Abstract: An antenna feed for decreasing the scan modulation of the radiated signal a radar which tracks by the method known as scan-with-compensation. The antenna feed is comprised of a coaxial line fed dipole located on the axis of a circular waveguide for radiating a single on-axis unmodulated pencil-beam during transmission. The antenna feed further comprises two parallel radiators located equally distant and on opposite sides of the transmitting circular waveguide radiator and functions during reception only. Rectangular waveguides connect the two parallel radiators with the central radiator so as to give rise to orthogonal signals in the central radiator upon reception of echo signals. An ATR tube connects the dipole to the central axial waveguide during transmission and isolates it during reception. The radiating dipole is mounted so as to remain fixed while the central circular waveguide and the two parallel reception waveguides rotate during scanning.

Abstract: A waveguide filter is herein described that employs a resonator ordering which allows a direct realization of all canonical couplings while retaining the advantages of a standard dual mode filter, the filter including a reflective plate in one end cavity and both input and output ports in the other end cavity, where one of the ports is a shunt port in a sidewall of the cavity structure and the other port is a coupling slot in the outer end wall.

Abstract: An automatic polarization decoupling circuit for decoupling first and second signals originally transmitted with orthogonal polarizations comprising a rotatable quarter-wave plate and a rotatable half-wave plate for linearizing the first signal and rotating its polarization direction to a reference polarization direction, an Orthomode (trademark) transducer for separating energy in the reference polarization direction from energy with a polarization in quadrature thereto and utilizing this quadrature energy as the decoupled second signal. The system further comprises a second Orthomode transducer for recombining the in-phase and quadrature energy separated by the first Orthomode transducer and applying this recombined energy to a second rotatable quarter-wave plate and a second rotatable half-wave plate for linearizing the second signal and rotating its polarization direction to a direction in quadrature with the reference polarization direction.

Abstract: This specification discloses a microwave circular polarizer for converting a linearly polarized microwave signal to a circularly polarized microwave signal and vice versa. A transducer, such as an Orthomode junction is used to obtain a power split or a power recombination of two orthogonal linear polarizations. To obtain the phase delay required to generate a circularly polarized signal from two linearly polarized signals, the polarizer includes a phase compensator with a pair of waveguides which have appropriate width and length so that signals passing therethrough develop a phase difference therebetween and a composite circularly polarized signal results. The amount of phase shift occurring in each of the waveguides varies with the frequency of the signal in such a way as to produce a high purity circular polarization over a broad frequency band. A phase shift of 90.degree.

Abstract: The cavity of a rotatable cylindrical waveguide supports the TE.sub.11 mode of propagation of a received wave and a transmitted wave. The proximal and distal ends of the cylindrical waveguide are adjacent and axially aligned with one end of a rectangular flexible waveguide and a fixedly disposed horn aperture, respectively. The transmitted wave propagates in the TE.sub.10 mode through the rectangular waveguide to the cylindrical waveguide. Additionally, the rectangular waveguide prevents propagation therethrough of the received wave. The cylindrical waveguide couples the transmitted wave to the horn. Rotation of the end of the rectangular waveguide rotates the polarization of the transmitted wave. A pair of slots in the cylindrical waveguide form passageways between the cavity thereof and a pair of filters that pass the received wave whereby the received wave propagates through the filters.

Abstract: A unidirectional phase shifter provides selectable phase changes for linearly polarized microwaves of electromagnetic radiation entering the phase shifter in one direction and constant insertion phase for linearly polarized microwaves entering the phase shifter in the opposite direction. The phase shifter consists of two ferrite phasor sections arranged such that the phase changes of the two sections add for one direction of signal flow and cancel for the other. Each phasor section includes a ferrite half-wave plate, at one end of which is coupled a ferrite quarter-wave plate, and at the other end of which is coupled a dielectric quarter-wave plate. The dielectric quarter-wave plate of one of the phasor sections is coupled to the ferrite quarter-wave plate of the other phasor section.

Abstract: A dielectric slab polarizer employs a unique configuration which provides improved impedance matching of the polarizer to the empty space of a waveguide section and, thereby, allows an approximate ninety degree differential phase shift transformation of RF field polarization to be achieved over a wider frequency bandwidth than heretofore attainable. The novel configuration of the slab polarizer is embodied by a flat middle section, conical tapered opposite end sections and reverse tapered intermediate sections which merge with the flat middle section and opposite end sections. The regions of merger between the respective intermediate sections and opposite end sections have a thickness greater than that of the middle section.

Abstract: A microwave diplexer apparatus for handling simultaneously two independent polarized transmitted signals at one frequency and two independent polarized received signals at a lower frequency. In the transmit mode of operation, a pair of input signals are applied to a first orthogonal mode transducer wherein the electric fields of the signals are established at right angles to each other. The orthogonal, linearly-polarizer signals are then transformed by a pin/ridge-loaded circular polarizer device to oppositely-rotating circularly-polarized signals and coupled via an antenna port of a second orthogonal mode transducer to an antenna for transmission to a desired target.

Abstract: The present invention provides a polarization coupler which is capable of coupling or separating dual linear polarized microwave signals having frequencies which extend over extremely wide frequency bands. The present polarization coupler (11) comprises a main waveguide (12) and a side-arm waveguide (13) with a plurality of septa (16) arranged at the junction to reflect energy of a first polarization (E.sub.1) between the main and side-arm waveguide while energy of a second polarization (E.sub.2) passes the junction unaffected.

Abstract: Input and output waveguides are each formed from an inner tubular conductor coaxially disposed within an outer tubular conductor. The proximal ends of the waveguides are coupled through relatively rotatable sleeves of a coupling assembly that maintains the waveguides coaxial with a central axis. The field strength of a wave at the distal end of the input waveguide defines two cycles of a sinusoid about the axis. The inner conductors each carry on their outer surface an equal number of evenly spaced ridges. The ridges in the input waveguide cause the field strength to be invariant at the proximal ends. The ridges in the output waveguide cause the field strength to define the two cycles of the sinusoid at the distal end of the output waveguide.

Abstract: A microwave diplexer apparatus for handling simultaneously two independent polarized transmitted signals at one frequency and two independent polarized received signals at a lower frequency. In the transmit mode of operation of the diplexer apparatus, a pair of input signals to be transmitted to a target are applied to a first orthogonal mode transducer wherein the electric fields of the signals are established at right angles to each other. The orthogonal linearly-polarized signals are then transformed by a pin/ridge-loaded circular polarizer device to oppositely-rotating circularly-polarized signals and coupled via an antenna port of a second orthogonal mode transducer to an antenna for transmission to the desired target.

Abstract: A single in-plane orthogonal mode launcher for generating circularly polarized waves having both right and left hand senses is disclosed. A 90.degree. hybrid provides first and second signals to respective input ports of the launcher. First and second coplanar sets of probes are orthogonally disposed in a cylindrical housing and connected to the first and second ports, respectively. The first set of probes generates a first vector signal. The second set of probes generates a second vector signal which is 90.degree. to the first vector signal. Since the input signals to the first and second sets of probes are 90.degree. out of phase, circularly polarized waves are thus generated.

Abstract: A plurality of dielectric plates are disposed side by side to form a dielectric plate assembly and matching layers are respectively disposed adjacent to both end faces of the dielectric plates. A plane wave is incident on one of the matching layers perpendicularly thereto and passes through the dielectric plate assembly and are emitted from the other matching layer. Ratios b/a and a/.lambda..sub.0 (a being the distance between the centers of adjacent ones of the dielectric plates, b the thickness of each dielectric plate and .lambda..sub.0 the free space wave length of the electric wave) are selected so that the frequency characteristics of the phase difference between the electric field components of the plane wave respectively perpendicular and parallel to the dielectric plates, which are produced by the passage of the plane wave through the dielectric plate assembly, has a value of 90.degree. at two different values of a/.lambda..sub.0.

Abstract: A balanced phase septum polarizer for converting a linearly polarized microwave signal to a circularly polarized microwave signal and vice versa. The septum polarizer includes a first waveguide, capable of propagating a circularly polarized microwave signal, and a septum that divides this waveguide into second and third waveguides each of which is capable of propagating a linearly polarized electric field microwave signal. The septum extends between opposite sides of the first waveguide and has an edge that is shaped to produce an inflection point in the phase angle vs. frequency function for the orthogonal electrical field components of the circularly polarized microwave signal. This results in a "balanced phase angle" relationship that permits reduction of the septum polarizer VSWR and improves significantly the axial ratio of the circularly polarized microwave signal.

Abstract: A circular polarizer in the form of a waveguide coupler containing a sloped septum and using discontinuities on the septum slope together with a waist constriction to achieve good isolation and low ellipticity over a wide band.

Abstract: A polarization selective screen allowing only electromagnetic waves having a desired linear polarization to pass therethrough, the screen includes an array of relatively thin, parallel and evenly spaced conductive flat ribbons supported between end portions of a frame structure, the broad surface of the ribbons being orthogonal to the plane of the screen and being supported and maintained in place under a predetermined tensional force by tension means such as spring-loaded ribbon hangers.

Abstract: A microwave system is disclosed for simultaneous amplification and radiation of CW and pulsed signals wherein signals from a CW amplifier tube and a pulsed power amplifier tube are transmitted to an antenna where they are radiated as signals with circular polarizations of opposite direction. In one embodiment interstage circuitry between the amplifiers and the antenna includes a magic "T" hybrid and a 90.degree. phase shifter.

Abstract: A transmission system for use in a communications satellite is disclosed which utilizes a power divider providing equal power output from N output ports having a uniform phase progression from port to port, the sense of which depends upon which of two input ports is excited. In an illustrated embodiment, one input port generates a first sense of circular polarization and the other generates the opposite sense. The two oppositely polarized circular waves are applied to the multiphase power divider. The cylindrical-bodied power divider has N output ports, where N is an odd integer, arranged at 360.degree./N about the cylindrical surface. Disposed within the power divider is an N-bladed septa for providing power division and isolation. A 180.degree. phase inverter is connected to (N-1)/2 output ports for providing a wave having a phase progression of 180.degree./N from the power divider.

Abstract: A broadband microwave polarizer device for introducing a differential phase shift between orthogonal components of linear orthogonally-polarized signals, the differential phase shift being relatively constant over a wide range of frequencies, for example, a range of frequencies of 5.925GHz to 6.425GHz.The polarizer device includes a section of waveguide having two opposing rows of pins at inner surface regions thereof, in a first common plane, and two opposing ridges at other inner surface regions thereof in a second common plane transverse to the first plane. By appropriate design of the pins and ridges, a relatively constant resultant phase shift .phi..sub.R may be achieved over the abovementioned bandwidth. The value of .phi..sub.R may be approximated byA.sub.O -B.sub.O +(A.sub.1 -B.sub.1)(f-f.sub.O) + (A.sub.2 -B.sub.2)(f-f.sub.O).sup.2,where f is a selected frequency of the orthogonally-polarized signals, f is the center frequency of the operating frequency bandwidth of the polarizer device, A.sub.O, A.

Abstract: Disclosed is a method for the determination of the optical anisotropy of a dielectric material such as fibrous glass-reinforced plastic resin, particularly the measurement of the state in which reinforcing fibers present in the dielectric material are oriented, by using a microwave characterized by connecting a fixed quarter-wave plate and a rotary quarter-wave plate to a conventional reflective type microwave measuring device in front of which the dielectric material is disposed, whereby the ratio of amplitude and the phase difference which represent the degree of anisotropy of the dielectric material can be determined.

Abstract: A microwave feed forward passive coupling system for separation of at least a first and a second signal portion into at least first and second signal components of differing frequencies. The first and second signal portions have a majority of the second and first components respectively and a minority of the first and second components respectively. A second sample of the second signal portion and a part of the first signal portion are combined to produce substantially the second component. In addition, a first sample of the first signal portion and a part of the second signal portion are combined to produce substantially the first component.

Abstract: A plural cavity waveguide filter comprising a plurality of cascaded waveguide cavities each resonating in first and second independent orthogonal modes is disclosed. The cavities may be either square and/or circular resonating in the TE.sub.101 or TE.sub.111 modes, respectively. The filter makes it possible to realize the general class of coupled cavity bandpass transfer filter functions by providing that the input and output couplings to the filter be physically connected to the first physical cavity. A general set of canonical couplings can then be achieved within the structure.

Abstract: A simplified waveguide switch is disclosed having a rotatable quarter wave plate for generating selected amounts of right hand and left-hand circular polarized waves. A linearly polarized signal, in the TE.sub.11 mode, is launched into a cylindrical waveguide member. A quarter-wave plate is disposed within the cylindrical waveguide and imparts a right or left-hand circular polarization to the linear wave depending upon the orientation of the quarter wave plate with respect to the linear wave. The rotation angle of the quarter wave plate is adjusted by a stepping motor.

Abstract: A spectrum reuse antenna system is described for transmitting orthogonally polarized RF waves at one frequency band to a satellite and for receiving orthogonally polarized RF waves from a satellite at a second frequency band through a common antenna. A local generator provides a first control signal which varies as a function of the typical rotation of the polarization of a transmitted wave at the one frequency band travelling through the ionosphere. The local generator also provides a second control signal which varies as a function of the typical rotation of the polarization of a received wave at the second frequency band travelling through the ionosphere. A driven means responsive to the first control signal causes a rotation of the polarization of the transmitted waves to correct for Faraday rotation in the ionosphere and a driven means responsive to the second control signal causes rotation of the polarization angle of the antenna system for the received waves to correct for the Faraday rotation.

Abstract: A system filter for double frequency utilization, including a broadband polarization filter in conjunction with frequency filters for separating two different frequency bands with each frequency band being doubly orthogonally polarized. The broadband polarization filter of singly symmetrical construction includes a doubly polarizable waveguide section which is axially divided by means of a partition into two symmetrical partial waveguides and the two frequency bands of the wave which is polarized parallel to the partition are each coupled out through a respective coupling window in two oppositely disposed walls of the waveguide section into a respective waveguide tee.

Abstract: A multiple polarization switch which provides horizontal, vertical, rightnd circular and left-hand circular polarization from a single microwave source for use with a quadrature feed antenna. The device is comprised of a hybrid coupler, isolation switch, and cross-over switch with a narrow band design accomplished by shunt pin diodes controlled by external D.C. current sources of the proper polarity.

Abstract: A multimode coupling system for coupling symmetrical waveguide mode signals and two or more tracking asymmetrical waveguide mode signals includes a funnel-shaped coupler with a plurality of coupling apertures located in the side wall thereof. A first four of these side wall apertures lie in a first common plane at a given distance from the small aperture end of the coupler. A second four of these apertures lie in a second common plane a second given distance from the small aperture end of the coupler. A first coupling circuit is provided between the first group of side wall apertures and an asymmetrical mode terminal, and a second coupling circuit is provided between the second four apertures in the second plane and a second asymmetrical mode terminal.

Abstract: An improved antenna feed providing control of the plane of polarization ecially useful with "scanning with compensation" radar tracking. An input transducer is coupled to first and second output transducers whereby the output transducers transmit two pencil-beam radiation patterns which are squinted by equal but opposite angles with respect to the scan axis. During reception, however, a non-reciprocal coupling means provides for separate sensing of the return signals rceived by the first and second output means and converts the signal received by the second output means so that it is in quadrature relationship with the signal received by the first output means.

Abstract: A monopulse radar antenna having an improved three-channel feedhorn for piding selectable polarization and greater target discrimination. The antenna feed employs a comparator having a difference port, a first sum port, and a second sum port utilizing a coupling pin or probe therein, between the comparator ports and an adjustable polarization device, for receiving and separating returned energy which has become cross-polarized with respect to the polarization of the transmitting sum arm, by reflection from an asymmetrical target. The three-channel feedhorn makes possible the identification of different types of targets, and the detection of hidden targets in rough terrain, forests, underbrush, and rough seas.

Abstract: A reciprocal latching ferrite phase shifter is fashioned from a single slab of ferrite material, such that the phase shifter comprises a monolithic ferrite structure, providing the overall functional characteristics of the phase shifter through an integrated combination of individual portions of the monolithic structure. The reciprocal function of the monolithic phase shifter assembly is provided through the use of dual non-reciprocal phase shifters connected in parallel, such that separate paths and selected phase shifts of zero to 360.degree. for linearly polarized transverse electric microwaves having operating frequencies in the range of two to 100 GHz, are provided for waves propagating in opposite directions.

Abstract: A system separating filter for separating first and second signals each consisting of a doubly polarized frequency band with the two bands being of different frequencies. The filter includes first, second and third series connected doubly polarizable waveguide sections with the first waveguide section having an inner cross section of such dimensions that both frequency bands can exist therein with their respective dual polarizations, and with the second waveguide section serving as a transition piece between the first waveguide section and the third waveguide section which has an inner cross section of such dimension that at least the second frequency band can exist.

Abstract: An interference reduction circuit to provide isolation in frequency reuse systems operates on two or more non-isolated signals by cross-coupling the signals such that the interfering signals are cancelled on each channel. In a dual-polarized frequency reuse system, cancellation is effected by adding a sample of an oppositely polarized channel of equal amplitude, but of opposite phase, to the interference. Practical implementation includes closed-loop, digital feedback control to permit dynamic signal-to-interference improvement involving no a priori knowledge of the nature of the incoming signals. The circuit has applications in satellites and earth stations in a communications satellite system.

Abstract: A tapered septum in a square waveguide transduces it into a pair of rectangular waveguides. The output waveguides will be excited as a function of the polarization of the signals present in the square waveguide. The septum has a special shape that includes a tapered portion and a transverse portion proportioned to maximize the transducer bandwidth and minimize reflected power.

Abstract: A three-port transducer has as a first port a waveguide capable of supporting transverse electric waves of any polarization. The waveguide is divided into three sections by means of a pair of tapered septums which taper in opposing directions. The width of the inner section of the three is made equal to the combined widths of the other two and is coupled to a rectangular waveguide which comprises a second transducer port. The two outer sections are coupled together to a second rectangular waveguide which comprises a third transducer port. The polarization of a signal applied to the first port will determine the amplitude and phase of the signals at the second and third ports.

Abstract: A compact device for launching circularly polarized electromagnetic waves utilizes a hollow waveguide terminated by a horn. Within that structure, a septum fin extends from the waveguide into the horn. The septum fin divides the hollow waveguide into two smaller waveguides, each of which is capable of independently supporting the TE.sub.1,0 mode of wave propagation. The fin is a tapered plate that has its maximum width within the waveguide and its minimum width in the horn. A signal injected into one port of the divided waveguide emerges from the horn as a circularly polarized wave having its polarization vector rotating clockwise whereas a signal injected into the other port emerges from the horn as a circularly polarized wave with its polarization vector rotating in the counter clockwise direction.

Abstract: An antenna element for use in a phased array antenna is disclosed. Such antenna element is a reciprocal device adapted selectively to radiate radio frequency energy of either circular or linear polarization. Such antenna element includes waveguide means for passing radio frequency energy and for radiating such energy; and means adapted to transform the polarization of the radio frequency energy as such passes through the waveguide means to radiate such radio frequency energy selectively with either linear or circular polarization. In a preferred embodiment the just-mentioned means includes a first and a second nonreciprocal quarter-wave plate having field orientations effectively 45.degree. with respect to each other. Such nonreciprocal quarter-wave plates flank a third nonreciprocal quarter-wave plate switchable so that its field orientation is either aligned with the field orientation of the first nonreciprocal quarter-wave plate or, while still aligned as before, turned 180.degree..

Abstract: A multicavity waveguide filter in which each of the cavities has a pair of orthogonally related modes of propagation. The cavities are positioned side by side with the long axis of each of the cavities being aligned parallel to each other. The cavities are tuned by tuning plungers which are simultaneously moved to predetermined positions within the cavity.

Abstract: An orthogonal mode waveguide junction having a dual mode common arm capable of receiving or transmitting energy simultaneously in two orthogonally related directions of polarization, an E-arm, and an H-arm meeting in a common junction region. Matching structure is included entirely within the junction region. The junction is usable over a great part of the band normally usable with a waveguide designed to the same center frequency.