Abstract: Dispersive properties of a linear dispersive delay line are retained in a spiral configuration by constraining the radius of curvature depending on a desired propagation mode. The compact form factor spiral can be either a continuous spiral or a piecewise linear approximation. The spiral comprises a highly dielectric waveguide such as titanium dioxide or barium tetratitanate. Preferably, a spacer with a low dielectric constant and a microstrip are disposed on the top surface. The microstrip prevents attenuation of low frequencies, thereby increasing the operating frequency range. A second dielectric spacer and a second microstrip can be deposited on the bottom surface of the waveguide. Alternatively, the bottom surface of the waveguide can face a ground plane. The waveguide can be fed by horns or half-horns.

Abstract: A selective frequency limiter having a magnetic material and a slow wave structure disposed to magnetically couple a magnetic field, produced by electromagnetic energy propagating through the slow wave structure, into the magnetic material.

Abstract: A delay line structure includes a flat spiral delay line and two grounding guard traces. The flat spiral delay line is disposed in the layout layer in a manner of extending from an input end, bending clockwise inward until reaching a U-turn part, continuously extending and bending counterclockwise outward to an out put end so as to form two coupling areas, which are spiral and have an opening respectively. The two grounding guard traces are disposed in the layout layer in a manner of extending from the openings respectively toward the coupling areas, having an interval between the grounding guard traces and the flat spiral delay line, wherein the grounding guard traces close to the openings of the coupling areas are electrically connected to the grounding circuit through a via respectively.

Abstract: Compact electro-mechanical impedance tuners for frequencies as low as 1 MHz use the concept of a cylindrical transmission line with the signal conductor being a spiral wire wound around a metallic cylinder and separated from it by a layer of dielectric material. A conductive wheel is running over the spiral wire and, as the cylinder rotates, the transmission phase between one terminal of the spiral wire and the wheel changes. By connecting a rotating parallel plate variable capacitor to the wheel creates an impedance tuner, capable of generating high reflection factors at very low frequencies at any area of the Smith chart. By cascading two or more such tuners allows tuning at harmonic frequencies at the rate of one frequency per tuner section. The reduction in size comparing with traditional transmission line tuners is of the order of 150:1.

Abstract: An electro-mechanical impedance tuner generates wideband and complete Smith chart reflection factor coverage at frequencies as low as 1 MHz. It comprises an in-line adjustable linear phase shifter and a variable capacitor connected in parallel to ground. The transmission line, which serves as an adjustable phase shifter of variable electrical length, is made as a cylindrical rotating spiral wire-over-ground transmission line, on which runs a sliding contact, connected with a variable capacitor; the capacitor can be, depending on the frequency, immersed in a dielectric liquid, such as oil (?r?3) or alcohol (?r?20) for increased capacitance. The cylindrical structure of the spiral transmission line allows for a compact, 1 meter long apparatus at 1 MHz, whereas the required linear electrical length for this type of impedance tuner would be 150 meters in air, or 100 meters when low cost polyethylene dielectric (?r?2.25) is used. Cascading two or more tuners allows pre-matching and harmonic tuning.

Abstract: The present invention provides a helical slow-wave structure, including a helix, a metal barrel and several supporting rods. The plurality of supporting rods may be inserted into the lines of the grooves tightly, this increases the contact area between the helix and the plurality of supporting rods. With a proper assembly method, the thermal contact resistance between helix and supporting rod may be decreased. So, the invention may enhance the capability of transferring the heat out of the helical slow-wave structure. The helix may have higher heat capacity, therefore, the helical slow-wave structure may become more firm, and more reliable.

Abstract: A printed solenoid inductor delay line system comprises discrete delay sections, where the inductor is implemented in the form of a printed, spiraling solenoid, with the solenoid axis in the plane of the multi-layer printed circuit board (PCB).

Abstract: An on-chip slow-wave structure that uses multiple parallel signal paths with grounded capacitance structures, method of manufacturing and design structure thereof is provided. The slow wave structure includes a plurality of conductor signal paths arranged in a substantial parallel arrangement. The structure further includes a first grounded capacitance line or lines positioned below the plurality of conductor signal paths and arranged substantially orthogonal to the plurality of conductor signal paths. A second grounded capacitance line or lines is positioned above the plurality of conductor signal paths and arranged substantially orthogonal to the plurality of conductor signal paths. A grounded plane grounds the first and second grounded capacitance line or lines.

Abstract: An improved E-field generator including a slow-wave transmission line structure is provided herein. In some cases, the improved E-field generator may include an inductively-loaded slow-wave transmission line structure driven by a power source at one end of the structure and terminated by a load at the other end of the structure. In other cases, the improved E-field generator may include a capacitively-loaded slow-wave transmission line structure. In either case, the improved E-field generator provides a frequency-independent, significantly increased electric field at a distance spaced from the generator without altering the dimensions of the generator and/or the input power supplied to the generator. The increase in generated field intensity is achieved by decreasing the phase velocity of the electromagnetic wave propagating along the parallel elements of the generator.

Abstract: A printed circuit board (PCB) including a notch filter, or other suitable filter, is implemented in a communication device for attenuating RFI in transmissions sent from the communication device. The filter includes filter line that runs between at least two conductor layers on the PCB, in a substantially repeating pattern, which maximizes the space available on each conductor layer for additional uses.

Abstract: A high performance single-pole-double-throw (SPDT) Transmitter/Receiver (T/R) FET switch utilizes a plurality of multi-gate FETs in series to realize low insertion loss, low harmonic distortion and high power handling capabilities. The SPDT switch consists of an antenna port, a transmitter branch coupled to a transmitter port through a plurality of multi-gate FETs in series and a receiver branch coupled to a receiver port through a plurality of multi-gate FETs in series. When a high power signal passes from the transmitter port to the antenna port through the transmitter branch, the receiver branch is required to be shut off electrically to prevent the high power signal from leaking to receiver port. This leakage can degrade the isolation of the switch and cause harmonic distortion. Furthermore, the transmitter branch is required to provide a resistance as small as possible to reduce the power loss when it passes through the transmitter branch to the antenna port.

Abstract: A compact, small-size delay line that has excellent flatness in group delay time characteristic and an excellent frequency characteristic, is constructed such that one coil is divided into four inductors, and four stages of LC-&pgr; type low pass filters including inductors and capacitors are contained within a laminated body. The inductors are defined by connecting together in series coil conductor patterns arranged in a matrix on insulating sheets provided in the laminated body. Mutually adjacent inductors are arranged so that their coiling directions are opposite to each other. The insulating sheets may be made of non-magnetic material having a dielectric constant of about 15 or lower.

Abstract: A phase shifter includes upper and lower conductive plates, and a dielectric strip sandwiched between the conductive plates, and a plurality of slots formed in the upper conductive plate, thereby forming a dielectric line. A rotator is positioned at either side of the dielectric strip so that the distance from the rotator to the dielectric strip varies as the rotator rotates. As the rotator rotates, the phase constant of the dielectric line progressively changes in the direction of electromagnetic propagation. The rotation of the rotator causes a change in feed phase with respect to the slots as the rotator rotates, thereby performing beam scanning.

Abstract: A high power ferrite microwave phase shifter that is both compact and low cost. The ferrite phase shifter includes a waveguide having a first cylinder and a second cylinder, the radius of the second cylinder being less than the radius of the first cylinder. The second cylinder is disposed within the first cylinder such that the two cylinders have a common axis of symmetry. The waveguide includes a first septum formed as a disk and disposed within the second cylinder. The disk has a pie-shaped aperture formed therethrough and is centrally disposed within the second cylinder so that the two cylinders and the disk share the same axis of symmetry. The second cylinder has an opening formed therethrough that is aligned with the pie-shaped aperture. The waveguide further includes a second septum that extends from the first cylinder to the disk center while bisecting the pie-shaped aperture, thereby separating an input from an output of the ferrite phase shifter.

Abstract: A method for constructing thermally and dimensionally stable traveling wave tube circuits having high dimensional stability, narrow tolerances, and very small size by providing a small hollow preform constructed of a desired material which is coated with a layer of photoresist material then exposed to a UV laser to form a desired pattern mask in the photoresist layer. The pattern masked preform is then etched to create a preform having a desired shape. After shaping, the photoresist coating is stripped from said shaped preform to form a traveling wave tube circuit. Optionally the travel wave tube circuit may be polished.

Abstract: A low-loss, phase stable, microwave transverse electromagnetic delay line having an increased lifetime and a reduced cost of manufacture. The microwave delay line includes a TEM transmission line having a central conductor, a dielectric material covering the length of the central conductor, and a solid outer conductor on which the dielectric-covered central conductor is wound. The outer conductor includes at least one guide formed on a surface thereof into which the dielectric-covered central conductor is disposed. The microwave delay line further includes two microwave connectors mounted at respective ends of the outer conductor and operatively coupled to corresponding ends of the central and outer conductors, and a metal cover configured to enclose the microwave delay line to prevent signal leakage and protect the microwave delay line from environmental damage.

Abstract: A meander line includes a electrically conductive plate, a plurality of transmission line sections supported with respect to the conductive plate, wherein the plurality of sections includes a first section located relatively closer and parallel to the conductive plate to have a relatively lower characteristic impedance with the conductive plate and a second section located parallel to and at a relatively greater distance from the conductive plate than the first section to have a relatively higher characteristic impedance with the conductive plate, and connector means for interconnecting the first and second sections and maintaining an impedance mismatch therebetween.

Abstract: A multilayer ceramic package 200 with a center ground via 202 for size reduction is disclosed. Package 200 includes dielectric layers 204A-204G each having a major surface 206. The package also includes an input electrode 208 and an output electrode 210 as well as a top ground plane 212 and a bottom ground plane 214. Package 200 includes a substantially spiral transmission line structure made from electrodes 216. Package 200 also includes a ground via 202 extending vertically through the plurality of dielectric layers 204A-204G. The center ground via 202 is substantially centered inside the substantially spiral transmission line structure and electrically isolated therefrom and connected to the top ground plane 212 and the bottom ground plane 214.

Abstract: An electrical delay line is described. Said line is free from early or late arriving false signals of sufficient amplitude to trigger subsequent stages in the circuitry. This has been accomplished through use of a novel approach to designing the delay line. Said approach is described and data is given comparing conventional delay lines with the present invention.

Abstract: A transmission line device (200) employs a first ground plane (118) that is disposed on a first dielectric substrate (202). A first conductive layer (210) that encloses a first area (213)is disposed on a second dielectric substrate (206), which substrate is positioned substantially adjacent to the first dielectric substrate (202). A second conductive layer (211) that encloses an area corresponding to the first area (213) is disposed on a third dielectric substrate (207), which substrate is positioned substantially adjacent to the second dielectric substrate (206). A coil structure is thereby provided that can be employed in the fabrication of a transmission line device, according to the invention.

Abstract: An electrical circuit (500) includes an input means (503) for providing an input signal, an output means for providing an output signal, and a transmission line device (421) disposed substantially between the input means (503) and the output means. The transmission line device inludes a first ground plane (505) disposed on a first dielectric substrate (502), and a first conductive layer (421-1) disposed, and enclosing a first area, on a second dielectric substrate (506) that is positioned substantially adjacent to the first dielectric substrate (502). The transmission line device (421) further includes a second conductive layer (421-2) that encloses an area corresponding to the first area on a first major surface of a third dielectric substrate (504) that is positioned substantially adjacent to the second dielectric substrate (506).

Abstract: A miniaturized cylindrical `channeline` delay line comprises a plurality of concentrically stacked cylindrical elements, surfaces of which are configured to form helically contoured `channeline` transmission line. The nested stack includes a first, generally cylindrical conductive spool body element, for example a lightweight and electrically conductive cylinder or spool, having a longitudinal axis and an outer, generally cylindrical surface in which a helical groove is formed. Concentrically surrounding this interior spool are one or more additional, generally cylindrical hollow electrically conductive hollow cylinders of successively increasing diameters. These additional electrically conductive hollow cylinders are sized, so that respective ones of the cylinders may be concentrically stacked about the longitudinal axis of the interior spool. Like the interior spool, each surrounding cylinder has a helical groove formed in its outer cylindrical surface.

Abstract: A traveling-wave tube, wherein the wire helix of prior art devices is replaced by a digital helix formed within a composite structure of thick or thin film substrates. The traveling-wave tube helix is formed from multiple substrate layers, each having conductive segments surrounded by insulating material. The superimposing of the substrate layers causes conductive segments from adjacent layers to partially overlap and form a continuous slow-wave structure between an input lead and an output lead, that mimics a traditional wire helix. The composite structure creation of the traveling-wave tube helix allows traveling-wave tubes to be miniaturized and increased in efficiency to point previously unachievable by traditional wire helix devices.

Abstract: The helix (10) of a slow-wave structure of a traveling wave tube is supported by a number of spaced dielectric blocks (34, 36) that are carried by a helical ribbon (26) in registry with the helix (10) itself. Registration of the ribbon (26) and its blocks (34, 36) with the helix structure (10) is facilitated by first winding a guide wire (40) in the spaces (16) between successive turns of the helix (10), to extend into and protrude radially outwardly from the spaces (16). After use of the guide wire (40) to align the ribbon-supported dielectric blocks (34, 36), the guide wire (40) is removed and the assembly of helix (10), blocks (34, 36) and supporting ribbon (26) is secured in its tubular envelope (20) by brazing, coining or heat-shrinking.

Abstract: Disclosed is a travelling-wave tube with helix. The helix is mounted in a metal sleeve and is held in a centered position by at least three dielectric rods. Parts of the helix are in contact with the rods. The helix is made out of a thin strip of a metal that is a good conductor of heat and electricity. Instead of having a rectangular cross-section, the thin strip now has a T-shaped cross-section, at least at all the parts of the helix that are in contact with the rods. The base of the T is brazed to the rods. This structure prevents the risk of electric arcs at the facing brazing beads on two consecutive turns of the helix. The disclosure can be applied to travelling-wave tubes operating in wide bandwidth and at high peak power and/or mean power values.

Abstract: A transmission delay line including a helical channel (2) formed in the surface of a cylinder (1), with a conductive sleeve (7) fitted to the cylinder to close the channel. A helical conductive member (4) is positioned within the channel (2) and spaced from the walls thereof by a dielectric material (5, 9).

Abstract: A latching type of microstrip reciprocal phase shifter is provided having a oroidal-shaped ferrite core with a length of microstrip conductor wound about the outer cylindrical surface of the core and a ground plane mounted on the inner cylindrical surface of the core surrounding the aperture in the core. A single control wire is passed through the aperture in the core and creates a circular magnetic field in the core surrounding the aperture when the core is pulsed with a unidirectional current pulse.

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

Abstract: A delay line is provided for effecting a desired delay in the transmission of electromagnetic waves in the microwave and millimeter range of the spectrum. The line comprises a length L of a dielectric waveguide for transmission of electromagnetic waves comprising a core of polytetrafluoroethylene having one or more layers of polytetrafluoroethylene overwrapped around the core, wherein T=KL/c, in which T is the total time delay , c is the velocity of light in free space and K is the delay constant of the dielectric waveguide. Preferably, the delay line is overwrapped around a mandrel.

Abstract: This distributed constant type electromagnetic delay line has an elongated bobbin which includes, laminated together, a substantially rectangular dielectric layer and a substantially rectangular ground plane, and further includes an electroconductive strip, constituted by a single layer solenoid fixedly secured to the bobbin by its outer surface. As a variation, this distributed constant type electromagnetic delay line may have an elongated bobbin which includes, laminated together: a first substantially rectangular dielectric layer; a second substantially rectangular dielectric layer; and a substantially rectangular ground plane sandwiched between the first and second dielectric layers; and may further include an electroconductive strip, constituted by a single layer solenoid fixedly secured to the bobbin and wound in a spaced manner around the outer surface of the bobbin confronting the ground plane.

Abstract: A substrate is disclosed with a shielded delay line imbedded therein to obtain a delay of a preselected duration. The delay line comprises a conductor formed in the shape of a helical coil to reduce its overall dimension. The substrate is formed by superimposing a plurality of layers of conductive and/or dielectric material to form a preselected profile.

Abstract: A variable delay line is disclosed which comprises an electromagnetic delay line formed of an inductance element and capacitors, a conductive plate disposed along the electromagnetic delay line and opposed thereto, and a movable contact adapted to move along the delay line while remaining in continuous contact with the conductive plate and the inductance element. The variable delay line has its delay characteristics improved by bending the aforementioned conductive plate in such a manner that it is separated from the delay line along the contact parts exposed to contact with the movable contact and, as a result, the stray capacitance formed between the delay line and the conductive plate is kept down to a negligibly small level.

Abstract: A tubular ring-bar slow wave structure is provided. The structure includes a plurality of axially spaced, coaxially aligned, generally parallel metallic rings connected by a plurality of generally axially parallel, alternately spaced metallic bars. The structure also includes a plurality of axially spaced, coaxially aligned, generally parallel dielectric support rings, each of which has a width that is narrower than the width of a metallic ring.

Abstract: A ladder circuit especially useful in backward wave oscillators operating in the 500 GHz to 2,000 GHz range comprises a waveguide (10) having disposed therein transversely oriented slabs (16) which contact an upper wall (22) of waveguide (10). The edges of slabs (11) adjacent the physical center of waveguide (10) along which is directed an electron beam (19) have respective curved segments (11) and stubs (12) and (13) of electrically conductive, non-magnetic material supported thereon. The ends of slabs (16) include metal layers (17) and (18) at respective opposite ends to provide a conductive leakage path. A ridge bar (20) is attached to the inside of the bottom wall (21) of the waveguide (10) and includes a concave upper surface which partially straddles electron beam (19). The inside width of the waveguide (10) is approximately one-half wavelength as determined by the frequency of operation of the backward wave oscillator.

Abstract: An improved slow wave circuit especially useful in backward wave oscillators includes a slow wave circuit (10) in a waveguide (12) as shown in FIG. 1. The slow wave circuit is comprised of rings 11 disposed between and attached to respective stubs (13,14). The stubs (13,14) are attached to opposing sidewalls of the waveguide (12).To the end that opposed, interacting magnetic fields will be established to provide a very high coupling impedance for the slow wave structure, axially orientated bars (20) are connected between rings in alternate spaces and adjacent to the attachment points of stubs 13. Similarly, axial bars (21) are connected between rings in the spaces which do not include bars (20) and at points adjacent to the attachments of bars (21).FIG. 2 shows the current loops (22,23) available because of the inventive structure.FIG. 3 shows that rings 11 may be half rings of 180.degree. arc.FIG. 4 illustrates that the rings or half rings (11) with stubs (13,14) may be formed of flat metal ribbons.

Abstract: A system of slow wave structures for coupling a first electromagnetic circuit to a second electromagnetic circuit includes an inner slow wave structure and an outer slow wave structure concentric with the inner structure. The outer structure is configured to provide for a greater phase velocity of electromagnetc waves than the inner structure, the phase velocities for each structure being proportional to the circumference of each structure so that the rate of circulation of a wavefront about the common axis of the two structures is the same for a wave propagating about the inner structure and a wave propagating about the outer structure. The structures are terminated in their characteristic impedances to provide for wave propagation in one direction without reflections.

Abstract: The present invention relates to a method for the manufacture of a hyperfrequency delay line. The method comprises using a single metal wire shaped by the coiling thereof, said operation comprising bringing the wire into the form of contiguous coils. Coiling is followed by a wire cambering operation during which the coils are deformed at regular intervals in the axis of the line by using wedges, in such a way that the line is formed by a succession of identical groups of three coils in which the first and third coils have identical but oppositely directed inclinations with respect to the axis and in which half of the second coil remains contiguous with the first coil and half remains contiguous with the third coil. Application to the manufacture of double helix delay lines, of ring and bar and ring and loop lines, used in travelling wave tubes functioning as amplifiers.

Abstract: An acoustic transmission member is disclosed for use in an encoding system utilizing acoustic energy wherein diverging sound waves are induced within the member in response to selected actuation of a striker positioned along the member. The time taken by each sound wave to travel through the member is measured in the system to provide an elapsed time interval unique to all strikers for generating a code indicative of the selected input. The acoustic transmission member is a rod formed into a series of coils or helixes with at least one coil length provided and when assembled disposed between adjacent striker positions. The coil configuration defines an expanded path, as compared to the straight linear distance between adjacent strikers, for the sound waves to travel.

Abstract: A microwave delay line, which has a periodic geometrical structure involving more particularly the repetition of first and second meshes so that the amplitude of the inverse mode of transmission is reduced compared with that of a helical line, which comprises rods made from a dielectric and good heat conducting material, arranged parallel to the line axis and regularly distributed over its periphery. These rods are equally subdivided into first and second groups, which are regularly distributed over the line periphery. The rods of the first group are brazed to the first meshes of the line and insulated from the second meshes and the rods of the second group are brazed to the second meshes of the line and insulated from the first meshes.

Abstract: An helical type line for travelling wave tube, with a variable diamter. The line is made on a skew surface constituted by a revolution surface on which flat surfaces have been made. The variation of the line diameter may be carried out by a variation of the revolution surface diameter, the flat surfaces being parallel to the axis of the revolution surface. That variation may be also carried out by a variation of the angle made by the flat surfaces in relation to the helix axis, the revolution surface being cylindrical.

Abstract: Two groups of conductors are wound helically with opposite pitch around a core and are further intertwined to establish a mesh, braid or plait. The conductors of each group are interconnected to establish the signal line and the return path for the delay line.