US 2542966

J.T. Randall et al,

High_Frequency oscillator

Filed August 20, 1941 (in Britain)

Granted in the US on 20 February 1951

John Turton Randall and Henry Albert Howard Boot, Birmingham, England, assignors to English Electric Valve Company Limited, Chelmsford, England, a company of Great Britain. (During WW II both men were engaged at Birmingham University Physical Science department. However, this patent was applied for in the aftermath of World War Two, and the assignors presumably were then employed somewhere else, AOB)

I have selected the US patent versions, as they provide better drawings (thus omitting GB588917, GB588186 and that like). That Mr J.T. Randall is mentioned first, might be owing to Randall's input that got ahead of Mr H.A.H. Boot's contribution (or, maybe he was higher in the academic hierarchy?).

US2648028 concerns the magnetron cathode, which was a very significant (essential) device, as this allowed high puls-power operations. See section below

Keywords to US2542966: This invention relates to high frequency electrical oscillators of the magnetron type. Such magnetrons depend for their operation upon the curvilinear motion imparted to a moving electron by a magnetic field, electrons emitted by the cathode are thus caused to follow substantially circular or spiral paths, and various arrangements exist wherby such electrons are caused to give up their energy to external circuits in which oscillatory currents of very high frequency may thereby be induced; A magnetron according to the invention is characterized by provision of a member comprising the anode within which a plurality of resonator cavities of substantially the same natural frequency, are disposed about and open into a central axially disposed anode-cathode space. ..... ; Consideration will now be given to the problem of designing a magnetron according to the invention to fulfill given requirements. In this connection three fundamental equations have been developed, there are:

V=2x10⁷.π² D² / N² W² A² 

H=7,24x10⁴ π /NWA 

P=4x10⁴ π³ D³ LE /N² W² A²    

where: V=potential difference between anode and cathode (volts); H=magnetic field (oerstedts); P=output power (kilowatts); D=diameter of central cavity 2 (cm); N=number of resonators 4;; L=axial length of resonators and, in form of magnetron shown in Figs 1 and 2, axial length of cathode 3 (cm); A=phase difference between oscillations in adjoining resonators (radians); W=wavelength (cms); E=efficiency (ratio of output to input power; These equations have been developed from first principles, and are based on thge hypothesis previously set out concerning the mode of operation of the device... ; It has been assumed that the cathode diameter=0.4D, as in magnetron design generally this dimension has been found to provide optimum field conditions at the cathode...

US2648028

John Turton Randall, Birmingham, and Henry Albert Howard Boot, London, England, assignors to English Electric Valve Company Limites, a company of Great Britain and Northern Ireland.

First application in Great Britain on 22 August 1941 (thus two days after their previous application, AOB)

Keywords of US2648028: This invention relates to high frequency electrical oscillators and more particularly to oscillators of the magnetron type. ..... the present invention is addressed primarily to improvements in the type of oscillator therein disclosed although the invention may be applicable to certain other oscillators... ; thermionic emission ...; Suitable emitting surfaces consist of thin coatings of oxides of thorium or aluminum  on a suitable metallic base. Calcium oxide and silicates of barium ... are also suitable (regard also Wehnelt's fundamental paper on oxide cathodes of 1904 in Annalen der Physik); As regards factor (1), almost any conducting surface will exhibit the effect, but it has been found that very satisfactory results are obtainable from the use of a thin semi-conducting (e.g. oxide) film on a metallic surface. In such cases the effect is believed to be enhanced by what is known as "thin film field emission' or the Malter effect: the current hypothesis concerning this effect is that secondary emission from the outer surface of the thin semi-conducting flim leaves positively charged areas on the surface, and these positive charges, separated from the main conducting surface only by thickness of the film, produce a powerful field which causes the emission of further electrons therefrom

Regard also, or go back to: Sayers' strapping patent US2546870

Regard also, or go back to: LMS10 vs CV64 TRE Report T 1858

Consider also, or go back to: H.J Fischer's book Radartechnik

Consider also, or go back to: Strapping theory

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