In this video, i have explained reflex klystron with following points 1. Klystrons amplify rf signals by converting the kinetic energy in a dc electron beam into radio frequency power. The brothers russell and sigurd varian of stanford university are the. Klystron tube technologies for very high power applications, such as. Reflex klystron free download as powerpoint presentation. Reflex klystron oscillator 10 mechanism of operation a reflex klystron consists of an electron gun, an accelerating grid, a single reentrant cavity and a repeller plate subscribe to view the full document. Pdf optimization of micromachined reflex klystrons for operation. On this channel you can get education and knowledge for general issues and topics. 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. Klystron oscillator reflex klystron traveling wave tube. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. This site is like a library, use search box in the widget to get ebook that you want. Reflex klystron oscillator operation applications of. A free powerpoint ppt presentation displayed as a flash slide show on id.
A coaxial magnetron uses a different architecture and has better stability. Microwave engineering reflex klystron tutorialspoint. A reflex klystron is oscillating at the frequency of its resonant cavity. The rf signal to be amplified is used for exciting the input buncher cavity thereby developing an alternating voltage of signal frequency across the gap a. Reflex klystron telecommunications engineering mechanics. Optimization of micromachined reflex klystrons for operation at. Reflex klystron is a single cavity law power microwave oscillator. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. Pure carrier wave operation and in external modulation facilities is also provided with the instrument for generalized use. So, electron beam is injected from the cathode and that injected beam travel with a. 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.
The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Us2944183a internal cavity reflex klystron tuned by a. In this klystron, a single pair of grids does the functions of both the buncher and the catcher. 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. The output power increases as the repeller voltage is made more negative. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the. A reflex klystron is an obsolete type in which the electron beam was reflected back along its path. Reflex klystron working, oscillator and applegate diagram. Klystron with modefrequency characteristics and also explaining two cavity klystron and two cavity klystron working. To study the mode characteristics of the reflex klystron tube and to determine its electronic tuning range. The velocities of electrons emitted from the cathode are modulated to produce a densitymodulated electron beam. Click download or read online button to get microwave and radar engineering book now.
Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. My apologies for the long answer but this is a complicated bit of technology and needs an appreciation of the physics behind it. And in the cavity gap, the velocity of the electrons is. The sylvania type 6bm6 is a broadband reflex klystron designed for cw operation. 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. The first papers on the theory of the reflex klystron were published by the soviet physicists ia.
A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. This is because the transit time of the electron bunches is decreased. Microwave and radar engineering download ebook pdf, epub. Ppt klystron powerpoint presentation free to view id. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. Klystron multi cavity klystron, reflex klystron, working.
So, electron beam is injected from the cathode and that injected beam travel with a uniform velocity till the cavity. From each mode and the band of frequencies over which the circuit can be. This is the reflex klystron oscillator, which will now be described. Pdf optimization of micromachined reflex klystrons for. A loop coupling is used inside the cavity to get the output. Reflexklystron oscillators ieee xplore a reflexklystron oscillator. Reflex klystron working download as powerpoint presentation. Home communication systems reference and training manuals figure 8. Figure 9 shows a reflex klystron commonly used in microwave equipment. Following equation or formula is used for reflex klystron calculator.
Reflex klystron consists of an electron gun, a filament surrounded by cathode and a focusing electrode at cathode potential. Microwave engineering cavity klystron tutorialspoint. Reflex klystron working free download as powerpoint presentation. 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. Connect the equipments and components as shown in the figure. Download microwave lab manual kami adalah komuniti perkongsian. Lowpower klystrons are used as oscillators in terrestrial microwave relay communications links, while highpower klystrons are used as output tubes in uhf television. The reflex klystron oscillator is a vacuum tube microwave signal generator and its operation depends on the principle of velocity modulation and transit time. The working of reflex klystron is somewhat similar to the working of twocavity klystron. 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 article about reflex klystron by the. Klystron amplifier klystron amplifiers are high power microwave. The reflex klystron contains a reflector plate, referred to as the. The klystron power supply also provides all the other d.
Reflex klystron calculator converters and calculators. If the reflector voltage is made slightly less negative, the. All these components are enclosed in a glass envelope. Klystron oscillator reflex klystron traveling wave tube biological effect of microwaves.
The dependence of these characteristics on the beam current, beam voltage, re flector voltage, load, and other klystron design factors. Set the variable attenuator at the maximum position a zero micrometer reading. The electron beam is accelerated towards the anode cavity. The multi cavity klystron consist of a glass envelope in which there is an electron gun composed of heater and cathode. Ph0101 unit 2 lecture 6 2 reflex klystrons the reflex klystron has been the most used. The electron gun emits the electrons with constant velocity. Each mode has a center frequency of 3,000 megahertz which is predetermined by the physical size of the cavity. The reflex klystron is a single cavity variable frequency microwave generator of low power and low efficiency. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. Klystron tube technologies for very highpower applications, such as. Voltages required for operation of reflex klystron tube such as beam, heater and reflector voltage.
The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Pdf a476, reflex klystron klystron application of reflex klystron klystron reflex klystron pin connection klystrons reflex klystron reflex klystron s band cavity resonator. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. Reflex klystron working vacuum tube microwave scribd. Archived from the original pdf on september 24, 2015. So, working principle of reflex klystron is velocity and current modulation. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. Microwave communication questions and answers pdf free download for ece mcqs objective type interview questions lab viva manual gate cat syllabus.
Reflex klystrons are the most widely used ultrahighfrequency device. A beam of electrons is produced by a thermionic cathode a heated pellet of low work function material, and accelerated by highvoltage electrodes typically in the tens of kilovolts. Optimization of micromachined reflex klystrons for operation at terahertz frequencies article pdf available in ieee transactions on microwave theory and techniques 5210. Klystron, including the reflex and multicavity klystron.
The twocavity klystron is a widely used microwave amplifier operated by the principles of. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. 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. The coarse frequency adjustment of a reflex klystron is accomplished by. The operation of reflex klystron is understood by some assumptions. Connect the components and equipments as shown in the fig. Klystrons make use of the transittime effect by varying the. Parametric analysis of micromachined reflex klystrons for. 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. Following is the list of useful converters and calculators. Unlike a klystron, a magnetron is not a coherent transmission source, but has a. 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.