This type of klystron oscillator is called a reflex klystron because of the reflex action of the electron beam. All these components are enclosed in a glass envelope. Klystron amplifier length limit load loss magnetic field magnetic flux density magnetron matched maximum measurement microwave mode negative operation oscillator output output power parameters passes path phase port positive potential principle propagation radius rectangular waveguide refer section. Often several modes of oscillation can be observed in a given klystron. To study the characteristics of the reflex klystron tube and to determine the its electronic tuning range equipments klystron power supply, klystron with mount, isolator, frequency meter, variable attenuator, xband detector, bnctobnc cable and oscilloscope theory reflex klystron is one of the most commonly used microwave low power generators. Reflex klystron is also known as a sutton klystron. This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. Mode characteristics of klystron oscillator youtube. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. Reflexklystron oscillators ieee xplore a reflexklystron oscillator. Hence the characteristics of the reflex klystron has been studied. Of the resulting frequency spectrum only a narrow band, which.
This is most widely used in applications where variable frequency is desired as. Klystron with modefrequency characteristics and also explaining two cavity klystron and two cavity klystron working. So, working principle of reflex klystron is velocity and current modulation. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. There are no two identical reflex klystrons, even if. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Apr 12, 2020 microwave engineering lab viva question bank, engineering edurev notes is made by best teachers of.
The reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. Microwave engineering reflex klystron this microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a. A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. Tuning range is achieved for different modes of operation as the repeller. 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 possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice.
The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. So, electron beam is injected from the cathode and that injected beam travel with a. The cavity resonator must be flexible on at least one wall due to the tolerances of the tube manufacturer. Klystron types there are two basic configurations of klystron tubes 1. The developements for the applications of pulse technik in high frequency engineering, attract our attentions. A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies. The main difference between two cavity reflex klystron amplifier. The power output is high in the first mode of operation of the reflex klystron. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. The transit time in reflex klystron obviously depends on the repeller and anode voltages, so that both must be carefully adjusted and regulated. Reflex klystron article about reflex klystron by the.
Microwave engineering cavity klystron tutorialspoint. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output. Each reflex klystron, therefore, has its own calibration protocol. Mode characteristics of klystron oscillator,power and frequency measurement. Different characteristics of reflex klystron can be determined using the whole associated package for reflex klystron experiments. A reflex klystron is an obsolete type in which the electron beam was reflected back. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron.
Reflex klystron oscillator operation application of. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. 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. 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. The schematic diagram of a reflex klystron tube is shown in fig. Multi cavity klystron two cavity klystronused as lowpower microwave amplifier two. This is the reflex klystron oscillator, which will now be described. The reflex klystron is a single cavity variable frequency microwave generator of low power and low efficiency. Once the cavity has been tuned to the correct frequency, both the anode and repeller voltages are adjusted to give the correct value of t from data supplied by the manufacturer. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids.
Reflex klystron in the reflex klystron also known as a sutton klystron after its inventor, robert sutton, the electron beam passes through a single resonant cavity. The reflex klystron is mostly used as a microwave oscillator. The reflex klystron is also called as sutton tube invented by robert sutton. To study the characteristics of reflex klystron to study the characteristics of reflex klystron. Characteristics of coaxial photonic crystal defect microcavity. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. But, these devices are replaced by semiconductor microwave devices.
This report deals with a method of modulating a reflex klystron whereby the. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. The brothers russell and sigurd varian of stanford university are the. Klystron multi cavity klystron, reflex klystron, working. The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Together, the magnetron and the klystron made possible airborne sband radar, a major factor in securing air.
It was the first working klystron that physicists and engineers there had been able to observe. Microwave engineering reflex klystron tutorialspoint. The rf signal to be amplified is coupled to input cavity. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes.
The dependence of these characteristics on the beam current, beam voltage, re flector voltage, load, and other klystron design factors. Reflex klystron used as a lowpower microwave oscillator 2. Article pdf available in ieee transactions on microwave theory and techniques 5210. There are no two identical reflex klystrons, even if they are manufactured in the same series. Pdf optimization of micromachined reflex klystrons for operation. To study the characteristics of the reflex klystron tube and to determine the its electronic tuning range.
To study the mode characteristics of the reflex klystron tube and to determine its electronic tuning range. A device is said to have negative resistance characteristics if, during its operation an increase in the voltage across it leads to decrease in its current. The reflex klystron amplifier is used as an oscillator in a modulator in microwave transmitters and radar receivers. Design of pulse power supply for klystron and its noise characterization. Study of the characteristics of the klystron tube objective to study the characteristics of the reflex klystron tube and to determine the its electronic tuning range equipments klystron power supply, klystron with mount, isolator, frequency meter, variable attenuator, xband detector, bnctobnc cable and oscilloscope theory. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. The 3k27 reflex klystron, with a fullrange tuner, is capable of covering the entire frequency range of 770 to 1150 megacycles by rotation of a single knob, and with an average power output of about 1 12 watts. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. After the focusing electrodes there is a cavity resonator which encircles the glass envelope.
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. 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. A microwave source of surprising range and endurance pdf. Important question and answers on reflex klystron with. Pdf design of pulse power supply for klystron and its.
The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are. Reflex klystron is a single cavity variable frequency generator. It is a low power tube with a single and work as an oscillator. A second type of reflex klystron, known as the 2k28, uses an external cavity. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. As shown electron beam is generated by electron gun which passes through the space between input cavity i. As power oscillator 5 50 ghz if used as a klystron amplifier. Important question and answers on reflex klystron with applications. Due to dc voltage in the cavity circuit, rf noise is generated. The reflex version of the klystron, perfected at sperry and in british laboratories, served as the local oscillator in superheterodyne radar receivers. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Klystron oscillator reflex klystron traveling wave tube.
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