Klystron amplifier vacuum tube electrical engineering. The following figure depicts an example of multicavity klystron amplifier. The simplest klystron tube is the twocavity klystron. Explain the bunching process of a twocavity klystron and derive the expression for bunching parameter. Thus basically klystron amplifiers possess less power than their counterparts magnetron and travelling wave tube. Archived from the original on june 19, the best known example is the klystron.
The catcher grids are placed along the beam at a point where the bunches are fully formed. Mcq in microwave communications part 2 ece board exam. Each klystron type, operating as a television visual rf amplifier, will deliver 5. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. An electronic oscillator can also be made from a klystron tube when the second cavity resonator is fed back to the first one with a coaxial cable or waveguide. Download scientific diagram schematic diagram of a two cavity klystron amplifier. Diagram of a twocavity klystron, used as an amplifier and rf signal source at microwave frequencies, and also as an oscillator. Introduction to the twocavity klystron amplifier technical. Microwave engineering ece questions and answers page 2. Diagram of a two cavity klystron, used as an amplifier and rf signal source at microwave frequencies, and also as an oscillator.
Helical waveguides have very nonlinear dispersion and thus are only narrowband but wider than klystron. Pdf subterahertz photonic crystal klystron amplifier. The two cavity klystron is a widely used microwave amplifier operated by the principles of velocity and density modulation. Other articles where two cavity klystron is discussed. The difference between the two cavity klystron and reflex klystron include the following. So lets see 2 cavity klystron amplifier first two cavity klystron amplifier 2 cavity klystron amplifier. Klystron 1 vacuum tube radio technology free 30day. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. Since all intermediate cavities in a multicavity klystron operate in the same manner, a. Klausst 72fvm 36betwixt 22 reflex klystron, volker muehlhaus 21asdf44 the process is referred to as modulation.
Here a high voltage electron beam is formed, focused and sent down along the glass tube through an input cavity, buncher. The klystron amplifier comprises an input cavity a plurality of intermediate cavities and an output cavity which are arranged along the path of an electron beam for focusing it, and an output waveguide coupled to the output cavity through a coupling opening. In font of cavity resonator a huge crowed of electrons assembles and excites cavity, the oscillation it the cavity takes place and hence we get the r. These will set up a field in the third cavity, which produces more concentrated bunches and. Can a two cavity klystron amplifier be used an oscillator. Klystrons are used as amplifiers at microwave and radio frequencies to produce both lowpower reference signals for superheterodyne radar receivers and to produce highpower carrier. Design and construction of a cavitytype combiner is described to be used in combining output power of pulsed transistor amplifier modules at s band. Two type of twtas, the helix for broadband applications and the coupled cavity for highpower applications are predominant. Two cavity klystron amplifiers working, amplification. The feedback path provides energy of the proper delay and phase relationship to sustain oscillations. In this tube there are two microwave cavity resonators, the catcher and the buncher.
Dhanalakshmi college of engineering department of ece. The klystron processed up to full power very easily with. Akash patil 090240111016 outline introduction two cavity klystron operation performance characteristics application. Thus the device used for amplifying microwave signals is known as two cavity klystron in the year 1937, american engineers russell and sigurd varian developed klystrons. In the output cavity, signals are amplified by bunched electrons. 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.
Klystron power amplifier how is klystron power amplifier. So far, weve taken b 1 in treating beamcavity interaction, which allows for the approximation of the beam as an ideal current source i. The information about klystron amplifier was influenced by the. The simplest klystron tube is the two cavity klystron. A fourway tm010 mode cavity power combiner achieved a transmis sion loss of less than 0. A single cavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. The function of the catcher grids is to absorb energy from the electron beam. Reflex klystron article about reflex klystron by the free. It is the interaction of the cavities with the beam that provides the high levels of amplification that the device can produce. F output from the cavity with the help of loop coupling. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Klystron tube article about klystron tube by the free.
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. Microwave engineering cavity klystron tutorialspoint. Sep 18, 1979 a preferred embodiment of a high power multi cavity klystron amplifier 1 embodying the invention and shown in fig. Explain the operation principle of the cavity klystron with neat sketch. The cavity in this story is a toroidshaped object with the following cross section. As for ec, the development issues for the klystron relate mainly to the cooling of the structure. Electromagnetic analysis of reentrant klystron cavity. With the signal applied in the first cavity, we get weak bunches in the second cavity. Multicavity klystron two cavity klystron amplifier principle velocity modulated tube high velocity electron beam is generated by an electron gun and sent down along a gas tube through an input cavity buncher, drift space field free and an output cavity catcher to a collector electrode anode. Klystron multi cavity klystron, reflex klystron, working.
Multicavity klystron amplifiers nippon electric co. The rf source is a klystron amplifier see section 17. A linear array of five probe antennas is used on a narrow wall of the rectangular waveguide for damping klystron harmonics. Work supported by department of energy contract deac0376sf00515. A preferred embodiment of a high power multi cavity klystron amplifier 1 embodying the invention and shown in fig. Ppt slac klystron lectures powerpoint presentation. Draw the electronic admittance diagram of reflex klystron. Microwave engineering ece questions and answers this is the electronics and communication engineering questions and answers section on microwave communication with explanation for various interview, competitive examination and entrance test. Reflex klystron reduced power from the bunches, in reflex klystron, reduces the reflex klystron of the cavity oscillations and causes a decrease in output power. One present version of the clw modulator meets the following performance. 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. Two cavity klystron amplifier is basically a velocity modulated tube. Other articles where twocavity klystron is discussed.
Draw the equivalent circuit diagram of a reflex klystron. Ppt slac klystron lectures powerpoint presentation free. As shown electron beam is generated by electron gun which passes through the space between input cavity i. A klystron is a specialized linearbeam vacuum tube evacuated electron tube. What is meant by frequency pushing and frequency pulling 6. Content introduction of two cavity klystron construction of two cavity klystron two cavity klystron amplifier performance characteristics application 3. Bb4c6c from alamys library of millions of high resolution stock photos, illustrations and vectors. In the llrf control system of an sband klystron, a pulse modulator generated 140kv95a at a fixed microperveance value of 1. In this video, i have explained two cavity klystron amplifier with following points 1. The two cavity klystron is the simplest klystron tube. Klystron twocavity klystron amplifier electronics desk. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Download scientific diagram schematic diagram of a twocavity klystron amplifier.
I think u1 may have to do with getting the reflex klystron started. After the electron gun there are two focusing electrodes used to keep the electron beam in the center around the glass envelope. A multi cavity klystron amplifier according to claim 1 wherein said output cavity comprises an electroconductive cylinder, electroconductive end plates connected to the opposite ends of said cylinder and provided with axial openings for passing said electron beam, drift tubes secured to the inner sides of said end plates, tuning means electrically connected to one side wall of said cylinder. Reinaldo perez, in wireless communications design handbook, 1998. There are two cavities known as buncher and catcher cavity. Amplification of such twocavity klystron is low and hence multicavity klystrons are used. The term klystron is taken from the stem form of a greek verb klys referring to the flow of waves breaking next to a shore, as well as the last part of the term electron. Review of highpower microwave source research this. The klystron is mounted directly on the top cover of the modulator. Then it is sent down to a field free drift space and then. Dhanalakshmi college of engineering department of ece ec6701. Since all intermediate cavities in a multicavity klystron operate in the same manner, a representative three cavity klystron will be discussed. Reflex klystron is a lowpower, lowefficiency microwave oscillator another tube based on velocity modulation, and used to generate microwave energy, it contain cathod. Perhaps we can digress a moment to discuss the cavity used in the buncher and the catcher.
The klystron was the first embodiment of the velocity modulation principle. Explain the operation mechanism of two cavity klystron amplifier with neat sketch. What is a klystron amplifier, types, differences and their. Oct 01, 2014 0type tube is the twocavity klystron, and it is followed by the reflex klystron. Obtain electronic efficiency from twocavity klystron. Amplification of such two cavity klystron is low and hence multi cavity klystrons are used. The following figure depicts an example of multi cavity klystron amplifier. Here we are going to study about two cavity klystron amplifier. A twt is sometimes preferred to the multicavity klystron amplifier because the former. Reflex klystron article about reflex klystron by the. Two cavity klystron amplifiers working, amplification and. The inventors of the klystron are two brothers namely sigurd varian and russel from the university of stanford in the year 1937, and available in the year 1939. Diagram of a twocavity klystron, used as an amplifier and rf.
Klystrons are a special type of vacuum tubes that find applications as amplifiers and oscillators at microwave frequencies. The configuration shown in the figure is correct for oscillator operation. A three cavity klystron is illustrated in figure 2 8. The traveling wave tube amplifier twta together with the klystron are known as linearbeam types of microwave devices. The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. Functional and schematic diagram of a twocavity klystron. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. Lowlevel rf control of a klystron for medical linear.
The klystron has six cavities, with each cavity having a series of oversized photonic crystal cells made up of a 5. Figure 2 shows the waveguide harmonic damper design employing coaxial probe antennas. What is the purpose of slow wave structures in twt. Mcq in microwave communications part 4 ece board exam. Water tubing is behind a boat and snow tubing is down a hill. Jul 31, 2018 on each side of the cavity hole is a grid that the electrons pass through. Explain the bunching process of a two cavity klystron and derive the expression for bunching parameter. Introduction a klystron is a vacuum tube that can be used either as a generator or as an. Sep 27, 2017 in this video, i have explained two cavity klystron amplifier with following points 1. The twocavity klystron is a widely used microwave amplifier operated by the principles of velocity and density modulation. Modulator components are all accessible, and are mounted in plugin modules on the side walls of the oil tank which holds the pulse transformer and klystron socket. The rf signal to be amplified is coupled to input cavity. Drift drift electron beam v, cavity v gap 2 i, i, fig. The location is determined by the transit time of the bunches at the.
When installed, the tube projects through holes in the center of the cavity resonators, with the sides of the cavities making contact with the metal rings on the tube. With the aid of the modeling we design a highly tunable cavity that can be tuned from 2 ghz to 22 ghz, and describe how the mode structure transforms from the klystron mode during the tuning. Has a high repeller voltage to ensure a rapid transmit time. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. Mwe unit 3 topic 36 two cavity klystron amplifier duration. It is known by this name due to its reflex action of electron beam. The two cavity klystron in figure 2 7a and b may be used either as an oscillator or an amplifier. Introduction a klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience.
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