Abstract: An electromagnetic radiation converter for receiving and converting microwave signals having a circular or linear polarization. The converter comprises a waveguide for transmitting both circularly and linearly polarized signals, and a first mode transducer for converting the vertical component of the microwave signal into a corresponding signal on a microstrip line, a second mode transducer for converting the horizontal component of the microwave signal into a corresponding signal on a microstrip line, and means for combining the outputs of the first and second transducers. When receiving a circularly polarized signal, the combination means adjusts the phase of the vertical and horizontal components of a circularly polarized signal such that the phase of the vertical and horizontal components are equal prior to being combined so as to produce a signal equivalent to the circularly polarized signal originally received.

Abstract: The radio frequency ferrite system for modulating, phase shifting, or attenuating radio frequency energy has a resonator, a ferrite polarizer, and coupling devices. The coupling devices are used to couple radio frequency signals to and from an interior of the resonator. The ferrite polarizer generates magnetic fields corresponding to an applied voltage or current. To produce phase modulation the ferrite polarizer may be used to detune the cavity from resonance by changing the orientation of the radio frequency signal with respect to a protrusion in the resonator. The ferrite system may be used for phase modulation, switching radio frequency signals, and amplitude modulation by arranging the coupling devices in various orientations and by simultaneously changing the polarization of radio frequency signals with the ferrite polarizer.

Abstract: A polarization separator for separating orthogonal polarization waves into a horizontal polarization wave component and a vertical polarization wave component is minimized in size. A metal pole in the form of a thin metal bar is disposed in a circular waveguide of a waveguide member into which the orthogonal polarization waves are introduced, and reflects the horizontal polarization wave component so that it is outputted through an output terminal formed in a circumferential wall of the waveguide member. Meanwhile, the vertical polarization wave component propagates in a substantially rectangular waveguide provided rearwardly of the metal pole and is outputted from another output terminal. Since the rectangular waveguide is formed in a cutoff structure for the horizontal polarization wave component, the reflection means can be formed from the metal pole in the form of a thin bar, and consequently, the polarization separator can be minimized.

Abstract: A power divider (20) includes two orthomode tee to cylindrical waveguide adapters (26, 34) coupled by a phase shift unit (48) having a slow-wave structure (68) located in a sidewall (82) of a waveguide section (50) at a position located 45 degrees between planes of rectangular ports of the adapters. The slow-wave structure includes a set of vanes (54) which are movable by means of a motor (58) to adjust their penetration through the sidewall of the waveguide section. Adjustment of the penetration provides for selection of an amount of differential phase lag introduced between components of electromagnetic waves propagating through the waveguide section between the two adapters. Pins (96) are formed integrally with the vanes by a notching of edge regions of the vanes. The pins introduce a relatively small amount of phase shift as compared to that introduced by the vanes. However, the phase dispersion of the pins counteracts a phase dispersion of the vanes for increased bandwidth of the power divider.

Abstract: A waveguide to microstrip converter allowing size reduction as well as providing good cross polar discrimination and input VSWR characteristic. The waveguide to microstrip converter includes a structure of an orthogonal transducer formed of a circular waveguide and a rectangular waveguide integrally formed with and orthogonal to the circular waveguide. A first probe and a second probe are respectively coupled to the circular waveguide and rectangular waveguide. An output terminal of the first probe and an output terminal of the second probe are formed on the same plane and connected to respective microstrip lines.

Abstract: A frequency converter for reception of satellite broadcasting, comprising first to fourth feeding lines, each being disposed perpendicularly to one another and vertically through the center of a patch on which a satellite signal with polarized wave components is electromagnetically focused, to allow vertically and horizontally polarized waves of the satellite signal to be excited thereat, first through fourth first-stage low noise amplifiers connected, respectively, to the first through fourth feeding lines, for blocking or transferring the vertically and horizontally polarized wave signals excited at the first through fourth feeding lines in response to a reception selection control, first and second phase shifters connected, respectively, to outputs of the first and second first-stage amplifiers, for shifting the vertically and horizontally polarized wave signals by a desired phase in response to the reception selection control, respectively, so that left and right circularly polarized waves can be generate

Abstract: A circularly polarized generator for transmitting circularly polarized transmitted electromagnetic waves and a circularly polarized wave reception antenna for receiving the electromagnetic waves is disclosed. A crank-shaped conductor pattern composed of a pair of U-shaped portions connected to each other so that the open sides of the letter U are directed oppositely to each other is affixed on a substrate, and has its one end arranged as a signal transmitting and receiving end for achieving minimum transmission losses and optimum axial ratio or intersecting polarized wave component discriminating factor as well as for reducing the size and weight and assuring ease of manufacture.

Abstract: A device for the filtering of electromagnetic waves propagating in a main rotational symmetrical waveguide element comprising at least one filtering section constituted of a rectangular waveguide section inserted in being spliced into the main waveguide element, each transition between said main waveguide element and each of said filtering sections being made by metal walls which are substantially perpendicular to said axis of symmetry, the number and the geometrical and dimensional characteristics of the filtering sections being chosen so as to constitute a filter with a pre-determined filtering profile. The device can be applied especially in dual band filtering, for example for the making of dual band or bi-polarization duplexers.

Abstract: A circularly polarized wave entering the horn is converted to a linearly polarized wave which appears in one of the ports depending on the sense of the polarization. The stepped configuration of the impedance matching section minimizes mutual coupling among horns of the respective assemblies of the array antenna.

Abstract: A 90.degree. coupling circuit cascaded with a pair of hybrid mode latchable phase shifters provides polarization agility for an RF radiator module of the type typically used in a phased array. For example, such radiator modules typically may utilize an active microwave integrated circuit (MIC), a monolithic microwave integrated circuit (MMIC) or a passive reciprocal hybrid mode element (RHYME) circuit. These circuits are arranged to provide duplex RF transmit/receive functions with controllable phase shifts at each radiator site in a phased array. By appropriately setting the two controllable phase shifters to different combinations of phase shifts (e.g., 0.degree. and/or 90.degree.) to a dual orthogonal mode radiator, different spatial polarizations for RF radiator transmit/receive functions can be defined. The radiator itself may include a square or circular waveguide including, in some cases, a reciprocal dielectric quarter-wave plate and a non-reciprocal ferrite quarter-wave plate.

Abstract: A converter for converting circularly polarized waves in a round waveguide into linearly polarized waves in a rectangular waveguide has two probes and a transmission line pattern all of which are formed of metal foil on a thin dielectric film board. The board is flexible and extends across the open ends of the two waveguides. The first probe has a square shape and the transmission line has two conductor arms connected to adjacent sides of the square. The other ends of the conductor arms are connected to the second probe with an impedance matching resistor formed on the film board between the two arms. One conductor arm is one-quarter wavelength longer than the other to convert from circularly polarized waveguide transmission to microstrip transmission.

Abstract: An antenna feed having a common circular waveguide with a longitudinally extending rectangular slot in a wall thereof and defining a receive port. An iris is rotatably connected adjacent the receive port permitting selective relative polarization of the transmit and receive signals. The relative polarization may be readily selected by a technician in the field without the need for changing antenna feeds when, for example, changing from co-polarization to cross-polarization. The iris includes a rectangular opening therein permitting the passage therethrough of the transmit signal while blocking the passage of a signal of the same frequency as the receive signal. The iris is positioned adjacent the receive port to enhance coupling of the receive signal into the receive port. The antenna feed provides high isolation between transmit and receive ports without the need for a filter on the transmit port.

Abstract: In order to isolate microwaves of a selected polarization from incident microwaves collected by means of a dish reflector (10), a ferrite polarizer (16) is positioned at the focal point of the reflector. A ferrite body (26) of the polarizer extends axially of a wave guide (18) with a convergent receiving end (28) positioned outside the wave guide at the focal point and a convergent transmitting end (30) positioned within the wave guide. The ferrite body is mounted in an end portion of the wave guide by means of a plastics dielectric bobbin (32). The bobbin encases all but the transmitting end of the ferrite body, which projects beyond the bobbin into the wave guide. A controlling coil (36) of the polarizer, which creates an axial magnetic field in relation to the ferrite body, is wound around the bobbin within the end portion of the wave guide.

Abstract: Disclosed is a novel two-way duplexer structure for the simultaneous transmission and reception of circularly polarized microwaves. This two-way duplexer of the type designed to connect a first set of two inputs/outputs to a second opposite set of two inputs/outputs, each input/output of said duplexer being connected to the combination channel of a combiner/divider, the two division channels of each combiner/divider each providing for the connection with one of the division channels of one of the combiners/dividers connected to a distinct input/output of the opposite set of inputs/outputs, through distinct phase-shifting means.

Abstract: Waveguide OMT, which can be utilized as an antenna feed, has two orthogonally polarized coaxial ports extending through the back wall of the waveguide. Cross coupling between the probes is minimized by locating the point of entry through the back wall and orienting each probe such that it couples to a primary waveguide mode, but does not couple to the first higher waveguide mode, or, for coaxial waveguide, does not couple to the TEM mode.

Abstract: A radio frequency multiplexer provides a desired channelization plan by directionally coupling high quality linearly polarized filters to a waveguide manifold. The multiplexer includes a waveguide manifold for transmitting signals in a plurality of different frequency channels, a polarization translating coupling aperture arrangement, a circular polarizer, and filter for each channel. Wide band signals traveling along the waveguide manifold exit the waveguide through the coupling aperture arrangement. The linearly polarized signal from the waveguide manifold translates to a circularly polarized signal through the coupling aperture arrangement and these circularly polarized signals are translated back to linearly polarized signals by the circular polarizer. The linearly polarized wide band signals from the circular polarizer are then filtered with the filter device which allows only signals in a channel to be separated to pass.

Abstract: A waveguide and a scaler ring assembly in which the waveguide has external threads and the scaler ring has internal threads for threaded mating engagement so that the position of the waveguide can be easily selected, and is maintained in a secure, close-fitted relationship. The scaler ring has means for attaching to an antenna dish.

Abstract: Dielectric waveguide-to-transmission line transition structures are disclosed which can be used to interface low loss dielectric waveguides with integrated electric circuits for operation in millimeter wave frequency ranges on the order of 100 GHz. Numerous transition designs are presented for interfacing signal propagation in rectangular or cylindrical coplanar metallic transmission lines to signal propagation in dielectric waveguides. In one embodiment of the present invention, a transition structure is provided which includes a first transition section for interfacing a dielectric waveguide to a microstrip transmission line, and a second transition section for interfacing the microstrip transmission line to a coplanar transmission line. In other embodiments of the present invention, the dielectric waveguide interfaces directly to a coplanar transmission line.

Abstract: The present invention is a high efficiency bi-directional spatial power combiner for extremely high frequency signals. In one embodiment, orthogonally polarized electro-magnetic waves are used to isolate signals going into and out of a planar array of amplifiers. A dual mode horn transmits vertically polarized fields to a MMIC planar array of amplifiers. Vertically polarized array elements receive the signals, amplify them, and retransmit back to the horn using horizontally polarized array elements. An ortho-mode transducer on the horn provides isolation for the two polarized signals. The backside of the array can be used for a heat sink, and to provide access for DC biasing of the array elements. In a second embodiment, monolithic grid oscillators are used in lieu of power amplifiers with orthogonal polarization array elements. The input signal and the output signal are of the same polarization. A circulator is used in lieu of an ortho-mode transducer to isolate the input signal from the output signal.

Abstract: The orthomode transducer between a circular waveguide and a coaxial cable consists of a circular waveguide section, into which two probes externally connected to coaxial connectors penetrate. The probe placed close to the input aperture of the waveguide is tuned by a screw and a metal plate belonging to the same axial plane and the other probe is tuned by a screw and a circular disc which closes the waveguide. The shapes of the plate and of the probes are such as to allow the best power coupling between the waveguide and the coaxial line over a wide operating band (10% of the mid-band frequency).

Abstract: A polarizer arrangement in accordance with the invention includes a circular depolarizer combined in a common component with a linear polarizer. The depolarizer material includes a recess within which a ferrite rod is located, a bias coil being wound around the polarizer and the rod. In another arrangement, a polyrod waveguide feed is also included in the component, being integrated with the circular depolarizer and the linear polarizer.

Abstract: An apparatus for the selective transmission or reflection of incident electromagnetic radiation. The apparatus comprises a plurality of dielectric substrates combined so as to form a stack, wherein at least two of the substrates comprise conductive elements extending in first and second directions on a surface of the substrates and at least one of the substrates includes diodes which connect adjacent conductive elements in at least the first direction. The apparatus is electronically controllable between a reflection mode and a transmission mode, wherein in the reflection mode the diodes are reverse-biased and electromagnetic radiation incident on the apparatus is substantially reflected and in the transmission mode the diodes are forward-biased and incident electromagnetic radiation is substantially transmitted.

Abstract: A microwave polarizing lens structure having two concentric hemispherical arrays of metallic linear scattering elements (dipoles) supported by thin walled dielectric shells. It has the property of controlling the sense of polarization, the ellipticity ratio and shape of the radiation pattern of the antenna contained within it.

Abstract: A radio signal polarization switching arrangement is responsive to linearly polarized radio signals, such as television signals from a satellite. The switching arrangement which is capable of selecting signals having either one of predetermined states of linear polarization comprises a dielectric support block which supports a ferrite rod axially in a circular waveguide. A metal or metallized layer is deposited on an external surface of the support block and an energizing coil is wound around the layer in axial alignment with the rod. The support block has a stepped configuration at opposite ends in order to compensate for the loading effect of the ferrite rod on the waveguide.

Abstract: An antenna arrangement for receiving television signals from a satellite comprises a parabolic dish which collects the signals and feeds them through a feedhorn, then through a polarization switch and to a low noise block to the receiver. The polarization switch comprises a ferrite rod supported in a dielectric holder within a circular waveguide. The ferrite rod is surrounded by a solenoid coil which is energizable to rotate the plane of polarization of the signals passed along the waveguide, so as to enable the switch to select either horizontally or vertically polarized signals. The current in the coil is switchable between two values, one having a predetermined magnitude in one direction through the coil and the other having the same predetermined magnitude but in the opposite direction through the coil. The current levels are seleced such that the corresponding angular positions for the plane of polarization are +45.degree. relative to the datum position for the polarization plane and -45.degree.

Abstract: The invention relates to matching asymmetrical discontinuities 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 discontinuities, 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 quarter wave transformer".

Abstract: A dual frequency feed assembly for an antenna system having two coaxial cavities, with a smaller, high-frequency cavity mounted coaxially within a larger, low-frequency cavity. A separately rotatable probe is mounted within each cavity. The smaller cavity is mounted within the larger cavity by any of several structures, such as a ring-shaped spider, a ring-shaped spacer in the form of a planar washer, or a harp extending rearwardly in the larger cavity.

Abstract: Adaptive phase and amplitude distributor for use with satellite antennae which require distribution of transmitter-generated microwave power over many elementary radiators having predetermined amplitude and phase characteristics thus achieving required radiation patterns. It consists essentially of two polarizers three circular waveguide rotating joints, all interconnected in a joint-to-polarizer-to-joint-to-polarizer-to-joint relation and followed by an orthomode.TM. transducer output which serves to separate the orthogonal components of the electromagnetic field. By rotating the two polarizers around the waveguide axis independently and by suitable choice of the rotating angles, it is possible to distribute the power entering at one port, say in the TE.sub.11 mode, on the two orthogonal components, still in TE.sub.11, with any amplitude and phase relationship at the output. The two components are separated by the orthomode.TM. transducer.

Abstract: An adaptive polarization combining system automatically adjusts the polarization of a polarization diverse antenna to match that of the incoming RF signal, thereby maximizing the received signal-to-noise ratio. Signals from the orthogonally polarized ports of the antenna are passed through a variable combiner circuit which is adjusted to maximize the combined signal at a single output port. Sample signals from each antenna port are provided to a calibration circuit which obtains phase and amplitude information from the two orthogonally polarized received signals and uses this information to control the combiner circuit phase shifters to adapt the combiner circuit to the polarization of the received signals. Therefore, the combining system can rapidly adapt electronically to polarization changes in the received signals.

Abstract: A dual frequency feed assembly employing a pair of coaxial circular wave guide cavities, each with respective probe. The higher frequency cavity, e.g. Ku band, is located within the lower frequency, e.g. C band cavity. A common motor is used to drive the two probes which have a common axis A. The lower frequency probe is coupled through the rear wall of the assembly to a rectangular waveguide. The higher frequency probe is also coupled through the rear wall of the assembly but via a coaxial line which is diverted from the axis A to exit beside the lower frequency waveguide. The two rectangular waveguides and the drive motor for the probes are all mounted on the rear of the assembly. In one embodiment of the invention the coaxial line extends from its probe to a housing on the body containing a signal processing circuit board. Connection to that board is made directly eliminating the need for any waveguide transmission line.

Abstract: The present invention is directed to a mode transformer for a microwave energy transmission circuit. This transformer is interposed between an electromagnetic wave source, operating in a predetermined frequency band, and a waveguide transmitting energy. This waveguide is excited by the electromagnetic wave source in a single chosen mode. The transformer has the shape of a conical tube whose large end is connected to the waveguide. The electromagnetic wave source is connected to the conical tube by a lateral opening. In the region of the conical tube where the excitation takes place the cross-section of the conical tube is smaller than that of the waveguide. At the center of the lateral opening, the cross-section of the conical tube is that which would be that of a waveguide of the same shape whose cut-off frequency, for the chosen mode, would be the central frequency of the working frequency band.

Abstract: A diplexing radiating element comprising at least a first radiating element in which two radiating electrical currents flow which are spaced apart from each other, and at least one second element in which two radiating magnetic currents flow which are spaced apart from each other. The invention is particularly applicable to space telecommunications.

Abstract: An apparatus is disclosed comprising a polarization mode selection switch for preselected wavelengths using a waveguide having a first array of PIN type diodes mounted in a plane extending substantially perpendicular to a longitudinal waveguide axis. The diodes are disposed at one-quarter wavelength intervals along a first series of parallel lines which are separated at about one-half wavelength intervals. A second PIN diode array is also mounted within the waveguide in a second plane extending substantially perpendicular to the waveguide axis with diodes disposed at one-quarter wavelength intervals along a second series of parallel lines that are also spaced about one-half wavelength apart. The second plane is substantially parallel and adjacent to the first plane with the second lines being oriented substantially perpendicular to the first lines.

Abstract: A capacitively coupled printed patch (3) as a high efficiency device to couple orthogonally polarized energy between a microstripline (5) and a waveguide (1). Coupling between the microstripline (5) and the patch (3) is achieved by the microstripline terminating in a narrow strip probe (4), the end of which lies close to, but not in contact with, an edge of the patch (3). Two separate probes (4) arranged mutually orthogonally are used to effect independent polarized couplings to produce independent linear orthogonal signals or independent left- and right-handed circularly polarized signals. The microstriplines (5) and patch (3) are supported on a common substrate (8) which extends transversely through the waveguide (1). The waveguide wall has a quarter-wavelength thickness (T) so that its inner edge (10) appears continuous to energy passing through the substrate (8).

Abstract: A monopulse antenna feed system utilizing multiple modes within the feed. A TEM mode and two TE.degree..sub.11 modes that are orthogonal and in phase quadrature are utilized in the antenna feed system to provide tracking information and data communication from a far-field source of circularly polarized radiation. The output from a port that is responsive to the TEM mode is compared with the output from a port that is responsive to the TE.degree..sub.11 modes to obtain tracking information and the output from the latter port also provides a channel for communication of data. The phase of the TEM mode relative to the phase of the TE.degree..sub.11 modes is indicative of the angular rotational position of a far-field source relative to the axis of the feed system and the relative amplitude of the TEM mode is indicative of the angular displacement of the far-field source away from the axis of the feed system.

Abstract: A device for exciting a waveguide with circular polarization from a plane antenna, said waveguide (10) being a rectilinear hollow waveguide closed at one of its ends (12), said antenna being excited by at least two coaxial ports (13, 14) fed in phase quadrature by a circuit including a hybrid coupler (15), and being constituted by a radiating plane metal pattern (11) disposed on the surface of an insulating substrate (18) closing the waveguide (10) perpendicularly to its axis of symmetry.

Abstract: A dual band integrated feedhorn includes a housing having a rotatable support for a C band coaxial waveguide, a clamp for a Ku band waveguide, a Ku band waveguide slideably mounted in the clamp for focus adjustment, and a pair of low noise blocks connected to the waveguide output probes for downconverting their incoming modulated carrier C and Ku band signals to modulated IF signals. A servo drives the support member to position the waveguides energy output coupling probes to match the polarization of the incoming RF energy; thus, eliminating the need for polarizers and reducing insertion loss significantly. The reduced insertion loss enables defocusing of the Ku band waveguide to widen the half power beamwidth to improve aiming accuracy without decreasing the gain and degrading performance. A position adjustable scalar and a pair of power modules are attached exteriorly of the housing. The scalar is positioned adjacent the end of the C band waveguide for focusing the C band waveguide.

Abstract: A dual frequency feed for use with an antenna permits reception of signals in both a low frequency band and a high frequency band and is comprised of a single feed through which both signals are propagated, a high frequency probe which extends concentrically within the throat of the feed for receiving the high frequency signal, a wave guide connected to the throat of the feed including a pair of turnstile junctions with four wave guides interconnecting the turnstile junctions, and a single output port with a polarization rotation device for receiving the low frequency signal. The four interconnecting wave guides may be either co-axial cables or generally rectangular wave guides.

Abstract: The present invention relates to a two-frequency radiating device comprising a waveguide radiating in a first frequency range opening out into a radiating element operating in a lower, second frequency range. The invention is particularly applicable to antennas.

Abstract: A hollow waveguide includes a conductive peripheral wall arrangement centered on a longitudinal axis. The waveguide is short-circuited at a first transverse plane. A center conductor is connected to the short-circuit and extends along the longitudinal axis to an abrupt open circuit termination at a second transverse plane. The arrangement is fed at a location between the first and second transverse planes to produce both a fundamental waveguide mode and a center-conductor coupled mode. The fundamental mode has an amplitude taper in the horizontal direction but not in the vertical direction. At the abrupt termination, a higher-order waveguide mode is generated which, when phase-shifted by 180.degree., provides an amplitude taper in a vertical direction. A radiating aperture located near the 180.degree. phase shift point produces a radiation pattern which is similar in both the verticla and horizontal planes.

Abstract: A polarization selector system, suitable for use with an antenna for radiating electromagnetic waves at a variety of preselectable polarizations, is formed of an orthogonal mode launcher of electromagnetic waves, and a hybrid coupling assembly for driving the launcher. The coupling assembly has a pair of waveguides sharing a common wall. A set of hybrid couplers of differing coupling ratios, and including a mechanically displaceable gate within each coupler, is disposed serially along the common wall.The gates are individually positionable to provide for coupling of differing amounts of electromagnetic power with 90 degree phase shift between the waveguides.

Abstract: Apparatus is disclosed for rotating the polarization of microwave signal received into a circular waveguide. This apparatus includes a septum mounted within a waveguide, with that septum including a plurality of discrete interlinked elements mounted to a shaft supported longitudinally of the axis of the waveguide and includes apparatus for rotating adjacent elements angularly about the shaft along with structure for restricting the relative angular rotation of adjacent such elements about the shaft so that the maximum rotation of each element relative to an adjacent element is limited to a predetermined angle for that element.

Abstract: Disclosed is a power divider in waveguide form, for a microwave power transmission circuit, working at high power in the rectangular TE.sub.10 mode. This power divider is formed by the juxtaposition of:a rectangular, input waveguide working in its fundamental mode, receiving the power to be divided through one of its ends, and having another closed end;a circular waveguide propagating the TM.sub.01 mode connected to the rectangular, input waveguide by a lateral opening in such a way that the axes of the two guides are perpendicular;a group of n output waveguides, placed at the output of the circular waveguide and distributed in a ring before its free end, working in the TE.sub.10 mode, each transmitting a fraction of the power introduced into the input. The device can be applied to microwave power transmission circuits.

Abstract: A polarizer has a plurality of short waveguide sections arranged so that rectangular-shaped sections alternate with circular-shaped sections. The two end sections are both circular. The rectangular sections have a minimum size at least as large as the minimum diameter of the circular sections. The size of the rectangular sections progressively changes from section to section with all sections of the polarizer being symmetrical about the centre point of the polarizer. The length of each section is less than half a wavelength at maximum operating frequency. The structure of the polarizer is simple and straightforward so that computer-aided analysis and design methods can easily be used. The polarizer has a relatively large bandwidth and can interface directly with corrugated circular waveguides.

Abstract: A diplexer for communicating signals in two different frequency bands with separate polarizations in each band may, for example, concurrently separate low frequency received signals of orthogonal polarizations from high frequency transmitted signals, also of orthogonal polarizations. To this end a common square waveguide leads to serially disposed, axially displaced, orthogonal mode transitions at which branches are made to closely coupled lowpass filters that communicate with separate ports for low frequency signal bands. A smaller square waveguide coupled to the second of the orthogonal mode transitions communicates with another orthogonal mode transition at which axially displaced branches communicate with other ports for high frequency signal bands.

Abstract: A corrugated waveguide having a circular bore and noncircularly symmetric corrugations, and preferably elliptical corrugations, provides birefringence for rotation of polarization in the HE.sub.11 mode. The corrugated waveguide may be fabricated by cutting circular grooves on a lathe in a cylindrical tube or rod of aluminum of a diameter suitable for the bore of the waveguide, and then cutting an approximation to ellipses for the corrugations using a cutting radius R.sub.0 from the bore axis that is greater than the bore radius, and then making two circular cuts using a radius R.sub.1 less than R.sub.0 at centers +b and -b from the axis of the waveguide bore. Alternatively, stock for the mandrel may be formed with an elliptical transverse cross section, and then only the circular grooves need be cut on a lathe, leaving elliptical corrugations between the grooves. In either case, the mandrel is first electroplated and then dissolved leaving a corrugated waveguide with noncircularly symmetric corrugations.

Abstract: A fin line circuit card containing a fin line slot feeds a dipole antenna ich extends a quarterwave outside the waveguide and provides an energy beam focal point at or near the open end of the waveguide. The dipole antenna thus maintains a wide and nearly constant beamwidth, low VSWR and a circular symmetric radiation pattern for use in electronic warfare direction finding and surveillance applications.

Abstract: An electrically-conductive flexible probe is mounted within a wave guide that receives radio-frequency electromagnetic radiation. A leading portion of the probe has an orientation that is adjustable between two positions that are angularly displaced with respect to each other by 90.degree.. A permanent bar magnet is connected to the leading portion of probe, and an electromagnet is mounted adjacent to the bar magnet so as to be capable of being magnetically coupled to the bar magnet.

Abstract: A microwave receiving device of this invention includes a primary radiator and a low-noise converter arranged integrally therewith. One end of a chassis of the microwave receiving device is connected to a flange having an opening shape designed to provide a predetermined directivity characteristics. A waveguide as a primary radiator having a circular cross section is arranged along substantially the entire length of the chassis. A circularly polarized wave generator is arranged in the waveguide to convert a circularly polarized wave propagating through the waveguide into a vertically polarized wave. The vertically polarized wave converted by the circularly polarized wave generator is converted into an electrical signal by a probe. The probe is connected to microwave circuit boards mounted in the chassis. A microwave circuit serving as a low-noise converter is formed on the circuit boards. The electrical signal from the probe is processed by the microwave circuit formed on the circuit boards.

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".