What is the maximum theoretical efficiency, frequency range of the reflex klystron. High efficiency klystrons using the com bunching technique. This amplifier is mainly used as an oscillator within a modulator of radar receivers as well as microwave transmitters. The modulator is the dc power supply for the klystron. Bunching process bunching process is called phase focusing effect. It was the first working klystron that physicists and engineers there had been able to observe.
This process is called liga and is a combination of deepetch lithography and electroforming. It means that the high frequencies can be amplified by multi cavity klystron. I have a doubt on how exactly a reflex klystron worksas an rf source. In wikipedia it says that, the electrons are fired into one end of the tube by an electron gun. C explain the resonant modes and the process of electronic tuning in reflex klystron. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. The bunching parameters measure deviations of the multiplicity distribution from a poisson distribution. The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are. Explain the principle of operation of a reflex klystron oscillator and derive an expression for the bunching parameter. Experiment4 study of the characteristics of the klystron tube. Microwave engineering reflex klystron tutorialspoint. D a reflex klystron has vo 2500 volt and frequency 6 ghz and drift space.
A reflex klystron achieves the same bunching by causing the beam to reverse. 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. The initial bunching process should gather as many electrons as possible. The reflex klystron is a singlecavity klystron that overcomes the disadvantages of the. Inspire your inbox sign up for daily fun facts about this day in history, updates, and special offers. So, this is how electrons move in this reflex klystron tube. Full text of klystrons and microwave triodes see other formats. Important question and answers on reflex klystron with. The onedimensional klystron code, dmki, 2 was used to determine that the klystron would operate with about the. From each mode and the band of frequencies over which the circuit can be.
Cavity grids and repeller are plane and parallel, and also very large in extent. Ec 1403 microwave engineering 16 marks questions with. Thermionic cathode is the most common electron gun4 in klystron since thermionic mode of emission of electrons is easy and inexpensive. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. Klystron amplifiers are used in a variety of industries, including satellite systems, television broadcasting, radar, particle accelerators, and in the medical field. Second order bunching in an optical klystron sciencedirect. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Design and analysis of 5045 sband klystron dc electron gun. Dhanalakshmi college of engineering department of ece. The bunching parameters measure deviations of the multiplicity distribution from a poisson distribution, since for this distribution. Operative principles comsol conference 2015 grenoble multiphysics design of a klystron buncher dc beam from gun modulated beam.
Reflex klystron telecommunications engineering mechanics. Following equation or formula is used for reflex klystron calculator. All these components are enclosed in a glass envelope. Maharashtra state board of technical education autonomous isoiec 27001 2005 certified summer 16 examination subject code. Understandexplain the principle of operation of a reflex klystron oscillator and derive an expression for the bunching parameter. Varian box 10 sperry gyroscope rhenium plating for klystron grids box 10 sperry gyroscope investigation of cycleweld process box 10 sperry gyroscope theory of modulation of reflex klystrons basic small signal theory box 10 graphical methods for analysis of velocity modulation bunching. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. 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. The buncher needs to be critically matched to the rf source at the working frequency. A microwave source of surprising range and endurance george caryotakis stanford linear accelerator center, stanford university, stanford ca 94309 abstract this year marks the 60th anniversary of the birth of the klystron at stanford university. The reflex klystron contains a reflector plate, referred to as the. Reflex klystron is invented by robert sutton, so another name of this klystron amplifier is sutton tube. The reflex klystron contains a reflector plate, referred to as the repeller.
Ece questions and answers on microwave engineering with explanation for various interview, competitive examination and entrance test. The power and spectra of the output signal are shown in figure 3, with the stability of the tube apparent, although there is a small ripple on the signal. Determine the amplification process in helix traveling wave tube twt. Velocity modulation is the process that causes the velocity modulated electron.
Klystrons article about klystrons by the free dictionary. 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. Uncorrelated particle production leads to the poisson statistics, thus deviations of the bunching parameters from the poisson values mean correlations between particles and. The reflex version of the klystron, perfected at sperry and. Oct 01, 2014 microwave linearbeam tubes 0 type 90 introduction we turn now to a quantitative and qualitative analysis of several conventional vac uum tubes and microwave tubes in common use. Other articles where twocavity klystron is discussed.
Archived from the original pdf on september 24, 2015. Explain in detail about 2cavity klystron amplifier. So, the design and manufacturing of electron gun is important in making a klystron. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. Microwave engineering ece questions and answers page 6. The main difference between two cavity reflex klystron amplifier.
What are the various modes of operation in the reflex klystron. Explain the bunching process of a twocavity klystron and derive the expression for bunching parameter. Reflex klystron calculator converters and calculators. In the process, he invented the microwave cavity i. Reflex klystron free download as powerpoint presentation. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. Difference between two cavity and reflex klystron two cavity klystron reflex klystron can act as both amplifier and. Maharashtra state board of technical education autonomous.
A method to achieve spatial bunching on the double frequency of the induced energy spread in an optical klystron is described. The reflex klystron oscillator in which the electron beam passes twice. Criteria necessary to construct such a second order buncher and the phase space evolution are presented. The bunched electrons in a reflex klystron can deliver maximum power to the cavity at. Now, let us see bunching process and the modes and reflex klystron, this vertical axis represent the distance from the cavity gap towards the repeller plate, and this. A reflex klystron is an obsolete type in which the electron beam was reflected back.
The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Explain the bunching process of a twocavity klystron and derive the expression for. Characteristics of a reflectiontype microwave modulator. How are oscillations produced in a reflex klystron. The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are still used as signal sources of low output. Ec 1403 microwave engineering 16 marks questions with answers. What changes occurs in the frequency due to the repeller voltage variation. Two cavity klystron is a amplifier where as reflex klystron is an oscillator. The first papers on the theory of the reflex klystron were published by the soviet physicists ia. This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. B derive an expression for the bunching parameter in the reflex klystron. It is known by this name due to its reflex action of electron beam. Application of multi cavity klystron this type of klystron is mostly used for the purpose of amplification of microwave length of frequencies.
Reflex klystrons are the most widely used ultrahighfrequency device. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. Because of security restrictions, which had been imposed by sperry for industrial reasons and by the national defense research council, little was known about this new microwave tube. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. Klystrons chapter microwave and rf vacuum electronic. What are the assumptions for calculation of rf power in reflex klystron.
Understand the velocity modulation process and power output in reflex klystron 12. What is a klystron amplifier, types, differences and their. From each mode and the band of frequencies over which the circuit can be tuned. So, this is how oscillations are sustained in the reflex klystron by to and fro movement of electrons from cavity to repeller space. Lowpower klystrons are used as oscillators in terrestrial microwave relay communications links, while highpower klystrons are used as output tubes in uhf television. Construction and principle of operation, velocity modulation and bunching process applegate diagram. Microwave engineering directional couplers tutorialspoint. Electrons are not intercepted by the cavity anode grid.
Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. This places an upper limit on the efficiency of the device. 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 repeller, instead of the output cavity used in other types of klystrons. 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. Determine the beam current density in multi cavity klystron amplifiers 11. Bunching of electrons is clearly visible in the central region.
In the output catcher cavity, each bunch enters the cavity at the time in the cycle. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. Reflex klystron is one of the most commonly used microwave low power generators. This type of a klystron is called a reflex klystron because of the reflex action of the electron beam. Now, let us see bunching process and the modes and reflex klystron, this vertical axis. If the antenna diameter is 3m and the receiver has a bandwidth of 2mhz with 10 db noise figure. However, these devices are substituted with semiconductor microwave devices.
Lowpower klystrons, particularly reflex oscillators, lost the battle to solidstate. They are manufactured for operation in the decimeter, centimeter, and millimeter wave bands. Reflex klystron the analysis of a reflex klystron is similar to that of a twocavity klystron to some extent and is subjected to the following approximations. Following is the list of useful converters and calculators. Which is impossible and not feasible to use other components for this purpose. In statistics as applied in particular in particle physics, when fluctuations of some observables are measured, it is convenient to transform the multiplicity distribution to the bunching parameters. Ec 1403 microwave engineering two marks questions with. The process can be repeated by including more cavities, until considerable amplification takes place, or until the increased space charge within the bunches prevents tighter bunching. Klystron multi cavity klystron, reflex klystron, working. In this article, well learn about the twocavity klystron s unique build and the concept of electron bunching. Electrons which cross the gap within 90 of the bunch centre are retarded and give up energy to the field of the cavity.
The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. A klystron size is determined by the size of the bunching cavities. Pdf optimization of micromachined reflex klystrons for operation. Pdf progress on a gridded electron gun for a sheet beam. Microwave engineering directional couplers a directional coupler is a device that samples a small amount of microwave power for measurement purposes. Single reentrant cavity as a resonator the electron beam. A loop coupling is used inside the cavity to get the output.321 256 622 1320 1565 1585 333 1202 329 811 1187 1421 358 889 436 1537 1399 42 514 1568 1383 1074 948 1221 181 1343 1033 766 191 783 293 1370 1252 1402 1152 229 1192