US Government as Represented by the Secretary of the Army

United States of America as Represented by the Secretary of the Air Force

Varian Associates, Inc.

Communications & Power Industries, Inc.

Hunter L McDowell

Michael L Tracy

Carl D Morrill

Werner F Heim

A crossed-field device such as a crossed-field amplifier or magnetron has a generally peripheral cathode body portion and an anode which cooperates with a crossed magnetic field to maintain emitted electrons on cycloidal and amplify an rf input signal as it travels to an rf outlet. A control electrode positioned generally at a drift region away from the crossed-field amplification region interrupts the sustained electron emission to shut down the device between working cycles, and an auxiliary electrode positioned internally of the cathode diverts electrons into a gap proximally of the control electrode to reduce the control electrode energy requirements. The cathode is carried by a support structure, and the auxiliary electrode may be a rod axially extending in a counter-bore in the support structure. The auxiliary electrode is dc biased and may advantageously operate at anode potential, thereby obviating the need for any additional power source for the auxiliary electrode. Preferably the auxiliary electrode forms an inverted magnetron arrangement with the cathode counterbore and diverts electrons from the active region without creating unwanted rf output signal components.

Crossed-field device

In a crossed-field amplifier tube, an input section of slow-wave circuit is part of the cathode electrode. An output section of slow-wave circuit is part of the anode electrode. The anode circuit is axially displaced from the cathode circuit in the direction of drift of the electron stream so that a non-propagating section of the anode faces at least a part of the propagating cathode circuit.

Cathode driven crossed-field amplifier

A meander line slow wave structure mounted on ceramic bars for a microwave evice such as an injected beam crossed-field amplifier includes frequency selective attenuator means which will preferentially attenuate waves at frequencies near and within the stopband of the slow wave structure by the placement of side absorber bars of attenuating material adjacent to the outer side surfaces of a plurality of meander line finger segments. The frequency selective absorber material, in its preferred form, comprises a beryllia and silicon carbide ceramic composition which additionally adapted to accommodate metallic absorber top plates, nichrome films, and slotted side ring configurations.

Frequency selective side absorber for a meander line

A broadband attenuator section in a meander line slow wave structure is dlosed for attenuating signals reflected between the output and input of the slow wave structure. The attenuator section comprises a multi-element ceramic support structure intermediate the meander line conductor pattern and the substrate wherein the support elements are comprised of a beryllium oxide-silicon carbide ceramic composition with a taper in the percentage of silicon carbide being provided in the transition region from a loss free section of the slow wave structure to a lossy attenuator section. The taper in percentage involves the use of ceramic support elements arranged in a sequence of 1%, 2% and 5% silicon carbide composition prior to the main attenuator section which is comprised of 10% silicon carbide - 90% beryllium oxide support elements.

Broadband slow wave structure attenuator

A ceramic substrate is metallized by a method including the steps of:

Method of metallizing a ceramic substrate

Crossed field amplifier collector efficiency is improved by decreasing the ratio of electron velocities to r.f. signal wave velocity at the output end of the amplifier slow wave circuit. In a preferred embodiment of the invention this is accomplished by tapering the sole emitting cathode so as to increase the cathode-slow wave circuit spacing in the output end of the interaction region prior to the collector. Alternatively, an increasing r.f. signal phase velocity taper can be used to provide the required decreased electron velocities to r.f. signal wave velocity ratio.

Growing community of inventors

Concord, MA, United States of America

Hunter L McDowell