English Electric Valve Company Limited

E2v Technologies (uk) Limited

Eev Limited

Alan H Pickering

Geoffrey J Rowlands

Michael B Brady

Peter Frederick Lewis

Roy Heppinstall

Steven Bardell

Michael Barry Clive Brady

Mark Bridges

Heinz P Bohlen

Kesar Saleem

Edward S Sobieradski

Howard T Pettas

Geoffrey Thomas Clayworth

Edward Stanley Sobieradzki

David R Tice

A magnetron has an output comprising a coaxial line which transmits energy from a wanted oscillator mode as a first coaxial waveguide mode and energy from an unwanted oscillator mode as a second cylindrical waveguide mode. Energy in the cylindrical waveguide mode is intercepted by slots in the coaxial line and absorbed by material . This enables the modes to be separated. Preferably, the output is taken from the axis of the magnetron and the wanted oscillator mode is the &pgr; mode.

Magnetrons having a coaxial line output with unwanted mode energy reduction

RF radiation absorbing material disposed between the cathode and anode

A linear electron beam tube has voltages provided thereto, an electron gun, and an output resonant cavity operatively arranged together. An internal body portion, an external body portion and an insulating portion are provided. The internal body portion, external body portion, and insulating portion at least partially define an annular input resonant cavity. The internal body portion is provided with a high voltage, with respect to the external body portion, and the internal and external body portions are separated by the insulating portion so that the internal and external body portions have no electrically conductive connection therebetween. The internal body portion is in electrical contact with the electron gun. The annular input resonant cavity at least partially defined by the internal and external body portions surrounds the electron gun. The annular input resonant cavity includes two transverse walls, at least one of the transverse walls being part of the internal body portion and part of the external body portion, and a member of insulating material disposed between these body portion parts.

Electron beam tube arrangements having the input cavity comprised of

A co-axial magnetron is provided with a cavity whose resonant frequency can be very rapidly altered in a cyclic manner so that the microwave output frequency of the magnetron can be chosen to lie within the available frequency band of the cavity. The cylindrical walls of the co-axial resonant cavity are constituted by or coupled to the inner surfaces of one or more tuning forks which are maintained in vibration by externally mounted electro-magnetic transducers. As the tines of the tuning forks vibrate, the effect is to cyclically increase and decrease the effective diameter of the cavity, thereby changing its resonant frequency. An adjustable end plate can be provided for the cavity so that fine tuning or slow rate tuning can be provided in addition to the frequency agility provided by the tuning fork.

Coaxial magnetron having cavity walls vibrated by tuning fork

A co-axial magnetron in which in order to provide attenuation of slot resonances the axial coupling slots in the anode member are opened out at either end into round apertures into which resistive attenuating material is introduced in the form of discs having thicknesses corresponding to the thickness of the wall of the anode member. The discs are held in place by thin copper cylinders inside and outside of the anode wall member and overlapping the attenuating discs on either side.

Co-axial magnetrons

A magnetron consists of a cathode structure mounted within an anode cavity arrangement. In order to prolong the operational life of the cathode structure electron emissive material is located within recesses formed in the outer surface of a cylindrical support. As the electron emissive material erodes away during operation of the magnetron its surface area remains substantially unreduced.

Magnetrons

A co-axial magnetron in which the microwave output frequency can be rapidly altered within a particular frequency band. A movable tuning plate is coupled to a mechanical tuning fork which is set into vibration by an alternating voltage applied to a solenoid.

Magnetron having cavity wall vibrated by tuning fork

In a co-axial multi cavity anode magnetron spurious resonances which would otherwise occur in the space between a magnetic pole piece and an anode shell are suppressed. The resonances may be suppressed by means of short circuit pins located within the anode shell.

Co-axial multi cavity anode magnetrons

A multipactor discharge tuned resonant cavity device, e.g. a magnetron, is arranged with two multipactor discharge electrodes so that in a discharge condition a net current flows from one electrode to the other. The net current is used to create a self-bias voltage on one of the electrodes which affects the operating frequency of the device.

Multipactor discharge arrangements

This invention relates to a co-axial magnetron in which a separate resonator incorporating a multipactor discharge arrangement is used to tune the operating frequency of the magnetron. The separate resonator is symmetrically coupled via couplers into the main resonator cavity of the magnetron. More than one separate resonant can be provided, in which case they are symmetrically coupled into the main resonant cavity to achieve correct tuning.

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Chelmsford, United Kingdom

Alan H Pickering