RU2211501C2 - Superhigh-frequency device with maple leaf type slow-wave structure - Google Patents

Abstract

FIELD: microwave engineering; developing traveling-wave tubes, klystrons, and their hybrids. SUBSTANCE: proposed slow- wave structure of microwave device is built of single part in the form of ring with radial projections carrying diaphragms with transit-time channels. These diaphragms cover projections made on both ends of middle plane of ring. Projections on one end of the latter are turned relative to those on other end through angle N, where N is number of projections, and through angle 2π/N relative to each other. Coupling slots are formed by radial surfaces of projections, inner surface or ring, and outer surface of diaphragms. Cylindrical drilling is made on each side of ring. Rings are joined along common axis by telescopic welds to form slow-wave structure of maple leaf type. EFFECT: simplified design; enhanced precision in manufacture. 2 cl, 3 dwg

Description

 The invention relates to techniques for ultra-high frequencies (microwave), and more particularly to vacuum electronic devices, and can be used in klystrons, traveling wave tubes (LEV) and their hybrids.

 Microwave devices are known [1, 2], in which the clover leaf retardation system (ZS) is assembled from diaphragms with span channels and radial slots, rings with internal protrusions. Rings are made of thin-walled tube.

 The need to perform many radial slots in the diaphragms, protrusions in the tubes with subsequent assembly and end brazing of the parts obtained in the mandrel is a complex process. In addition, when soldering diaphragms with rings along the planes, both radial and longitudinal errors arise, which does not allow fabrication of a ZS and, therefore, a microwave device with high accuracy.

 Closest to the technical nature of the proposed is the design, as claimed in [3]. In it, ZS is assembled from diaphragms with radial slots and rings with protrusions made of metal plates. Disks and rings are silver, collected in a bag and heated. After the melting of silver and cooling, a microwave device with a soldered ZS is obtained.

 As in previous cases, the prototype device ЗС is made of two alternating parts, which are connected by soldering on a plane, i.e. butt we sleep, and it has the same disadvantages.

 Thus, the object of the invention is to simplify and improve the accuracy of manufacturing a microwave device with ZS "clover leaf".

The problem is achieved in that in a microwave device with a clover leaf retardation system containing rings with N (N is an integer) inner protrusions rotated relative to each other by an angle of 2π / N and to the protrusions in adjacent rings by an angle π / N, diaphragms with span channels, communication slots, the outer diameter of the diaphragms with span channels is made equal to the diameter of the cylindrical surface on which the ends of the protrusions are located, these diaphragms are installed with overlapping protrusions of adjacent rings, the communication slots are formed by radial surfaces protrusions, the inner surfaces of the rings and the outer surfaces of the diaphragms with span channels, the rings with the protrusions are cut perpendicular to the axis of the device into two parts, one part relative to the other is rotated through an angle α lying within π / N≥α≥0, from the side of the cut in each of the parts of the rings, cylindrical grooves are made to a depth h lying within
7.4 • 10 ^-4 λ√U≥h≥0,
where λ is the length of the electromagnetic wave synchronous with the electron beam, cm;
U is the accelerating voltage of the electron beam, B, the rings along the cuts are connected by telescopic joints.

 In FIG. 1 is a longitudinal sectional view of a multi-beam microwave device with a “clover leaf” ZS operating at a higher level (for example, the 1st spatial harmonic).

 In FIG. 2 shows the same multipath microwave device in section by the plane AA.

 Figure 3 shows a single-beam microwave device with ZS "clover leaf", operating on the main (0-th spatial harmonic).

In these figures:
1) metal rings
2) radial protrusion,
3) aperture
4) span channels
5) communication slots,
6) cylindrical grooves,
7) telescopic junctions,
8) the junction of the rings with telescopic joints.

 On the left in FIG. 1, 3 there is an electron gun (not shown), on the right is an electron collector (not shown).

 Not shown are also input devices, energy output, gaps in the AP. All these nodes have known constructions (see, for example, [4]).

A microwave device with a “maple leaf” ZS contains metal rings 1, on both sides of the middle plane BB of which there are N radial protrusions 2 (the number of protrusions is determined by the required frequency band of the device) with an outer diameter of D _k and an inner diameter of D _m ( Figure 1). These protrusions are rotated at an angle of 2π / N relative to each other, and at an angle of π / N with respect to the protrusions on the other side of the middle plane.
Installed on the end surfaces of the protrusions 2 of the diaphragm 3 with a thickness of t and an outer diameter of D _m with span channels 4 overlap these protrusions on both one and the other side of the plane. The diaphragms 3 in FIG. 3 are made with one, and in FIG. 1.2 with four passage channels 4, because The claimed device can be either single or multipath.

 Communication slots 5 are formed by the radial surfaces of the protrusions 2, the inner surfaces of the rings 1 and the outer surfaces of the diaphragms 3.

 Cylindrical grooves 6 of depth h are made on both sides of the rings 1 (Fig.1, 2).

 Telescopic junctions 7, after the rotation of the rings 1 with respect to each other at an angle α (Figure 2), connect them and form the ST of the microwave device (Figure 1).

 As you can see, in the claimed microwave device ZS "clover leaf" is made of a single element - ring 1 with a diaphragm 3 having span channels 4.

In our technical solution, the ZS rings of the known device 3 are cut into two parts in order to perform the ZS using telescopic junctions (soldering mainly along two coaxial cylindrical surfaces). In this case, it becomes possible to rotate the obtained rings relative to each other by an angle α within
π / N≥α≥0.
All internal angles of rotation that are multiples of π / N lead to repeating structures.

 To reduce the size of the fillet formed during the soldering of the rings, it is necessary to move their radial protrusions from the junction. In this case, there will be no angles at which solder is pulled out under the action of capillary forces, which will ensure greater accuracy of the proposed device. The claimed microwave device with the CS "clover leaf" works both at the 0-th spatial harmonic and at the closest to zero + 1-th spatial harmonic.

 Known microwave devices at zero spatial harmonics operate at a phase shift of (0.5-0.7) π [4] (phase shift of an electromagnetic wave by one cell of a slow-wave system). In this case, the bandwidth of the AP is about 25%, and the working band of the device is up to 10%. The presence of cylindrical grooves reduces the passband of the ES, therefore, when operating at the 0th harmonic, their depth h should be minimal and in the limit equal to 0.

When the device is operating at + 1-th harmonic, the working phase shift is (2.0-2.5) π, and it will be possible to obtain the passband of the ZS of about 25% if the axial length of the radial protrusions in the rings of the same value is 0.5π, as when working at the 0th harmonic. In this case, the greatest possible phase depth of the groove h is 0.75π .. Expressing this value through the working wavelength λ and the accelerating voltage of the electron beam U, taking into account the fact that the minimum groove depth is 0, we obtain
7.4 • 10 ^-4 λ√U≥h≥0.
This relation covers both the case of work at the 0th and at the + 1st spatial harmonics.

 Thus, halving the number of parts to be joined, using telescopic junctions when assembling the device, eliminating the need to make many radial slots in diaphragms with span channels, accurate fixing of the diaphragms relative to the radial protrusions of the rings makes it possible to simplify the manufacture of the device, and reduce chaotic violations of periodicity, axial symmetry, minimize fillet formation at junctions, i.e. to increase the accuracy of manufacturing the device.

 Details - rings with protrusions and diaphragms having span channels, from which ZS is assembled, can be made on ordinary metal-cutting and electric-spark machines. Having processed rough parts on metal-cutting machines and finished on electric sparks, it is possible to ensure dimensional performance with an accuracy of several microns. This ultimately will allow to obtain high values of instrument parameters and their repeatability.

 The possibility of rotation of the rings in relation to each other gives an additional advantage of the proposed device in comparison with the known. When turning, the direct connection between the slots in adjacent rings decreases, which leads to an expansion of the band of amplified frequencies. The largest relative rotation of the slits α = π / 2N also gives the largest gain band.

 In addition, the rotation allows you to change the wave impedance of the ES and thus achieve better coordination with energy input / output waveguides and loads.

The simplest to manufacture and with the largest band of amplified frequencies is a microwave device with ZS "clover leaf", in which the diaphragms overlap the protrusions of adjacent rings at a length of t / 2, cylindrical grooves have the same depth h and the angle of rotation of the slits α is π / 2N.
The construction described above is a particular example. Other designs consistent with the spirit of the claimed invention may be apparent to those skilled in the art of developing traveling wave tubes.

Literature
1. M. Chodorow, US Pat. 3233139, Cl. 315-3.5, 8.02.60.

 2. M. Chodorow, R. Craig, Some new circuits for high power traveling wave tubes. PIRE, 1957, 45, 8, 1106.

 3. N.W. Harris, US Pat. 3375475, Cl. 333-31, 26.03.68.

 4. J. F. Gittins, Power traveling wave tubes. The English Universites Press LTD. London E.C.I. 1964.

Claims (2)

1. Microwave device with a clover leaf retardation system containing rings with N (N is an integer) internal protrusions rotated relative to each other by an angle of 2π / N and to the protrusions in adjacent rings by an angle of π / N, of the diaphragm with span channels, communication slots, characterized in that the outer diameter of the diaphragms with span channels is made equal to the diameter of the cylindrical surface on which the ends of the protrusions are located, diaphragms with span channels are installed with overlapping protrusions of adjacent rings, the communication slots are formed by radial surfaces the protrusions, the inner surfaces of the rings and the outer surfaces of the diaphragms with span channels, rings with N protrusions are cut perpendicular to the axis of the device into two parts, one part relative to the other is rotated through an angle α lying within π / N≥α≥0, from the side cut in each of the parts of the rings made cylindrical grooves to a depth h lying within
7.4 • 10 ^-4 λ√U≥h≥0,
where λ is the length of the electromagnetic wave synchronous with the electron beam, cm;
U is the accelerating voltage of the electron flow, while the rings are cut through sections connected by telescopic junctions, V.  2. The microwave device according to claim 1, characterized in that the diaphragms with span channels overlap the protrusions of adjacent rings at a length t / 2, where t is the thickness of the diaphragm, the grooves in each part of the rings from the side of the cut are made of the same depth with a diameter equal to the inner the diameter of the ring, the angle of rotation of one part of the cut ring with respect to the other is π / 2N.

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