1) microwave tube is used to generate high power microwave oscillation. In magnetron, the direction of electron movement, radial DC electric field and axial direction are constant.
The magnetic fields are perpendicular to each other, so they belong to orthogonal field devices. Early magnetrons (negative resistance magnetron and cyclotron magnetron)
Because the efficiency is extremely low, it has no practical significance. The first multi-cavity magnetron was built by Soviet engineers .. alekseev and .. 1936 Malyolov.
It was made between 65438 and 0937. 1939, British physicists H.A. bout, H. and J.T. Landauer also made a multi-cavity magnetron. In the second one.
In the second world war, multi-cavity magnetron was widely used in military radar transmitter and played a great role. To 1945, its working frequency has been
Up to 30 GHz. The so-called magnetron generally refers to a multi-cavity magnetron. Magnetron is characterized by high power, high efficiency and reliable operation.
Low voltage, small volume, light weight and low cost. Magnetron is mainly composed of cathode, anode, energy coupling device, magnetic circuit and tuning device.
Assembly (figure 1 magnetron structure). There is no tuning device in the fixed frequency magnetron. Working principle of magnetron
Usually working in mode, the phase difference of microwave electric field between two adjacent resonant cavities is just 180, that is, the direction of microwave electric field is just opposite (Figure 2 is in
The movement of electrons under the action of external DC electric field, magnetic field and microwave field). Although this microwave field is a standing wave field, in the case of mode,
In this case, it is equivalent to two microwave fields with opposite directions on the circumference, and the phase velocities of the two fields are equal. Emit from cathode
Electrons do cycloidal motion under the action of orthogonal electromagnetic fields. Adjust DC voltage and constant magnetic field to make the average drift speed of electrons in the circumferential direction
Degree =/is exactly equal to the phase velocity of the microwave field moving in its direction (where is the average DC field generated by DC voltage in the interaction space)
Value, which is the axial constant magnetic induction intensity), electrons can move synchronously with the microwave field. In the process of synchronous motion, it is in the microwave deceleration field.
The electrons in the microwave field will gradually give their DC potential energy to the microwave field, and will move closer to the anode, and finally be collected by the anode. This part of electrons
Transferring energy into microwave field is beneficial to establish stable microwave oscillation in magnetron, so it is called favorable electron. In the field of microwave acceleration
Some electrons gain energy from the microwave field and move to the cathode, eventually hitting the cathode. This part of electrons is called unfavorable electrons. There are unfavorable electrons.
When the cathode explodes, a large number of secondary electrons are produced, which increases the number of interacting space electrons. The maximum deceleration field is in the electron cluster.
Heart. The electrons on both sides of it are forced to move to the center of the cluster. The maximum accelerating field region is the divergence of electrons.
The electrons in the center and nearby are subjected to a force deviating from the divergent center, which moves to the left and right respectively and is converted into favorable electrons. Thus, in oscillation
In the process of establishing, there are fewer and fewer unfavorable electrons and more and more favorable electrons, which are concentrated in the center of the cluster and gradually form spokes in the interaction space.
Like an electronic cloud. This phenomenon that electrons with different phases automatically cluster into a spoke-shaped electron cloud in the interaction space is called automatic phase.
Focus. The microwave field in the interaction space decays exponentially with the distance from the anode surface. Therefore, the microwave field on the cathode surface is extremely weak.
The cluster effect of electrons is very small, and there are no obvious electron spokes near the cathode, but almost evenly distributed electron hubs are formed.
Among the electrons in the interaction space, favorable electrons account for the vast majority, and they are all in the process of moving to the anode, which is beneficial to electron cyclotron.
The interval is longer, and they can fully convert DC potential energy into microwave energy; Less electrons return to the cathode and are emitted from the cathode.
It hits the cathode shortly after launch, so it absorbs less energy from the microwave field. In this way, all electrons in the interaction space interact with the microwave field.
The overall effect is that electrons provide DC potential energy to the microwave field, and a stable microwave oscillation is established in the magnetron. positive electrode
Resonance system The anode resonance system consists of a group of closed resonance cavities arranged along the circumference. Magnetron as an oscillator needs some energy storage.
In order to maintain microwave oscillation, anode resonance system is required to have high quality factor. At the same time, in the magnetron, the energy of oscillation is needed.
It can only be used if it is output through an output device. Therefore, the design of energy coupling elements in anode resonance system is very important. Coupled output is necessary.
A certain amount of energy should be used, and the anode resonance system should have a high quality factor, maintain a sufficiently high energy storage, and maintain the stability of the magnetron.
Work. The magnetron works in mode. In order to ensure the stable operation of modules, there should be a good mode division between adjacent modules, so
Anode resonance system with diaphragm belt or rising sun cavity is often used. The anode resonance system of fig. 3 magnetron is a common magnetron.
Structure of anode resonance system. Classification and application The working state of magnetron connection can be divided into pulse magnetron and continuous wave magnetron.
According to the structural characteristics, it can be divided into ordinary magnetron, coaxial magnetron and anti-coaxial magnetron; According to whether the frequency is adjustable, it can be divided into fixed frequency magnetic control.
Electron tube and frequency adjustable magnetron. Frequency adjustable magnetron can be divided into mechanically tuned magnetron and frequency agile magnetron. There is also a kind of borrowing.
Voltage-tuned magnetron with frequency tuning by changing anode voltage. The working pulse width of pulsed magnetron can reach 0.004.
0 ~ 60 microseconds, the working frequency is between 250 MHz ~ 120 GHz, and the pulse power is from tens of watts to tens of megawatts, with high efficiency.
It can reach 70% and its service life can reach tens of thousands of hours. Pulsed magnetron is widely used in guidance, fire control, altimetry, airborne, shipboard, meteorological and other mines.
Tazhong Continuous wave magnetron is used in electronic countermeasures, industrial heating and microwave physiotherapy. Low power is between 400 ~ 1000 watt.
The expensive CW magnetron is also widely used in household microwave ovens. In order not to interfere with the normal work of radar and communication equipment, medical and industrial heating
The working frequency of magnetron for cooking is usually 9 15 25 MHz and 2450 50 MHz. Frequency-adjustable magnetron, especially
Frequency agile magnetron can improve the anti-jamming ability of radar. Voltage-tuned magnetron is usually used as the power supply of electronic countermeasures equipment.
Source, can provide several watts to hundreds of watts of continuous wave power. It has the advantages of fast tuning speed and good tuning linearity. Low power voltage tuning magnet
The tuning range of the control tube can reach 2: 1, 4: 1, or even 20: 1, which can greatly improve the electronic countermeasures capability of various radars. Its main disadvantage is loss.
The output power is not large enough to be used in radar electronic countermeasures. Coaxial magnetron Coaxial magnetron is a common magnetron.
The wing cavity (called inner cavity) is formed by adding a coaxial cavity (called outer cavity) with high quality factor, and the coaxial cavities are coupled with each other on the back wall of the inner cavity.
The closed gap couples the fields of the inner cavity and the outer cavity (coaxial magnetron structure in Figure 4). Coaxial magnetron has the advantages of good mode division and good operability.
It has the advantages of high efficiency and good frequency stability, and is often used in moving target display, precision tracking and ranging radar. The anti-coaxial magnetron consists of an inner anode and an outer cathode.
And the cathode area can be increased. The working wavelength of coaxial magnetron can be as short as millimeter wave band. This magnetic control
The characteristics of this tube are high power, high efficiency and good frequency stability.
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klystron
2) A microwave electron tube that realizes amplification or oscillation by periodically modulating the speed of the electron beam. In klystron, enter the letter of the cavity gap.
The electric field of 1 modulates the electron velocity and forms density modulation in the drift electron beam; Gap between density modulated electron beam and output cavity
The microwave field is converted into energy, and the electrons give the microwave field kinetic energy to complete the function of amplification or oscillation. USA 1937
Physicists Varian, R.H. and S.F. Varian made a double-cavity klystron oscillator. The reflection klystron was designed by Soviet engineers in 1940. ..
Tjevakovic, .. Daniel Tjevi, ... Booth Kunovits and ... Ke Varenko developed them respectively. Electronic travel
Trajectory, klystron is divided into direct klystron and reflective klystron. Direct klystron is usually referred to as klystron for short. Projectivity
The structure of klystron includes the following parts: electron gun, resonant cavity, wiping system, inter-cavity drift tube and energy.
Coupler, collector and focusing system. A klystron with two resonant cavities is called a double-cavity klystron; There are more than two resonant cavities.
Multi-cavity klystron The double-cavity klystron (schematic diagram of +0A klystron in Figure 65438) has only two resonant cavities, namely the input cavity and the output cavity. pass by
The electron beam generated by the electron gun first reaches the gap of the input cavity. The input microwave signal is sent to the input cavity through the energy coupler and is in the gap of the resonant cavity.
Forming an external microwave signal voltage. Here, the electron beam is modulated by the speed of the microwave field and then enters the field-free drift tube. In the process of drifting
Electrons gather and form density modulation in the electron beam. The density modulated electron beam exchanges energy with the microwave field in the gap of the output cavity,
Electrons provide energy to the microwave field and complete the function of amplification or oscillation. Microwave power is sent to the load through the energy coupler. Double cavity
The gain of klystron is only about 10 dB. In order to improve the gain, one or more intermediate cavities can be arranged between the input cavity and the output cavity.
Cascaded amplifier. This kind of klystron is called multi-cavity klystron (figure 1b klystron schematic diagram). The introduction of the intermediate cavity can also improve the efficiency; if
The frequency of each cavity is slightly different, which can expand the broadband. Multi-cavity klystron has the characteristics of high gain, high efficiency, good stability and high output power.
The disadvantage is narrow frequency band. The stable gain of multi-cavity klystron can reach 80 dB, the highest efficiency can reach 75%, and the pulse power can reach 60 MW.
The afterwave power can reach 65438±0mw. The general frequency band is only 1% ~ 2%, and individual high-power pulse klystrons can reach 10% ~ 12%. electric current
After the electron cluster is emitted from the cathode, it is accelerated by high voltage, and all electrons reach the input cavity at the same speed. wait for
The amplified microwave signal enters the input cavity, and the microwave signal voltage is established on the gap. The voltage across the gap varies sinusoidally with time. Are you online?
At the same time, the electrons reaching the gap are subjected to different instantaneous voltages (electron bunching in klystron in Figure 2). = Time, gap
The gap voltage is equal to zero. At this time, the electrons passing through the gap neither accelerate nor decelerate, but still move forward at the original speed.
. =, the gap voltage is negative maximum (the voltage direction is negative when electrons are subjected to deceleration force and positive when they are subjected to acceleration force). exist
At this time, the speed of electrons passing through the gap slows down. After passing through the gap, these electrons move forward at a lower speed than before and gradually fall behind.
After a certain distance, these electrons gather with the electrons passing through the gap later (). =, the gap voltage is positive.
Maximum value. At this time, the electrons passing through the gap are accelerated. After passing through the gap, these electrons move forward at a higher speed than before.
After a certain distance, these electrons will catch up with the electrons flying out of the gap at any time. The electrons passing through the gap between ~ decrease.
Speed, electrons are accelerated through the gap between ~. In this way, the injected electrons are velocity modulated in the gap of the input cavity and drift without field.
After flying in space for a certain distance, fast electrons catch up with slow electrons and form electron groups there. This is the phenomenon of electron clustering. So,
In the second cavity, the electron density changes periodically with time, that is, density modulation (electron clusters in klystron in Figure 2) is formed. This produces electricity.
The sub-beam current contains a certain AC component. When the electron group passes through the gap of the output cavity, it is in the microwave deceleration field. When electrons slow down, they will put
Kinetic energy is given to the microwave field of the output cavity to complete the amplification of the input signal. The commonly used electron gun for electron gun klystron is cathode control gun.
, anode control gun, grid control gun, non-interception grid control electron gun and magnetron injection hollow injection electron gun (see traveling wave tube, high current electron optics).
There are two kinds of resonator in common use: double-entry cylindrical resonator and double-entry angle cylindrical resonator (Figure 3: Klystron is commonly used.
Resonant cavity). Cylindrical cavity is used for klystron with fixed frequency or small tuning range, which is tuned by capacitor. The resonant cavity can be installed outside the tube (external cavity
Type I klystron) or in-tube (intracavity klystron). Klystron with longer working wavelength and wider frequency band can be made into external cavity type. invest
The cavity or output cavity is connected with the microwave system outside the tube through an energy coupler. The frequency band of a simple output cavity is very narrow. In order to broaden the frequency band of the output circuit, we can
Filter output circuit and distributed interaction circuit (distributed interaction klystron) or slow wave circuit output section (traveling wave speed klystron) are adopted.
The common focusing methods of medium-speed klystron in focusing system include uniform permanent magnet focusing, periodic permanent magnet focusing, uniform electromagnetic focusing and electrostatic focusing.
When the collector electrons hit the collector, the remaining kinetic energy is converted into heat energy. In order to conduct away heat, it is very necessary to collect high and medium power klystrons.
Liquid cooling, air cooling or evaporative cooling shall be adopted. Application of direct-fired klystron application of continuous wave amplification klystron in tropospheric scattering
Signal and microwave relay communication, satellite communication ground station, TV transmitter, airborne and ground radar, microwave industry heating and converting energy into micro
In the form of waves. The working frequency of modern CW amplifier klystron is between 220 MHz and 36 GHz, and the output power is from several hundred watts.
To 1 MW. Pulse amplification klystron is used in radar and charged particle accelerator. Working frequency of modern pulse amplification klystron
Cloth in the range of 220 MHz to 18 GHz, pulse power from 1 kW to 60 MW. In the direct-fired klystron, part of it is lost.
The output power can be fed back to the input cavity to form an oscillator, which can be used in parametric amplifiers, navigation stations and so on. Double cavity klystron can be used for frequency doubling.
Single cavity klystron for generating microwave oscillation. It has the characteristics of simple structure, reliable operation, small volume, light weight and low power consumption.
Low voltage, electromechanical tuning, little change of parameters with ambient temperature, strong radiation resistance. The output power of the reflex klystron is 65438 00 MW.
Watts to 2.5 watts, working frequency between 800 MHz and 220 GHz, mechanical tuning range 1% ~ 15% (millimeter wave tube reaches 40%), electronic
The tuning range is 0. 1% ~ 1.0%. The efficiency is 20% ~ 30%. Reflective klystron includes cathode, resonant cavity, reflector and energy in structure.
Quantity coupler and other parts (Figure 4 schematic diagram of reflection klystron). Electrons are emitted from the cathode, accelerated and passed through the resonant cavity.
Gap. It is modulated by the microwave electric field velocity outside the gap, and then enters the deceleration field between the resonant cavity and the reflector (the potential of the reflector is negative to the cathode).
Extremely). Under the action of deceleration field, all electrons will be reflected back. Rotating process of electron beam in deceleration field under velocity modulation
Density modulation is formed in. When the electron beam passes through the gap again, the collected electrons provide energy to the cavity microwave field to maintain oscillation. Oscillating operation
This rate is sent to the load through the energy coupler. Electrons are collected by cavity walls or other metal parts. Reflective klystron is widely used in the field of low power.
Signal sources, oscillators and various microwave equipment, but due to the competition of semiconductor devices, the output has a downward trend. However, in the 1980s.
At first, it was still the largest tube type produced in microwave tubes.
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Traveling wave tube
3) Microwave electron tube with amplification function by continuously modulating electron beam speed. In traveling wave tube, electron beam is transmitted through slow wave circuit.
Microwave fields interact with each other. In the slow-wave circuit with 6 ~ 40 wavelengths, the electron beam constantly gives kinetic energy to the microwave signal field.
And the signal is amplified. 1943, physicist Kompfner r made the world's first traveling wave tube in Britain, 1947, American physicist.
The scientist J Pierce published a theoretical analysis of TWT. Modern traveling wave tubes have become the key technologies for radar, electronic countermeasures, relay communication, satellite communication,
Important microwave electronic devices for TV direct broadcast satellites, navigation, remote sensing, remote control, telemetry and other electronic equipment. The characteristic of traveling wave tube is frequency bandwidth,
High gain, large dynamic range and low noise. The bandwidth (the difference between the high and low frequencies of the band/the center frequency) of the traveling wave tube can reach more than 100%.
The gain is in the range of 25 ~ 70 dB, and the noise coefficient of low noise TWT can reach 1 ~ 2 dB at the lowest. Traveling wave tube is structurally
Comprises an electron gun, a slow-wave circuit, a concentrated attenuator, an energy coupler, a focusing system and a collector (Figure 1 TWT structure diagram).
The function of the electron gun is to form an electron beam that meets the design requirements. The focusing system keeps the electron beam in the required shape and ensures the smooth passage of the electron beam.
The slow wave circuit interacts effectively with the microwave field, and finally the electron beam is received by the collector. The microwave signal to be amplified is input with energy.
The coupler enters the slow-wave circuit and propagates along it. The electrons exchange energy with the advancing microwave field, so that the microwave signal is amplified.
. The amplified microwave signal is sent to the load through the output energy coupler. The principle of traveling wave tube, electron beam and slow wave
Interaction of microwave fields in circuits. The microwave field propagates along the slow-wave circuit. In order to generate an effective phase between the electron beam and the microwave field
Interaction, the DC motion speed of electrons should be slightly higher than the phase velocity (phase velocity) of microwave field propagating along slow wave circuit, which is called synchronous rod.
Pieces. The input microwave signal creates a weak electromagnetic field in the slow-wave circuit. After the electron beam enters the interaction region of the slow-wave circuit, firstly,
It is modulated by the speed of the microwave field. As the electrons move forward, density modulation is gradually formed. Most electrons gather in the deceleration field.
And that residence time of electron in the deceleration field is relatively long. Therefore, part of the kinetic energy of the electron beam is converted into the energy of the microwave field, thereby generating a microwave signal.
It's magnified. Under the condition of synchronization, the interaction between electron beam and traveling wave microwave field continues along the whole slow wave circuit. this is
The fundamental difference between traveling wave tube and klystron in principle. Electron gun TWT commonly used electron guns are Pierce parallel current electron gun and leather.
Wells convergent electron gun, high conductivity electron gun, anode-controlled electron gun, grid-controlled electron gun, grid-controlled electron gun without interception (Figure 2: grid-controlled electron without interception).
Gun schematic diagram), low noise electron gun, etc. Traveling wave tube working in pulse mode can be controlled by cathode voltage.
Realizing the modulation of electron beam is called negative control. Cathode control needs to be equipped with a high power modulator, which is bulky, complex and consumes a lot of power. use
The additional modulation anode controls the electron beam, which is called positive control. The pulse voltage required for positive control is also relatively high. Install one between cathode and anode.
The control grid constitutes a grid-controlled electron gun. In this case, the electron beam can be controlled only with a lower pulse voltage, so the pulse voltage can be reduced.
Modulator volume, weight and power consumption. In a grid-controlled electron gun, the control grid intercepts about 10% of the electron beam current. Traveling wave time
When the electron beam power of CRT is high, the dissipation power of control grid increases, which leads to the increase of grid temperature, the increase of grid electron emission, grid deformation and even.
Burning. In order to solve this problem, a grid-controlled electron gun without interception can be used. The intercept-free grid-controlled electron gun is located between the control grid and the cathode.
A cathode grid is placed, which has the same potential as the cathode and is precisely aligned with the control grid in structure, so that the intercepted current of the control grid is reduced to the total current.
Less than one thousandth. The use of non-interception grid-controlled electron gun can not only improve the average power capacity of grid-controlled traveling wave tube, but also reduce the modulator.
The power of. The common focusing methods in traveling wave tube of focusing system are uniform permanent magnet focusing, reverse field focusing and periodic permanent magnet focusing.
And uniform electromagnetic focusing (see high current electron optics). The DC speed of electron beam in slow wave circuit depends on the working voltage of traveling wave tube.
. When the working voltage of TWT is 2.5 kV, the DC speed of electron beam is about 10% of the speed of electromagnetic wave in free space. operating voltage
When the voltage is 50 kV, the DC speed of electron beam is about 40% of the speed of electromagnetic wave in free space. In order to generate an effective phase between the electron beam and the microwave field
The phase velocity of the microwave field should be slightly lower than the DC velocity of the above electron beam. Therefore, the phase velocity of microwave field in TWT should be obviously lower than its own phase velocity.
Through that propagation speed of electromagnetic wave in space. Slow wave circuit is a device to reduce the phase velocity of microwave field. In the selected working mode,
The main characteristics and parameters of slow-wave circuits are dispersion characteristics and coupling impedance. The dispersion characteristic represents the phase of microwave field propagating in slow-wave circuit.
The relationship between speed and frequency. For the slow-wave circuit of broadband traveling wave tube, the change of phase velocity with frequency should be as small as possible within the bandwidth, that is,
The dispersion is very weak. In this way, the phase velocity synchronization of electron beam and microwave field can be ensured in the whole frequency band. Coupling impedance is the expression of electron beam.
A parameter of the intensity of interaction with microwave field. The greater the coupling impedance, the stronger the coupling between microwave field and electron beam, and the stronger the coupling between electron beam and microbeam.
The more energy is exchanged between wave fields. In addition, in practical application and production, slow-wave circuits are required to have high mechanical strength and good heat dissipation performance.
Simple structure and easy processing. There are two kinds of slow-wave circuits commonly used in traveling wave tubes: spiral circuit and coupling cavity circuit (Figure 3
Slow wave circuit commonly used in traveling wave tube). Spiral slow-wave circuit includes spiral line, loop line, loop line, etc. Spiral (fig. 3a traveling wave
The slow-wave circuit commonly used in electron tubes has a simple structure and weak dispersion, so the frequency band is wide. The disadvantage is that the heat dissipation ability is poor and it is easy to reflow when the working voltage is high.
Wave oscillation. Helical lines are mostly used in broadband, medium and small power traveling wave tubes, and the working bandwidth can reach more than 100%, I-band (8 ~ 10 GHz) and J-wave.
The pulse power of a section of (10 ~ 20 GHz) spiral traveling wave tube has reached 10 kW. The ring rod wire (the slow-wave circuit commonly used in the traveling wave tube of fig. 3b) is the same screw.
Compared with helix, helix has high coupling impedance, strong heat dissipation and good mechanical strength, and is not easy to cause backward wave oscillation, but has strong dispersion. Working electricity of annular pole wire
The voltage 10 ~ 30 kV and the bandwidth 15% ~ 20% are widely used in medium power traveling wave tubes. Loop line (fig. 3c, usually used for traveling wave tube, is slow.
Wave circuit) has good performance in suppressing backward wave oscillation and has also been applied. The coupled cavity slow wave circuit includes Hughes circuit (Figure 3d
Slow wave circuits commonly used in traveling wave tubes), clover circuits (slow wave circuits commonly used in traveling wave tubes in fig. 3e), and the like. Their characteristic is powerful machinery.
It is suitable for high-power traveling wave tube with high heat dissipation, but its frequency band width is relatively narrow. The pulse power of Hughes circuit TWT is 1.
To several hundred kilowatts, the bandwidth is about 10%. Clover circuits are mostly used in traveling wave tubes with pulse power above 500 kW. In addition, the traveling wave tube
The slow-wave circuits used in are also interdigital slow-wave lines (also used in O-type backward-wave tubes), meander lines and Karp lines. Concentrated attenuation
There should be good impedance matching between the input and output energy couplers and the slow-wave circuit and between all parts of the slow-wave circuit. Bad collocation
Will cause electromagnetic wave reflection. The reflected wave causes feedback, which will lead to parasitic oscillation in traveling wave tube. In order to avoid this oscillation, it is necessary to use slow-wave electricity.
Install a centralized attenuator somewhere on the road. A concentrated attenuator consists of a lossy coating or a lossy ceramic sheet. At the concentrated attenuator, reflection
When the wave is absorbed, the feedback can be eliminated and the oscillation can be suppressed. Although the microwave field in the working mode in the concentrated attenuator is also attenuated
However, the density modulation already formed in the electron beam will re-establish the microwave field in the next circuit. Collector electron injection
After interacting with the microwave field, it is emitted from the slow-wave circuit and finally hits the collector. In order to improve the overall efficiency of TWT, we can adopt
Bucking collector. Application of traveling wave tube Pulse traveling wave tube is used in ground fixed and mobile radar, airborne fire control radar, electricity.
Sub-countermeasure equipment, etc. Traveling wave tube with pulse power 10 kW to 4 MW and frequency band width of 8% ~ 30%; Pulse power 5 kW, frequency
The bandwidth can reach 67%; If the pulse power is 1 kW, the bandwidth can reach more than 100%. High-power CW TWTs are mostly used in satellite communication.
The output power of Shin Earth Station can reach 14 kW at 10 GHz and 1 kW at 38 GHz. A multimode traveling wave tube for an electronic warfare system may
Working in various pulse states and continuous wave states. The pulse rise ratio (pulse power/CW power) of multimode traveling wave tube is 3 ~ 12 dB. print
Traveling wave tube and small traveling wave tube are small in size, light in weight and low in cost, and are suitable for occasions with large consumption, such as phased array radar. Space traveling wave tube
It is a special pipe used in space, with the characteristics of high reliability, long service life and high efficiency. Communication satellites and live TV satellites mostly use lines.
As a launch tube, the service life of the wave tube can reach more than 10 years. O-type backward wave tube in traveling wave tube, energy flow is transmitted along slow wave circuit.
The direction is the same as that of electrons, so the TWT is a forward wave amplifier. In a backward wave tube, the energy flow transmitted along the slow wave circuit.
The direction of electrons is opposite to that of electrons. There are two kinds of backward wave tubes: O-type backward wave tube and M-type backward wave tube. O-type backward wave tube can be divided into working state.
There are three kinds of oscillators, amplifiers and frequency converters, but only backward-wave oscillators are widely used. Therefore, the backward wave tube usually refers to the backward wave oscillation tube. O
The electronic tuning range of W-type backward-wave oscillator is large, which can reach more than 67%, and the highest working frequency can reach 1250 GHz. It is one of the traditional microwave tubes.
A practical device that can reach submillimeter band. O-type backward wave oscillator is used for signal source and low power oscillator.