1. A multi-stage depressed collector with dual corrugated electrodes, comprising: at least one clamping structure in the form of a collector adapter (1); a conical bottom plate attached to the last electrode (2); a plurality of collector electrodes sequentially applied with increasing depression potential (3, 4, 5, 6); at least one insulating material (7) arranged at the contact position of each electrode collector; and a beam refocusing section (BRS) having at least three periodic permanent magnets (PPM), wherein the plurality of collector electrodes comprises dual corrugation having two sections of positive slope taper region (8) followed by a short zero-slope region (9).

2. The multi-stage depressed collector as claimed in claim 1, wherein the at least three periodic permanent magnets are having a reduced magnetization value configured to introduce an optimized leakage magnetic field within the plurality of collector electrodes.

3. The multi-stage depressed collector as claimed in claim 1, wherein the plurality of collector electrodes is further configured to apply genetic algorithm-based code for optimization of the collector electrode geometry parameters, collector voltages, and leakage magnetic field values.

4. The multi-stage depressed collector as claimed in claim 1, wherein the collector adapter (1) is fabricated with a non-magnetic material to introduce leakage magnetic field from the beam refocusing section.

5. The multi-stage depressed collector as claimed in claim 4, wherein the non-magnetic material used for fabricating the collector adapter (1) is Monel.

6. The multi-stage depressed collector as claimed in claim 1, wherein the plurality of collector electrodes material is high conductivity oxygen-free copper and at least one insulating material is ceramic.

7. The multi-stage depressed collector as claimed in claim 1, wherein the collector electrode material is made of a material selected from a group consisting of a metal conductive material, a carbon-based conductive material, and combinations thereof.

8. The multi-stage depressed collector as claimed in claim 7, wherein the metal conductive material is at least one of copper, nickel, nickel-copper alloy, and combinations thereof.

FIELD OF THE INVENTION
[0001] The present invention is directed generally to the technical field of vacuum electronics, more specifically, to a multistage depressed collector with dual corrugated electrons.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] As a final power amplifier, traveling wave tubes are widely used in electronic equipment such as radar, electronic warfare, satellite communications, and precision guidance. An important factor to measure the quality of the traveling wave tube is the efficiency of the traveling wave tube. There are generally two ways to improve the efficiency of the traveling wave tube: one is to increase the electronic efficiency of the interaction between the electrons and the slow wave structure to improve the overall efficiency of the traveling wave tube; the other is to use a step-down collector to recover the energy of the remaining electrons after the interaction, thereby improving the efficiency of the entire tube. Among them, it is difficult to improve the efficiency of the traveling wave tube through the first method. Therefore, it is the most effective and easiest way to use the step-down collector to improve the overall tube efficiency of the traveling wave tube. The multi-stage step-down collector classifies the remaining electrons after the wave injection interaction according to energy, so that they are collected on electrodes of different voltages, and the remaining electrons are returned to the power supply for reuse, thereby improving the overall efficiency of the traveling wave tube.
[0004] CN202003944U relates to a multistage depressed collector for ribbon electronic beam traveling wave tubes, which belongs to the technical field of vacuum electronics. The multistage depressed collector comprises a plurality of stages of electronic collecting electrodes which are depressed sequentially. Each collecting electrode's main body comprises an electronic beam channel, a transition cavity, and an elliptic cylinder cavity which are connected sequentially. Compared with previous stages of electronic collecting electrodes, the sizes of the sections of the electric beam channels of later stages of electronic collecting electrodes are increased gradually and the eccentricity of the sections of the electric beam channels is reduced gradually, and the sizes of the sections of the elliptic cylinder cavities of the later stages of electronic collecting electrodes are increased gradually and the eccentricity of the sections of the elliptic cylinder cavities are reduced gradually. The tail stage of the electronic collecting electrode comprises a metal baffle plate and a cone electrode. The cone electrode extends into the elliptic cylinder cavity of the previous stage of the electronic collecting electrode. The multistage depressed collector has a simple structure, is easy to process, and can be used for well-collecting electronic beams of the ribbon electronic beam traveling wave tubes which react with each other and has high collecting efficiency and low electron reflux rate.
[0005] CN111916322B discloses a multi-stage depressed collector with a deflecting magnetic field that belongs to the technical field of vacuum electronics. The collector is arranged in a deflection magnetic field vertical to the direction of incident electrons so that most of the electrons are all hit on the same side of the collector under the action of the deflection magnetic field, and the heat dissipation efficiency of the collector can be effectively improved. In addition, this document has the advantages of simple structure, easy processing, high collection efficiency, and no backflow. The collector with 3-stage blades is used for collecting residual electrons after interaction in a 220GHz strip-shaped traveling wave tube, the collection efficiency is as high as 98.86%, and most of the electrons hit the side wall of the collector.
[0006] Since the use of the step-down collector can effectively improve the efficiency of the traveling wave tube, scientific and technological workers are paying more and more attention to the collector. So far, a variety of collector structures have been proposed and studied, but most of the existing multi-stage step-down collectors are based on the conventional circular electron beam design, composed of multiple cylindrical cavity electrodes, and the latter stage. The cylindrical cavity electrode is generally larger than the previous stage cylindrical cavity electrode, which completes the sorting and collection of electrons of different energy through potential difference between the electrodes. This structure determines that the size of the traditional collector is often too large, and it is difficult to process and assemble. Moreover, since the electron beam channel inside the collector is parallel to the electron beam channel of the slow wave structure, it may cause the phenomenon of electron beam backflow and decrease in the performance of the entire tube. In addition, in the conventional collector structure, electrons will escape to the surroundings during the collection of electron beams. Hence, there is a need of providing a multi-staged depressed collector with increased collector efficiency.
[0007] The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.

OBJECTS OF THE INVENTION
[0008] It is an object of the invention to provide a multi-staged depressed collector with increased collector efficiency.
[0009] It is another object of the invention to provide a multi-staged depressed collector which is economical and consumes lesser power.
[0010] It is another object of the invention to provide a multi-staged depressed collector having an optimized leakage magnetic field within the electrode collectors.
[0011] It is an object of the invention to provide a multi-staged depressed collector with increased collector efficiency without increasing the size or the weight of the collector electrode.

SUMMARY OF THE INVENTION
[0012] This summary is provided to introduce a selection of concepts in a simplified format that is further described in the detailed description of the present disclosure. This summary is not intended to identify key or essential inventive concepts of the present disclosure, nor is it intended for determining the scope of the present disclosure.
[0013] According to an embodiment of the present disclosure, the multi-stage depressed collector with dual corrugated electrodes comprises at least one clamping structure in the form of an adapter, a conical end plate attached to the last electrode, a plurality of collector electrodes sequentially applied with increasing depression potential, at least one insulating material arranged at the contact position of each collector electrode, and a beam refocusing section (BRS) having at least three periodic permanent magnets (PPM). The plurality of collector electrodes further comprises dual corrugation having two sections of positive slope taper region followed by a short zero-slope region.
[0014] According to an embodiment of the present disclosure, at least three periodic permanent magnets are having a reduced magnetization value configured to introduce an optimized leakage magnetic field within the plurality of collector electrodes.
[0015] According to an embodiment of the present disclosure, the design optimization of the multi-stage depressed collector is carried out using a genetic algorithm-based code for optimization of the collector electrode geometry parameters, collector voltages, and leakage magnetic field values.
[0016] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. The disclosure will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other aspects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
[0018] Figure 1 illustrates a 3-D schematic cross-sectional view of the multi-stage depressed collector with dual corrugated electrodes, in accordance with an embodiment of the present disclosure.
[0019] Figure 2 shows a 3-dimensional external circumferiential view of the multi-stage depressed collector with dual corrugated electrodes, in accordance with an embodiment of the present disclosure.
[0020] Figure 3 shows a 2-dimensional schematic of cross-sectional view of the multi-stage depressed collector with dual corrugated electrodes, in accordance with an embodiment of the present disclosure.
[0021] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION OF THE INVENTION
[0022] For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein would be contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art. The system, methods, and examples provided herein are illustrative only and are not intended to be limiting.
[0023] The term “some” as used herein is to be understood as “none or one or more than one or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments, without departing from the scope of the present disclosure.
[0024] The terminology and structure employed herein is for describing, teaching, and illuminating some embodiments and their specific features. It does not in any way limit, restrict or reduce the spirit and scope of the claims or their equivalents.
[0025] More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do not specify an exact limitation or restriction and certainly do not exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must not be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “must comprise” or “needs to include.”
[0026] Whether or not a certain feature or element was limited to being used only once, either way, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there needs to be one or more . . . ” or “one or more element is required.”
[0027] Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having ordinary skills in the art.
[0028] Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfill the requirements of uniqueness, utility and non-obviousness.
[0029] Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.
[0030] Any particular and all details set forth herein are used in the context of some embodiments and therefore should not be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.
[0031] The present invention provides a multi-stage depressed collector electrode with dual corrugated electrodes. In order to enhance the collector efficiency in a high electronic efficiency space Traveling-Wave Tube (TWT), the electrode shape of the collector has been modified in the present invention.
[0032] The present invention provides a multi-stage depressed collector with dual corrugated electrodes comprises at least one clamping structure in the form of an adapter, a conical end plate attached to the last electrode, a plurality of collector electrodes sequentially applied with increasing depression potential, at least one insulating material arranged at the contact position of each collector electrode, and a beam refocusing section (BRS) having at least three periodic permanent magnets (PPM). The plurality of collector electrodes further comprises dual corrugation having two sections of positive slope taper region followed by a short zero-slope region.
[0033] According to an embodiment of the present disclosure, at least three periodic permanent magnets are having a reduced magnetization value configured to introduce an optimized leakage magnetic field within the plurality of collector electrodes.
[0034] According to an embodiment of the present disclosure, the plurality of collector electrodes applies a genetic algorithm-based code for optimization of the collector electrode geometry parameters, collector voltages, and leakage magnetic field values.
[0035] According to an embodiment of the present disclosure, the invention comprises a clamping structure in the form of collector adapter fabricated with a non-magnetic material configured to introduce the leakage magnetic field from the beam refocusing section. The non-magnetic material used for the fabrication of the collector adapter is Monel.
[0036] According to an embodiment of the present disclosure, the plurality of collector electrodes material is made of high conductivity oxygen-free copper and at least one insulating material is alumina ceramic.
[0037] According to an embodiment of the present disclosure, the collector electrode material may be made of a material selected from a group consisting of a metal conductive material, a carbon-based conductive material, and combinations thereof.
[0038] According to an embodiment of the present disclosure, the metal conductive material is at least one of, copper, nickel, nickel-copper alloy, alloy, and combinations thereof.
[0039] The electrode geometry of the present invention contains two-step corrugations in each electrode. This disclosed electrode modification has created a waviness pattern in the retarding electric field of the collector. This type of induced modification in the electric field results in alternating patterns of converging and diverging lens effects towards the electrode region. The electrons with low kinetic energy which are present at the outer circumference of the beam, get affected by this effect, and kinetic energy gradually reduces as it lands softly on the corresponding electrode surface. In view of the foregoing, the collector efficiency of the multi-stage depressed collector has increased.
[0040] Further, in addition to the change in the electrode geometry, the performance of the collector has been studied by introducing leakage magnetic field within the plurality of collector electrodes. The leakage field has been optimized by changing the percentage magnetization values of the three periodic permanent magnets (PPM) in the Beam Refocusing Section (BRS). The optimized electrode geometry, along with the optimized leakage magnetic field, results in a significant increase in the collector efficiency of the space TWT. Since there are many parameters to optimize, a genetic algorithm-based code has been employed for the optimization of electrode geometry parameters, collector voltages, and leakage magnetic field values.
[0041] The results of the optimized dual corrugated collector have been compared with the conventional electrode multi-stage depressed collector in the following table 1. It is evident from the table that an increase of 2.3% has been achieved using the dual corrugated collector as compared to the conventional collector with an optimized leakage magnetic field. This 2.3% increase in efficiency translates to an average power saving of ~20.9 W per TWT. Hence, in a typical communication satellite with 60 such TWTs, total power savings amounts to ~1.25 kW, which in turn results in a cost saving of $2.08 million dollars in the launch cost of the satellite. Also, these calculations are based on the Lockheed Martin Corporation’s patent assigned in 2003. Hence, the cost saving with present economic inflammations would be at least twice the projected amount.

Table 1: Comparison of the performance of the dual corrugated multi-stage depressed collector with conventional collector
Parameter New collector Conventional collector
With Leakage field Without magnetic field
Primary Secondary Primary Secondary Primary Secondary
Collector Efficiency (%) 86.3% 82.0% 85.4% 81.0% 85.1% 79.7%
Percentage Backstreaming current (%) 0.0% 1.4% 0.0% 3.6% 0.0% 0.6%
Percentage Body current (mA) 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

[0042] It could further be seen that introducing the leakage magnetic field has yielded in 1% increase in the collector efficiency and a decrease in the backstreaming current by 2.2%. Since the external magnets are not used for introducing a magnetic field in the collector, it does not increase the size or weight of the space TWT.
[0043] Another novelty employed in the design is the Genetic Algorithm (GA) based optimization approach. Since there are many parameters to optimize namely electrode geometry parameters, collector voltages, and leakage magnetic field values, and these parameters are non-linearly correlated, traditional design approaches are time-consuming and ineffective. The probability of the design getting trapped onto a local optimal result is quite high with the traditional approaches. Hence, the innovative design approach of using GA is very effective and very quick, which is an additional novelty in the disclosed design.
[0044] Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0045] Figure 1 shows a 3-dimensional schematic of cross-sectional view of the multi-stage depressed collector with dual corrugated electrodes. The multi-stage depressed collector with dual corrugated electrodes in this figure shows a clamping structure in the form of an adapter (1), a conical end plate attached to the last electrode (2), a plurality of collector electrodes which are applied sequentially with increasing depression potential (3)-(6). Further, figure 1 shows an insulating material (7) which is arranged at the contact position of each collector electrode, and a beam refocusing section (BRS) having at least three periodic permanent magnets (PPM). The collector electrodes further comprises dual corrugation having two sections of positive slope taper region (8) followed by a short zero-slope region (9).
[0046] A 3-dimensional external circumferential view of the multi-stage depressed collector with dual corrugated electrodes is shown in figure 2. This figure shows an insulating material (7) which is arranged at the contact position of each collector electrode and a clamping structure which is in the form of an adapter (1).
[0047] Further, a 2-dimensional schematic of a cross-sectional view of the multi-stage depressed collector with dual corrugated electrodes is shown in figure 3. This figure shows the cross-sectional view of a clamping structure which is in the form of an adapter (1), a conical end plate attached to the last electrode (2), a plurality of collector electrodes which are applied sequentially with increasing depression potential (3)-(6). Further, the figure shows an insulating material (7) which is arranged at the contact position of each collector electrode. The collector electrodes as shwon in the cross-sectional view further comprises dual corrugation having two sections of positive slope taper region (8) followed by a short zero-slope region (9).
[0048] Below mentioned are some of the non-limiting advantages of the invention:
1. Modification in collector electrode results in an increase of collector efficiency by 2.3%, considering the effect of secondary electrons, which translates to an average power saving of ~20.9 W per TWT. Hence, in a typical communication satellite with 60 such TWTs, total power savings amounts to ~1.25 kW, which in turn results in a cost saving of $2.08 million dollars in the launch cost of the satellite. Also, these calculations are based on the Lockheed Martin Corporation’s patent assigned in 2003. Hence, the cost saving with present economic inflammations would be at least twice the projected amount.
2. The use of a leakage magnetic field has resulted in an additional 1 % increase in the collector efficiency and a decrease in the back streaming current. However, since only the leakage magnetic field has been used, there is no increase in either the size or the weight.
3. The overall length and the diameter of the electrodes are the same as in the conventional collector which provides the flexibility of using similar insulator ceramics. Hence, the change in the electrode geometry doesn’t require any change in the dimensions of the insulators.
[0049] The figures and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of the embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible.

We Claim:

1. A multi-stage depressed collector with dual corrugated electrodes, comprising:
at least one clamping structure in the form of a collector adapter (1);
a conical bottom plate attached to the last electrode (2);
a plurality of collector electrodes sequentially applied with increasing depression potential (3, 4, 5, 6);
at least one insulating material (7) arranged at the contact position of each electrode collector; and
a beam refocusing section (BRS) having at least three periodic permanent magnets (PPM),
wherein the plurality of collector electrodes comprises dual corrugation having two sections of positive slope taper region (8) followed by a short zero-slope region (9).

2. The multi-stage depressed collector as claimed in claim 1, wherein the at least three periodic permanent magnets are having a reduced magnetization value configured to introduce an optimized leakage magnetic field within the plurality of collector electrodes.

3. The multi-stage depressed collector as claimed in claim 1, wherein the plurality of collector electrodes is further configured to apply genetic algorithm-based code for optimization of the collector electrode geometry parameters, collector voltages, and leakage magnetic field values.

4. The multi-stage depressed collector as claimed in claim 1, wherein the collector adapter (1) is fabricated with a non-magnetic material to introduce leakage magnetic field from the beam refocusing section.

5. The multi-stage depressed collector as claimed in claim 4, wherein the non-magnetic material used for fabricating the collector adapter (1) is Monel.

6. The multi-stage depressed collector as claimed in claim 1, wherein the plurality of collector electrodes material is high conductivity oxygen-free copper and at least one insulating material is ceramic.

7. The multi-stage depressed collector as claimed in claim 1, wherein the collector electrode material is made of a material selected from a group consisting of a metal conductive material, a carbon-based conductive material, and combinations thereof.

8. The multi-stage depressed collector as claimed in claim 7, wherein the metal conductive material is at least one of copper, nickel, nickel-copper alloy, and combinations thereof.