Contents
What is beam coupling coefficient?
Beam coupling coefficient of the hollow cavity on the voltage and the radius of beam. The value of the frequency just inflects the relative magnitude of the beam coupling coefficient and has no influence on the variation with respect to the beam radius.
What is meant by beam loading in klystron?
Beam loading, or the change in resonant frequency and quality factor of a cavity due to an electron beam, plays an important role in klystron operation. The effect of a finite magnetic field leads to less than a 5% change in quality factor and less than a 1% change in resonant frequency for a low perveance klystron.
What is electronic admittance of reflex klystron?
Reflex klystron is a microwave device that works on principle of velocity modulation in addition to current modulation. 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.
What is bunching process in klystron?
The klystron utilizes a phenomenon called electron bunching which goes as follows: Electrons in a beam leaving a source at high velocity all have a roughly equal velocity in the direction of travel. The grid’s negative charge pushes back on the electrons as they pass through the negative left grid slowing them down.
What is transit angle?
the product of (1) the transit time and (2) the angular frequency of the sinusoidal component of the current. It is the phase delay occurring during the charge transit time.
Why is transit time is so important in reflex klystron oscillator?
This travel time is called as transit time, which should have an optimum value. The following figure illustrates this. The anode cavity accelerates the electrons while going and gains their energy by retarding them during the return journey.
What is the difference between klystron and magnetron?
It must operate only as oscillator. Magnetron devices are tunable. This means that output frequency can be changed by varying resonant frequency of cavity. There are two ways to tune the magnetron viz….Magnetron.
| Klystron | Magnetron |
|---|---|
| It can be used both as amplifier and oscillator. | It can only be used as oscillator. |
What is the major disadvantage of klystron amplifier?
Following are the disadvantages of Klystron: ➨Two cavity klystron amplifier is not low-noise device. Due to this fact, usually it is used in the transmitter and not in the receiver. ➨It is a narrow band device due to use of resonant cavities.
What are the applications of reflex klystron?
The reflex klystron amplifier is used as an oscillator in a modulator in microwave transmitters and radar receivers. But, these devices are replaced by semiconductor microwave devices. In this type of klystron amplifier, the electron beam flows through a single resonant cavity.
What is bunching process?
Once the electrons leave the buncher cavity, they drift with a velocity along the space between two cavities. The effect of velocity modulation produces, bunching of electron beam or current modulation.
What is the basic principle of klystron amplifier?
Basically, the operating principle of Klystron is such that the kinetic energy of a moving electron beam is utilized for amplifying and generating microwave signals. TWT i.e., Travelling Wave Tubes are also used for amplification of RF signals and have similar applications as klystrons.
What is transit angle effect?
Transit angle effects The grid potential during the negative half cycle thus removes energy that was given to the electron during the positive half cycle. Consequently, the electrons may oscillate back and forth in the cathode-grid space or return to the cathode.