RU2239256C1 - Multibeam klystron - Google Patents

Abstract

FIELD: microwave electronic devices.

SUBSTANCE: proposed multibeam low-voltage, medium-power klystron designed for use as final amplifier in transmitters of radar stations, communication lines, and other radio installations operating in continuous and quasi-momentum modes in short-wave section of SHF band and in long-wave section of EHF band has electron guns and collectors, input, output, and intermediate resonators in the form of waveguides, microwave energy input and output units incorporating vacuum-tight dielectric microwave windows, microwave interaction units periodically positioned over their length in vicinity of maximum of microwave electric field quadrature-axis component, end electrodynamic reflecting members disposed between microwave interaction units in vicinity of maximum of microwave magnetic field quadrature-axis component; microwave interaction units are provided with transit-time channels whose axes are perpendicular to waveguide axes; novelty is that each microwave interaction unit is made in the form of a number of parallel metal plates disposed in parallel with waveguide walls and perpendicular to transit-time channel axis. In addition microwave energy output unit is made in the form of waveguide coupled with output resonator waveguide with aid of electrodynamic coupling members in vicinity of maximum of microwave magnetic field quadrature-axis component, and vacuum-tight dielectric microwave windows are disposed in electrodynamic coupling members. The latter may be made in the form of waveguide sections and may incorporate resonance-tuned diaphragms disposed on output resonator end.

EFFECT: enhanced electronic efficiency and gain factor, enlarged amplified frequency band.

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Description

The invention relates to the field of microwave microwave devices, in particular to medium-voltage low-power multi-beam klystrons used as terminal amplifiers in transmitters of radar stations, communication systems and other radio engineering installations operating in continuous and quasi-pulse modes in the short-wavelength part of the centimeter and long-wavelength millimeter wavelengths .

Known multi-beam klystron medium power (RF patent No. 2075131, IPC H 01 J 25/10, published 10.03.1997), containing a multi-beam electron gun, electron collector, nodes input and output microwave energy, input, output and intermediate single-gap ring resonators. The resonators are made in the form of segments of a U-shaped waveguide folded into a ring. The dimensions of the resonators provide, in the range of operating frequencies, the excitation of a standing wave of type H ₁₀₀ . In the resonator waveguides, the space between the wall with a rectangular protrusion and the flat wall forms an annular microwave gap along which the span channels are periodically located so that their axes are parallel to the axis of the resonator. To prevent the excitation of resonators on other types of waves, at least one of the resonators has radial slots located diametrically opposite in the plane of the input / output energy. Absorption elements are installed in the slots.

However, this design of the klystron is not suitable for use in the short-wavelength part of the centimeter and long-wave part of the millimeter range, because the resonators used in this wavelength range are very small. Due to this, they have a small Q-factor Q and a small total area of the openings of the passage channels, limiting the total current of the multipath electron beam in the range of 0.4-0.6 A. Therefore, it is impossible to realize a large output microwave power (above one kilowatt) and a large gain (above 35 dB) when operating in continuous and quasi-pulse mode with a low (not higher than five kilovolts) accelerating voltage at the resonators.

Also known is a medium-power multi-beam klystron (RF patent No. 2125319, IPC H 01 J 25/10, published January 20, 1999) containing a multi-beam electron gun, electron collector, microwave input and output nodes, input, output, and dual-gap intermediate linear resonators made in the form of shorted ends of coaxial waveguide segments. The dimensions of the resonators provide, in the range of operating frequencies, the excitation of a standing wave of type H ₀₁₁ . The space between the inner conductor and the waveguide wall forms two successive microwave gaps in the direction of electron motion. The span channels are linearly arranged along the waveguide axis, in two rows so that their axes are perpendicular to the waveguide axis, the distance between adjacent span channels is the same, and the length of each row of channels does not exceed 0.25 Λ, where Λ is the wavelength in the waveguide.

However, this klystron design is also not suitable for use in the shortwave of the centimeter and longwave of the millimeter ranges for the same reasons as the previous design of the klystron.

Closest to the claimed is a multi-beam klystron (US patent No. 3248597, NKI 315-5.16, published 04/26/1966), containing several electron guns and electron collectors, input and output nodes of microwave energy, input, output and intermediate single-gap linear resonators made in the form of shorted waveguides at the ends. The dimensions of the resonators in the operating frequency range excite a standing wave of the H _10n type. Along the waveguides in the maximum region of the transverse component of the microwave electric field, microwave interaction nodes are periodically placed in the form of two pole pieces located on opposite walls of the waveguide with passage channels whose axes are perpendicular to the axes of the resonator waveguides. Pole lugs form one microwave gap in the direction of electron motion. Between the structures of the microwave interaction in the maximum region of the transverse component of the magnetic microwave field are reflecting electrodynamic elements such as inductive diaphragms, made in the form of rods. The microwave energy input unit containing the vacuum-tight dielectric microwave window is located in the input cavity, and the microwave energy output unit containing the vacuum-tight dielectric microwave window is located in the output cavity.

This design of the klystron is suitable for use in the shortwave of the centimeter and longwave of the millimeter range. In it, the total current of the multipath electron beam can be significantly higher than 0.5 A due to the use of a large number of electron guns. Therefore, in this klystron it is possible to realize large values of the microwave output power (above one kilowatt). However, in the required wavelength range with a low accelerating voltage on the resonators (several kilovolt units) and a small current density in electron beams (not higher than 10 A / cm ² ), its electronic efficiency does not exceed 10-15%, and the gain - 10-15 dB, because the presence in the nodes of the microwave interaction of the input, output and intermediate resonators of only one microwave gap does not provide high efficiency of interaction of electron beams with the microwave field. In addition, the klystron can operate with a large microwave output power only in the pulsed mode, because in the continuous and quasi-pulsed modes, the vacuum-tight dielectric microwave windows are destroyed in the known designs of the microwave energy leads.

The invention is aimed at solving the problem of creating a low-voltage, multi-beam klystron of medium power, operating in continuous and quasi-pulse modes in the shortwave part of the centimeter and longwave parts of the millimeter range, which has a high electronic efficiency, a large gain and a wide band of amplified frequencies.

To solve this problem, in a multipath klystron containing electron guns and collectors, input, output and intermediate resonators in the form of waveguides, microwave energy input and output nodes, in which vacuum-dense dielectric microwave windows are located, microwave interaction nodes located in waveguides periodically along their length in the region of maxima of the transverse component of the microwave electric field, and reflecting electrodynamic elements located between the nodes of the microwave interaction in the region of the maximum transverse component In this case, the microwave interaction nodes are provided with passage channels whose axes are perpendicular to the axes of the waveguides; according to the invention, each microwave interaction node is made in the form of a series of parallel metal plates located parallel to the waveguide walls and perpendicular to the axis of the passage channel. In addition, the microwave energy output unit is made in the form of a waveguide connected to the output resonator waveguide by means of electrodynamic coupling elements in the maximum regions of the transverse component of the magnetic microwave field, and vacuum-tight microwave dielectric windows are located in the electrodynamic coupling elements. Moreover, the electrodynamic communication elements can be made in the form of segments of waveguides, as well as the electrodynamic communication elements can contain resonant diaphragms located on the side of the output resonator.

, соответствующем выполнению в СВЧ-зазорах условия пространственно-фазового синхронизма между СВЧ-полем и формирующимися сгустками электронов. В выходном резонаторе для обеспечения высокого электронного коэффициента полезного действия с помощью данного выражения определяется длина первого периода узла СВЧ-взаимодействия, а длина последующих периодов должна уменьшаться по закону, обеспечивающему в СВЧ-зазорах выполнение условия пространственно-фазового синхронизма по мере торможения сгустков электронов.Microwave interaction nodes containing several microwave gaps in the direction of electron motion allow them to realize a cascade interaction of electrons with the transverse component of the standing microwave electric field. As the calculations show, due to this, the intensity of the electron beam modulation in the input and intermediate cavities with respect to velocity, which determines the value of the klystron gain, will be proportional to their Q factor Q and the number P of microwave gaps in the nodes of the microwave interaction, and the energy exchange between the output resonator The microwave field and the resulting electron clusters, which determines the value of the electronic efficiency, will be proportional to Q and P at the nodes of the microwave interaction of this resonator. In order for the intense and speed-modulated beams in the input and intermediate cavities to be provided at the wavelength λ of the input signal and at the accelerating voltage V, the period length L between the plates at the microwave interaction nodes should be given by the expression

corresponding to the fulfillment in the microwave gaps of the condition of spatial-phase synchronism between the microwave field and the forming electron clusters. To provide a high electronic efficiency in the output resonator, using this expression, the length of the first period of the microwave interaction node is determined, and the length of subsequent periods should be reduced according to the law, which ensures in the microwave gaps the fulfillment of the spatial-phase synchronism condition as the electron clusters are decelerated.

Reflecting electrodynamic elements located in the waveguides of the input, intermediate, and output resonators provide, at the nodes of the microwave interaction, the phase synchronization of the microwave fields in the microwave gaps.

The implementation of the node output microwave energy in the form of a waveguide, which is connected to the waveguide of the output resonator in the regions of the maxima of the transverse component of the magnetic microwave field through electrodynamic coupling elements containing vacuum-tight dielectric microwave windows, can reduce the share of the output microwave energy passing through each a vacuum-tight dielectric microwave window is proportional to the number N of electrodynamic coupling elements and thereby prevent the destruction of vacuum-tight dielectric microwave windows during the operation of the clist rona in continuous and quasi-pulse modes with large output powers. The presence in the electrodynamic coupling elements of resonant diaphragms makes it possible to ensure the quality factor of the output resonator, which is necessary for highly efficient interaction of electron bunches with the microwave field in the microwave gaps.

Since the modulation coefficients of electron beams in velocity in the input and intermediate resonators, as well as the energy exchange in the output resonator are proportional to the Q factor of the resonators and the number of microwave gaps P at the microwave interaction nodes, the required values of the gain and electronic efficiency can be realized for lower values of Q due to an increase in R.

Thus, it is possible to increase the passband of the resonators and, therefore, increase the band of amplified frequencies.

The foregoing allows us to conclude that there is a “inventive step” in the claimed invention.

The invention is illustrated by drawings, where in Fig.1 shows a front view of a klystron; figure 2 is a side view; figure 3 is a top view; figure 4 is a view of the node microwave interaction; figure 5 is a view of the plate node microwave interaction with span channels.

The following notation is introduced on these figures:

1 - electronic guns,

2 - input resonator,

3 - intermediate resonator,

4 - output resonator,

5 - waveguide node output microwave energy, made in the form of a linear resonator,

6 - electrodynamic communication elements made in the form of segments of waveguides,

7 - node input microwave energy

8 - a waveguide through which microwave energy is output to the load,

9 - node microwave interaction in the input resonator,

10 - node microwave interaction in the intermediate cavity,

11 - node microwave interaction in the output cavity,

12 - plates in the nodes of the microwave interaction,

13 - span channels for electron beams,

14 - reflecting electrodynamic elements,

15 - vacuum-tight dielectric microwave windows,

16 - resonant diaphragms,

17 - electron collectors,

18 - pole tips of the magnetic focusing system

19 - magnets,

20 - reflecting electrodynamic elements having a transfer characteristic, such as the nodes of the microwave interaction (11).

A klystron consists of electron guns (1), an input linear resonator (2), an intermediate linear resonator (3), an output linear resonator (4)), which are made in the form of shorted waveguides at the ends. The microwave energy output unit is made in the form of a shorted waveguide at the ends (5). The waveguides of the output resonator (4) and the microwave energy output unit (5) are interconnected in the regions of the maxima of the transverse component of the magnetic microwave field by means of several electrodynamic coupling elements (6). The microwave energy input unit (7) is located in the waveguide (2). This node has a vacuum-tight dielectric microwave window (15). The microwave energy is output to the load from the waveguide (5) of the microwave energy output unit by means of the waveguide (8). Along the waveguides (2), (3) and (4), the microwave interaction nodes (9), (10), (11) periodically formed by the plates (12) are periodically located. Span channels pass through the walls of the waveguides and through the plates in the transverse direction, the axes of which are perpendicular to the axes of the waveguides. In the waveguides (2), (3) and (4) between the microwave interaction structures (9), (10), (11) there are reflecting electrodynamic elements (14). In the electrodynamic coupling elements (6) there are vacuum-tight dielectric microwave windows (15) and resonant diaphragms (16). The klystron also has electron collectors (17), pole pieces (18) of the magnetic focusing system, and magnets (19).

The work of the klystron is as follows.

In electron guns (1), electron beams are formed, which enter the passage channels (13) of the microwave interaction nodes (9) - (11) and are focused by a longitudinal magnetic field, the configuration of which is determined by the pole tips (18) of the magnetic system. The input microwave signal is supplied to the input resonator waveguide (2) through the microwave energy input unit (7) and excites in it an electromagnetic field of a standing wave of type H _10n , which in the microwave gaps formed between the plates (12) of the microwave interaction nodes ( 9), modulates electron beams in speed. The intensity of the modulation in speed will be proportional to (Q _I P P _I ), where Q _I P and P _I - the quality factor and the number of microwave gaps in the nodes of the microwave interaction of the resonator (2), respectively. After passing through the resonator (2), the electron beams pass through the passage channels into the microwave gaps of the microwave interaction nodes (10) of the intermediate resonator (3), where they are additionally modulated by velocity and grouped into bunches. In this case, the speed is proportional to the intensity modulation (Q P _{Bx Bx)} (Q _{pr pr} P) and modulation current - is proportional to (Q P _Bx $\genfrac{}{}{0ex}{}{\text{2}}{\text{in}}$ ) (Q _pr P $\genfrac{}{}{0ex}{}{\text{2}}{\text{etc}}$ ), where Q _CR and P _CR are the quality factor and the number of microwave gaps in the nodes of the microwave interaction of the resonator (3), respectively. From the resonator (3), the bunches fall into the microwave gaps of the microwave interaction nodes (11) of the output resonator (4). Passing through microwave gaps, electron bunches in the resonator (4) excite an electromagnetic field with an intensity proportional to (Q _o P _o ), where Q _o and P _o are the Q factor and the number of microwave gaps in the structures of the microwave interaction of the resonator (4), respectively . Therefore, the resulting gain of the klystron will be proportional to (Q in _x Q _pr Q _out ) (P $\genfrac{}{}{0ex}{}{\text{2}}{\text{in}}$ P $\genfrac{}{}{0ex}{}{\text{2}}{\text{etc}}$ P _out ). Thus, the gain in a klystron will multigap linear resonators including at microwave gaps _Rin P, P _O and P _ave in the range of 2-10 on one or more orders of magnitude higher compared to the known multipath klystron (see. Prototype), wherein by using linear single-gap resonators (P _in = P _ave = P _out = 1) is proportional to the gain _(Bx Q Q Q _{O etc.).} Passing through the microwave gaps of the microwave interaction nodes of the output resonator (4), the electron clusters, giving off their kinetic energy to the microwave field, are gradually decelerated. Therefore, to ensure a high electronic efficiency, it is necessary to reduce the distance between the plates (12) in the nodes of the microwave interaction (11) according to the law, which ensures in the microwave gaps that the condition of spatial-phase synchronism between the microwave field and electron bunches is satisfied as they decelerate. From the waveguide of the output resonator (4), the electromagnetic field energy is transformed in parts through electrodynamic coupling elements (6), in which the resonant diaphragms (16) and vacuum-tight dielectric microwave windows (15) are located, into the waveguide (5) of the microwave energy output unit , from which the total energy of the microwave field through the hole in the wall of the waveguide (5) enters the load through the waveguide path (8). Spent electron clusters fall into collectors (17).

- длина волны в волноводе. Период L=Δ +d, в котором расположены пластины (12) в узлах СВЧ-взаимодействия (9), (10), (11), должен быть равен или быть меньше b/P, где Р - требуемое число СВЧ-зазоров в узлах СВЧ-взаимодействия, d - толщина пластин (12), Δ - длина СВЧ-зазора. Причем должно выполняться условие Δ ≤ d. Во входном (2) и промежуточном (3) резонаторах при заданных величинах длины волны λ входного сигнала и ускоряющего напряжения V на резонаторах величина периода L решетки, образуемой пластинами (12) в узлах СВЧ-взаимодействия (9), (10), определяется из выражения

. В узлах СВЧ-взаимодействия (11) выходного резонатора (4) с помощью данного выражения определяется L первого СВЧ-зазора. Для последующих СВЧ-зазоров величина L должна уменьшаться по определенному закону, например линейному. Фазовый сдвиг поперечной составляющей электрического поля в СВЧ-зазорах смежных узлов СВЧ-взаимодействия должен быть равен (2k+1)π , поэтому узлы СВЧ-взаимодействия должны быть расположены вдоль волноводов резонаторов с периодом L_p≈ (k+0,5)Λ , где k=1, 2, 3, 4 определяется поперечными размерами электронных пушек (1) и полюсных наконечников (18) магнитной системы.In the klystron, the input (2), intermediate (3) and output (4) resonators can be made in the form of segments of a rectangular waveguide shorted at the ends. The dimensions of the resonator waveguides (2) - (5) provide, in the operating frequency range, the excitation of a standing wave only of type H _10n . For this, the size of the wide wall a of these waveguides must be greater than half the wavelength λ of the input microwave signal, which is within the resonant passband of the resonators (2), (3), (4) and (5), and the size of their narrow wall b must be equal to or be less than a. The width δ of the plates (12) at the microwave interaction nodes (9), (10), (11) should be less than 0.5 Λ, and the diameter of the region within which the openings of the passage channels (13) are located should not exceed 0.25 Λ where

is the wavelength in the waveguide. The period L = Δ + d, in which the plates (12) are located in the microwave interaction nodes (9), (10), (11), should be equal to or less than b / P, where P is the required number of microwave gaps in nodes of the microwave interaction, d is the thickness of the plates (12), Δ is the length of the microwave gap. Moreover, the condition Δ ≤ d must be fulfilled. In the input (2) and intermediate (3) resonators for given wavelengths λ of the input signal and the accelerating voltage V on the resonators, the period L of the lattice formed by the plates (12) at the microwave interaction nodes (9), (10) is determined from expressions

. In the nodes of the microwave interaction (11) of the output resonator (4), using this expression, the L of the first microwave gap is determined. For subsequent microwave gaps, the value of L should decrease according to a certain law, for example, linear. The phase shift of the transverse component of the electric field in the microwave gaps of adjacent nodes of the microwave interaction should be equal to (2k + 1) π, therefore, the nodes of the microwave interaction should be located along the waveguides of the resonators with a period L _p ≈ (k + 0.5) Λ, where k = 1, 2, 3, 4 is determined by the transverse dimensions of the electron guns (1) and the pole pieces (18) of the magnetic system.

The reflecting electrodynamic elements (14) in the waveguides (2), (3), (4) can be made in the form of segments of a rectangular waveguide having a length L _o <0.5Λ and transverse dimensions a and b _o <0.5 b.

The energy input unit (7) can be made in the form of a T-shaped waveguide joint, in which a vacuum-tight dielectric window (15) is arranged, made in the form of a cylindrical half-wave dielectric resonator, and a resonant diaphragm (16). It is advisable to place the energy input (7) in the middle of the waveguide of the input resonator (2) on its wide wall. In this case, the number N of microwave interaction structures (9), (10), (11) in the waveguides of the resonators (2), (3) and (4) should be even.

The waveguide (5) can be shorted at the ends and have the same length and transverse dimensions as the resonator waveguide (4), but instead of the microwave interaction nodes (11), reflecting electrodynamic elements (20) are made in the form of rectangular segments waveguide. The length and transverse dimensions of these segments of the waveguide are selected so that their transfer characteristic is equivalent to the transfer characteristic of the microwave interaction nodes (11).

The waveguides of the electrodynamic coupling elements (6) can be made in the form of segments of a rectangular waveguide having a length L _w ≈ (2m + 1) Λ / 4 and transverse dimensions a and b _w <0.5b, where m = 1, 2, 3, 4 is determined by the dimensions of the collectors (17) and pole pieces (18). The ends of the waveguides (6) are located on the wide walls of the waveguides of the resonators (4) and (5). The resonant diaphragm (16) is located in the waveguides (6) between their end on the side of the resonator (4) and the vacuum-tight dielectric microwave window (15). Vacuum-tight dielectric windows (15) can be made in the form of a cylindrical half-wave dielectric resonator.

It is advisable to arrange the hole for the extraction of microwave energy from the waveguide (5) in the middle of the waveguide (5) on its wide wall, the opposite wall, on which the waveguides of the electrodynamic coupling elements are located (6).

Claims (4)

1. A multipath klystron containing electron guns and collectors, input, output, and intermediate resonators in the form of waveguides, microwave energy input and output nodes, in which vacuum-tight microwave dielectric windows are located, microwave interaction nodes located in the waveguides periodically their length in the region of the maxima of the transverse component of the microwave electric field, and reflecting electrodynamic elements located between the nodes of the microwave interaction in the region of the maximum of the transverse component of the magnetic microwave field m microwave interaction nodes are equipped with passage channels whose axes are perpendicular to the axes of the waveguides, characterized in that each microwave interaction node is made in the form of a series of parallel metal plates located parallel to the walls of the waveguide and perpendicular to the axis of the passage channel and the axes of the waveguides. 2. The device according to claim 1, characterized in that the node output microwave energy is made in the form of a waveguide connected to the waveguide of the output resonator by means of electrodynamic communication elements in the maximum regions of the transverse component of the magnetic microwave field, and the vacuum-tight dielectric microwave windows are in electrodynamic communication elements. 3. The device according to claim 2, characterized in that the electrodynamic communication elements are made in the form of segments of waveguides. 4. The device according to claim 2, characterized in that the electrodynamic communication elements are equipped with resonant diaphragms located on the side of the output resonator.

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