In klystron amplifiers, which are physi cally long, it is difficult to keep the electron beam properly formed during its travel through the rf section. Pdf subterahertz photonic crystal klystron amplifier. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. On each side of the cavity hole is a grid that the electrons pass through.
A klystron amplifier in which the drift tube is in the form of a casing and a central member disposed coaxially about the same centerline to form a coaxial space between the central member and the casing which runs parallel to the centerline, and through which the klystrons electron beam flows. There are few intermediate cavities used between buncher cavity and catcher cavity. Introduction a klystron is a vacuum tube that can be used either as a generator or as an. Mwe unit 3 topic 36 two cavity klystron amplifier duration. As shown electron beam is generated by electron gun which passes through the space.
Klystron 1 vacuum tube radio technology free 30day. With the signal applied in the first cavity, we get weak bunches in the second cavity. The rf source is a klystron amplifier see section 17. A klystron is a microwave vacuum tube using cavity resonators to produce velocity modulation of the electron beam and produce amplification. Klystrons are a special type of vacuum tubes that find applications as amplifiers and oscillators at microwave frequencies. 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. Perhaps we can digress a moment to discuss the cavity used in the buncher and the catcher. 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. It is the interaction of the cavities with the beam that provides the high levels of amplification that the device can produce.
Klystron tube article about klystron tube by the free. Microwave engineering ece questions and answers page 2. In this tube there are two microwave cavity resonators, the catcher and the buncher. Microwave engineering cavity klystron tutorialspoint. Connectlosb 41pu wvguino the output of the 8562 klystron, klystron. The klystron was the first embodiment of the velocity modulation principle. Lowlevel rf control of a klystron for medical linear. Obtain electronic efficiency from twocavity klystron. Bb4c6c from alamys library of millions of high resolution stock photos, illustrations and vectors. Derive the equation for power output and efficiency of two cavities and four cavity klystron amplifiers. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the. F input signal to the buncher cavity with the help of loop coupling. The vacuum tube consists of a cathode, which is heated by a filament.
The following figure depicts an example of multicavity klystron amplifier. Twocavity klystron amplifier 62801 circuit and wiring. Two cavity klystron amplifiers working, amplification. What is meant by frequency pushing and frequency pulling 6.
Microwave tubes and circuits from the book electronic communication systems by george kennedy. As for ec, the development issues for the klystron relate mainly to the cooling of the structure. Klystron twocavity klystron amplifier electronics desk. Download scientific diagram schematic diagram of a two cavity klystron amplifier. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons.
Other articles where twocavity klystron is discussed. In the llrf control system of an sband klystron, a pulse modulator generated 140kv95a at a fixed microperveance value of 1. Amplification of such twocavity klystron is low and hence multicavity klystrons are used. An electron beam is formed in an electron gun and passed through the gaps associated with the two cavities fig. 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 casing and central member are maintained at ground potential, which maintains the space charge. Diagram of a twocavity klystron, used as an amplifier and rf signal source at microwave frequencies, and also as an oscillator. Cpi also offers a series of compact kpas with the same feature sets as the gen iv, but utilizing traditional klystron technology. The adobe flash plugin is needed to view this content. The klystron has six cavities, with each cavity having a series of.
At a very high temperature, the cathode emits electrons. Amplification of such two cavity klystron is low and hence multi cavity klystrons are used. Klystron multi cavity klystron, reflex klystron, working. Download scientific diagram schematic diagram of a twocavity klystron amplifier.
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. All amplifiers are available as single units or in redundant or combined systems. The following figure depicts an example of multi cavity klystron amplifier. Figure 2 shows the waveguide harmonic damper design employing coaxial probe antennas. As a result, the effective smallsignal gain of the klystron at 85% saturation reduces the impedance control by factors of 5 to 20 as compared to a linear power amplifier. Other articles where two cavity klystron is discussed.
So lets see 2 cavity klystron amplifier first two cavity klystron amplifier 2 cavity klystron amplifier. Draw the equivalent circuit diagram of a reflex klystron. Multicavity klystron amplifiers nippon electric co. These electrons move at a uniform speed towards the anode until they are attracted by it. A linear array of five probe antennas is used on a narrow wall of the rectangular waveguide for damping klystron harmonics. 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. Functional and schematic diagram of a twocavity klystron. The direct and comb loop feedback around the rf cavities in pepii is critical in reducing longitudinal instabilities driven by the cavity impedance. Ppt slac klystron lectures powerpoint presentation. Content introduction of two cavity klystron construction of two cavity klystron two cavity klystron amplifier performance characteristics application 3.
Electromagnetic analysis of reentrant klystron cavity. The kaband eik amplifier provides up to 800 watts of kaband power. Draw the electronic admittance diagram of reflex klystron. Klystron amplifier vacuum tube electrical engineering.
This is the multiple choice questions in chapter 11. A preferred embodiment of a high power multi cavity klystron amplifier 1 embodying the invention and shown in fig. A klystron is a specialized linearbeam vacuum tube evacuated electron tube. Ppt slac klystron lectures powerpoint presentation free to download id. Akash patil 090240111016 outline introduction two cavity klystron operation performance characteristics application. Review of highpower microwave source research this. Klystron amplifiers include twocavity power klystrons and multicavity power klystrons. Diagram of a twocavity klystron, used as an amplifier and. 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. 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. 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. One very important item that is required for highpower klystron amplifier operation is an axial magnetic field a magnetic field parallel to the axis of the klystron. The catcher grids are placed along the beam at a point where the bunches are fully formed. The function of the catcher grids is to absorb energy from the electron beam.
Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. The cavities in the klystron are usually adjusted by an inductive tuning slug. When switch on the circuit, the electrons starts emitting from the cathode. 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. The simplest klystron tube is the twocavity klystron. In this video, i have explained two cavity klystron amplifier with following points 1. The location is determined by the transit time of the bunches at the. These include the two cavity amplifier or oscilator, the reflex klystron, and the multicavity high power amplifier. What is the purpose of slow wave structures in twt.
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