Abstract: A mode suppressor structure designed to maintain TE.sub.01 mode matching in an overmoded waveguide, while at the same time allowing efficient coupling of unwanted modes for dissipation in the mode filtering structure of the overmoded waveguide, and in a manner which is non-intrusive on the TE.sub.01 mode and thus promotes high power operation.

Abstract: A quasi-optical component for microwave radiation comprises a quasi-optical element (16a) which radiates incident microwave radiation along a major axis (19) and which has a characteristic transverse dimension (D) which is smaller than 50-times one wavelength. It is distinguished by the fact that a cooled absorption device (17) is provided which is arranged closely in front of the quasi-optical element (16a) in such a manner that at least one high-power secondary peak (20) of the diffraction due to the characteristic transverse dimension is destroyed.

Abstract: An optical converter for efficient conversion of millimeter wavelength whispering-gallery gyrotron output into a linearly polarized, free-space Gaussian-like beam. The converter uses a mode-converting taper and three mirror optics. The first mirror has an azimuthal tilt to eliminate the k.sub..phi. component of the propagation vector of the gyrotron output beam. The second mirror has a twist reflector to linearly polarize the beam. The third mirror has a constant phase surface so the converter output is in phase.

Abstract: Mode converting signal launchers for efficient coupling signals between dielectric insular and image waveguides and TEM mode transmission lines. The launcher includes a conductive ground plane and an elongated high permittivity dielectric waveguide adjacent to the ground plane. A TEM mode transmission line provides an elongated conductive strip fixed adjacent to the dielectric waveguide such that a coupling region is formed having a length of at least two times the wavelength in the dielectric waveguide.

Abstract: A two-dimensional periodic conductive post array structure is used to suppress higher order wave propagation within a large microstrip housing assembly without attentuating the desired TEM mode of propagation. Substantially vertical conductive posts are spaced at appropriate wavelength periods in the X and Y directions on top of and through a microstrip substrate in a so called "waffle-wall" type configuration. The periodic post structure provides high microwave signal isolation by functioning as a band rejection filter both above the microstrip substrate and within the substrate to isolate between nearby active and passive circuit functions located on the microstrip substrate. The desired TEM mode microstrip transmission line is routed through the conductive post matrix to provide the signal, control and DC paths between circuit chips and other active and passive circuit functions.

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

Abstract: Conversion from a whispering gallery or volume mode to a more useable mode, such as the HE.sub.1,1 mode is achieved in a waveguide mode converter that includes input and output sections. The input section includes overlapping circular and coaxial waveguides. Microwave energy in a whispering gallery or volume mode within the circular waveguide is coupled through an array of N equally spaced axial slots placed in the common wall separating the circular waveguide and the coaxial waveguide to coaxial TE and TM modes. Helical grooves placed in one of walls of the coaxial waveguide convert the coaxial mode to a quasi parallel plate mode wherein the common wall separating the inner circular waveguide from the outer coaxial waveguide functions as one plate, and the outer wall of the coaxial waveguide functions as the other plate. The quasi parallel plate mode propagates microwave energy spirally through the coaxial waveguide in a direction k, where k makes an angle .theta. to the waveguide axis.

Abstract: A UHF-TV broadcast system comprising an antenna mounted on an elevated supporting structure for broadcasting UHF-TV to a prescribed region, and a transmission line having a horizontal run leading to the supporting structure for the antenna, and a vertical run leading to the antenna, the transmission line comprising a circular non-coaxial waveguide having an inside diameter large enough to support the propagation of electromagnetic energy therethrough in at least the circular, non-coaxial TE.sub.11 mode, and a multiplicity of conductive elements extending transversely across the interior of the waveguide at intervals along the length of the waveguide perpendicular to the electric field vector of TE.sub.11 -mode energy having a desired polarization, for suppressing unwanted TE.sub.11 -mode energy that is cross-polarized relative to the desired polarization.

Abstract: A waveguide mode converting apparatus especially of the TM.sub.01 to TE.sub.11 converting type and usable in circuit waveguide apparatus with desirable high efficiency and relatively small physical size is disclosed. The mode converter employs the combination of an asymmetrically shaped conical frustum waveguide segment together with a radially disposed fin having tapered input and output or ramp surfaces. Details of a 1.3 gigahertz embodiment of the mode converter including dimensions are included along with the results of efficiency measuring and indications of alternate arrangements of the invention.

Abstract: In a radial power combiner/divider in which radial slots are provided for suppression of undesired modes, certain undesired modes which are not adequately suppressed by the radial slots are allowed to be propagated in a central coaxial transmission line and suppressed therein by means of longitudinal slots in the outer conductor. In an alternative embodiment, the central transmission line of the combiner/divider is in the form of a circular waveguide, and the suppression means comprises thin, spaced coaxial cylinders of dissipative material.

Abstract: A feed horn employing a novel compensator design which substantially reduces off-axis cross polarized components of circularly polarized energy over a wide range of angular directions. The compensator comprises a plurality of L-shaped compensating conductors disposed in a generally symmetrical fashion about a longitudinal axis of the feed horn. The conductors extend inwardly from the output aperture of the feed horn and then radially outwards a predetermined distance away from the axis toward the horn sidewall. The conductors are disposed at an angle relative to the axis, which angle is generally defined by an cone whose apex is the same as the apex of the feed horn. A nonconducting support structure supports the conductors within the feed horn. A dielectric matching member is disposed in the feed horn to eliminate unwanted energy reflections.

Abstract: A dielectric waveguide for the transmission of electromagnetic waves is provided comprising a core of polytetrafluoroethylene (PTFE), one or more layers of PTFE cladding overwrapped around the core, a mode suppression layer of an electromagnetically lossy material covering the cladding and an electromagnetic shielding layer covering the mode suppression layer. The mode suppression layer is preferably a tape of carbon-filled PTFE. Another electromagnetically lossy material layer may be placed around the shield to absorb any extraneous energy.

Abstract: A high-power, end-fed, circular, non-coaxial waveguide UHF-TV broadcast antenna comprising a single-moded, circular, non-coaxial waveguide having an inside diameter dimensioned to support only the circular non-coaxial TE.sub.11 mode of energy propagation through the waveguide at the design frequency of the operating frequency band, the waveguide having multiple radiating elements removing energy from the waveguide at intervals along the length of the waveguide, and conductive means extending transversely across the interior of the waveguide at least in the regions between longitudinally adjacent pairs of the radiating elements, the conductive means being perpendicular to the electric field vector of the TE.sub.11 -mode energy having a desired polarization, for suppressing TE.sub.11 -mode energy that is cross-polarized relative to the desired polarization, the waveguide and the conductive means defining a feed port at one end of the waveguide for receiving UHF-TV signals having the desired polarization.

Abstract: A high power TV antenna for operation at the ultra high frequency (UHF) frequency F includes a radiating antenna located at the top of a tower structure (often hundreds of feet high), a transmitter at the bottom of the tower and a main circular waveguide transmission line of diameter D1 between the transmitter and the antenna carried by the tower; the feed to and/or from the transmission line including transition sections such that wave propagation in the transition sections is below cutoff for the TM01 mode while it is above cutoff for the dominant TE11 mode while wave propagation in the main circular waveguide transmission line of diameter D1 is substantially totally in the dominent TE11 mode even while it is above cutoff for the TM01 mode, whereby the transition sections tend to inhibit wave propagation in the system in the undesired TM01 mode.

Abstract: A microwave band pass filter for filtering electromagnetic signals has a set of cavities arranged serially, with a block of dielectric material filling each cavity to define regions of each cavity which are loaded with dielectric material and regions which are free of the dielectric material. Each cavity may be viewed as a resonator for a fundamental mode of progagation of an electromagnetic wave while each block can be viewed as a resonator for higher-order modes of propagation of electromagnetic power. The cavities are separated by walls having slots aligned with the free regions of the cavities for coupling power from the fundamental mode while minimizing interaction with power of the higher-order modes. The filter enables the construction of an enlarged passband while inhibiting the presence of the spurious higher-order modes in a stop band bordering the passband.

Abstract: A dielectric waveguide for the transmission of electromagnetic waves is provided comprising a core of polytetrafluoroethylene (PTFE), one or more layers of PTFE cladding overwrapped around the core, the core and/or cladding having mode suppression filters of an electromagnetically glossy material embedded therein, and an electromagnetic shielding layer covering the cladding. The mode suppression filters are preferably mica cards.

Abstract: A waveguide bandpass filter includes a fenestrated conductive septum which may be printed on a dielectric circuit board. The center frequency is tuned by a dielectric plate parallel with the septum and contiguous with the fenestrations which is movable in a direction orthogonal to the septum.

Abstract: Inside a parallelepipedic guide section there is provided at least one partition located so as to divide the inner volume of the guide section into a main waveguide portion capable of supporting an orthogonally polarized signal and two secondary waveguide portions extending in the same direction as the main waveguide portion. The secondary waveguide portions are so dimensioned such that one of these waveguide portions is capable of supporting a horizontally polarized signal and that the second waveguide portion is capable of supporting a vertically polarized signal.

Abstract: A polarization diplexer which branches from a circular or quadratic waveguide in the axial direction into pairs of rectangular waveguides respectively lying opposite each other with the first pair of two rectangular waveguides lying opposite one another and fed by a symmetrical hybrid junction comprising straight subarms and wherein the first pair are symmetrical. The second pair of rectangular waveguides comprises two rectangular waveguides lying opposite each other which is fed by a second electrically symmetrical hybrid junction having subarms straddled over their broad dimension. The invention can also be utilized as a polarization frequency diplexer.

Abstract: An extremely narrow-band bandpass electromagnetic filter comprises a waveguide (1) dimensioned below cutoff and having two or more active sections (30) each containing a dielectric resonator (6). The number of resonators (6) corresponds to the number of poles of filtering. The physical dimensions of the waveguide (1) can advantageously be further reduced by means of passive coupling means (40), where the waveguide (1) cross-section is smaller than in the active sections (30). Each passive coupling means (40) inductively couples adjacent active sections (30). Mode suppression rods (10) electrically connect opposing waveguide walls (2, 3) midway between each pair of adjacent dielectric resonators (6). Preferred embodiments are illustrated, in which the resonators (6) are tranversely oriented within the waveguide (1). Electromagnetic energy travels within the waveguide (1) in a single TE.sub.10 evanescent mode (TE.sub.01.delta. within the resonators (6)).

Abstract: An overmoded waveguide transition comprises a flared waveguide section having different transverse cross-sections at opposite ends thereof, the longitudinal shape of a section of the transition adjacent an end thereof being defined by the equation:(r.sup.p /a)-(l.sup.p /b)=1where a and b are constants, r is the radius of the transition, l is the axial distance along the transition measured from one end, and the exponent p has a value greater than two.

Abstract: A dielectric resonator microwave bandpass filter includes a printed circuit board supported within a cut-off waveguide, with dielectric resonators and coupling loops on an upper surface of the board and a well beneath the board so that the resonators are well spaced from ground planes. Tuning screws beneath the resonators, and coupling adjustment screws above the board adjacent to the coupling loops and between adjacent resonators, provide for adjustments to provide desired filter characteristics within a wide range. Isolators within the waveguide have ports coupled to the resonators via microstrip transmission lines comprising conductive tracks on the board and ports coupled to coaxial connectors in end walls of the waveguide. The waveguide is formed from a cast body and a flat lid.

Abstract: A transition device achieves transformation of the signal carrier mode of a continuous wave guide, into the hybrid mode, the corresponding mode for carrying signals in corrugated structures, by employing a tapered waveguide transition of circular cross-section having dual-depth circumferential slots in the interior boundary surface thereof. The transition device utilizes a mutual resonance property of the slots at the port which connects to a continuous waveguide to achieve satisfactory operation in two frequency bands. At the port which is connected to a corrugated horn, the quarter wavelength self resonance of the individual slots provides the desired hybrid mode under balanced hybrid condition in these two bands. A gradual transition of the electrical characteristics is achieved along the length of the transition device through an adjustment of slot dimensions.

Abstract: A thin plate member of electrically conductive material is disposed within a rectangular waveguide. The plate member has the thickness less than one tenth of the wavelength of a frequency to be suppressed, an opening whose maximum dimension is less than the length of the short side of the waveguide, and a gap formed between two opposite projections extending from the edge of the opening. The plate member is arranged, in said rectangular waveguide, parallel with the electric field and perpendicular to the magnetic field.

Abstract: A compact waveguide power combiner/divider is characterized by low reflection and dissipation losses. The device includes a radial waveguide having an inlet opening and a plurality of radial outlet openings, and a coupling pin is arranged in the radial waveguide to couple energy from the inlet opening with the radial waveguide. A mode suppression device is connected with the radial waveguide and contains a plurality of radially arranged slots corresponding with the outlet openings. A tuning mechanism arranged within the radial waveguide optimizes the coupling of undesired modes with the slots. An undesired mode absorption device is arranged in cooperation with the slots of the mode suppression device so that undesired modes are isolated from desired modes with low reflection and dissipation losses.

Abstract: A coupler employing two similar sections of waveguide which extend coliney in longitudinal succession. Adjacent ends of the guide sections are spaced apart to form a gap in the boundary of the sections. A third section of waveguide is disposed external to and coaxial with at least a part of each of the two waveguide sections to provide a boundary surrounding the gap. Electromagnetic energy propagating down one of the two similar sections of waveguide in a first mode and entering the gap is converted partly to a plurality of other modes. The converted energy is reconverted to the first mode upon reaching the other of the two similar sections of waveguide. The electric field pattern exciting the section of waveguide at the end of the gap and propagating down it is exclusively in the first mode.

Abstract: A radial power amplifier includes a coaxial input port and a radial power splitter. The radial power splitter includes a radial transmission line and a number of radial transmission line to microstrip transitions spaced about the radial transmission line for splitting input signal equally among a number of microstrip terminals. A like number of amplifier modules have their input terminals coupled to the microstrip terminals by intermediary coaxial transmission lines. A radial power combiner symmetrical with the radial power splitter includes a second set of microstrip terminals, one terminal being adjacent the output terminal of each amplifier module. The second set of microstrip terminals is coupled by a microstrip to radial transmission line transition to a second radial transmission line. The amplified signals from the amplifier modules converge along the second radial transmission line towards the common output port at which the amplified signal appears.

Abstract: A power splitter/combiner includes a radial waveguide and a coaxial common port coupled to the center of the radial waveguide. The radial waveguide has a plurality of transmission lines around its periphery at equally spaced locations. Because of its symmetry, the power at each of the peripheral transmission lines is related to the power at the common port in proportion to the number of peripheral transmission lines. For operation at high frequencies, the radial waveguide, the transmission lines and the transition from radial waveguide to the transmission lines have their structural details defined by a printed circuit (PC) board having a low temperature dielectric material. The PC board includes a plurality of radial slots to control undesired circumferential modes. A resistance arrangement is coupled across the open end of each radial slot to dissipate circumferential power.

Abstract: A microwave phase shifting device utilizing the rotation lateral to a longitudinal axis across a square or circular waveguide by a slab of dielectric material to provide a differential phase shift between a linear to circular polarization in a high frequency microwave signal.

Abstract: In an ultra high frequency (UHF), high power broadcast television (TV) antenna system that includes a radiating antenna located at the top of a tower structure many hundreds of feet high, a transmitter at the bottom of the tower and a circular waveguide transmission line between the transmitter and the antenna carried by the tower, an undesired polarization mode that is transverse to the desired polarization mode for which the antenna system is adjusted is excluded at the top of the tower structure at the end of the circular waveguide transmission line so that the undesired polarization mode does not energize the radiating antenna and, in particular, the undesired polarization mode does not energize the antenna and produce a ghost image in a TV receiver after reflecting from the bottom end of the circular waveguide transmission line back up to the antenna and does not add a standing wave in the circular waveguide transmission line.

Abstract: A microwave power distributing and synthesizing device includes: a first base and a second base facing the first base at a predetermined distance and having a hole. A coaxial line element including an inner conductive member coaxially penetrates through the hole of the second base and is spaced from an inner wall of the hole by the second base of a predetermined distance. The coaxial line element is supported on the first base at a bottom end and forms an antenna protruding from the hole of the second base into an input waveguide at a top end. At least one electric field distributing and synthesizing member is arranged perpendicularly to the coaxial line element and a plurality of waveguides are connected to the electric field distributing and synthesizing member.

Abstract: To ensure stability of tubes comprising a delay line of the ceiling and ring type or of the ceiling and bar type, resonating slits are disposed in the ceilings of the line.

Abstract: Filter comprising a rectangular waveguide extended at both ends by rectangular guide-to-rectangular guide couplers and provided with lateral secondary guides. In order to enable the use of cylindrical secondary guides without introducing unwanted resonances, said couplers are given, at their ends, rectangular internal cross sections both the height and width whereof are smaller at the end coupled to the primary guide than at the end remote from the primary guide.

Abstract: An improved microwave switch incorporating a fin line structure is described. Microwave switches incorporating fin line structures enable microwave energy to be passed to a load or reflected back to the source, by controlling the conductance state of diodes mounted on the fin line structure. The present invention enables the electrical performance of such switches to be greatly improved. The height of a waveguide channel in the vicinity of the fin line structure is very greatly reduced thereby forcing a waveguide mode of propagation into a slot line so that the fin line structure receives substantially all of the energy supplied to the switch. Higher order modes which are generated at the fin line structure are attenuated by lossy material positioned in choke cavities mounted on either side of the fin line structure.

Abstract: A phased-overmoded, tapered waveguide transition has a central section which is tapered linearly in the longitudinal direction and two end sections which are tapered curvilinearly in the longitudinal direction. One of the end sections and at least a portion of the other end section are overmoded and, therefore, give rise to higher order modes of the desired microwave signals propagated therethrough. The lineraly tapered central section shifts the phase of higher order modes generated at one end of the transition so that at least a major portion of such higher order modes is cancelled by higher order modes generated at the other end of the transition.

Abstract: A UHF broadcast antenna system uses circular waveguide for the run from the high-power final amplifier to the antenna. Undesired cross-polarization components are formed in the circular waveguide due to unavoidable tolerances. Correction of the cross-polarization components is accomplished by a correction apparatus for sampling the principal polarization-plane signal, and reinjecting the sample with controlled amplitude and phase into the circular waveguide in the plane of the cross-polarization component for cancelling the cross-polarization.

Abstract: A waveguide connection formed between a rectangular waveguide (11) and an elliptical waveguide (12) having a cutoff frequency and impedance different from those of the rectangular waveguide (11) comprises an inhomogeneous stepped transformer (10) having multiple sections (31,32,33) all having inside dimensions small enough to cutoff the first excitable higher order mode in a pre-selected frequency band, each section (31,32,33) of the transformer having an elongated transverse cross section which is symmetrical about mutually perpendicular transverse axes (X,Y) which are common to those of the waveguides (11,12), the dimensions of the said cross section increasing progressively from step to step in all four quadrants along the length of the transformer in the direction of both transverse axes (X,Y) so that both the cutoff frequency and the impedance of the transformer (10) vary monotonically along the length of the transformer (10).

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: For damping undesired high frequency electromagnetic oscillations on HF technology components, such as coaxial lines, waveguides and resonators, as well as for the use in resonant circuits of VHF amplifiers with high HF power electron tubes, an absorber is proposed, which can be stablely coupled in mode-selective manner, while having a negligible influence on undesired low frequency and/or other electromagnetic oscillations, while having a predetermined high-pass characteristic.Absorber elements are used, which comprise a pocket made from a material having a high electrical conductivity with an opening on one longitudinal side and surrounding a ferritic, dielectric or ohmic absorber rod.For amplifying the absorption effect and for the predetermined setting of the absorption direction, a plurality of these absorber elements can be arranged with a predetermined geometry with respect to the component generating, transporting and/or emitting the HF power.

Abstract: A cyclotron resonance maser microwave amplifier includes coaxial input and output waveguides. Coupling apparatus for cyclotron resonance maser microwave amplifiers and other microwave power systems is provided for transferring microwave power between first and second waveguides. Geometry permits unwanted modes to be effectively attenuated. The coupling apparatus includes first and second coaxial hollow metallic circularly cylindrical members. The first member forms a first waveguide section. A second waveguide section coaxial therewith is bounded internally by the first member, and externally by the second member. The first member has a plurality of apertures for transferring microwave power between the first and second waveguide sections. The apertures are small relative to the radius of the first member and are spaced around the circumference of the first member in a generally symmetrical array.

Abstract: A waveguide structure carrying microwaves with two mutually orthogonal planes of polarization and in two different frequency bands, transmitted and received by an associated antenna, comprises two orthomode transducers in the form of coaxial cylindrical guide members of different inner diameters, the smaller-diameter transducer terminating in a short-circuiting end wall while the larger-diameter transducer, adjoining same at an annular shoulder, extends to a feed horn confronting a reflector. Each transducer is formed with two elongate peripheral access slots, opening onto respective rectangular-section branches, which are longitudinally bisected by mutually perpendicular axial planes while being relatively offset in axial direction.

Abstract: An unsymmetrically corrugated TE.sub.01 mode circular waveguide bend. Unsetrical corrugations approximately one-quarter wavelength deep are utilized to suppress energy transfer to other modes inherent in smooth wall circular guide bends. The corrugations are comprised of a plurality of adjacent internal ridges and valleys having substantially parallel walls such that the distance between the parallel walls of the internal ridges are at least twice the distance between the parallel walls of the internal valleys.

Abstract: A window assembly for a hollow waveguide of circular cross-section, with improved bandwidth and cooling capability for handling high microwave power transmissions over wide frequency ranges, is disclosed. A plate or disc of dielectric of refractive index n.sub.1 extends sealingly across the waveguide and has two parallel faces which exhibit a pattern of corrugations. One of these faces is in contact with a dielectric fluid of refractive index n.sub.2, and means are provided for cooling and circulating the fluid over said one face. Each of the corrugations extends into the fluid a distance proportional to the inverse of the geometric mean of the product of the refractive indices n.sub.1, n.sub.2. In a preferred embodiment, a second plate is included, separated from the first by a region in which said dielectric fluid is circulated, and in which at least both the faces in contact with the fluid are corrugated.

Abstract: A TE.sub.01 circular mode waveguide expansion joint, tapered transition dce in which the expansion joint includes a linear tapered section, the greatest diameter of which does not exceed the cutoff diameter for the TE.sub.02 spurious mode. A second taper of the cosine or other suitable type minimizes TE.sub.02 mode generation as the guide diameter increases past the TE.sub.02 cutoff value. The expansion, transition device simultaneously performs the functions of expansion section and waveguide diameter transition for the TE.sub.01 circular mode while minimizing spurious mode generation.

Abstract: A mode suppressor for use with circular waveguides which are over-sized to provide a low-loss transmission path for signals in the TE.sub.11 mode and which carry an electric field which is perpendicular to the longitudinal axis of the waveguide. The mode suppressor includes resistance cards located in planes which are generally parallel to the longitudinal axis of the circular waveguide and generally perpendicular to the electric field of the TE.sub.11 mode. Resistance cards are also contained in secondary waveguides which are coupled to the sidewalls of the circular waveguide. The resistance cards in the secondary waveguide lie in a plane parallel to the TE.sub.11 electric field and perpendicular to the longitudinal axis of the circular waveguide. The TM and TE.sub.on modes (where n is an integer of 1 or greater) are suppressed by the resistance cards lying parallel to the longitudinal axis. The TE.sub.21 and TE.sub.31 modes are suppressed by the resistance cards contained in the secondary waveguides.

Abstract: The invention relates to a double polarization wide band waveguide.The waveguide according to the invention comprises a polygonal waveguide having a symmetry of order 4 with respect to a center of symmetry. The waveguide is provided with a plurality of conductive ridges located on the inner face of the sides of the waveguide in accordance with a symmetry of order 4 with respect to the center of symmetry and with a central conductive core, whose cross-section has the same symmetry of order 4n with respect to the center of symmetry.

Abstract: A polarization separator or diplexer for ultra-high frequencies utilizing waveguide sections of rectangular and/or round cross-section in which the signals passing through are phase synchronized over a particular frequency range and which can be manufactured very inexpensively and is operable over a broad frequency band and wherein the arms of the series branching waveguides and the E and H offset portions have a ratio of the narrow to wide sides of at least 1:4 and the first portion of the double branching for providing a connection and transition to the coaxial waveguide comprises an impedance level transformer which has variations in the cross-section of the inner conductor and the outer conductor.

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: A broadband, low loss, microwave integrated circuit power combiner for field effect transistors and other solid state amplifiers has a single metallized MIC substrate contained within a waveguide structure. An array of fin-line transitions from plural microstrip lines to a standard output waveguide can be tapered and placed directly in the waveguide taper region. Undesired higher order modes are absorbed by resistance metallization strips at the tips of the fin-lines or by resistor networks which bridge the microstrip lines.

Abstract: For conducting very high microwave power at very high frequencies, circular waveguide transmitting a circular-electric-field mode is used. The vacuum-tight window of an electron tube is often the element with lowest power-handling capability. The inventive window has two dielectric plates with a space between them. There is a gap in the waveguide inner wall through which a dielectric fluid is circulated between the plates to cool them. The gap leads to a region containing wave-absorbing material such as water to absorb modes other than the circular-electric-field mode.