Abstract: A frequency selective limiting device is described incorporating a pair of generally planar ferrite members and a plurality of signal-carrying conductors positioned between the ferrite members. The plurality of signal-carrying conductors are located on a single YIG substrate. A D.C. bias field may be generated by a common magnetic source positioned on the surface of the substrate opposite the plurality of signal-carrying conductors.

Abstract: A lumped constant non-reciprocal circuit element includes an insulator substrate, a predetermined number of conductor layers formed on a top surface of the insulator substrate for forming electrostatic capacitors, a shielding conductor layer formed on a top surface of the insulator substrate, and a conductor layer formed on a bottom surface of the insulator substrate and electrically connected to the shielding conductor layer. A magnetic member is disposed on the shielding conductor layer formed on the insulator substrate, and a predetermined number of mutually insulated central conductors are disposed on the magnetic member such that one end of each central conductor is connected to the shielding conductor layer and the other portion of each central conductor is connected to each electrostatic capacitor-forming conductor layer. Also means are provided for applying a dc magnetic field to the magnetic member.

Abstract: A frequency selective limiting device is described incorporating a planar ferrite member and at least one signal-carrying conductor positioned thereon. A conductor is located on the ferrite member to confine a portion of an RF magnetic field produced by the microwave signals within the ferrite member. In one embodiment of the invention, the conductor comprises coplanar ground planes positioned adjacent to the signal-carrying conductor, thereby forming a coplanar waveguide. Alternatively a pair of coplanar conductors may form a slot line. In another embodiment a second ferrite member is positioned in confronting relationship with the first ferrite member carrying the conductors.

Abstract: A plurality of frequency selective limiting units are prepared on a common substrate. A plurality of generally linear signal carrying conductors are formed in spaced relation on a first ferrite member, the opposite side of which contains a lower ground plane. A second ferrite member is bonded to the first ferrite member with a nonconductive adhesive to form a layered structure. Grooves are formed in a free surface of the structure to a depth sufficient to cut through the first and second ferrite members and to expose the lower ground plane. The structure is metallized in a conformal manner so that the metallization is in contact with the lower ground plane. The units are separated by dicing to thereby provide a plurality of individual FSL's.

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: A resonance absorption-type microstrip line isolator including a ground conductor; a magnetic member provided on the ground conductor; and a central conductor provided on the magnetic member, portions of the magnetic member on both sides of the central conductor being magnetized oppositely. The magnetic member may be replaced by a composite member constituted by at least two magnetic members and at least one nonmagnetic dielectric member. Further, to achieve the miniaturization of the isolator, the central conductor may be in a meandering shape.

Abstract: A fabricated dielectric aperture assembly includes a first layer of electrically conductive material having an opening therethrough to define a first aperture, a second layer of electrically conductive material spaced from the first electrically conductive layer and having an opening therethrough to define a second aperture and a plurality of solid dielectric layers interposed between the first and second layers of electrically conductive material. The first and second layers of electrically conductive material with the multiple layers of dielectric material interposed therebetween form a generally laminar assembly. A grid-like structure is embedded in the laminar assembly and extends between the first and second electrically conductive layers. The grid-like structure has an inner wall, an outer wall portion, an interior bounded by the inner wall and a plurality of openings extending from the inner wall to the outer wall.

Abstract: An insert for non-reciprocal waveguide device comprises a layer of ferrite and a layer of energy absorbing material with a spacer layer between them. The device works by reason of asymmetrical interaction of the microwave energy and the ferrite whereby energy is preferentially absorbed in the reverse direction. The spacer layer affects the distribution of electromagnetic fields so that there is a relatively low attenuation associated with one direction and a relatively high attenuation associated with the reverse direction.

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 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 miniature circulator which is microwave integrated circuit compatible and based on microstrip transmission techniques is described. The circulator includes a dielectric or semiconductor substrate having microstrip transmission lines formed thereon and a patterned metalization formed as the node metalization for the circulator. The substrate may carry other circuits such as power combiners, amplifiers, and switches. The substrate further includes monolithic capacitors over the substrate at the center of the circulator in a first embodiment or disposed along the periphery of the patterned metalization in the second embodiment. The capacitors are used to capacitively couple the patterned metalization or node metalization to the ground plane conductor. The value of capacitance is selected to provide value broadband performance.

Abstract: By combining four hexagonal ferrite spheres under the same electromagnet structure, a magnetically tuneable bandpass filter can be built in waveguide yielding high off resonance isolation, while keeping insertion loss to a reasonable value. Implementations of this filter in A, Q, U, and V bands have typical off resonance isolation greater than 70 dB and insertion loss less than 13 dB for full-band tuning. The filter can be utilized as a preselector for swept-frequency signal analyzers, for example.

Abstract: A semiconductor device useable as an electromagnetic isolator. The device has a semiconductor substrate epitaxial with a layer of metal, the latter deposited so as to generate a residual magnetic flux. A waveguiding structure is disposed transverse to the flux effective to cause electromagnetic signals propagating in the waveguiding structure to be attenuated a different amount depending on the direction of propagation. The waveguiding structure is preferably a seminconductor layer deposited epitaxially with the substrate in a channel in the metal.

Abstract: A frequency selective limiting device is described incorporating a plurality of individual attenuating units spaced apart from one another in substantially parallel relation and positioned between a pair of ground planes. Each individual attenuating unit is interposed between a pair of magnetic strips. In one embodiment of the invention, each individual attenuating unit includes a microstrip conductor positioned between a dielectric substrate layer and a layer of ferrite material. In an alternate embodiment of the invention, each individual attenuating unit includes a microstrip conductor positioned between a pair of planar ferrite members, the pair of ferrite members and microstrip conductor being mechanically supported by a dielectrical substrate layer. In both embodiments of the invention, adjacent attenuating units are serially connected by microstrip jumpers to provide a flow path for microwave signals passed through the limiting device.

Abstract: Means are provided for radiating electromagnetic waves from a receiving end zone of a dielectric line for transmitting electromagnetic waves without the need for a metal horn antenna or a metal waveguide, and matching problems are thereby substantially avoided. Said means are provided by shaping the end of the line to specified contours, by varying the dielectric constant of the material of the line in a gradient longitudinally near the end zone of the line, and by arranging a reflecting mirror or lens to receive the waves emitted from the line. This waveguide is useful in wireless communications, radar transmission and similar applications.

Abstract: A lumped constant non-reciprocal circuit element such as a circulator or an isolator comprising a set of mutually insulated central conductors, a garnet plate not more than 0.6 mm in thickness, a ceramic substrate having a central bore for accommodating the garnet plate and patterned electrodes formed thereon, and a permanent magnet for applying a DC magnetic field to the garnet plate. Because of this structure, this circuit element is very thin with good insertion loss properties.

Abstract: A microstrip resonance isolator is provided comprising a dielectric waveguide element which is mounted on the top surface of a length of microstrip transmission line dielectric substrate having an electrically conductive ground plane on the bottom surface of the substrate. The waveguide element has a rectangular rod-shaped central section and two oppositely-inclined ramp-shaped sections at the ends of the central section. The dielectric constant of the waveguide element is substantially more than the dielectric constant of the microstrip transmission substrate. A microstrip conductor is provided on the top surface of the substrate from one end thereof to the other end thereof and passes over the top surface of the dielectric waveguide element. A thin, rectangular substrate of hexagonal, grain-oriented ferrite material is mounted on one side of the waveguide element between the ramp-shaped end sections.

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: A microstrip resonator (311) for a circulator/isolator is disclosed employing radial (815, 817, and 819) and circumferential (821, 823, and 825) slots to load the resonator and reduce the frequency of resonance. A resonator of small physical size is thus formed having a discontinuous outer ring (segments 807, 809, and 811) and a central triangle portion (827) each electromagnetically coupled to a ferrite element.

Abstract: A miniaturized and integrated gyromagnetic device in which a center conductor is mounted between a pair of dielectric wafers and ferrite conductors to define a circular inner configuration. A pressure washer is welded to a square casing and mounts a magnet, the wafers, ferrite conductors and a pair of ground plates to absorb thermal expansion during operation.

Abstract: A fin-line resonance isolator has layers of hexagonal ferrite material that are stacked relative to one another so that the overall length of the isolator remains substantially constant as the number of layers of ferrite material increases. The isolator has substrate materials that are arranged so that the plane of circular polarization is shifted to a center of the isolator. Isolators of the present invention are capable of producing improved responses over prior art isolators while reducing insertion loss and achieving a weight and volume saving.

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 nonreciprocal microwave device for surface electromagnetic waves (SEW waves) as applicable to isolators which provide high isolation comprises a flat metallic core, part of which is placed between two plates of gyromagnetic material and part of which is placed between two absorption loads. Parasitic volume waves are generated by resonance but resonance of waves of higher modes is prevented by forming in the core at least one zone for strong coupling with the SEW waves which propagate in the direction opposite to the low-loss direction at the edge of the core opposite to the edge at which the SEW wave propagates in the forward direction.

Abstract: A transmission line comprising a multi-layer dielectric slab structure including: a dielectric substrate layer (30) having a thickness d.sub.s and permittivity .epsilon..sub.s ; a conductive ground plane (31) on the bottom surface of the dielectric substrate layer (30); a dielectric guiding layer (32) having a thickness h and permittivity .epsilon..sub.g, where .epsilon..sub.g >.epsilon..sub.s, attached to the top surface of dielectric substrate layer (30); at least one elongated and relatively narrow dielectric loading strip layer (33) having a width W, thickness d.sub.1, and permittivity .epsilon..sub.1, where .epsilon..sub.g >.epsilon..sub.1, attached to the top surface of the dielectric guiding layer (32); and a conductive coating (34) on the top surface of the dielectric loading strip layer (32). Such a structure permits single mode propagation over a relatively wide band.

Abstract: A transmission line comprising a multi-layer dielectric slab structure including: a dielectric substrate layer (30) having a thickness d.sub.s and permittivity .epsilon..sub.s ; a conductive ground plane (31) on the bottom surface of the dielectric substrate layer (30); a dielectric guiding layer (32) having a thickness h and permittivity .epsilon..sub.g, where .epsilon..sub.g >.epsilon..sub.s, attached to the top surface of dielectric substrate layer (30); at least one elongated and relatively narrow dielectric loading strip layer (33) having a width W, thickness d.sub.1, and permittivity .epsilon..sub.1, where .epsilon..sub.g >.epsilon..sub.1, attached to the top surface of the dielectric guiding layer (32); and a conductive coating (34) on the top surface of the dielectric loading strip layer (32). Such a structure permits single mode propagation over a relatively wide band.

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

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

Abstract: A waveguide having reduced windloading yet a relatively wide bandwidth for the dominant mode of propagation comprises an elongated cylinder having substantially parallel plates forming an interior waveguide portion which in cross-section is a doubly-truncated circle. The plates are symmetrically disposed about the central axis of the elongated cylinder.

Abstract: A signal termination device is illustrated using planar circuit technology for providing both broadband capabilities from DC to over ten gigahertz while maintaining small size and high power dissipation capabilities. This is accomplished by plating a series cascade of resistors and transmission lines such that the sum of the resistors is equal to the desired termination impedance and the impedance of the interconnecting transmission lines is equal to the sum of the remaining resistors between that point and ground. The use of the intervening transmission lines enhances the power handling capability of the resistor elements and enhances uniform power densities in the resistor elements.

Abstract: Method for the controlled suppression of magnetostatic waves within magnetic garnet films for microwave circuit applications, based upon the adoption of multilayer structures of epitaxial garnet films of low magnetic losses and high magnetic losses.

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

Abstract: A coaxial microwave load for a ferrite isolator formed by a three-plate three-port type junction circulator comprising an assembly including by a body of conductive material, a rod of insulating material which is covered with a layer of resistive material, and a washer of insulating material. The assembly is placed in a mounting block of conductive material having an axial bore to receive the assembly and the mounting block is covered with a layer of insulating material whereby the load is electrically insulated.

Abstract: A dielectric waveguide ferrite resonance isolator capable of operating in e millimeter wave frequency range in a dielectric waveguide transmission line in which a thin rectangular hexagonal ferrite material is affixed to a side of the dielectric waveguide and then placed between the pole pieces of an electromagnet in order to magnitize and fully orient the ferrite material is improved by positioning a grooved block of dielectric having a low dielectric constant and high thermal conductivity against the face of the hexagonal ferrite so as to use the high thermal conductivity dielectric as a heat sink thereby extracting heat from the hexagonal ferrite.

Abstract: A transmission line is provided, at least a portion of the wave energy transmitting part of the line being made of a dielectric material shaped to create a physical condition which preserves the deflected wave surface of the electromagnetic wave along the portion of the transmission line. The physical condition for preserving the deflected wave surface is formed by providing at least one linear portion which retards the speed of energy transmission so as to prevent the rotation of the electric field surface of the electromagnetic wave. The wave energy transmitting portion composed of dielectric material is preferably made to have an oval cross-section in which the ratio between the major axis and the minor axis has a value not lower than 4/3. Alternatively, the wave energy transmitting portion can be made to have a rectangular cross-section.

Abstract: A continuous strip of coiled material is provided with protrusions, such as barbs, which are oriented to eliminate mutual interference when the coiled material is stacked in a compact, collapsed nested condition and wherein each turn of the coil is permanently fixed at equiangularly spaced multiple points alternately to its adjacent trailing and leading turns of the coil. An intrusion detection system signals intrusion into the space encompassed by the above mentioned coil and features a microwave energy source, receiver and detector for indicating a reduction in received microwave energy at the receiver indicative of intrusion into or other disruption of the energy guided path determined by the coil.

Abstract: A dielectric waveguide ferrite resonance isolator capable of operating in the millimeter frequency range in a dielectric waveguide transmission line is provided. The isolator comprises a thin sheet of hexagonal ferrite material that has been affixed to a side of the dielectric waveguide and then placed between the pole pieces of an electromagnet in order to magnetize and fully orient the ferrite material.

Abstract: A low loss leakage transmission line including a cylindrical dielectric tube the wall thickness d.sub.2 of which is selected to satisfy ##EQU1## where .epsilon..sub.1 is the dielectric constant of the internal space within the tube, .epsilon..sub.2 is the dielectric constant of the material which forms the tube, and n is a positive odd integer. A loss layer may be disposed around the cylindrical dielectric tube to capture any lost wave energy. In one embodiment, a plurality of cylindrical dielectric tubes of different dielectric constants are coaxially arranged with the wall thickness of each of the tubes satisfying the above formula.

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

Abstract: An isolator is described for use in a low-noise maser amplifier, which provides low loss across a wide bandwidth and which can be constructed at moderate cost. The isolator (40) includes a train of garnet or ferrite elements (50, 52) extending along the length of a microwave channel (14) parallel to the slow-wave structure (24), with the elements being of staggered height, so that the thin elements (50) which are resonant to the microwaves are separated by much thicker elements (52). The thick garnet or ferrite elements reduce the magnetic flux passing through the thin elements (50), to permit altering of the shape of the thin elements so as to facilitate their fabrication and to provide better isolation with reduced loss, by increasing the thickness (T) of the thin elements and decreasing their length (L) and width (W).

Abstract: A multi-port microwave device, such as an isolator or circulator, for transmission of electromagnetic energy in TEM and higher order modes non-reciprocally between parts. The device exhibits low insertion loss, high return loss (low VSWR) and high isolation and is operable over a 100 percent or more bandwidth. The microwave device includes a composite ferrite body between a circuit conductor and a ground plane. The composite ferrite body includes ferrite material having a saturation magnetization gradient for providing different frequency characteristics over the frequency pass band of the device.

Abstract: An improved transmission line or waveguide that can tolerate damage from ordnance fragments without severe degradation of performance. Ordnance fragment penetration into a waveguide tends to produce jagged inward protrusions or loose metal chips of the type which can cause arc-over and high standing wave ratios. The present invention provides a transmission line or waveguide made of a brittle nonconductive material such as plastic or composite material which is coated on the surfaces bordering the interior volume with a solder, conductive paint, or other conductive material. Thus, any penetration of the waveguide will leave a clean hole without jagged protrusions which could precipitate arcing and degrade the waveguide VSWR. An alternative embodiment comprises the construction of the waveguide walls from a brittle conductive material which would leave a clean hole after penetration.

Abstract: The polarizer with a circular waveguide in the inner wall of which are formed identical circular corrugations positioned in a plane perpendicular to the longitudinal axis XX of the guide. The corrugations have four quadrants: a first pair of quadrants opposed by the apex in which the depth of the corrugations is less than in the second pair. By positioning the waveguide in such a way that the incident field E is parallel to the limit between two adjacent quadrants, the phase velocity of the orthogonal components C.sub.1, C.sub.2 of field E is dependent respectively on the admittance of the quadrants of the first pair and the quadrants of the second pair. This leads to a phase difference at the polarizer outlet and the corrugations are defined so that this difference is substantially 90.degree..

Abstract: Millimeter wave transmission lines are disclosed for propagating electromagnetic waves of a wavelength ranging from about 10 mm to about 0.4 mm. The transmission lines comprise a fiber of co-crystallized thallium bromo-iodide consisting of from about 40 mole percent to about 46 mole percent thallium bromide and from about 60 mole percent to about 54 mole percent thallium iodide. The fiber may be cladded with a dielectric material having a dielectric constant less than that of the fiber. A number of alternate fiber and cladding cross-sectional configurations are disclosed including circular, square, rectangular, and elliptical.

Abstract: A resonance isolator in which microwave ferrite bars are positioned in and in contact with a waveguide to achieve unilateral absorption and in which ceramic permanent magnet bars are positioned on the outside of the waveguide adjacent to the ferrite bars and are insulated by a thin sheet of thermally insulating material that also acts as a spacer to adjust the magnetic field. The waveguide may be made with nonmagnetic sheet metal and the ferrite bars may be used as extruded. The isolator is adapted to connect between a microwave generator, such as a magnetron, and a microwave load, such as a heating chamber, and forms an integral feed unit. The isolator effectively reduces the peaks of the standing wave caused by the power reflected by a load and protects the generator against premature degradation and extends its useful life time.

Abstract: A magnetostatic wave device having a microstrip transmission line in conjunction with a YIG thin film biased for magnetostatic wave operation at a level where relatively lower power input microwave signals are highly attenuated up to a critical point past which the relative attenuation is greatly reduced. Such devices may be utilized as signal-to-noise enhancers in microwave circuits such as frequency memory loops.

Abstract: A doppler detector for measuring the speed and/or the direction of a moving body utilizing the principle of the doppler effect that the reflected frequency from a moving body is slightly changed has been found. The present doppler detector comprises a rectangular waveguide inserted between a microwave oscillator and an antenna, an elongated ferri-magnetic body inserted between a pair of H planes of said waveguide, and said body being magnetized in the axial direction of the same, and a pair of diodes each inserted between H planes of said waveguide so that the first diode being symmetrical with the second diode concerning the lateral plane including the center axis of said ferri-magnetic body.

Abstract: The present invention relates to a hybrid mode waveguide or feedhorn antenna for transforming the TE.sub.11 mode into the HE.sub.11 mode. The waveguide or antenna comprises a first waveguide section of uniform cross-section at the TE.sub.11 mode entrance port which in the antenna arrangement changes to a second section which flares outward toward the antenna mouth, and a spiro-helical projection bonded with a dielectric layer to the inner surface of the waveguide or antenna. The spiro-helical projection comprises a closely spaced helically wound wire structure formed of dielectrically coated wires which in the first section decrease in gauge size in small adjacent portions thereof as the helix progresses away from the TE.sub.11 mode entrance port and in the remainder of the helical projection, the same or decreasing gauge wire in adjacent portions can be used.

Abstract: A helical circular wave guide which reduces loss around curves. It includes contiguous turns of copper wire coated with a thermoplastic material, said helical turns being surrounded by a first tube made of aluminium in contact with the helix and by a second tube made of steel held centered in relation to said first tube by supports made of plastic material.

Abstract: The invention relates to mode filters for millimetric waves. The mode filter provided includes a circularly sectioned waveguide divided into a number of equal sectorial channels. Dielectric mode perturbing material is provided in all but one of the channels. This material extends in the direction of the H-field so as not to interfere with a wanted mode of a propagated signal but to perturb the current lines of an unwanted TE.sub.On mode so that an -unwanted TE.sub.On mode in the channel containing the dielectric material undergoes a .pi.radian phase shift relative to the TE.sub.On mode in the remaining channel which remaining channel has a conductive sectorial ridge of the same cross section as the sectorial channels and extending in the direction of the H-field the ridge being of such a radius that differential phase shifts produced by the perturbation effect of the mode perturbing material of the wanted mode cut-off frequency are substantially reduced.

Abstract: A microwave circulator comprising a substrate having a resonator affixed to one side thereof and a ferrite element affixed to the other. The side of the substrate to which the ferrite element is secured is covered with metal on the surface surrounding the ferrite element and is electrically and mechanically coupled to a metallized coating on the periphery of the ferrite element. The surface of the ferrite element projecting from the substrate is also metallized.