mode waveguide embodiments of various forms may be used to build guided-wave circuits covering broad bandwidths extending to terahertz frequencies.

Abstract: A tunable band-pass filter includes: a rectangular waveguide including a first and a second waveguide parts, which are acquired by dividing the rectangular waveguide along an E-plane of the rectangular waveguide at a center position of an H-plane in the rectangular waveguide; a metal plate sandwiched by the first and the second waveguide parts in such a way as to be parallel to the E-plane; at least one dielectric plate arranged in the rectangular waveguide in such a way as to extend in a longitudinal extension direction of the metal plate; and a drive mechanism changing a relative position relationship between the dielectric plate and the metal plate from the outside.

Abstract: Systems and methods for a filtering wave energy using a rectangular-to-circular waveguide transition are discussed herein. An exemplary system comprises a rectangular-to-circular waveguide transition and a filter card. The rectangular-to-circular waveguide transition may include a front section and a back section opposite the front section, the rectangular-to-circular waveguide transition defining a circular hole extending from the front section of the rectangular-to-circular waveguide transition through the back section, the rectangular-to-circular waveguide transition further having a first arcuate region on the face of the transition, the first arcuate region defining a first cavity extending from the circular hole through the first arcuate region, the rectangular-to-circular waveguide transition also having a second arcuate region defining a second cavity opposite the first cavity, the second cavity extending from the circular hole through the second arcuate region.

Abstract: A parallel plate waveguide structure may be configured to suppress spurious propagating modes by including a lossy frequency selective surface (FSS). The electromagnetic material properties of individual layers disposed between the conductive plates of the waveguide may be engineered to extend the suppression band of the fundamental TE mode up to the cutoff frequency of the second TE mode. Examples of mode suppression structures are presented and analyzed by transverse resonance models. Applications include, for example, cavity mode suppression in microwave and millimeterwave assemblies at the board, package, and chip level.

Abstract: A parallel plate waveguide structure configured to suppress parallel-plate waveguide modes is described. The electromagnetic material properties of individual layers disposed between the conductive plates of waveguide may be selected to allow an apparent stopband to form. Several physical examples of electromagnetic bandgap (EBG) structures are presented that are analyzed by full wave simulations and transverse resonance models.

Abstract: A parallel plate waveguide structure may be configured to suppress spurious propagating modes by including a lossy frequency selective surface (FSS) formed from a resistive film. The electromagnetic material properties of individual layers disposed between the conductive plates of the waveguide may be engineered to extend the suppression band of the fundamental TE mode up to the cutoff frequency of the second TE mode, and to simultaneously create a multi-octave TM mode suppression band. Applications include, for example, cavity mode suppression in microwave and millimeterwave assemblies at the board, package, and chip level.

Abstract: An ortho-mode transducer may include an annular common waveguide defined by an outside surface of an inner conductor and an inside surface of an outer conductor, the outside surface and the inside surface concentric about a waveguide axis. A first port may couple a first TE11 mode to the annular common waveguide. A second port may couple a second TE11 mode to the annular common waveguide, the second TE11 mode orthogonal to the first TE11 mode. A TEM probe may suppress resonance of a TEM mode within the annular common waveguide.

Abstract: A parallel plate waveguide structure may be configured to suppress spurious propagating modes by including a lossy frequency selective surface (FSS). The electromagnetic material properties of individual layers disposed between the conductive plates of the waveguide may be engineered to extend the suppression band of the fundamental TE mode up to the cutoff frequency of the second TE mode. Examples of mode suppression structures are presented and analyzed by transverse resonance models. Applications include, for example, cavity mode suppression in microwave and millimeterwave assemblies at the board, package, and chip level.

Abstract: An ultrafast sampler includes a series of Schottky diodes configured with a coplanar waveguide to form a nonlinear transmission line (NLTL) that compresses a local oscillator input to form a series of strobe pulses. Strobe pulses of opposite polarity are capacitively coupled to sampling diodes to obtain samples of a signal applied to a signal input. The samples are directed along an intermediate frequency waveguide to, for example, a signal processor such as an oscilloscope, for storage and analysis. The intermediate frequency waveguide is configured so that conductors of the intermediate frequency waveguide receive signal samples of a common polarity and strobe samples of opposite polarities so that portions of strobe pulses delivered to a signal processor are distinguished from signal samples.

Abstract: An LSE mode, which is a parasitic mode, can be effectively suppressed by a simple structure, and a reduction in size and weight can be thereby facilitated. Further, a metal body 3 is arranged in the vicinity of a dielectric waveguide 1 of an NRD guide to suppress the LSE mode, the NRD guide being configured to propagate electromagnetic waves through the dielectric waveguide 1 which is sandwiched between parallel conductor plates with a gap of less than a ½ wavelength. This metal body 3 has an arbitrary shape, and may have a discoid shape, an elliptic shape or a prismatic shape. Furthermore, an even distance d is maintained between the metal body 3 and the dielectric waveguide 1, and a phase constant difference can be suppressed by changing this distance d.

Abstract: The present invention provides a waveguide for the TM mode having a simpler configuration. The waveguide has: a pair of main ground electrodes (2a) and (2b) disposed so as to face each other in parallel with each other with a dielectric block (4) in between; and a pair of side walls (3a) and (3b), each constructed of a plurality of sub ground electrodes (11) provided between the pair of main ground electrodes (2a) and (2b), the sub ground electrodes (11) stacked in parallel with the main ground electrodes (2a) and (2b) with a interval along a direction orthogonal to the main ground electrodes (2a) and (2b). Electromagnetic waves in the TM mode may propagate in a region (5) surrounded by the pair of main ground electrodes (2a) and (2b) and the pair of side walls (3a) and (3b).

Abstract: A compact circular waveguide system can connect circular waveguides through a bend while avoiding excessive interaction between the orthogonal modes of the circular waveguides. A compact bend system with circular waveguide input and output can be achieved by providing short quarter wave transformers. The quarter wave transformers can be positioned at the transitions between the circular waveguides and a single-mode quasi-rectangular waveguide segment. Within the single-mode quasi-rectangular waveguide segment, a bend can be formed without concern for mixing of the orthogonal modes of the circular guided wave. The undesired mode of propagation can be substantially reduced or eliminated within the quarter wave transformers with a resistive mode suppressor. The compact system can be machined out of a single block of material from the outside flange faces.

Abstract: A superconductor filter comprises a plurality of resonance elements arranged between input-output lines formed on a substrate. Metal conductor sections serving to inhibit the spatial coupling between the adjacent resonance elements are arranged between prescribed resonance elements, and a prescribed resonance element is coupled with another resonance element by a coupling transmission line. It follows that each resonance element is coupled with another resonance element by the direct coupling via the coupling transmission line or by the spatial coupling via the space.

Abstract: The invention relates to a method for conversion of waveguide modes from a mode of type TM01 to mode of type TE11 for transmission of power within the microwave range. The invention also relates to a mode-converting arrangement and an antenna arrangement with such a mode converting arrangement. The mode-converting arrangement comprises an incoming waveguide (1) for reception of power of the type TM01-an outgoing waveguide (6) for outputting power of mode type TE11 and a waveguide-mode-converting section (2-5) arranged between the incoming and outgoing waveguides. According to the invention, incoming power of mode type TM01 is divided in an input section (2) between two or more waveguides with cross-sections in the shape of circle sectors.

Abstract: A calibration structure for probing devices.

Abstract: A nonreflective waveguide terminator includes a waveguide portion and an electromagnetic wave absorber. The portion has a rectangular opening in a plane perpendicular to a radio-wave propagation direction. The portion has one open end in the direction and the other end closed by a terminating metal internal wall. The portion has a radio-wave propagation space surrounded by first and second metal internal walls parallel to a radio-wave electric field, and third and fourth metal internal walls perpendicular to the field. The exterior shape of the absorber is a parallelepiped. The absorber has a rear-end surface positioned at a predetermined distance from the terminating wall and parallel to the terminating wall or is provided against the terminating wall. The surface of the absorber having the largest rectangular area is on the third or the fourth metal internal wall.

Abstract: Waveguides and backplanes systems are disclosed. A waveguide according to the present invention includes a first conductive channel, and a second conductive channel disposed generally parallel to the first channel. A gap is defined between the first and second channels that allows propagation along a waveguide axis of electromagnetic waves in a TE n,0 mode, wherein n is an odd number, but suppresses electromagnetic waves in a TE m,0 mode, wherein m is an even number. An NRD waveguide is disclosed that includes an upper conductive plate and a lower conductive plate, with a dielectric channel disposed between the conductive plates. A second channel is disposed adjacent to the dielectric channel between the conductive plates. The upper conductive plate has a gap above the dielectric channel that allows propagation along a waveguide axis of electromagnetic waves in an odd longitudinal magnetic mode, but suppresses electromagnetic waves in an even longitudinal magnetic mode.

Abstract: In a waveguide twist which provides orthogonal rotation of both direction and polarization, TE10—mode energy in waveguide W1 is coupled via iris I1 to a transformer cavity capable of exciting both TE10 and TE01 modes. The TE01 mode is coupled via iris I2 to output waveguide W2. Transformers may be interposed between one or both waveguides and their associated irises to increase bandwidth. The configuration facilitates manufacture in two halves by simple machining or casting.

Abstract: In a high-frequency transmission line that is used in a high-frequency band such as the microwave band or the millimeter wave band, at least one resistive film is disposed in a plane that is substantially perpendicular to an electric field of an operating transmission mode, and the resistive film attenuates, by dielectric loss, an unwanted mode having an electric field that is perpendicular to the electric field of the operating transmission mode.

Abstract: An amplitude adjustment device such as an amplitude compression device and amplitude expansion device is basically configured by a PWM modulator, a demodulator and an amplitude detector. Herein, the PWM modulator effects pulse-width modulation on an input signal to produce a pulse-width modulated signal, which is demodulated by the demodulator to produce an output signal. In addition, the amplitude detector detects an amplitude of a demodulated signal or an amplitude of the input signal to produce a control signal. A modulation factor of the pulse-width modulation is adjusted based on the control signal. In the case of the amplitude compression device, an input/output gain is changed inversely proportional to the amplitude of the input signal or amplitude of the output signal. Thus, it is possible to compress a dynamic range with respect to input/output characteristics.

Abstract: Waveguides and backplanes systems are disclosed. A waveguide according to the present invention includes a first conductive channel, and a second conductive channel disposed generally parallel to the first channel. A gap is defined between the first and second channels that allows propagation along a waveguide axis of electromagnetic waves in a TE n,0 mode, wherein n is an odd number, but suppresses electromagnetic waves in a TE m,0 mode, wherein m is an even number. An NRD waveguide is disclosed that includes an upper conductive plate and a lower conductive plate, with a dielectric channel disposed between the conductive plates. A second channel is disposed adjacent to the dielectric channel between the conductive plates. The upper conductive plate has a gap above the dielectric channel that allows propagation along a waveguide axis of electromagnetic waves in an odd longitudinal magnetic mode, but suppresses electromagnetic waves in an even longitudinal magnetic mode.

Abstract: A waveguide fitting for connecting in particular a rectangular waveguide to an elliptical waveguide can be assembled particularly easily and yet provides a very low-reflection connection if the fitting at least at one end is conductively provided with the first section of a sleeve of which the second section is designed to receive the end region of the waveguide to be connected and which is divided at least in this second section by narrow capillary-action axial slots into radially springing lamellae which, after insertion of the waveguide, abut against the outer wall thereof, and in addition the inner wall at least of the second section of the sleeve is designed to receive a solder deposit. To make the connection, it is then necessary only to heat the whole junction with an external heat source until the solder in the solder deposits melts and fills the gaps between the inner wall of this section of the sleeve and the outer wall of the waveguide.

Abstract: A surface-mountable millimeter-wave waveguide filter is constructed using irises in a rectangular waveguide formed in a dielectric material such as glass. The filter structure is surface-mountable, has a single dielectric layer, and can be manufactured using a suitable monolithic microwave integrated circuit (MMIC) process. The filter has potential applications in millimeter-wave systems such as Local Multipoint Distribution System (LMDS) and Autonomous Cruise Control (ACC) radar for automobiles.

Abstract: Waveguides and backplanes systems are disclosed. A waveguide according to the present invention includes a first conductive channel, and a second conductive channel disposed generally parallel to the first channel. A gap is defined between the first and second channels that allows propagation along a waveguide axis of electromagnetic waves in a TE n,0 mode, wherein n is an odd number, but suppresses electromagnetic waves in a TE m,0 mode, wherein m is an even number. An NRD waveguide is disclosed that includes an upper conductive plate and a lower conductive plate, with a dielectric channel disposed between the conductive plates. A second channel is disposed adjacent to the dielectric channel between the conductive plates. The upper conductive plate has a gap above the dielectric channel that allows propagation along a waveguide axis of electromagnetic waves in an odd longitudinal magnetic mode, but suppresses electromagnetic waves in an even longitudinal magnetic mode.

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: Electrodes are formed on both top and bottom surfaces of a dielectric plate and grounded coplanar lines, as transmission lines, are formed on the top surface of the dielectric plate. A plurality of micro-strip lines, each composed of high-impedance lines and low-impedance lines alternately connected in series, is arranged at a pitch shorter than the wavelength of a wave traveling along the grounded coplanar lines. A spurious mode propagation blocking circuit thus constructed prevents a spurious mode wave, such as a parallel-plate mode, from traveling.

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: This invention relates to the design of a microwave component utilizing geometric shapes positioned within the channel of a waveguide structure so as to produce microwave manipulation characteristics, with associated near and far fields, whereby predetermined performance requirements may be satisfied.

Abstract: A dielectric-waveguide attenuator, a dielectric-waveguide terminator, and a wireless apparatus incorporating the same in which the length of a dielectric waveguide is shortened in a direction in which an electromagnetic wave propagates to reduce the size of the overall module. The two parts of a split dielectric strip are placed between an upper conductive plate and a lower conductive plate to form the dielectric waveguide, and a substrate having at least two resistance-film patterns formed thereon is positioned between the two dielectric strips. With this arrangement, the resistance films both attenuate signals and also discontinuously change line impedance at a plurality of places and synthesize the electromagnetic waves reflected at the parts where the line impedance discontinuously changes so that the reflected waves cancel each other.

Abstract: A first printed circuit board is attached to an upper surface of a chassis, and a second printed circuit board is attached to a lower surface of the chassis. The chassis has a thickness of a certain degree, which can reduce a mutual effect of first and second local oscillators, and can suppress occurrence of a spurious signal. Thus, a satellite broadcast receiving device can be provided in which the mutual effect of two local oscillating circuits can be reduced and thus occurrence of a spurious signal is suppressed.

Abstract: Electrodes are formed on both top and bottom surfaces of a dielectric plate and grounded coplanar lines, as transmission lines, are formed on the top surface of the dielectric plate. A plurality of micro-strip lines, each composed of high-impedance lines and low-impedance lines alternately connected in series, is arranged at a pitch shorter than the wavelength of a wave traveling along the grounded coplanar lines. A spurious mode propagation blocking circuit thus constructed prevents a spurious mode wave, such as a parallel-plate mode, from traveling.

Abstract: A mode filter for connecting two electromagnetic waveguides with different cross-sections includes a tubular section (4) with openings at both ends. The cross-sections of the openings match the cross-sections of the two different waveguides, while the interior space (11) of the tubular section (4) transitions from one cross-sectional shape into the other cross-sectional shape. Undesirable modes of the electromagnetic waves which are to be transmitted, are minimized by flat elements (14, 15) protruding radially inwardly into the transition region and extending axially along the tubular section (4). The flat elements (14, 15) are made of a material with a high electrical conductivity. The elements (14, 15) are arranged diametrically opposed from each other and aligned in the same plane and separated by a gap (16). The axial length of the flat elements is short in relation to the length of the tubular section (4).

Abstract: To implement a high-gain amplifier in a microwave frequency band, it is proposed to interconnect amplification circuits and to cover the housing that contains them with a lid. In the space between the lid and the amplification circuits, inside the housing, waveguides are provided whose cutoff frequency is such that it allows none of the modes that can be present at the frequencies of the working band to propagate. It is shown that, by forming such waveguides in said space, instead of filling it with absorbents, much better radio isolation is obtained between the output and the input to avoid interfering reinjections. As a result, in the same housing, it is possible to achieve amplification of up to 90 dB, whereas, hitherto, the limit of 45 dB per housing could not be exceeded.

Abstract: A microwave antenna comprises a single moded metal waveguide tapering inwardly to a cutoff dimension near the distal end thereof. The antenna also comprises a first solid dielectric waveguide mounted coaxially within the distal end portion of the metal waveguide and tapering outwardly toward the inwardly tapering portion of the metal waveguide. The first dielectric waveguide extends beyond the distal end of the metal waveguide in the axial direction. The antenna also comprises a second dielectric waveguide surrounding the first dielectric waveguide beyond the distal end of the metal waveguide and having a dielectric constant lower than the dielectric constant of the first dielectric waveguide. A distal end portion of the first dielectric waveguide tapers inwardly toward the axis thereof, to launch signals propagating toward the distal end of the first dielectric waveguide into the second dielectric waveguide.

Abstract: A combination tuner and harmonic suppressor apparatus is provided for a klystron having a gap defined across a resonant cavity. The apparatus comprises a back cavity coupled to the resonant cavity by a coupling iris. Harmonic resonances within the resonant cavity are conducted to the back cavity through the coupling iris. An absorber disposed within the back cavity absorbs and attenuates the energy of the harmonic resonances. The coupling iris can be capacitively tuned to optimally conduct the harmonic frequencies into the back cavity. The apparatus further comprises an open-ended diaphragm providing a wall of the resonant cavity, disposed between the back cavity and the resonant cavity. A bellows provides a barrier between a vacuum environment within the klystron and a non-vacuum environment external to the klystron, and enables a broad range of movement of the diaphragm.

Abstract: A leaky wall filter for use in an EIK comprises a plurality of guidelets intersecting perpendicularly with a wall of an output waveguide of the EIK. The guidelets would propagate 2.pi. mode oscillation frequencies from the EIK out of the output waveguide. A load matched to the 2.pi. mode disposed at the end of the guidelets provides termination for the 2.pi. mode oscillation frequencies and prevents the initiation of oscillation. The load comprises a plenum disposed at an end of the guidelets opposite to the output waveguide, a window having a first surface within the plenum, and a water load provided at a second surface of the window. The 2.pi. mode oscillation frequencies propagating through the guidelets are impedance matched by the window and coupled into the water load for termination. Since a portion of the operating frequency power also leaks through the guidelets into the plenum due to insertion loss, this combined RF power also couples into the water load and is converted into thermal energy.

Abstract: A plasma processing apparatus has a waveguide along which microwaves are propagated from a microwave generator to a plasma-forming region in a low-pressure processing chamber. The waveguide has a large cross-sectional area, to enable a large region of plasma to be achieved. Uniformity and stability of the plasma are improved by a mode restrictor which inhibits mixing of propagation modes which is otherwise liable to occur in a wide waveguide. The mode restrictor consists of electrically-conductive dividers which divide the waveguide cross-section into an array of sub-guides before the plasma-forming region.

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 mode trap to trap and absorb transverse modes formed by a beam in a linear accelerator includes a waveguide having a multiplicity of electrically conductive (preferably copper) irises and rings, each iris and ring including an aperture, and the irises and rings being stacked in a side-by-side, alternating fashion such that the apertures of the irises and rings are concentrically aligned. An absorbing material layer such as a dielectric is embedded in each iris and ring, and this absorbing material layer encircles, but is circumferentially spaced from its respective aperture. Each iris and ring includes a plurality of circumferentially spaced slots around its aperture and extending radially out toward its absorbing material layer.

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 device for absorbing resonances in a large circular cavity such as a microwave rotary joint that utilizes a horizontally positioned resonance absorber positioned in the balun cavity to absorb the resonances or undesired modes. The resonance absorber forms a folded slot with a resistor across its arms to interrupt the circumferential flow of current in the rim of the cavity without affecting the normal desired mode.