It was used as a local oscillator in some radar receivers and a modulator in microwave transmitters the 1950s and 1960s, but is now obsolete, replaced by semiconductor microwave devices. What is a klystron amplifier, types, differences and their. Characteristics of the reflex klystron tube to study the characteristics of the reflex klystron tube and to determine its electronic tuning range. Sep 27, 2017 in this video, i have explained reflex klystron with following points 1. Engineering interview questions,mcqs,objective questions,class notes,seminor topics,lab viva pdf free download. The klystron slac national accelerator laboratory stanford. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. The reflex klystron also known as a sutton tube after one of its inventors, robert sutton was a low power klystron tube with a single cavity, which functioned as an oscillator. Home lab manual lecture notes about us contact sitemap privacy. During the first week you will operate a reflex klystron which will be the source of xband. This amplifier is mainly used as an oscillator within a modulator of radar receivers as well as microwave transmitters. Following equation or formula is used for reflex klystron calculator. I was an aetm3c in the navy and also remember those local oscillators. Optimization of micromachined reflex klystrons for operation.
Moreover it uses repeller inplace of catcher cavity. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. The reflex version of the klystron, perfected at sperry and. They propagate in free space freely means that attenuation in free space is. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector. Another drawback inherent in tetrode operation is that the output circuit of the device appears electrically in series with the input circuit and the load 1. Reflex klystron working, oscillator and applegate diagram. Parametric analysis of micromachined reflex klystrons for.
As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. In this video, i have explained reflex klystron with following points 1. The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. This hole is exactly located in the center of broad wall because the. Klystron oscillator reflex klystron traveling wave tube. In convenient laboratory magnetic fields gauss the free electron gyration frequency cy\iotron. The electronic tuning range of the reflex klystron is usually referred to as the variation in frequency between half power pointsthe points in the oscillating mode where the power output is half the maximum output in the mode. What is probably the primary advantage of the reflex klystron over the twocavity klystron is the mechanism used to tune the device. Important question and answers on reflex klystron with.
Operation the klystron was the first embodiment of the velocity modulation principle. Harrison, klystron technical manual, sperry gyro scope company. A microwave source of surprising range and endurance. A reflex klystron is oscillating at the frequency of its resonant cavity. The operation of reflex klystron is understood by some assumptions. Reflex klystron working free download as powerpoint presentation. Microwave engineering kg reddy college of engineering. A reflex klystron consists of an electron gun, a cavity with a pair of grids and a repeller plate as shown in the above diagram. Let us assume that a reference electron e r crosses the anode cavity but has no extra velocity and it repels back after reaching the repeller electrode, with the same velocity.
What is the principle of operation of a multicavity klystron. The dependence of these characteristics on the beam current, beam voltage, re flector voltage, load, and other klystron design factors. Article pdf available in ieee transactions on microwave theory and techniques. Lowpower klystrons are used as oscillators in terrestrial microwave relay. Following is the list of useful converters and calculators. Reflex klystron article about reflex klystron by the free. There are no two identical reflex klystrons, even if. Reflex klystron free download as powerpoint presentation. This klystron is totally dissimilar from cavity klystron because it has a single cavity and used for modulation otherwise demodulation. To study the characteristics of reflex klystron to study the characteristics of reflex klystron. Klystron, including the reflex and multicavity klystron. Klystron works on the principle of velocity modulation of electrons. Jan 07, 2019 a reflex klystron consists of an electron gun, a cavity with a pair of grids and a repeller plate as shown in the above diagram. Reflex klystron oscillator dig schematic diagram of reflex klystron oscillator reflex klystron oscillator the reflex klystron oscillator is a vacuum tube microwave signal generator and its operation depends on the principle of velocity modulation and transit time.
Microwave engineering cavity klystron tutorialspoint. Ph0101 unit 2 lecture 6 2 reflex klystrons the reflex klystron has been the most used. To study the characteristics of reflex klystron labappara. Reflex klystron article about reflex klystron by the. If the reflector voltage is made slightly less negative, the. Draw the electronic admittance diagram of reflex klystron. The basic principle of operation of the microwave tubes involves a transfer of power from a. Since there is no longer a field free drift space in which the velocitymodulated electrons can become bunched, reflectorbunching is the mechanism by which densitymodulation is achieved in the reflex klystron, and the operation is as follows. Jan 31, 2019 since there is no longer a field free drift space in which the velocitymodulated electrons can become bunched, reflectorbunching is the mechanism by which densitymodulation is achieved in the reflex klystron, and the operation is as follows. Reflex klystron oscillators ieee xplore a reflex klystron oscillator.
Pdf optimization of micromachined reflex klystrons for operation. Different characteristics of reflex klystron can be determined using the whole associated package for reflex klystron experiments. This type of klystron is mostly used for the purpose of amplification of microwave length of frequencies. Product description a small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. It was used as a local oscillator in some radar receivers and a modulator in microwave transmitters the 1950s and 1960s, but is now obsolete, replaced by semiconductor. The coarse frequency adjustment of a reflex klystron is accomplished by. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical engineers russell and sigurd varian, which is used as an amplifier for high radio frequencies, from uhf up into the microwave range. Microwave communication questions and answers pdf free download for ece mcqs objective type interview questions lab viva manual gate cat syllabus. Typical operational problems with a klystron input drive power is too low and klystron is not saturated although this is required if the tube is included in a feedback loop reduced output power, efficiency, and increased output power amplitude jitter wrong cathode filament current wrong perveance. What is the purpose of slow wave structures in twt. Reflex klystron used as a lowpower microwave oscillator 2. You will measure its relative output power as a function of frequency and become familiar with the range of operation possible with this 2k25 tube.
Define reflex klystrons, some characteristics and applications. Reflex klystron calculator converters and calculators. There are no two identical reflex klystrons, even if they are manufactured in the same series. Klystron amplification, power output, and efficiency can be greatly improved by the addition of intermediate cavities between the input and output cavities of the basic klystron. The microwave absorption spectrum of oxygen introduction. Slow wave structures are also otype but have nonresonant periodic structures for electron interactions.
The first papers on the theory of the reflex klystron were published by the soviet physicists ia. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Pure carrier wave operation and in external modulation facilities is also provided with the instrument for generalized use. Reflex klystron telecommunications engineering mechanics. Set the variable attenuator to maximum and klystron cathode power supply to. Reflex klystron is invented by robert sutton, so another name of this klystron amplifier is sutton tube. What is meant by frequency pushing and frequency pulling 6.
The electron beam is accelerated towards the anode cavity. Reflex klystron amplifier electronics club microwave engineering. A block diagram of the apparatus is shown in figure 1. The reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. A small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide. Study of the characteristics of the klystron tube objective. The losses due to circuit factors can be reduced by a judicious use of the microwave.
The two cavity reflex klystron is a widely used microwave amplifier operated by the. In this klystron, a single pair of grids does the functions of both the buncher and the catcher. Yes, they had a bellows that was externally adjusted to cause the separation between grids that coupled to a resonant chamber as reflex. Klystron tube 2k25 the klystron tube 2k25 is a single cavity variable frequency microwave generator of low. Experiment4 study of the characteristics of the klystron tube. What are the assumptions for calculation of rf power in reflex klystron. Request pdf parametric analysis of micromachined reflex klystrons for operation at millimeter and submillimeter wavelengths a tool for the simulation of high frequency reflex klystrons is. Klystron oscillator reflex klystron traveling wave tube biological effect of microwaves.
To understand the operation of a reflex klystron i think you need to start with a basic understanding of a tuned circuit made up from a capacitor. Microwave engineering reflex klystron tutorialspoint. Klystron multi cavity klystron, reflex klystron, working. Klystron tube article about klystron tube by the free. Which is impossible and not feasible to use other components for this purpose. They are manufactured for operation in the decimeter, centimeter, and millimeter wave bands.
The schematic diagram of a reflex klystron tube is shown in fig. Reflex klystron oscillator operation application of. My apologies for the long answer but this is a complicated bit of technology and needs an appreciation of the physics behind it. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. The reflex klystron contains a reflector plate, referred to as the. Description of special versions of modern klystron tubes. On this channel you can get education and knowledge for general issues and topics. The ranges of all these voltages are given in the specification data sheet. Connect the components and equipments as shown in the fig. This type of klystron oscillator is called a reflex klystron because of the reflex action of the electron beam. This is the reflex klystron oscillator, which will now be described. The name of this klystron is taken due to its reflex act of electron beam.
Classification of the klystrons, mode of operation of the twocavity, multicavity and reflex klystrons. It is a amulticavity klystron bbwo ccfa dtwt ansb q110 one of the reason why vaccum tubes eventually fail at microwave frequencies is that their anf increase btransit time become too. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. The klystron power supply also provides all the other d. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable.
Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. The general construction of the reflex klystron oscillator and a two. The power output is high in the first mode of operation of the reflex klystron. And the another difference is that in twocavity klystron at this place there is a collector which is used to collect the electron beam coming from the output cavity. The main difference between two cavity reflex klystron amplifier.
Oct 03, 2016 on this channel you can get education and knowledge for general issues and topics. Here high velocity electron beam is formed, focused and sent down along a glass tube through an input cavity buncher, a field free drift space and an output cavity catcher to collector electrodeanode. Can a two cavity klystron amplifier be used an oscillator. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the. However, these devices are substituted with semiconductor microwave devices.
This type of a klystron is called a reflex klystron because of the reflex action of the electron beam. The twocavity klystron is a widely used microwave amplifier operated by the principles of velocity and current. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. Reflex klystrons are the most widely used ultrahighfrequency device. Twystron is a hybrid amplifier which uses a combination of klystron and slow wave structures.
Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. To understand the operation of a reflex klystron i think you need to start with a basic understanding of a tuned circuit made up from a capacitor c and inductor l. Ppt and pdf similar books klystron theory klystron diagram klystron download download reflex klystron operation pdf read online read online reflex klystron operation pdf. Optimization of micromachined reflex klystrons for operation at terahertz frequencies article pdf available in ieee transactions on microwave theory and techniques 5210. During the first week you will operate a reflex klystron which will be the source of xband 8.
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