An electron beam is formed in an electron gun and passed through the gaps associated with the two cavities fig. Twocavity klystron amplifier 62801 circuit and wiring. It is given the name reflex klystron because of its reflex action of electron beam. Slow wave structures are also otype but have nonresonant periodic structures for electron interactions. What is probably the primary advantage of the reflex klystron over the twocavity klystron is the mechanism used to tune the device. I think u1 may have to do with getting the reflex klystron started. To study the mode characteristics of the reflex klystron tube and to determine. All these components are enclosed in a glass envelope. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. A singlecavity klystron in which the electron beam is reflected back through the cavity resonator by a repelling electrode having a negative voltage. Reflex klystron amplifier, microwave klystron amplifier slideshare.
Optimization of micromachined reflex klystrons for operation at. For proper working as an oscillator the output voltage needs to be fed back to the input and if positive feedback is taken then only the klystron will oscillate. Reflex klystron working, oscillator and applegate diagram youtube. Find powerpoint presentations and slides using the power of, find free presentations research about two cavity reflex klystron ppt. Find powerpoint presentations and slides using the power of, find free presentations research about reflex klystron. A loop coupling is used inside the cavity to get the output. A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form.
The velocities of electrons emitted from the cathode are modulated to produce a densitymodulated electron beam. The twocavity klystron has mechanical tuning, but the reflex. So basically what was the need for reflex klystron when we had multicavity klystron. Microwave engineering cavity klystron tutorialspoint.
The brothers russell and sigurd varian of stanford university are the. Reflex klystron working free download as powerpoint presentation. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. Reflex klystron free download as powerpoint presentation. In general depending upon the bunching cycles, there are n plus 3 by 4 mode n reflex. This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. Important question and answers on reflex klystron with. Difference between two cavity klystron and reflex klystron.
Reflex klystron article about reflex klystron by the. Reflex klystron oscillator operation application of. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. In this klystron, a single pair of grids does the functions of both the buncher and the catcher. The conventional vacuum tubes, such as triodes, tetrodes, and pentodes, are. Reflex klystron amplifier, microwave klystron amplifier. To study the characteristics of reflex klystron to study the characteristics of reflex klystron. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. These include the two cavity amplifier or oscilator, the reflex klystron, and the multicavity high power amplifier. The 2k28 reflex klystron has a lead protruding through the top of the glass envelope which is used to connect the reflector voltage to the tube. This is the reflex klystron oscillator, which will now be described. What is the difference between the two cavity klystron. The reflex klystron also known as a sutton tube after one of its inventors, robert sutton was a low power klystron tube with a single cavity, which functioned as an oscillator.
Twystron is a hybrid amplifier which uses a combination of klystron and slow wave structures. The reflex klystron contains a reflector plate, referred to as the. Ece questions and answers on microwave engineering with explanation for various interview, competitive examination and entrance test. Reflex klystron used as a lowpower microwave oscillator 2. It is known by this name due to its reflex action of electron beam. Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable.
Series attempts to cover the basic principles underlying the operation of klystrons and planar grid tubes as oscillators and amplifiers. It was used as a local oscillator in some radar receivers and a modulator in microwave transmitters the 1950s and 1960s, but is now obsolete, replaced by semiconductor microwave devices. Performance of an sband klystron at an output power of 200 mw. A klystron is a specialized linearbeam vacuum tube, invented in 1937 by american electrical engineers russell and sigurd varian, which is used as an. The dependence of these characteristics on the beam current, beam voltage, re flector voltage, load, and other klystron design factors. The reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. 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. A reflex klystron is oscillating at the frequency of its resonant cavity. The reflex klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29.
Microwave engineering reflex klystron tutorialspoint. Reflex klystron working, oscillator and applegate diagram. View and download powerpoint presentations on reflex klystron ppt. Ph0101 unit 2 lecture 6 2 reflex klystrons the reflex klystron has been the most used. Reflex klystron oscillators ieee xplore a reflex klystron oscillator. 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. Microwave engineering ece questions and answers page 2. View and download powerpoint presentations on two cavity reflex klystron ppt.
Figure 9 shows a reflex klystron commonly used in microwave equipment. The average power output of this tube is about 70 mw. If the reflector voltage is made slightly less negative, the. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. On this channel you can get education and knowledge for general issues and topics. Yenkapally, moinabad mandal himayathnagar post, hydreabad75.
As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. This microwave generator, is a klystron that works on reflections and oscillations in a single cavity, which has a variable frequency. 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. Pdf study of a reflex klystron emmanuel markoulakis. 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. Klausst 72fvm 36betwixt 22 reflex klystron, volker muehlhaus 21asdf44 the process is referred to as modulation. Klystron multi cavity klystron, reflex klystron, working. Microwave communication questions and answers pdf free download for ece mcqs objective type interview questions lab viva manual gate cat syllabus.
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