Abstract: A phase shifter subarray which is useful with a phased array antenna, includes a plurality of phase shifter elements which have substantially equal finite lengths and which are mounted on a ferri-magnetic substrate. An electrical coil is disposed around selected portions of the substrate and a common feed is connected to each of the phase shifter elements to transmit energy through the phase shifter elements to the radiating elements of the antenna. A driver is connected to the coil, and the driver is activated to induce a magnetic flux in the selected portions of the substrate. This flux influences that part of each phase shifter element which is mounted in the selected portions of the substrate and, consequently, the phase of the wave energy which passes through the influenced part of each phase shifter element is shifted to predictably direct the beam radiated from the antenna.

Abstract: A polariser particularly suitable for use in receiving satellite television signals includes a ferrite rod located within a waveguide, a yoke co-extensive with the ferrite member and a coil wound around the yoke. The yoke preferably is "U" shaped and includes an arm which projects into the waveguide at the end of the ferrite rod remote from the input of the waveguide.

Abstract: A microwave ferrite phase shifter wherein three parallel microstrip lines are disposed on a planar ferrite substrate surface opposite a ground plane disposed on an opposite planar surface of the substrate, the lines defining two sets of quadrature E-fields within the substrate to produce a circularly polarized wave therein, the amount of phase shift between the input and output ports of the phase shifter being determined by the magnitude of a magnetic field produced in the substrate in the direction of its axis by a current-carrying coil, for example.

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

Abstract: The invention is directed to an FSL in which a pair of planar ferrite members have planar surfaces in confronting relationship and at least one signal carrying conductor is supported between the ferrites and is closely coupled thereto. A magnetic biasing field is established having field lines disposed at an angle relative to the conductor such that the FSL has an increased attenuation at low frequencies resulting in a relatively flat limiting characteristic across the bandwidth. The conductor may lie in a plane parallel to the field lines or transverse to the field lines. In one embodiment the conductor zigzags in the plane of the field.

Abstract: A transitioning microstrip circulator. A Y-shaped circulator having two ps coupled to a first planar substrate and a third port coupled to a second planar substrate. The first and second planar substrates are substantially parallel and have the circulator sandwiched between them. The circulator selectively directs a millimeter wave signal along a millimeter wave transmission line to a selected port. Thereby, a signal can be coupled to circuit elements placed on each substrate. Circuit elements placed on the first and second substrate are stacked one on top of the other. This permits design flexibility and smaller packages for electronic devices.

Abstract: A miniaturized waveguide mode ferrite RF phase shifter is efficiently transitioned to a matched impedance microstrip transmission line mode at either end to result in an ultra small, efficient and lightweight essentially "planar" phase shifter device having a single ferrimagnetic toroid.

Abstract: An RF phase shifter combines a non-reciprocal ferrite 180.degree. stage with one or more reciprocal diode phase shifting stages to produce an essentially planar phase shifter that is ultra small, efficient and lightweight. Such phase shifter elements may be used in phased arrays to produce an array offering major improvements over existing planar substrate all diode phase shifters while maintaining the phase gradient between array elements and without switching the ferrite shifter between the transmit and receive modes.

Abstract: A high power, high frequency, Y-junction three port circulator containing at least one metal plate in the Y-junction covered with ferromagnetic material and an external magnet producing a magnetic field through the ferromagnetic material so that it is magnetized to saturation magnetization when the temperature of the material is within a predetermined temperature range; and a method and means of maintaining the temperature of the ferrite material within said predetermined range even while the circulator operates in a variable ambient environment at high power, including means connected to the metal plate for heating and cooling the plate, thereby controlling the temperature of the ferromagnetic material to maintain the temperature thereof within said predetermined temperature range.

Abstract: A monostable circuit with device-status feedback control to an external timing terminal is used to controllably change the magnetization state of a ferrite phase shifter core. A pair of such bistable circuits with suitable feedback controls permits a single command pulse of controlled duration to controllably both reset a ferrite core to a saturated magnetic state and then subsequently set the core to a desired non-saturated magnetization state (corresponding to the time duration of the single command pulse). By addition of suitable steering circuits, the controlled resetting and setting of one or more pairs of such ferrite cores can also be achieved using the same single command pulse. The ability to both reset and set plural ferrite phase shifter cores with but a single command pulse of controlled duration permits considerable simplification of beam steering control wiring for a two-dimensional phased array of RF radiators (e.g., so as to provide electronic beam steering control).

Abstract: A miniaturized waveguide mode ferrite RF phase shifter is efficiently transitioned to a matched impedance microstrip transmission line mode at either end to result in an ultra small, efficient and lightweight essentially "planar" phase shifter device having wide application in the microwave industry.

Abstract: A matching network matches an output impedance of a source with an input impedance of a load. The matching network includes a plurality of transmission line stubs. Each transmission line stub includes a first transmission line conductor, a second transmission line conductor running parallel to but not in electrical contact with the first transmission line conductor, and ferrite dielectric material between the first transmission line conductor and the second transmission line conductor. A magnetic field is used to vary the relative permeability of the ferrite dielectric material.

Abstract: A Faraday rotator device containing (a) a Faraday rotator, (b) a wire winding encircling the Faraday rotator for changing the magnetization state of the Faraday rotator, and (c) a hollow yoke surrounding the Faraday rotator and the wire winding for forming a substantially closed magnetic circuit together with the Faraday rotator, the hollow yoke having an opening in each of front and rear walls in alignment with the Faraday rotator for permitting a light to pass through the hollow yoke and the Faraday rotator. The optical switch containing a pair of polarizers disposed on front and rear sides of the Faraday rotator device, the magnetization direction of the Faraday rotator being reversible to change the optical path. The hollow yoke is made of a soft magnetic material or a semi-hard magnetic material.

Abstract: A semi-flexible double-ridge waveguide comprises a corrugated tube formed into a special dumbbell-shaped cross-section defined by parameters which are conveniently optimized to realize improved power-handling capability as well as improved attenuation and VSWR factors across extended dominant-mode operational bandwidths. The dumbbell-shaped cross-section efficiently removes the problems typically associated with the use of conventional rigid waveguide, including difficulty of installation as well as the need for precise alignment of components, by combining flexibility and ease of manufacture, even for long lengths of waveguide, through use of a continuous, uncomplicated and relatively inexpensive process.The dumbbell-shaped cross-section is totally devoid of corners and other abrupt protrusions and is defined by a geometric equation in which specific parameters can be correlatively optiminzed to improve desired electrical properties of the waveguide.

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: In the production of a waveguide, a pipe of a glass which is soluble in an acid or an alkali is used in order to obtain a smooth inner peripheral surface of a reflecting layer of the waveguide. After the reflecting layer is formed on the outer periphery of the pipe, the glass pipe is dipped in an etchant to be dissolved and removed. A reinforcement layer can be applied to the waveguide, and the reinforcement layer is made of a resin in order to keep the flexibility of the waveguide. In this case, the reinforcement layer of a resin is formed on the outer periphery of the reflecting layer on the pipe, and thereafter the pipe is dipped in the etchant and is removed. The waveguide of a circular cross-section can be flatted. In this case, the reinforcement layer made of a thermoplastic resin is heated to be softened, and then a compressive force is applied to the waveguide radially thereof to flatten the waveguide.

Abstract: Apparatus and method for enabling viscous fluids to be discharged from a container. The container is provided with an outlet positioned for gravity discharge of the contents. Microwave energy is delivered to an inlet opening of the container for the purpose of heating the stored fluids in a controlled area which includes the inlet and outlet. The microwave energy is effective to heat the viscous fluids to a flowable state while fluids are simultaneously discharged from the outlet. The energy level can be controlled based on the level of viscous fluid in the tank so that the viscous fluid is not overheated.

Abstract: A circulator for duplexing microwave signals is shown to consist of a pair of folded magic-T hybrid junctions with a nonreciprocal phase shift section disposed between the parallel ports of such junctions, the nonreciprocal phase shift section being made up of U-shaped ferrites supported between the insides of H-plane walls in a rectangular waveguide and U-shaped permanent magnets adjustably supported on the outsides of the H-plane walls so that the magnetic flux in the U-shaped ferrites may be changed as required.

Abstract: A fast switching ferrite phase shifter is disclosed featuring both reciprocal operation and fast switching speeds. Reciprocal operation in transmit and receive modes is achieved by employing two latching, toroidal non-reciprocal phase shifters; one for transmitting and one for receiving. The exemplary embodiment utilizes input and output circulating devices which include a Faraday rotator and septum polarizer for appropriately routing signals through one or the other of the phase shifters depending upon the direction of input signal propagation. The phase shifter achieves fast switching since the latching, toroidal, non-reciprocal phase shifters are transversely magnetized devices and are disposed entirely within a waveguide so that the generated magnetic field is confined entirely within the waveguide. The phase shifters do not intersect the waveguide walls and, thus, during a switching operation, the magnetic field is not switched through conductive waveguide walls.

Abstract: A microstrip nonreciprocal latching phase shifter has a ferrite rod with ramp-shaped dielectric waveguide members at the ends thereof mounted on one surface of a microstrip dielectric substrate having a ground plane on the opposite surface thereof. The dielectric constants of the ramp members and the rod are substantially the same and the substrate dielectric constant is substantially less than the dielectric constant of the ramp members. A dielectric plate is on top of the rod. A microstrip conductor mounted on the substrate, the ramp members and the plate in axial alignment with the rod extends between the ends of the substrate. The rod has a rectangular longitudinally-extending passageway therein filled by a dielectric core insert having a dielectric constant greater than the dielectric constant of the rod. A single control wire is disposed in and aligned with the core insert.

Abstract: A device-implemented method for driving a ferrimagnetic load (10), such as a phase shifter in an antenna array, which precisely meters the amount of magnetic flux imparted to the load (10) by sensing the voltage applied to a winding and integrating the sensed voltage over time. The time intergrated voltage is proportional to the magnetic flux imparted to the load (10) and is constantly compared to a preprogrammed value stored in a memory (18). When the sensed voltage reaches the preprogrammed value, the voltage is removed from the load (10) so that a metered amount of magnetic flux, proportional to the preprogrammed value, remains in the load (10). The load (10) is initially reset by delivering current in one direction through its winding until saturation is reached. The load (10) is set with a metered amount of magnetic flux by delivering current in the opposite direction through the winding.

Abstract: A millimeter wave microstrip Y-junction circulator is provided comprising a ection of microstrip dielectric substrate having a cone-shaped ferrite element mounted on one side thereof together with three, Y-junction oriented sections of microstrip conductor extending from the base of the ferrite element and an electrically conductive ground plane mounted on the other side thereof. The ferrite element is covered with a cone-shaped microstrip conductor which electrically interconnects the three Y-oriented sections of microstrip conductor. When the ferrite element is fabricated of a spinel type of ferrite, a small permanent magnet is mounted on the ground plane beneath the ferrite element to provide a unidirectional magnetic field which produces a circulator action with respect to RF energy applied to the three sections of microstrip conductor.

Abstract: A phase shifter suitable for operation at very high high-frequency power is composed of a waveguide in which ferromagnetic material is distributed along at least one plane extending in the direction of wave propagation. The ferromagnetic material is exposed to a static magnetic field oriented parallel to the plane. The ferromagnetic material is shaped so that it forms a plurality of three-dimensional regions which extend in the direction of the applied static magnetic field from one waveguide wall to the opposite waveguide wall. These regions may be provided by a plurality of ferromagnetic rods, preferably housed in one or more dielectric containers to direct a flow of coolant fluid, or by a ferromagnetic body having a plurality of bores. Such bores also preferably direct a flow of coolant fluid.

Abstract: A nonreciprocal latching phase shifter includes a slab of a high dielectric contant material disposed within a closed magnetization path provided in response to a current fed through a ferrite toroid. A substantial portion of the electromagnetic energy is confined to the dielectric slab, with a remaining small portion of such energy leaking from the slab and interacting with the adjacent ferrite whose state of magnetization is varied in response to the current fed through the ferrite to provide a predetermined phase shift to the electromagnetic energy. In one embodiment, a plurality of parallel high dielectric bars is disposed within a ferrite toroid providing the closed magnetization path to provide a low-cost single toroid multi-element phase shifter. In a second embodiment, a plurality of ferrite toroids, each having a second plurality of dielectric members disposed therein, is arranged to provide a low-cost phase shifter array.

Abstract: A microstrip reciprocal phase shifter is provided comprising a rectangular ferrite rod having an upwardly sloping ramp member at one end thereof and a downwardly sloping ramp member at the other end thereof. The ramp members are made of dielectric waveguide having a dielectric constant substantially the same as the dielectric constant of the rod. The rod and ramp members are disposed on one surface of a microstrip dielectric substrate having a dielectric constant substantially lower than the dielectric constant of the ramp members and a ground plane on the other surface thereof. Input and output sections of microstrip conductor are placed on the surface of the substrate in axial alignment with the rod and ramp members.

Abstract: A junction circulator suitable for high power, high-frequency use has a microwave junction zone which is penetrated by a static magnetic field. Disposed in the microwave junction zone is a ferromagnetic resonator composed of different dielectric media, at least one of which has ferromagnetic characteristics. The interfaces between the various dielectric media form three-dimensional bodies which extend over the entire height of the junction zone and which have cross sections that do not change in the direction of the static magnetic field. These interfaces may be provided by parallel ferrite rods, or a ferrite body with parallel bores.

Abstract: A hyperfrequency circulator is provided in which the gyrator is integrated in the wave-guide, comprising a wave-guide whose two main faces are pierced with two holes, aligned with the center of symmetry of the junction. Through these holes a one-piece gyrator passes formed by at least one magnet, a pole piece, a solid dielectric resonator and a second pole piece. The gyrator is cylindrical in shape, and the pole pieces each have a flange of the same diameter as the holes in the wave-guide, the cooling plates immobilizing the one piece gyrator in the wave-guide.

Abstract: A flexible low-loss dielectric waveguide is made from a flexible low-dielectric constant hollow cylinder filled with high-dielectric constant powder. Alternatively, a rigid or semi-rigid waveguide comprises a groove formed in a low-dielectric constant substrate filled with high-dielectric constant powder.

Abstract: In a high power, high-frequency junction circulator which includes a cooled ferrite structure disposed in a microwave junction zone where it is subjected to a static magnetic field, the ferrite structure is composed of a plurality of stacked ferrite balls. A coolant flows around the balls to carry away heat.

Abstract: A rotation mechanism for a waveguide feeder is disclosed which is applicable to an antenna rotating section of a satellite tracking antenna system and others. The mechanism includes two flexible waveguides which extend parallel to each other. The flexible waveguides are connected at one end to each other and at the other end to an upper waveguide feeder and a lower waveguide feeder, respectively.

Abstract: A millimeter wave wideband circulator which employs a triangular ferrite prism with symmetrically grooved sides. The prism is configured to support a pair of closely-spaced higher order resonance mode sets which function to enlarge the bandwidth of the circulator and to suppress spurious mode resonances in the center and roll-off portions of the bandpass. The simplicity of the junction design combined with the non-critical alignment requirement of the ferrite prism makes practical the fabrication of a multi-junction millimeter wave circulator in a single integrated housing.

Abstract: A stripline circulator includes a pair of dielectrically supported ferrite discs and a pair of spaced hemispherical ferrite caps each one disposed over a corresponding one of the ferrite discs. The ferrite caps provide in combination with the ferrite discs a uniform DC magnetic field within the ferrite discs to reduce the insertion loss of the circulator at frequencies less than the so-called magnetization frequency of the ferrite material and thus, extend the operating bandwidth of the circulator. The ferrite caps are spaced from the ferrite discs by a thin layer of metallization having a thickness larger than the skin depth thickness of a microwave signal over the desired microwave frequency band. The ferrite discs are preferably comprised of signal crystalline ferrite materials oriented in a hard-axis orientation which generally is the [100] direction for materials where the first order anisotropic constant K.sub.1 is negative.

Abstract: A switchable dielectric waveguide circulator is provided for millimeter wave frequency applications comprising a ferrite right prism having two polygonal prism bases and at least three lateral prism faces. A control wire is threaded through a number of bores formed in the prism in a plane between the bases. Each of the bores is spaced a distance from a different one of the apices of the prism so that a control current passing through the control wire creates a circular magnetic field about each bore which combine to form a resultant magnetic field between the prism bases which cause the prism faces to act as circulator ports. The rotational direction of circulator coupling action is reversed by reversing the direction of the control current. Both Y-junction and T-junction circulator configurations are shown.

Abstract: A junction circulator for high power, high-frequency use employs cooled ferrite material disposed in the microwave junction zone where it is exposed to a static magnetic field. The cooled ferrite material is provided by a plurality of small ferrite particles which are suspended in a liquid coolant.

Abstract: A millimeter wave switchable microstrip Y-junction circulator is provided comprising a monlithic, wye-shaped ferrite element disposed on one surface of a section of microstrip dielectric substrate having three, Y-junction oriented sections of microstrip conductor on the same one substrate surface and an electrically conductive ground plane on the opposite substrate surface. The ferrite element has a central right prism-shaped portion with two equilateral triangular-shaped prism bases and three rectangular prism faces and three downwardly-sloping arm portions which extend radially outwardly from the prism faces of the central portion. The top base of the ferrite element central portion and the top surface of the ferrite arm portions which do not rest on the substrate are provided with microstrip conductors which cooperate with the ground plane to convey millimeter wave signals applied to the three Y-junction oriented microstrip sections on the substrate to the ferrite element central portion.

Abstract: A flexible waveguide (1) has corrugated seamless walls (2) the corrugations of which are inclined to the transverse planes of the waveguide, that is, planes perpendicular to the longitudinal axis of the waveguide, at an angle of substantially 45.degree.. The inclined corrugations, which may be annular or helical, permit both flexing and twisting of the waveguide.

Abstract: A "Spacercore" design is used to provide the cores of the electromagnets which are used to bias ferrite slabs in phase shifters of a high power RF attenuator. The phase shifters require a given flux to provide a phase shift from zero to 90.degree.. With laminations of high permeability silicon steel, the core weight may be substantially reduced by including a filler comprising spacers of non-magnetic material (such as lightweight transformer pressboard. With 14-mil silicon steel laminations and 64-mil spacers, this construction provides a core which weighs 25 percent of a full ferrite core for the same flux density.

Abstract: A ferromagnetic resonator comprises a nonmagnetic substrate, a ferrimagnetic thin film element formed on a major surface of the nonmagnetic substrate, a strip line for example formed on another major surface of the nonmagnetic substrate and electromagnetically coupled to the ferrimagnetic thin film element, a conductive wall facing the strip line and spaced therefrom a predetermined distance, an end of the strip line being connected by the conductive wall to ground potential and a bias magnetic field source applying a D.C. magnetic field to the ferrimagnetic thin film perpendicular to the major surface thereof. Such an arrangement enables a drastic reduction in the effective dielectric constant of the transmission lines, whereby a filter with a high center frequency of the order of at least ten gigahertz can be achieved despite the short type structure.

Abstract: A microwave ferrite circulator has a conductive junction with three equal angular conductors connected to serve as ports of the circulator. Ferrite plates are positioned on opposite sides of the conductive junction. Magnetic members form a magnetic coupling path between a permanent magnet and the ferrite plates. A bimetal strip is positioned in the magnetic coupling path between the magnet and the ferrite plates for altering the coupling as a function of temperature to thereby compensate for changes in tuning due to changes in temperatures of the circulator.

Abstract: A magnetically tuned resonant circuit having a resonant frequency which is substantially invariant with external applied static and dynamic stresses is provided. The magnetically tuned resonant circuit includes a housing which provides a magnetic flux return loop. A central post of the magnetically tuned resonant circuit includes a pair of pole pieces, upper and lower portions of the housing, a magnet and an RF structure. The RF structure including a pair of coupling loops and a YIG sphere disposed between the coupling loops is disposed between the pair of pole pieces. In a first embodiment, the elastic compliance of the center post portion of the magnetically tuned resonant circuit is increased by a predetermined amount by providing a nonmagnetic collar around a first one of the pole pieces disposed between said pole piece and the RF structure.

Abstract: A waveguide or waveguide phase shifter is terminated with a short circuit provided by a rigid conductive block which is sized to be a close tolerance fit within the waveguide. The block has grooves in its faces adjacent to the waveguide walls. The walls of the waveguide are deformed to project into these grooves to permanently secure the waveguide to the block.

Abstract: An electrically controlled radio frequency tuner used in conjunction with an antenna. The antenna used both as a transmitter and a receiver. The tuner eliminating waveform reflection and circulator feedthrough of transmitted signals which heretofore reflected back into the receiver creating a noise threshold that decreased the sensitivity of the receiver.

Abstract: A flexible waveguide for transmitting waves from a sensor mounted on a gimbal includes a cable comprising an outer flexible sheath and a plurality of flexible polytetrafluoroethylene fibers bundled within the sheath and including a termination flange coupled to at least one end thereof with the flange including a wedge-shaped plug and a tapered cavity engaging the end of the cable.

Abstract: A magnetically tuned resonant circuit for coupling r.f. energy between input and output coupling circuits thereof in a first mode of operation and isolating such energy between such coupling circuits in a second mode of operation includes a current path circuit provided to selectively change the resonant frequency of the magnetically tuned resonant circuit. In a first embodiment of the current path circuit, a microstrip transmission line used to form one of such coupling circuits, having a pair of planar spaced strip conductor portions adjacent a resonant body, is configured to provide the current path around such body. In the presence of an external magnetic field H.sub.DC, a pulse of current is fed around the current path and in response thereto provides a pulse magnetic field H.sub.DCp in the region of the resonant body. Such field H.sub.DCp either aids or opposes the external magnetic field H.sub.DC and in response thereto shifts a resonant frequency .omega..sub.

Abstract: The signal-to-noise enhancer can be used in frequency memory loops to prevent loop capture by noise. If a frequency selective limiter is incorporated in the loop, more than one signal can be stored simultaneously because the limiter prevents the loop amplifier from saturating. At present, the limiter must be a separate device. The frequency selective signal-to-noise enhancer/limiter apparatus comprises an enhancer apparatus and a limiter apparatus on a single substrate, using a single pair of magnets to bias both units.

Abstract: An electrically controlled radio frequency attenuator for electrically and magnetically controlling the attenuation transmitted power in a waveguide.

Abstract: An apparatus and method for selectively orientating a ferrimagnetic body along a selected temperature invariant crystallographic axis includes a first pair of coils disposed for producing a magnetic field along a first direction, and a second pair of coils disposed within the first pair of coils for producing a magnetic field along a second direction, the direction of such second field being displaced at a predetermined angle .theta., with respect to the direction of said first field. A platform upon which the ferrimagnetic body is supported is disposed at an intersection of such fields and has a surface disposed at a predetermined direction with respect to a horizontal plane. A series of alternate pulsed magnetic fields is generated in turn by each pair of coils and the body rotates in response to each one of such fields. After pulsed fields have been generated, the so-called "easy axis" of the crystallographic structure of the body is aligned with the axis of the coils.

Abstract: A phase-shifter apparatus which imposes a desired phase shift on an electromagnetic wave traveling through a waveguide, and divides the power in an output waveguide into two parts. The phase shifter apparatus includes a quarter-wave plate for changing the polarization of the linearly polarized wave to a circularly polarized wave, a rod of ferromagnetic material with a magnetic field for imposing a desired phase shift on the circularly polarized wave traveling through the rod, a quarter-wave plate for converting the circularly polarized wave to a linearly polarized wave, and a septum polarizer in the output wave guide for dividing the power. The output waveguide has the power divided between two ports, and independent phase shifts are imposed on the electromagnetic waves of each port.

Abstract: Resonators magnetically tunable over a broad rf frequency range capable of operation at relatively low rf frequencies (VHF band) are disclosed as well as tunable devices based on them. The resonators comprise a resonator body made of a ferrimagnetic single-crystal material which is generally flat, and is generally rotationally symmetrical with respect to an axis of rotation, for example disk-like or oblate spheroidal-like. The axis of rotation of the resonator body is oriented with respect to the crystalline lattice in a particular way depending on the anisotropy. The same orientation is required for the dc field whose magnitude determines the resonance frequency. The resonators are particularly useful in broadband tunable rf and microwave filters and oscillators, and can be tuned by means of the dc field to resonate from about 50 MHz to several GHz.

Abstract: A ferromagnetic resonator employing a disk of ferrimagnetic material is disclosed. The ferromagnetic resonator comprises a disk of ferrimagnetic material such as yttrium iron garnet (YIG) and a magnet applying D.C. magnetic field perpendicularly to a surface of the disk, and microstrip line applying RF magnetic field to the disk. The disk of ferrimagnetic material is processed to have a groove at a predetermined position on one surface of the disk, or to have a predetermined area in a central portion of the disk with a thickness smaller than that of peripheral portion of the disk, so that spurious response caused by magnetostatic mode other than the uniform mode is suppressed.