Tuning range is achieved for different modes of operation as the repeller voltage. Reflex klystron used as a lowpower microwave oscillator 2. This is precision engineered polar pattern microwave test bench, which is widely used for measuring the polar pattern and gain of an antenna. Klystron multi cavity klystron, reflex klystron, working. A simple regulated power supply for characteristics. Microwave and radar engineering presents the essential features of microwave and radar engineering. A simple regulated power supply for characteristics studies of klystron oscillators view the table of contents for this issue, or go to the journal homepage for more. Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Following is the list of useful converters and calculators. As shown electron beam is generated by electron gun which passes through the space between input cavity i.
A reflex klystron is an obsolete type in which the electron beam was reflected back. Velocity modulation, power output and frequency versus reflector voltage electronic admittance. Microwave engineering example problems tutorialspoint. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. Reflex klystron devices are targetted for low power and are small in.
Why is pulse modulation required in reflex klystron. Reflex klystron oscillator operation application of. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into microwave power. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. 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. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. Tube for outer space february 1961 radio electronics article. 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. Mode characteristics of klystron oscillator,power and frequency. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids. Following equation or formula is used for reflex klystron calculator. Mode characteristics of klystron oscillator youtube. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice.
Piskunov, working as a group, and, independently, by the soviet engineer v. But for instance, the very old 723ab reflex klystron, which gives a watt or two of rf, uses ordinary receiver type power supplies, less than 1 kv and no xray precautions were ever required. Special variation to the basic klystron tube is called as reflex klystron. Microwave engineering reflex klystron tutorialspoint.
Ets may be calculated using the relation ets f2 f1 v2 v1 where f1, f2 being half power frequencies in ghz, and v2 and v1 are corresponding repeller voltages for a particular mode. Electrons are not intercepted by the cavity anode grid. The reflex klystron contains a reflector plate, referred to as the. In addition, note that the power output for the various modes. Theoretical output characteristics of a typical xband reflex klystron for a fixed accelerator voltage, v0. Thus the mode characteristics of reflex klystron, mode number, transit time, electronic tuning range etr and electronic tuning sensitivity. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical. Mcq in microwave tubes and circuits from the book electronic communication systems by george kennedy. Reflex klystron amplifier, microwave klystron amplifier. Exp 1 mode characteristics of reflex klystron vacuum tube. It focuses on the needs of students who take up the subject at undergraduate and postgraduate levels of electronics and communications engineering courses. Multi cavity klystron two cavity klystron used as lowpower microwave amplifier two. And the same goes for the length, if the cavity is rectangular.
Reflex klystron calculator converters and calculators. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. Reflex klystron the analysis of a reflex klystron is similar to that of a twocavity klystron to some extent and is subjected to the following approximations. In addition, these are also used for experiments measuring the standard gain horn antenna, parabolic dish antenna, slotted broad wall. The main difference between two cavity reflex klystron amplifier. Your browser does not currently recognize any of the video formats. Cavity grids and repeller are plane and parallel, and also very large in extent.
Klystron types there are two basic configurations of klystron tubes 1. Optimization of micromachined reflex klystrons for operation at. The power output is high in the first mode of operation of the reflex klystron. A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies.
Microwave engineering example problems in this chapter, let us have some fun by solving a few numerical problems related to microwaves. The ordinary type otype traveling wave tube construction features. This is the reflex klystron oscillator, which will now be described. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. Electron emitted from the cathode are accelerated and passed through the positive resonator towards negative reflector, which retards and, finally, reflects the electron. To study the mode characteristics of fiber optic cable and observe the lower order. The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are. Study and analyze the characteristics of reflex klystron. Klystron article about klystron by the free dictionary. From each mode and the band of frequencies over which the circuit can be tuned. The transit time in reflex klystron obviously depends on the repeller and anode voltages, so that both must be carefully adjusted and regulated. Shuichi noguchi, kek6th ilc school, november beamoperation cavity voltage. A small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide.
This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. This influences the desired mode of operation because the most powerful mode has the. Microwave test benches polar pattern microwave test. Reflex klystron amplifier, microwave klystron amplifier slideshare. Reflex klystron or gunn diode characteristics and basic microwave parameter. Rectangular waveguides tetm mode analysis, expressions for fields, characteristic equation and cutoff frequencies, filter characteristics, dominant and degenerate modes, sketches of te and tm mode fields in the crosssection, mode characteristics phase and group velocities, wavelengths and impedance. Reflex klystrons were developed in 1940 by the soviet engineers n. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. 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. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode.
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. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. Ece 662 microwave electronics ppt video online download. 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. Figure 9 shows a reflex klystron commonly used in microwave equipment. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. The rf signal to be amplified is coupled to input cavity. Your browser does not currently recognize any of the video formats available. All these components are enclosed in a glass envelope. Microwave tubes klystron,magnetron,twt traveling wave tube. Ppt and pdf similar books klystron theory klystron diagram klystron download download reflex klystron operation pdf read online. Reflex klystron telecommunications engineering mechanics. Microwave test bench setup at rs 50000 unit microwave. Microwave engineering cavity klystron tutorialspoint.
It follows that the width of the cavity should be just about a halfwavelength of the microwave energy, or any multiple of that. Experiment4 study of the characteristics of the klystron tube. Apr 12, 2020 microwave engineering lab viva question bank, engineering edurev notes is made by best teachers of. Click here to visit our frequently asked questions about html5. To study mode characteristics of a reflex klystron and hence to determine mode number, transit time, electronic tuning sensitivity ets and electronic tuning range etr to study the characteristics of wave propagation in a waveguide by studying standing wave pattern and hence to plot. Microwave spectrum and bands, applications of microwaves. The difference between normal klystron and reflex klystron is that reflex klystron uses single cavity. The first papers on the theory of the reflex klystron were published by the soviet physicists ia.
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