Abstract: The converter disclosed is interposed between a generator of electromagnetic waves and circular, output waveguide propagating the TE.sub.01 mode. It is formed by the series mounting of a rectangular waveguide, having one of its end closed and a circular waveguide propagating the TM.sub.01 mode, connected to the rectangular waveguide by a lateral opening, in such a way that the axes of the two waveguides are perpendiuclar, also included in the series mounting is a group of intermediate waveguides placed after the circular waveguide, distributed in a ring before its free end. Each intermediate waveguide is formed by a sequence of waveguide pieces working in the rectangular TE.sub.10 mode and gradually offset in rotation with respect to one another, in the same direction. The overall offset among the pieces of one and the same intermediate guide will be 90.degree.. The converter can be applied to the conversion of modes in high power microwave transmission circuits.

Abstract: A waveguide mode converter converts electromagnetic power being transmitted in a TE.sub.0n or a TM.sub.0n mode, where n is an integer, to an HE.sub.11 mode. The conversion process occurs in a single stage without requiring the power to pass through any intermediate modes. The converter comprises a length of circular corrugated waveguide formed in a multiperiod periodic curve. The period of the curve is selected to couple the desired modes and decouple undesired modes. The corrugation depth is selected to control the phase propagation constant, or wavenumbers, of the input and output modes, thereby preventing coherent coupling to competing modes. In one embodiment, both the period and amplitude of the curve may be selectively adjusted, thereby allowing the converter to be tuned to maximize the conversion efficiency.

Abstract: The structures for confining or guiding high frequency electromagnetic radiation have surfaces facing the radiation constructed of high temperature superconducting materials, that is, materials having critical temperatures greater than approximately 35.degree.K. The use of high temperature superconductors removes the constraint of the relatively low energy gaps of conventional, low temperature superconductors which precluded their use at high frequencies. The high temperature superconductors also provide larger thermal margins and more effective cooling. Devices which will benefit from the structures of the invention include microwave cavities, millimeter-wave/far infrared cavities, gyrotron cavities, mode converters, accelerators and free electron lasers, and waveguides.

Abstract: In an angle diversity receiving system, the primary and diversity signals are produced by a waveguide signal separator coupled to a single receiving antenna.The separator operates by converting selective higher order modes in the antenna into fundamental modes that will propagate in its two output waveguides. The result is a robust system that operates over a frequency band wide enough to cover both the 4 GHz and 6 GHz common carrier bands with both horizontally and vertically polarized signals, and that can use a wide variety of antennas.

Abstract: A horn antenna arrangement comprising an H-plane sectoral horn 19 in combination with a feeder waveguide 2 in which radio-frequency energy is launched and propagated in the fundamental rectangular waveguide TE(1,0) mode and provided with a mode-converting section 25 of suitably shaped waveguide of reduced height in which the fundamental TE(1,0) rectangular type mode in, e.g. a planar arcuate input cross section 26, is smoothly and gradually converted into the fundamental TM(0,1) mode of an H-plane sectoral horn in an output cross section 30 which is cylindrically curved about the z axis forming the central axis of sectoral flare for the horn 19, substantially without generating any higher horn modes.

Abstract: A transition is provided between a first rectangular waveguide and a second circular wrapped rectangular waveguide. The second waveguide takes the form of an elongated metallic annular wall having upper and lower ends and a partition member extending radially inward from the annular wall and having an inner edge located near the central axis of the annular wall. The partition member extends longitudinally for a length corresponding with that of the annular wall. An elongated metal probe is secured to the lower end of the partition member. The first rectangular waveguide has parallel rectangular broad walls interconnected by narrower walls. The first waveguide is oriented perpendicular to the central axis of the annular wall and has a circular aperture in one of the broad walls facing the lower end of the second waveguide with the aperture being in coaxial alignment with the annular wall.

Abstract: The invention relates to matching asymmetrical discontinuites in transmission lines to give low reflection coefficients (less than five percent) over a wide frequency band (corresponding to at least an octave in wavelength). A group of asymmetrical discontinuites, such as impedance steps in a waveguide, are matched by considering a reference plane whose position varies with frequency at which the reflection coefficient for waves transmitted in one direction is equal to that for waves transmitted in the opposite direction. Matching elements are then provided which have a reflection coefficient at the reference plane which is equal and opposite to the reflection coefficient of the discontinuities. Matching is less difficult if the distance between the steps is less than a quarter of a guide wavelength at all frequencies in the wide band mentioned above and such an arrangement is a "reduced quarterwave transformer".

Abstract: In view of the introduction of cellular radio, there is a requirement for an antenna of simple construction which can be sold in a consumer market. While the invention meets this need it also has application to the problem of providing TM.sub.01 to TE.sub.01 made converters. The invention employs radial conductors printed on a dielectric substrate and aligned with the transverse electric field in a waveguide supporting the TM.sub.01 mode. Circumferential conductors, each coupled to one of the radial conductors, act as monopoles radiating the required field in an antenna where the radial conductors project through apertures in the waveguide. For the mode converter, both radial and circumferential conductors are inside the waveguide, with the radial conductors aligned with the transverse electric field of the TM.sub.01 mode. Arrangements for maximizing the field at the position of the radial and circumferential conductors are described as are means for preventing the propagation of unwanted modes.

Abstract: Slow-wave structures are formed by the method of this invention in the form of helical or coupled-cavity structures. A helical waveguide form of slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then totally eroded away to form a slow wave structure having a helical radially-extending portion, or if only partially eroded with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The helix is extended into a rectangular waveguide for coupling the slow-wave structure to the source and to the load. The coupled-cavity forms of waveguide slow-wave structures are formed by machining disks from a solid rod of copper.

Abstract: A monopulse antenna feed system utilizing multiple modes within the feed. In one embodiment a TEM mode and one or two TE.phi..sub.11 modes are utilized in the antenna feed system to provide a data and a reference signal responsive to the one or two TE .sub.11 modes and to provide an error indicating signal responsive to the TEM mode that provides monopulse tracking operation. The relative phase of the TEM mode and the one or two TE .sub.11 modes is indicative of the off-axis orientation of a far-field source relative to the axis of the antenna system. The relative amplitude of the TEM mode is indicative of the angular departure the source from the axis.

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 low noise microwave amplifier wherein a length of a pair of broad or wider walls inside the rectangular waveguide is shortened at least near a portion where a probe for introducing a microwave signal into the amplifying portion is provided. A cutoff frequency of the waveguide near the portion where the probe is provided is raised and comes to 80% to 90% of the lower limit of the frequency of the desired amplification band of the amplifier. An input microwave having a frequency component below the cutoff frequency is prevented from flowing into the amplifier, whereby the generation of oscillation is effectively prevented.

Abstract: A transformation device for connecting waveguides of different cross section includes a waveguide element which is provided with at least two successive transforming sections and has a rotationally symmetrical recess extending in axial direction over all transforming sections. Inserted in the recess along a respective portion thereof are a plurality of insulating rigs so that one of said transforming sections adjoining the connection plane with one of the waveguides is defined by said recess while subsequent transforming sections are defined by the insulating rings of corresponding varying inner diameter.

Abstract: A microwave multiplexer has a set of independently tuneable signal channels coupled to a common waveguide. Each of the channels has input and output 3 dB couplers which are joined by cylindrical radiators carrying circularly polarized waves. Both TE and TM waves are propagated within a plurality of resonant cavities within each of the filters. Coupling between the cavities is provided by an array of slots and an array of probes wherein the slots couple TE waves and the probes couple TM waves. Adjustment of the slots and the probes provides for independent coupling coefficients for the two propagation modes. A set of coaxial line probe structures connect between the input and output couplers to end cavities of a filter for the launching of TM waves, there being discs in the end cavities adjacent the probes for converting energy of a TM wave to a TE wave, thereby providing both the TM and the TE wave propagation.

Abstract: The middle stage of a Marie-type mode launcher is configured by sliding together a pair of reusable multi-wedge shaped mandrels which, when placed together in the direction of the longitudinal axis of the launcher, form a compound mandrel from which a TE.sub.20 rectangular to crossed TE.sub.20 rectangular stage may be electroformed. One mandrel has a first double wedge-shaped section that tapers from a rectangular open end (that joins with the rectangular output end of the first stage) to an edge that is effectively diagonally located between opposing vertices of intersecting surfaces of adjacent pairs of four tapered sections that form the `X`-shaped open output end of the middle stage. The taper of the first section is a dual taper, in directions parallel with the sides of the rectangular input end of the middle stage.

Abstract: A linearally polarized multiport multimode feed for a reflector type antenna generates a plurality of beams, each in a different pointing direction, from a single radiating aperture. Each beam possesses a distinct phase center determined by the waveguide modes establishing the aperture distribution for that beam. The feed is linear and bilateral, therefore may be utilized in a receiving or transmitting antenna.

Abstract: A coupler for extracting energy in the TE.sub.21 mode from a circular waveguide propagating energy in both the TE.sub.11 and TE.sub.21 modes, characterized in that an annular iris on the inner circumference of the waveguide and a longitudinally stepped transition portion of the waveguide define therebetween a TE.sub.21 mode resonant cavity which is coupled via a narrow axially extending rectangular slot contained in the wall portion of the waveguide which defines the cavity. At least one external resonant chamber may be provided on the waveguide through which the TE.sub.21 mode energy is extracted and transmitted to a detector thereof via the slot, which chamber cooperates with the resonant cavity to define a multiple resonant filter for improving the matching to the TE.sub.21 mode while reducing the perturbation to the TE.sub.11 mode.

Abstract: A microwave filter composed of at least two cavity resonators disposed adjacent one another, and a coupling aperture disposed between the resonators for coupling microwave energy between the resonators, one of the cavity resonators being operative to propagate microwave energy having a TE mode and the other of the cavity resonators being operative to propagate microwave energy having a TM mode, wherein the coupling aperture is constructed for coupling the TE mode in the one cavity resonator with the TM mode in the other cavity resonator.

Abstract: The present invention relates to fiber structures and methods for obtaining tuned response to high frequency electromagnetic radiation, particularly at microwave frequencies. In one embodiment, a woven fabric is prepared with ferrite filled fibers oriented perpendicular to dielectric filled fibers. The fill of the fibers is selected to reflect radiation having a known frequency and polarization. In other embodiments, tuned structures are provided by disposing sheets containing oriented ferrite and dielectric fibers parallel to one another and moving the layers relative to one another to achieve the desired impedance for incident radiation.

Abstract: High magnetic permeability composites are obtained by incorporating ferrite fibers in the composites. The ferrite fibers consist of a polymer and particulate ferrite fill at a concentration above the percolation threshold for the ferrite fill in the polymer (typically greater than 30 volume percent). The aspect ratio and ferrite concentration of the fibers are selected to minimize demagnetization fields in the fibers. The fibers can be dispersed in low concentration in an unoriented fashion in the composites to impart high magnetic permeability to the composite. In other embodiments, the fibers are oriented in the composites to impart high magnetic permeability to the composite for incident radiation of a particular linear polarization.

Abstract: A directive antenna (for a groundstation or a satellite) has a plurality of discrete receptional states which provide predetermined electronic displacements from boresight of the optimum direction of reception. The direction of the target is obtained by rapid switching from one receptional mode to another. The receptional modes are preferably provided by switchable mode converters, e.g. 6A, 6B, 7A and 7B, which are coupled with the waveguide so as to convert higher order propagation modes, e.g. TM01, TE21(H) and TE21(V), to the fundamental.

Abstract: For high power application of overmoded waveguide, air cooling is provided by applying air flow to the overmoded waveguide either directly or indirectly, through an air inlet which does not significantly disturb the internal electromagnetic fields.

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: In a waveguide-to-microstrip line coupling arrangement, a microstrip line is placed on an outer surface of a wall of a waveguide which is coupled with the microstrip line via a metallic post connected at its one end to a center strip conductor of the microstrip line and is inserted inside the waveguide via through-holes made in a ground plane of the microstrip line and in the wall of the waveguide where the diameter of the through-hole made in the ground plane is made smaller than that of the through-hole made in the wall of the waveguide. The waveguide has a short-circuited end and the metallic post is placed close to the short-circuited end. The coupling arrangement may be used in a microwave frequency converter having an microwave integrated circuit including a local oscillator and a mixer, where the MIC is located on an outer surface of a longitudinal wall extending from a short-circuited end to an open end.

Abstract: A sharp, mode-transducing bend structure for circular TE.sub.01 overmoded waveguide systems is formed by first transducing from circular TE.sub.01 waveguide into multiport rectangular TE.sub.10 waveguide, performing the desired bend, and then transducing from the multiport rectangular TE.sub.10 waveguide back into the circular TE.sub.01 waveguide.

Abstract: A polarized signal receiver waveguide assembly, or feedhorn, for receiving a selected one of linearly polarized electromagnetic signals in one waveguide of circular cross-section and for launching or transmitting the selected signal into a second waveguide, the axes of the waveguides being disposed at a right angle. The first waveguide has a closed end wall, formed as a hemispherical cavity having a hemispherical concave surface. A probe comprising a signal receiver portion disposed in a plane perpendicular to the axis of the first waveguide and a launch or transmitter portion having its axis perpendicular to the axis of the second waveguide has its launch or transmitter portion mounted in a controllably rotatable dielectric rod, such that rotation of the rod causes rotation of the signal receiver portion for alignment with a selected one of the polarized signals.

Abstract: A high frequency connector for interconnecting a microstrip circuit and an external circuit. That portion of a center conductor which is adjacent to the microstrip circuit is deviated from the axis of the connector and resiliently supported, thereby eliminating an intermediary element for interconnection to promote easy and positive interconnection. The connector is desirably applicable to TEM mode waves lying in the frequency band of 0.3-30 GHz.

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 radar rotary joint usable at all frequencies, but particularly useful at millimeter wavelengths includes an inner housing, an outer housing, bearings for rotatably interconnecting the inner and outer housing, and irises for converting the mode of incoming and exiting electromagnetic energy. The inner housing has a TE.sub.11 mode circular waveguide, a TM.sub.01 mode circular waveguide and a right angle transition for converting the TE.sub.11 mode to TM.sub.01 mode and an outer surface forming a bearing support, an outer bearing housing for enclosing the bearings and bearing retainers for retaining the bearings between the outer bearing housing and the bearing supporting surface of the inner housing. The outer housing is attached to the outer bearing housing and includes a TM.sub.01 mode circular waveguide, a TE.sub.11 mode circular waveguide and a right angle transition for converting the TM.sub.01 mode to the TE.sub.11 mode. An inline junction input iris attached between a TE.sub.

Abstract: A waveguide connection comprising the combination of a rectangular waveguide, an elliptical waveguide having a cutoff frequency and impedance different from those of said rectangular waveguide, an inhomogeneous stepped transformer joining said rectangular waveguide to said elliptical waveguide, said transformer having multiple sections all of which have inside dimensions small enough to cutoff the first excitable higher order mode in a preselected frequency band, each section of said transformer having a transverse cross-section defined by the equation: (2x/a).sup.p +(2y/b).sup.

Abstract: This transformer (9) is formed by a waveguide, of approximately elliptical cross-section, and with increasing eccentricity (e) along the axis (z) of the transformer. This transformer (9) is connected on one side to the cavity (1) of a gyrotron (11) and on the other side to a section of guide (13) having the same cross-section as the final cross-section of the transformer and of which the cross-section is constant along the axis (z) of the transformer.The transformer receives from the gyrotron cavity a complex mode, of TE.sub.on type, and changes said mode into a mode in which the electrical field is approximately parallel to a given direction (z). A system of two mirrors (M.sub.3 and M.sub.4) enables a single beam of plane waves (19) to be obtained from the two beams of plane waves (14 and 15) obtained at the output of the section of waveguide (13).

Abstract: A microwave microstrip/slotline frequency-halving circuit configuration is disclosed in which the frequency division is based on the principle of parametric subharmonic generation. The circuit comprises a subharmonic resonator formed partially by the overlap of an open-circuited microstrip line on one side of a dielectric substrate and a short-circuited slotline in the ground-plane on the other side of the substrate. The resonator is completed by a pair of varactor diodes symmetrically placed in holes in the dielectric substrate so as to form connections between the end of the microstrip line and the two sides of the slotline below. An input signal at frequency 2f entering via the microstrip line results in the propagation of a signal at frequency f in the output slotline.

Abstract: A four-port network which is connected to a microwave antenna feed horn for separating four signal paths associated, in pairs, with two polarizations and two frequency bands, and with the network also being utilized for the derivation of antenna tracking signals according to the monopulse principle. A conductor is disposed along the longitudinal axis of the waveguide connecting the antenna feed horn with the four-port network, with this conductor extending, on the one hand, to the region of the antenna feed horn throat and, on the other hand, into the four-port network so as to couple in signals of a higher order mode for the derivation of the antenna deviation signals.

Abstract: A method and device for transducing multiple rectangular TE.sub.10 modes to circular TE.sub.01 mode. Multiple TE.sub.10 modes are transitioned into an intermediate mode which is transitioned into a circular TE.sub.01 mode and vice versa. Unique pyramidal structure provides overmoded high power operation without cooling and/or pressurization.

Abstract: The first section of a Marie'-configured TE.sub.10 rectangular mode to TE.sub.01 circular mode waveguide launcher is modified to provide an effectively true linear taper for the injected TE.sub.10 mode wave to the emitted TE.sub.20 mode wave. As a result, the first section is well matched at the low end of the frequency band as well as being resonance free to frequencies above the upper end of the band of interest. According to this modification, rather than have a single taper for the triangular shaped lower portion of the first section, the lower triangular portion has a second taper extending from the intersection at the lower wall of the input to the height of the exit wall at the output. This second taper provides an effective true linear taper for the input section.

Abstract: A frequency converter is constituted by an unobstructed circular waveguide unit through one end of which received signals are fed thereto and conveying signals in the TE11 mode, a rectangular waveguide unit having a rectangular waveguide microstrip line converter unit in its output end and conveying signals in the TE10 mode, a circular-rectangular waveguide converter unit connecting the output end of the circular waveguide unit and the rectangular waveguide unit to convert the mode of transmission of signals from the TE11 mode in the circular waveguide unit to a principal transmission mode TE10 in the rectangular waveguide unit, and a microwave integrated circuit extending in the direction of and being on the H-wall side of the circular-rectangular waveguide converter unit and the rectangular waveguide unit and connected to the rectangular waveguide-microstrip line converter unit for processing the received signals and delivering the received signals as signals of an intermediate frequency.

Abstract: A circular waveguide dual antenna feed for TVRO reception, which transfers horizontally and vertically polarized received signals in the circular waveguide simultaneously into two coaxial lines parallel with and offset from the circular waveguide axis. For coupling to existing LNA's, the separate coaxial lines from the circular waveguide are extended into a rectangular waveguide which couples to the input-mixer of the conventional LNA. Alternatively, the separate coaxial lines can be coupled separately to two LNA's or they can be combined into a single output terminal. Switching means are provided in each channel so that each channel can be rendered operative or inoperative, as desired. Diode switches are shown. The device requires no moving parts.

Abstract: A compact satellite broadcasting receiver comprises a circular waveguide, a strip-line-shaped probe projected into the circular waveguide, a reflecting element provided downstream of the probe in the circular waveguide and a microwave circuit having a strip line provided around the circular waveguide and connected with the probe. Furthermore, a satellite broadcasting receiver capable of simultaneously receiving two kind of microwaves polarized perpendicularly to each other is realized by joining two compact satellite broadcasting receivers as mentioned above with their strip-line-shaped probes placed at a right angle.

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: The configuration of a waveguide antenna feed is determined by a shaped body of solid dielectric material which is coated with a conductive material. The conductive material functions as a waveguide wall for constraining electromagnetic wave propagation within the dielectric body. The body includes a mode converter and a coupler to a lead-in structure. A polarization converter, if desired, can be integral with the dielectric body.

Abstract: A microwave coupler for coupling microwave energy from a first waveguide to a second waveguide disposed side by side along a propagation length includes a common coupling means, and specifically, orifices along the propagation length wherein the coupling orifices are sized to promote coupling of a favored field mode of electromagnetic energy according to a Bessel function distribution of energy along the length of the waveguide. The Bessel function distribution provides for wideband, low-loss coupling of the favored field mode and maximal isolation from non-favored field modes. The invention is particularly useful for extracting a type TE.sub.21 circular mode signal from a signal containing TE.sub.11 and TE.sub.21 circular modes wherein the TE.sub.21 mode signals are used for generating elevational and azimuthal tracking signals.

Abstract: A compact waveguide junction for coupling rectangular waveguide of one frequency band to a coaxial waveguide, and a second rectangular waveguide of a second frequency band to the interior of the hollow center conductor of the coaxial waveguide.

Abstract: A polarized signal receiver, transmission and launch probe in a waveguide assembly for receiving a selected one of linearly polarized electromagnetic signals in one of the waveguides and for launching the selected signal into a second waveguide, the axes of the waveguides being disposed at right angle. The probe comprises a signal receiver probe portion disposed in a plane perpendicular to the axis of the first waveguide and a launch probe portion having its axis perpendicular to the axis of the second waveguide. The launch probe portion is mounted in a controllably rotatable dielectric rod, such that rotation of the rod causes rotation of the signal receiver portion for alignment with a selected one of the polarized signals. The transmission line between the signal receiver probe portion and the signal launch probe portion consists of a pair of bifurcated branches forming a rectangle disposed along the axis of the first waveguide.

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 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: An adapter of a coaxial transmission line to a waveguide is provided for connecting the waveguide to a microwave circuit of coaxial lines which is formed by milling out the lines within a plate of a soft metal. The coaxial transmission lines are of rectangular, preferably square, cross-section with the outer conductors thereof being provided by the walls of the channel. The inner conductors of the coaxial lines are rod-shaped, the inner conductors also being of rectangular or square cross-section. An aperture is provided in an outer wall of the coaxial line. A stem connects with an inner conductor and passes through the aperture to extend outwardly therefrom. A waveguide is positioned with its propagation axis parallel to the stem, the waveguide enclosing the stem and being secured to the outer walls of the coaxial lines. The stem is placed adjacent the inner wall of the waveguide, but spaced apart therefrom to support a transverse electromagnetic wave.

Abstract: A system is disclosed for coupling orthogonal polarized microwave signals from a reflector to signal processing circuits. The system includes successively a horn, a bandpass filter, a polarizer, a mode separator, and a housing for containing the circuits. The system is constructed from two half-shells. The horn, bandpass filter and polarizer form a waveguide portion which is coupled to the circuits by the mode separator.

Abstract: A mode converter is disclosed which selectively generates a predetermined higher order mode(s) from an incident fundamental mode. This mode converter comprises a dielectric region having an effective-dielectric-constant/thickness profile which is the same as the amplitude profile of the desired higher order mode(s).

Abstract: The present invention relates to hybrid mode feeds which are capable of handling very wide bandwidths. In the present feed arrangements, a dominant TE.sub.11 mode is converted to the HE.sub.11 hybrid mode which is then launched. The TE.sub.11 to HE.sub.11 mode conversion is achieved by inserting a circular dielectric rod (12) into a flared end (11) of a smooth-walled cylindrical feedhorn until a small cylindrical section of the dielectric rod engages with the inner wall (15) of the unflared portion of the feedhorn. In one feed arrangement, the other end of the dielectric rod is similarly inserted into a flared end (21) of a corrugated cylindrical feedhorn section (22) until a short longitudinal section of the cylindrical portion of the rod is concentric with the corrugations of an unflared section of the feedhorn to provide a transition for the HE.sub.11 mode into the corrugated waveguide for subsequent launch.

Abstract: A millimeter-wave phase shifter for use at high millimeter-wave frequencies is disclosed. The phase shifter employs continuous aperture ferrite and corrugated horns to make a reciprocal phase shifter in the frequency range of interest. Applied linearly polarized energy is expanded in cross-section by means of a first corrugated horn. The expanded energy is focused by a first lens, circularly polarized and applied to a ferrite phase shifting section. The phase shift applied to the energy is controlled by means of phase control circuitry and a yoke and coil arrangement. The phase-shifted energy is then converted to linearly polarized energy by a second circular polarizer focused by a second lens and contracted in cross-section by a corrugated horn. The use of the corrugated horns, polarizers, lenses and ferrite phase shifting components allows a much larger device to be fabricated and hence physical tolerances are reduced by an order of magnitude for the frequency range of interest.