A klystron is a specialized linearbeam vacuum tube evacuated electron tube the name klystron comes from the stem form. The name klystron comes from the greek verb klyzo referring to the action of waves breaking against a shore, and the suffix. Microwave engineering reflex klystron tutorialspoint. Nd 15 reflex klystron if a fraction of the output power is fed back to the input cavity and if the loop gain has a magnitude of unity with a phase shift of multiple 27t, the klystron will oscillate. Reflex klystron oscillator operation application of. The reflex version of the klystron, perfected at sperry and in british laboratories, served as the local oscillator in superheterodyne radar receivers. 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. Just as in the klystron, this velocity modulation later translates to current modulation, which then induces an rf current in the circuit, causing amplification. This is the reflex klystron oscillator, which will now be described. Reflex klystron oscillator pdf source of an electronbeam and the radiofrequency por tion of the klystron is independent of the electron source. This is widely used in application where variable frequency is desired as. Reflex klystron is also known as a sutton klystron. Jul 31, 2018 one major type is the reflex klystron, which is used primarily as an oscillator. What is the operating frequency and power output of a reflex klystron.
The reflex klystron is also called as sutton tube invented by robert sutton. Klystron, including the reflex and multicavity klystron. With the signal applied in the first cavity, we get weak bunches in the second cavity. But, these devices are replaced by semiconductor microwave devices. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice.
The twocavity klystron utilizes an electron source heater. Reflex klystron amplifier electronics club microwave engineering. The power gain of a two cavity klystron amplifier is about 30 db. Multi cavity klystron used as lowpower microwave amplifier reflex klystron reflex klystron reflex klystron single reentrant cavity as a resonator. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids.
Klystron power supply, klystron tube, isolator, frequency meter, variable attenuator, detector mount, waveguide stand, vswr meter and bnc cable. The two cavity reflex klystron is a widely used microwave amplifier operated by the principle of velocity modulation and current modulation. This type of klystron is mostly used for the purpose of amplification of microwave length of frequencies. Microwave engineering cavity klystron tutorialspoint. Klystron amplifiers are high power microwave vacuum tubes they are used in some coherent. Together, the magnetron and the klystron made possible airborne sband radar, a major factor in securing air superiority for the raf. Reflex klystron is a lowpower, lowefficiency microwave oscillator another tube based on velocity modulation, and used to generate microwave energy, it contain cathod. Reflex klystron is invented by robert sutton, so another name of this klystron amplifier is sutton tube. These will set up a field in the third cavity, which produces more concentrated bunches and. Amplification of such twocavity klystron is low and hence multicavity klystrons are used.
Reflex klystron consists of an electron gun, a cathode filament, an anode cavity. However, these devices are substituted with semiconductor microwave devices. Explain the working principle of reflex klystron and derive expression for power and efficiency. Nd 15 reflex klystron if a fraction of the output power is fed back to the input cavity and if the loop gain has a magnitude of unity with a phase shift of. Important question and answers on reflex klystron with. To study the characteristics of reflex klystron the reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. Jan 07, 2019 reflex klystron pdf posted on january 7, 2019 by admin 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. I think u1 may have to do with getting the reflex klystron started. This name is given by the name of its inventor robert sutton, it allow the passage of electron beam through a single resonant cavity. The main difference between two cavity reflex klystron amplifier and reflex klystron is that the. Oct 03, 2016 mwe unit 3 topic 36 two cavity klystron amplifier duration.
For this article, however, we will focus on another popular type. 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. There are few intermediate cavities used between buncher cavity and catcher cavity. Frequency extension source modules to extend signal generator capability from 50 to 325 ghz. Due to dc voltage in the cavity circuit, rf noise is generated in the cavity. What is a klystron amplifier, types, differences and their. All the electrons injected from the cathode arrive at the first cavity with uniform velocity. The main difference between two cavity reflex klystron amplifier. Klystron amplifier vacuum tube electrical engineering. What is a klystron amplifier, types, differences and their applications. Laddertype rf circuit supports high efficiency and thermal stability at. Additional cavities serve to velocitymodulate the electron beam and produce an increase in the energy available at the output.
Reflex klystron article about reflex klystron by the. One major type is the reflex klystron, which is used primarily as an oscillator. Electron emitted from the cathode are accelerated and passed through the positive resonator towards negative reflector, which. The velocities of electrons emitted from the cathode are modulated to produce a densitymodulated electron beam. Construction 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. The electron beam emitted from the cathode is accelerated by the grid and passes through the cavity anode to the repeller space between. Current is obtained primarily by secondary emission from the negative. Reflex klystron is one of the most commonly used microwave low power generators. But, these devices are replaced by semiconductor microwave. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. The electron beam emitted from the cathode is accelerated by the grid and passes through the cavity anode to the repeller space between the cavity anode and the repeller electrode.
A klystron is a vacuum tube that can be used either as a generator or as an amplifier of power, at microwave frequencies klystron types there are two basic configurations of klystron tubes 1. Klystron amplifier klystron amplifiers are high power microwave. The twocavity klystron utilizes an electron source heater, an anode, and a cathode like a conventional. 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. Often several modes of oscillation can be observed in a given klystron. The electrons are originally accelerated to high velocity by a potential of several hundred volts and enter a narrow gap that forms part of a cavity resonator system see. Klystron oscillator reflex klystron traveling wave tube magnetron. As shown in the given diagram it is composed of heater, cathode, focusing electrodes and repeller anode. Reflex klystron or repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. These reflex klystrons continued to occupy a significant position in the testing world, and by the mid80s, reflex klystrons were available up into the 100s of gigahertz. To study the characteristics of reflex klystron to study the characteristics of reflex klystron. Reflex klystrons can be frequencymodulated by a voltage applied to the repeller. All these components are enclosed in a glass envelope. Although the power output of a klystron is quite sufficient for relay repeater service, this type of direct modulation is not satisfactory, because the cumulative distortion.
Different characteristics of reflex klystron can be determined using the whole associated package for reflex klystron experiments. Since all intermediate cavities in a multicavity klystron operate in the. Reflex klystron used as a lowpower microwave oscillator 2. It is a low power tube with a single and work as an oscillator.
The helix travelingwave tube twt, the coupledcavity twt, the forwardwave am plifier fwa, and the backwardwave amplifier and oscillator bwa and bwo are also 0type tubes, but they have nonresonant periodic structures for electron inter actions. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons. Microwave engineering reflex klystron this microwave generator, is a klystron. What is the principle of operation of a multicavity klystron. The reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. In order to achieve higher overall gain, one way is to connect several twocavity tubes in cascade, feeding the output to each of. The schematic diagram of a reflex klystron tube is shown in fig. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Nov 09, 2016 reflex klystron working, oscillator and applegate diagram.
The configuration of a typical presentday distributed emission amplifier is similar to that of the magnetron except that the device has an input for the introduction of rf energy into the circuit. Each klystron type, operating as a television visual rf amplifier, will deliver 5. As rf amplifier it requires 30w in input to generate 25 kw pulses at frequencies. 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 working, oscillator and applegate diagram. Lowpower klystrons are used as oscillators in terrestrial microwave relay. In this type of klystron amplifier, the electron beam flows through a single resonant cavity.
The two cavity reflex klystron is a widely used microwave amplifier operated by the. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range. 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. Reflex klystron is a single cavity variable frequency generator of low power and low efficiency. Dhanalakshmi college of engineering department of ece. Which is impossible and not feasible to use other components for this purpose.
The accompanying graphic shows a circuit diagram with a repeller klystron. The electrons are fired into one end of the tube by an electron gun. Introduction to the twocavity klystron amplifier technical. Dig schematic diagram of two cavity reflex klystron oscillator mechanism of operation 1. Mwe unit 3 topic 36 two cavity klystron amplifier duration. As rf amplifier it requires 30w in input to generate 25 kw pulses at frequencies from 960 to 1215 mhz. The electron beam is modulated as it was in the other types of klystrons by passing it through an oscillating resonant cavity but here the similarity ends. Dhanalakshmi college of engineering department of ece ec6701. A reflex klystron is an obsolete type in which the electron beam was reflected back along its path by a high potential electrode, used as an oscillator. Principles of twocavity klystrons twocavity klystron geometry. A loop coupling is used inside the cavity to get the output. To study the characteristics of reflex klystron labappara. Normally 3 to 4 modes are obtainable with the reflector voltage range available with the klystron power supply.
The brothers russell and sigurd varian of stanford university are the. Other articles where twocavity klystron is discussed. What is the difference between the two cavity klystron. The electron gun emits the electron beam, which passes through the gap in the anode cavity. Klystron multi cavity klystron, reflex klystron, working. What is the maximum theoretical efficiency of the reflex klystron. Klausst 72fvm 36betwixt 22 reflex klystron, volker muehlhaus 21asdf44 the process is referred to as modulation.
The reflex klystron amplifier is used as an oscillator in a modulator in microwave transmitters and radar receivers. This type of klystron oscillator is called a reflex klystron because of. Rigid design shear strength precisely engineered experiments. The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. This amplifier is mainly used as an oscillator within a modulator of radar receivers as well as microwave transmitters. It is known by this name due to its reflex action of electron beam. The following figure depicts an example of multicavity klystron amplifier. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into.
Oct 01, 2014 0type tube is the twocavity klystron, and it is followed by the reflex klystron. Threecavity linear beam klystron, designed for pulsed operation in tacan ground or shipboard beacons. Experiment4 study of the characteristics of the klystron tube. Klystron amplifier scalings cathode current density. The electrons are originally accelerated to high velocity by a potential of several hundred volts and enter a narrow gap that forms part of a cavity resonator system see figure, where they are acted upon by a radiofrequency field, which causes a.
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