Hughes Aircraft Company

Other

Arthur E Manoly

Robert T Longo

Ralph Forman

Zaher Bardai

Randy K Rolph

Mario A Barillas

Elmer E Reed, Jr

John T Benton

Otto Sauseng

Arlene E Lamb

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.

Slow-wave structure having block supported helix structure

Outgassed materials liberated in spaces between pointed field emitter tips and an electrode structure during electrical operation of a field emitter device are vented through passageways to a pump or gettering material provided in a separate space. The passageways may include channels formed through an insulating layer between a base for the field emitters, and the electrode structure, with the channels interconnecting adjacent spaces in a row direction. Where the electrode structure includes a gate electrode layer and an anode layer, similar channels may be formed through an insulator layer provided therebetween. The field emitters may be formed in an arrangement of rows and columns, with the spacing between the columns smaller than the spacing between the rows. Holes are formed by anisotropic etching through the anode, gate electrode, and insulator layers down to the base. Subsequent isotropic etching of the insulator layers through the holes in the anode and gate electrode layers is controlled to cause sufficient undercutting in the insulator layers that adjacent holes merge together only in the row direction to form the channels.

Field emitter structure and fabrication process providing passageways

Outgassed materials liberated in spaces between pointed field emitter tips and an electrode structure during electrical operation of a field emitter device are vented through passageways to a pump of gettering material provided in a separate space. The passageways may include channels formed through an insulating layer between a base for the field emitters, and the electrode structure, with the channels interconnecting adjacent spaces in a row direction. Where the electrode structure includes a gate electrode layer and an anode layer, similar channels may be formed through an insulator layer provided therebetween. The field emitters may be formed in an arrangement of rows and columns, with the spacing between the columns smaller than the spacing between the rows.

Field emitter structure providing passageways for venting of outgassed

A plurality of field emitters in the form of hollow, upstanding pointed cones or pyramids formed by a molding process extend from a surface of an electrically conductive layer. An electrically conductive mesh is adhered to an opposite surface of the conductive layer by a high temperature brazing process in electrical connection with the conductive layer. The mesh provides a strong metal base with good thermal conductivity for mounting. Additional elements such as a gate and anode structure may be formed on the conductive layer in alignment with the field emitters to form a field emitting triode array or the like.

Field emitter structure and fabrication process

An integral conductively-loaded encasing barrel for a slow-wave structure is formed by electrical discharge machining a plurality of circumferentially spaced longitudinally extending slots in the interior surface of the barrel. The machining discharge is established between a portion of the interior surface of the barrel and an electrode wire which is moved in a longitudinal direction within the barrel while the barrel is moved in a preselected manner in a plane transverse to the direction of movement of the wire. A subassembly comprising a slow-wave structure and a plurality of longitudinally disposed electrically insulating support rods in contact with and circumferentially spaced about the outer surface of the slow-wave structure is secured within the barrel with the support rods disposed within respective machined slots. The radially inwardly projecting portions of the barrel between the slots provide integral conductive loading for the slow-wave structure.

Traveling-wave tube slow-wave structure with integral

Conical field emitter elements are formed on a surface of a substrate after which a layer of metal is deposited on top of the substrate surface and over the field emitter elements. A layer of oxide is then deposited over the metal layer. Another layer of metal is deposited over the layer of oxide to form a gate metal layer. A layer of photoresist is then deposited over the gate metal layer. The layer of photoresist is then plasma etched in an oxygen atmosphere to cause portions of the photoresist above respective field emitter elements to be removed and provide self-aligned holes in the photoresist over each of the field emitter elements. The size of the holes may be controlled by appropriately controlling process parameter, including plasma etching time and power and/or initial photoresist thickness. The exposed gate metal layer is etched using the layer of photoresist as a mask. The photoresist layer is removed, and the layer of oxide is etched to expose the field emitter elements. Another oxide layer and an anode metal layer also may be formed over the gate metal layer to produce a self-aligned triode structure.

Self-aligned gate process for fabricating field emitter arrays

A plurality of longitudinally disposed dielectric support rods are attached to the outer circumferential surface of a helical slow-wave structure to form a subassembly. The subassembly is mounted in a light press-fit relationship within an enveloping structure comprising a plurality of annular nonmagnetic spacer elements repectively interposed between and abutting a plurality of annular ferromagnetic pole pieces. Plastically deforming force is applied by means of a pair of dies to the outer surface of the spacer elements to crimp the spacer elements onto the support rods and thereby firmly hold the slow-wave structure-rod subassembly within the enveloping structure.

Method for securing a slow-wave structure in enveloping structure with

A high-power coaxial cable is disclosed comprising an inner conductor, an outer conductor coaxially disposed about and spaced from the inner conductor, and insulating fittings disposed between the inner and outer conductors near opposite ends of the cable to maintain a desired spacing between the inner and outer conductors. The insulating fitting at one end of the cable has a plurality of longitudinal holes therethrough to reduce the dielectric constant and the impedance of the fitting. The fitting is formed in two like sections joined at right angles to one another along a substantially 45.degree. interface, thereby defining a short 90.degree. turn for the inner conductor near the end of the cable. The fitting sections are retained in position by a surrounding mounting block, the opposite ends of which respectively receive a conductive sleeve and an end of the outer coaxial conductor in press-fit relationship.

High-power coaxial cable

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.

Ring-bar slow wave structure and fabrication method

Helical slow-wave structure assemblies including a helical dielectric supporting member are disclosed along with methods for fabricating such assemblies. After the slow-wave structure helix is wound on a mandrel, a masking helix is coaxially wound about the slow-wave structure helix in the same sense as the slow-wave structure helix over the helical space between turns of the slow-wave structure helix and in overlapping relationship with portions of adjacent turns of the slow-wave structure helix. The supporting helix is formed by plasma spraying dielectric material into the helical space between turns of the masking helix. The dielectric material is ground to a predetermined radial dimension, and the mandrel and the masking helix are removed. By utilizing a masking helix of tapered width, a dielectric supporting helix of tapered width may be fabricated to provide a slow-wave structure assembly with a tapered phase velocity. A slow-wave structure helix having a radially outwardly extending longitudinal ridge may be utilized to provide a structure of wide bandwidth.

Helical slow-wave structure assemblies and fabrication methods

In the disclosed attenuation arrangement a plurality of axially extending boron nitride support rods having a substantially rectangular cross-section are disposed about the peripheral surface of a helical slow-wave structure. An attenuating coating is provided on the substantially radially extending opposing lateral surfaces of each rod, with the substantially circumferentially extending opposing lateral rod surfaces being free from attenuating material.

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Rancho Palos Verdes, CA, United States of America

Arthur E Manoly