US2168296A

US2168296A - Microwave oscillator and associated circuit

Info

Publication number: US2168296A
Application number: US146178A
Authority: US
Inventors: Vries Gerrit De; Lindern Carl G A Von
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1936-06-05
Filing date: 1937-06-03
Publication date: 1939-08-01
Anticipated expiration: 1956-08-01
Also published as: GB478413A; NL46806C; FR822638A; DE675311C

Description

lg- 1939- G. DE VRIES ET AL 2,163,295

MICROWAVE OSCILLATOR AND ASSOCIATED CIRCUIT Filed June 3, 1937 mvs NTO RS 5 GERR/T ogre/5s u By C L volv LINDERN ATTORNEY charge tube for use in carrying out our invention.

Patented Aug. 1, 1939 MICROWAVE OSCILLATOR AND ASSOCIATED CIRCUIT Gerrit de Vries and Carl G. A. von Lindern, Eindhoven, Netherlands, assignors to N. V. Philips Floeilampenfabrieken, Eindhoven, Netherands Application June 3, 1937, Serial No. 146,178 In the Netherlands June 5, 1936 energy from the direct current source IS. The tube envelope I! is cemented into a base 18 in the usual manner. The part a comprises the

anodes

2 and 4 and the part b the

anodes

6, 8, l0 and I2. The cathode of the magnetron is designated by 3. The magnetic field coil I5 is disposed substantially in coaxial relation to the linear cathode 3. The

anodes

2 and 4 of the part a are interconnected via an oscillatory circuit 5 to which the oscillations to be multiplied are supplied. The

anodes

6, 8, l0 and [2 of the part b are divided into two groups in such manner that each anode pertains to a group other than that of the adjacent anodes. Thus, the anodes 6 and i0 pertain to one group and the anodes 8 and I2 to the other group. The anodes 6 and [0 or 8 and I2 respectively of each group are interconnected electrically through a. conductor F or 9 respectively and the middle points of the conductors l and 9 are interconnected via a circuit I l tuned to the doubled frequency of the oscillations occurring in the circuit 5. Y The mid- .dle points of the circuits 5 and II are connected to the positive pole of the source of voltage which supplies the requisite anode voltage and the negative pole of which is connected to the cathode 3. The source of voltage which supplies the cathode supply voltage is designated by Hi.

The circuit described operates as follows.

When oscillations are supplied to the circuit 5 an electric alternating field is set up the fre quency of which is equal to the frequency of the said oscillations between the

anodes

2 and 4 and there is in addition a magnetic field. Under the 4 Claims.

This invention relates to a micro-wave oscillator circuit and more particularly to a circuit arrangement including a magnetron discharge tube and means for multiplying or dividing the frequency of oscillations generated. Magnetron discharge tubes as commonly built for use in oscillation generators are characterized by a linear cathode co-axially disposed with respect to a cylindrical anode system. According to our invention the anode system is divided into two groups, arranged lengthwise of the cathode so that these groups are in effect separated by a plane normal to the electrode axis. One of these groups preferably contains a number of segments which is a multiple of the number of segments in the other group. The segments of the second group are joined together by a resonant circuit while diametrically opposed segments of the first group are joined together by mutually independent resonant circuits. These resonant circuits are so tuned that fundamental frequency oscillations may be generated by virtue of the charges built up on the anode segments of the group having a lesser number, while oscillations of a frequency harmonically related to the fundamental frequency are developed in the resonant circuits interconnecting diametrically opposed anode segments of the group having the greater number.

It is well known that when a magnetic field is applied to the discharge zone of a magnetron oscillator tube a cloud of electrons is caused to rotate about the axis of the cathode. Accordingly, we make use of this phenomenon in providing a frequency multiplied for use in an ultrahigh frequency system. In order that the invention may be clearly understood and readily carried into effect it will now be described more fully with reference to the accompanying drawing in which- Figure 1 shows a preferred circuit arrangement including the electrode system of the magnetron discharge tube; and

Fig. 2 illustrates a suitable magnetron disthe cathode is traversed by the electrons emitted from, the cathode, the electrons emitted from that part of the cathode 3 which is inside the part b of the tube being carried along by them and describing also a spiral path around the cathode. The speed at which the said path is traversed by the electrons is such that during a half period of the oscillations occurring in. the circuit 5 the electrons have traversed a path along the circumference of the cylindrical surface formed by the anodes which covers an angle of 180. While this path is being traversed part of the electrons pass in the part b of the tube in succession past the

anodes

6 and 8 or H! and The circuit illustrated in Fig. 1 includes a magnetron comprising a number of anodes which jointly form a cylindrical surface and which are divided by a surface normal to the axis of the cylindrical shell into two systems a and b. The tube itself is shown in Fig. 2, where the electrode system which is contained in the envelope IT is shown in perspective. Means for exciting I the discharge zone magnetically is illustrated in Fig. 2 as by the magnetic field coil l5 which derives its period of the oscillations supplied to the circuit 5 the circuit connected between the

anodes

6 and 8 on the one hand and the anodes l0 and I2 on the other hand is excited once at the anode 8 or H! respectively and once at the anode 8 or l2 reinfluence of these two fields a spiral path around l2 respectively so that during half the oscillations The circuit described is suited both for multiplying and for dividing high frequency and ultrahigh frequency oscillations. In the latter case the oscillations the frequency of which is to be divided are supplied to the circuit 1 I, after which oscillations having a frequency which is half the frequency of the oscillations supplied to the circuit H can be derived from the circuit 5. The oscillations the frequency of which is to be multiplied or to be divided may also be generated by the magnetron itself,

The circuit is in addition suited for genera??? a frequency which is the p harmonic of the scillations supplied to the circuit 5 or of the oscillations set up in the circuit 5.

The ratio of the number of anodes of the part a and the number of anodes of the part b governs the harmonic or sub-harmonic that can be obtained by means of the circuit according to the invention. If the part b of the tube shown in Fig. 1 were to contain six anodes, then the circuit according to the invention could be used for tripling the oscillations supplied to the circuit 5 or set up in this circuit, since in this case three anodes are traversed during half the oscillation period of the oscillations occurring in the circuit 5 so that the time which elapses between the excitement in phase opposition of the circuit connected between the groups of anodes is a third of half the oscillation period of the oscillations occurring in the circuit 5.

If in the circuit according to the invention use is made of a magnetron in which the part a of the tube consists of 4 anodes, the part b of 8 or 12 anodes, the circuit is also suited for doubling or tripling the frequency of the oscillations occurring in the circuit 5. In that case then four anodes of the part a are divided into two groups and the anodes pertaining to one of the groups are connected via an oscillatory circuit to the anodes of the other group as shown in Fig. 1 for the

anodes

6, 8, I0 and I2 of the part b.

The circuit according to the invention may be used particularly when there is a need for ultrahigh frequency oscillations having a constant frequency. Ultra-high frequency oscillations having a frequency of the order of magnitude of 410 megacycles and higher can no longer be generated by a retroactively coupled generator and though a magnetron generator is suited for the generation of oscillations having such a high frequency, the frequency of the oscillations generated by a magnetron generator depends to a marked extent on the voltages supplied to the electrodes of the magnetron and the frequency of the oscillations generated is consequently variable.

In order to permit of obtaining oscillations having a constant frequency of the above-mentioned order of magnitude use may be made of a feed-back coupled generator which is arranged for the generation of a sub-harmonic of the desired frequency, the generated oscillations being supplied to a frequency multiplier according to the invention.

What we claim is:

1. An oscillator in combination with means for producing energy harmonically related to the frequency of the oscillations generated, said oscillator comprising a magnetron discharge tube having a system of cylindrically formed anode segments and a linear cathode coaxially disposed within the anode system, said segments being arranged in two groups lengthwise of the cathode, the ratio between the numbers of segments in said two groups being the same as the ratio between the two frequencies which are harmonically related, magnetic field exciting means for producing a rotating cloud of electrons within the two groups of anode segments, a resonant circuit interconnecting the anode segments of the group having the lesser number of segments, a

resonant circuit interconnecting different pairs of diametrically opposed anode segments of the further characterized in that the number of anode segments in one group bears the same ratio to the number of segments of the other group as the ratio between the two frequencies to which the resonant circuits of the two groups are respectively tuned.

4. In a magnetron oscillator and frequency multiplier system of the type wherein the cylindrically formed anode segments are arranged about a linear cathode in two groups, one group being separated from the other by a plane normal to the electrode axis, and the number of segments in one group being a multiple of the number of segments in the other group, the method of deriving an ultra-high frequency wave which bears a harmonic relation to a fundamental Wave generated by said oscillator, which comprises applying a magnetic field to the discharge Zone, applying operating potentials to the electrodes of one group at suitable values for generating the fundamental frequency, resonating the oscilla- 4 tory energy charges which are built up on the electrodes of that group, causing a single cloud of electrons to rotate within the entire discharge zone in unison with the fundamental frequency, and deriving the harmonically related frequency by resonating the oscillatory energy charges which are built up on the electrodes of the other r up.

GERRIT DE VRIES.

CARL G. A. VON LINDERN.