Reflex klystron contains of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. Rigid design shear strength precisely engineered experiments. Reflex klystron oscillator pdf source of an electronbeam and the radiofrequency por tion of the klystron is independent of the electron source. Principles of twocavity klystrons twocavity klystron geometry. Important question and answers on reflex klystron with. Reflex klystron working, oscillator and applegate diagram youtube. The name of this klystron is taken due to its reflex act of electron beam. 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.
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 whole set up is as shown in the following figure. Explain the working principle of reflex klystron and derive expression for power and efficiency. The reflex klystron makes use of velocity modulation to transform a continuous electron beam into. Multi cavity klystron used as lowpower microwave amplifier reflex klystron reflex klystron reflex klystron single reentrant cavity as a resonator.
The electron beam emitted from the cathode is accelerated by the grid and passes through the cavity anode to the repeller space between. A small hole in the broad wall of the waveguide is provided, through which output coupling pin of klystron tube enters into the waveguide. The reflex klystron amplifier is used as an oscillator in a modulator in microwave transmitters and radar receivers. Oct 03, 2016 two cavity klystron amplifiers working. It was the first working klystron that physicists and engineers there had been able to observe. Microwave engineering cavity klystron for the generation and amplification of microwaves, there is a need of some special tubes called as microwave tubes.
Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron figure 29. Reflex klystron article about reflex klystron by the. Describe the principal construction and the mode of operation of o klystron. The power gain of a two cavity klystron amplifier is about 30 db. One major type is the reflex klystron, which is used primarily as an oscillator. This is the reflex klystron oscillator, which will now be described. Slow wave structures are also otype but have nonresonant periodic structures for electron interactions. The twocavity klystron utilizes an electron source heater, an anode, and a cathode like a conventional. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range.
Archived from the original pdf on september 24, 2015. Single reentrant cavity as a resonator the electron beam. Dhanalakshmi college of engineering department of ece. It is a low power tube with a single and work as an oscillator. What are the assumptions for calculation of rf power in reflex klystron.
The operation of reflex klystron is understood by some assumptions. The reflex klystron contains a reflector plate, referred to as the repeller, instead of the output cavity used in other types of klystrons. Together, the magnetron and the klystron made possible airborne sband radar, a major factor in securing air superiority for the raf. 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 working free download as powerpoint presentation. The velocities of electrons emitted from the cathode are modulated to produce a densitymodulated electron beam. The reflex klystron is also called as sutton tube invented by robert sutton. As we have already discussed the fundamental principle of operation of a reflex klystron is velocity and current modulation. Sprehn, rettig, peebles and luhmann, of ucla, described experiments in phase locking a 280 ghz backwardwave oscillator and a 140 ghz reflex klystron to a 35 ghz reference. For this article, however, we will focus on another popular type. A reflex klystron is an obsolete type in which the electron beam was reflected back along its. Reflex klystron article about reflex klystron by the free.
The bunching cavities regulate the speed of the electrons so that they arrive in bunches at the output cavity. What is a klystron amplifier, types, differences and their. Following is the list of useful converters and calculators. Klystron is a microwave generator that works on reflections and oscillations in a single cavity, which has a variable frequency. What is the principle of operation of a multicavity klystron. F input signal to the buncher cavity with the help of loop coupling. Reflex klystron consists of an electron gun, a cathode filament, an anode cavity, and an electrode at the cathode potential. 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. Lowpower klystrons are used as oscillators in terrestrial microwave relay. The reflex klystron contains a reflector plate, referred to as the. Following equation or formula is used for reflex klystron calculator. Experiment4 study of the characteristics of the klystron tube. Their work was preceded by the description of velocity modulation by a.
The expected lifetime of a tetrode in uhf service is usually shorter than a klystron ofthesamepowerlevel. 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 in microwave. 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.
Reflex klystron free download as powerpoint presentation. It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. Reflex klystron oscillator operation application of. Microwave engineering reflex klystron tutorialspoint. Reflex klystron working, oscillator and applegate diagram engineering funda. Jul 31, 2018 one major type is the reflex klystron, which is used primarily as an oscillator.
When we switch on the klystron, the heater of reflex klystron is heated up. The essential elements of klystron are electron beams and cavity resonators. Voltages required for operation of reflex klystron tube such as beam, heater and reflector voltage. 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. The klystron power supply also provides all the other d. 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.
The reflex klystron oscillator is a lowpower, lowefficiency microwave oscillator, illustrated schematically in figure 118. Klystron for high gradient accelerator research, in aip conf. How reflex klystron works electrical engineering stack exchange. Normally we use separate components in devices such as radio transmitters and receivers but as frequencies increase the two components merge into one structure and become a. Reflex klystron vacuum tube manufactured goods free.
Explain the operation mechanism of two cavity klystron amplifier with neat sketch. 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. Electron beams are produced from a source and the cavity klystrons are employed to amplify the signals. The electron gun emits the electron beam, which passes through the gap in the anode cavity. A collector is present at the end to collect the electrons.
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. Frequency extension source modules to extend signal generator capability from 50 to 325 ghz. Microwave engineering cavity klystron tutorialspoint. The main difference between two cavity reflex klystron amplifier. 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. The focusing electrodes keep the flow of electrons in the center of glass envelope. Oct 01, 2014 336 microwave linearbeam tubes 0 type table 901 linear beam tubes 0 type cavity \ resonant reflex klystron twystron linearbeam tubes 0type i slowwave structure forwardwave coupledcavity twt i backwardwave chap. The passthrough effect, therefore, contributes to the overall operating efficiency of the transmitter.
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. 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. The electron beam is accelerated towards the anode cavity. Jan 16, 2017 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. Reflex klystron used as a lowpower microwave oscillator 2. Klystron, thermionic electron tube that generates or amplifies microwaves by controlling the speed of a stream of electrons. When switch on the circuit, the electrons starts emitting from the cathode. Modern semiconductor technology has effectively replaced the reflex klystron in most applications. This effect is used to good advantage for automatic frequency control in receivers, and in frequency modulation for transmitters. Reflex klystron vacuum tube manufactured goods free 30.
What is the difference between the two cavity klystron. 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. In this video, i have explained reflex klystron with following points 1. Multi cavity klystron two cavity klystron used as lowpower. Dhanalakshmi college of engineering department of ece ec6701. Typicallifetimesof8,000to15,000hourshavebeenreported. This klystron is totally dissimilar from cavity klystron because it has a single cavity and used for modulation otherwise demodulation. The pulse generator driving this klystron has maximum peak power rating of 14. Cavity of a repeller klystron another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron repeller klystron. Pdf design of pulse power supply for klystron and its.
This type of klystron oscillator is called a reflex klystron because of the reflex. Now understand the concept of reflex klystron in microwave engineering in details through following questions and answers. Other articles where twocavity klystron is discussed. These electrons move at a uniform speed towards the anode until they are attracted by it. It is known by this name due to its reflex action of electron beam. To study the characteristics of reflex klystron the reflex klystron utilizes velocity modulation to convert regular electron beam energy into microwave power. Klystron oscillator reflex klystron traveling wave tube magnetron. 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. In this klystron, a single pair of grids does the functions of both the buncher and the catcher grids.
Another tube based on velocity modulation, and used to generate microwave energy, is the reflex klystron. Reflex klystron is one of the most commonly used microwave low power generators. To study the characteristics of reflex klystron labappara. The reflex version of the klystron, perfected at sperry and in british laboratories, served as the local oscillator in superheterodyne radar receivers. Reflex klystron calculator converters and calculators. Different characteristics of reflex klystron can be determined using the whole associated package for reflex klystron experiments. The difference between reflex and twomulti cavity klystron is that, reflex klystron uses single cavity for modulationdemodulation. The bunches of electrons excite microwaves in the output cavity of the klystron. Initially when the electron beam is emitted by the electron gun, then the early electrons. 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. At microwave frequencies, however, the transit time or angle is large compared to. Reflex klystron is also known as a sutton klystron. The microwaves flow into the waveguide, which transports them to the.
But, these devices are replaced by semiconductor microwave. 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. Introduction to the twocavity klystron amplifier technical. Twystron is a hybrid amplifier which uses a combination of klystron and slow wave structures. Nov 09, 2016 reflex klystron working, oscillator and applegate diagram engineering funda. The schematic diagram of a reflex klystron tube is shown in fig. 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. Klystron multi cavity klystron, reflex klystron, working. In order to achieve higher overall gain, one way is to connect several twocavity tubes in cascade, feeding the output to each of.