This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. Department of electronics and communication subject microwave engineeringeec 603 unitiii 1. Due to dc voltage in the cavity circuit, rf noise is generated in the cavity. Which is impossible and not feasible to use other components for this purpose. Amplification of such twocavity klystron is low and hence multicavity klystrons are used. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. Reflex klystron free download as powerpoint presentation. To read and print pdf files, download adobe acrobat reader. Introduction to the twocavity klystron amplifier technical. Pdf lowfrequency klystron for accelerator applications. A 2cavity klystron amplifier has accelerating voltage volt and frequency 5 ghz and cavity gap 1 mm.
Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. For this article, however, we will focus on another popular type. Of the resulting frequency spectrum only a narrow band, which. Employs a power saver feature to optimize khpa efficiency to meet your operating condition. Reflex klystron is one of the most commonly used microwave low power generators. It is known by this name due to its reflex action of electron beam. Experiment4 study of the characteristics of the klystron tube. Following are the benefits or advantages of klystron.
Sep 27, 2017 in this video, i have explained two cavity klystron amplifier with following points 1. Inspire your inbox sign up for daily fun facts about this day in history, updates, and special offers. What are the high frequency limitations of conventional tubes. The microwave energy modulates the velocities of electrons in the beam, which then enters a drift space.
The reflex klystron contains a reflector plate, referred to as the. Microwave engineering cavity klystron tutorialspoint. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. The main difference between two cavity reflex klystron amplifier and reflex klystron is that the. Two cavity klystron amplifier is not lownoise device. The development of reflex klystron as local oscillator. Jul 31, 2018 technical article introduction to the twocavity klystron amplifier july 31, 2018 by mark mitchell klystron amplifiers are used in a variety of industries, including satellite systems, television broadcasting, radar, particle accelerators, and in the medical field.
We know that british carefully planned all the developmental steps for their radar sets, including the use of microwaves when elsewhere the upper limit of usable frequencies was around 500 mhz. The klystron amplifier is a device used to amplify microwave frequency signals that reach high stages of power gain by applying the principles of the vacuum tube as well as the electron bunching concept. Explain with suitable sketch the operation of twocavity klystron amplifier. Article pdf available in ieee transactions on microwave theory and techniques 5210. With the signal applied in the first cavity, we get weak bunches in the second cavity. In klystron, each cavity operates independently and there is no mutual coupling. Pdf optimization of micromachined reflex klystrons for operation. Gen iv klystron high power amplifier cband highly efficient provides up to 2. For use as an amplifier, a klystron receives microwave energy at an input cavity through which the electron beam passes. The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. Reflex klystron working, oscillator and applegate diagram engineering funda, microwave engineering.
Klystron amplifier free download as powerpoint presentation. The twocavity klystron is a widely used microwave amplifier operated by the. Microwave engineering ece questions and answers page 2. One major type is the reflex klystron, which is used primarily as an oscillator. The losses due to circuit factors can be reduced by a judicious use of the microwave. Two cavity klystron amplifiers working, amplification and.
When used as an amplifier, the weak microwave signal to be amplified is applied to. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. Cw products xband, klystrons microwave power products. These will set up a field in the third cavity, which produces more concentrated bunches and so on. When used as an amplifier, the weak microwave signal to be amplified is applied to the buncher cavity through a coaxial cable or waveguide, and the amplified signal is extracted from the catcher cavity. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. Multi cavity klystron used as lowpower microwave amplifier. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. In general helix travelling wave tubes contains a electron gun and rf interaction circuit. Question bank department of electronics and communication.
The disadvantages of the klystron are that it is usually large and it requires high voltages e. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. Find the gap transit angle and the optimum length of drift space. 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. In this tube there are two microwave cavity resonators, the catcher and the buncher.
Mar 24, 2016 microwave frequencies are millimeter waves so we need to generate them through amplifiers or oscillators,in this video we will learn generation of microwave frequencies using reflex klystron. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. Draw the schematic diagram of helix travelling wave tube. Multistage depressed collector klystron allows the amplifier to use less power and produce less heat than other khpas. On this channel you can get education and knowledge for general issues and topics. The helix travelingwave tube twt, the coupledcavity twt, the forwardwave am plifier fwa, and the backwardwave amplifier and oscillator bwa and bwo are also 0type tubes, but they have nonresonant periodic structures for electron inter actions. This type of klystron is mostly used for the purpose of amplification of microwave length of frequencies. The 6229 employs a grounded anode and a negatively pulsed cathode to generate 0.
The uhf region range of klystron amplifier ranges from 300 mhz3 ghz to 400 ghz. Reflex klystron telecommunications engineering mechanics. Klystron multi cavity klystron, reflex klystron, working. In a velocitymodulated linear beamtype device, such as a klystron or a travelingwave beam tube, stored potential beam energy affects both the bunching process and the process of dc to re energy. The following figure depicts an example of multicavity klystron amplifier. The main difference between two cavity reflex klystron amplifier. An equivalent circuit of the 2k25 amplifier was develop. State the characteristics of the twocavity klystron amplifier. A reflex klystron is an obsolete type in which the electron beam was reflected back. Microwave engineering reflex klystron tutorialspoint. Construction 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. Oct 01, 2014 0type tube is the twocavity klystron, and it is followed by the reflex klystron. 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.
Jensen abstract this report deals with a method of modulating a reflex klystron whereby the message to be transmitted is modulated on a subcarrier, which in turn modulates the klystron through its repeller. The klystron amplifier is capable of some of the highest power levels used in radar many hundreds of kilowatts of average power. The 6229 is a cavity resonatortype magnetron used in the nike i missile guidance unit. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. There are two cavities known as buncher and catcher cavity. At present, klystron and twt amplifiers can deliver a peak power output up to 30 mw megawatts with a beam voltage on the order of 100 kv at the frequency of 10 ghz. The experimental results of microwave amplification by the reflex klystron 2k25 have been reported.
Reflex klystron working, oscillator and applegate diagram. Scribd is the worlds largest social reading and publishing site. Archived from the original pdf on september 24, 2015. Important question and answers on reflex klystron with. A klystron is used either as an amplifier in the microwave region or as an oscillator. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. It means that the high frequencies can be amplified by multi cavity klystron. 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. Klystrons can be used in the uhf region 300 mhz to 3 ghz up to 400 ghz. 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. Why is pulse modulation required in reflex klystron. The general construction of the reflex klystron oscillator and a two. Ece questions and answers on microwave engineering with explanation for various interview, competitive examination and entrance test.
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