What is the efficiency of TWT?

Uniform structure TWTs are usually operated such that the beam velocity is equal to or greater than the cold phase velocity in the supporting slow-wave structure. Typical efficiencies for synchronous structures are about 25%, which can be in- creased to 30-35% by use of a structure with a lower phase velocity.

What is helix TWT?

Helix TWT – in which the radio waves interact with the electron beam while traveling down a wire helix which surrounds the beam. Coupled cavity TWT – in which the radio wave interacts with the beam in a series of cavity resonators through which the beam passes. These function as narrowband power amplifiers.

What are the two basic types of TWT?

A traveling-wave tube (TWT) is a specialized vacuum tube used in wireless communications, especially in satellite systems. The TWT can amplify or generate microwave signals. Two common types of TWT include the Klystron and the magnetron .

How bunching is achieved in TWT?

The faster electrons catch up with the slower electrons and bunching occurs. They repel the electrons in the wire and generate a new one traveling wave in the helix. The energy from bunches would increase the amplitude of the traveling wave in a progressive action that would take place all along the length of the TWT.

Why helix structure is efficient in TWT?

A simple method is described for the initial design of a helix slow-wave structure of this kind to achieve high overall efficiency. It is shown that the use of a section with increased phase velocity increases the beam efficiency of a TWT while reducing the generation of second harmonic power.

What is the primary purpose of helix TWT?

Prevent the electron beam from spreading in the long tube. Reduce the axial velocity of the RF field. Ensure broadband operation. Reduce the noise figure.

What is need of helix in TWT?

Helix acts as a slow wave structure. Applied RF field propagated in helix, produces an electric field at the center of the helix. In TWT, the electron gun focuses the electron beam, in the gap between the anode plates, to the helix, which is then collected at the collector.

What is TWT short for?

‘TWT’ is the abbreviation for ‘Time Will Tell’, most commonly used in the early 2000s via text message.

What is difference between klystron and TWT?

Interaction between EM field and beam of electrons in TWT is continuous over the entire length. Interaction in klystron occurs only at the gaps of resonant cavities. In coupled cavity TWT, coupling effect takes place between cavities. In klystron each cavity operates independently and there is no mutual coupling.

Which type of slow wave structure is used in TWT?

A TWT consists of an electron source, a magnetic focusing system, input and output ports of RF wave, slow-wave structure and collector. The slow-wave structure is held by three bars. TWT system is placed in a metal enclosure or ceramic [2].

What is slow wave structure?

Slow-wave structures are wave-guides or transmission lines in which the wave travels with a phase velocity equal to or less than a certain predesignated velocity of wave propagation.

Why attenuator is used in TWT?

The role of the RF attenuator placed in the center portion of the slow-wave circuit is to prevent feedback oscillation in the TWT. After passing over the slow-wave circuit, the electron beam reaches the collector, and the electron energy is converted to heat and dissipated.

How to calculate the efficiency of a system?

Look at Equation 1 for a theoretical example of an ideal system where each individual component is 99 percent efficient (η is the symbol used for efficiency). Even using ideal values, a system with six different com- ponents results in 94.15 percent efficiency.

What is the formula for a traveling wave tube calculator?

Following equation or formula is used for Traveling Wave Tube (TWT) calculator. Following is the list of useful converters and calculators. ARTICLES T & M section TERMINOLOGIES Tutorials Jobs & Careers VENDORS IoT Online calculators source codes APP. NOTES T & M World Website

How much power can a coupled cavity TWT produce?

A coupled-cavity TWT can achieve 60 kW output power. Operation is similar to that of a klystron, except that coupled-cavity TWTs are designed with attenuation between the slow-wave structure instead of a drift tube. The slow-wave structure gives the TWT its wide bandwidth. A free electron laser allows higher frequencies.

How does a traveling wave tube work in a TWT?

High-power TWTs often use multi-stage collectors as shown in Figure 1. The input voltage creates an additional axial electric field that moves as fast as the electron beam on the wire of the helix. This electric field accelerates (in the positive half-wave) or decelerates (in the negative half-wave) the electrons in the electron beam.