Traveling Wave Tubes (TWTs) consist of different elements. The most important element of TWT is the RF circuit. RF circuits in helix TWTs need a dielectric support to hold the helix; this support also has an effect on electromagnetic properties of RF circuits. A novel dielectric support is proposed to reduce the second harmonic of helix TWTs. The dielectric support in this structure consists of two sections. The first section consists of dielectric material as used in all TWT(s) supports, and the second one is a ferrite rod replacing a portion of the dielectric support. This configuration can act as a tunable band stop filter. The center frequency of the filter can be adjusted based on the second harmonic of the input frequency to reduce the second harmonic of TWT without any loss on fundamental amplified signal.

In this paper, the new slow-Wave structure called Wave-ring helix to enhance the power of the Traveling Wave tubes is introduced. In this new structure, without increasing the length and radius of the helix, the Wave motion path can be increased to radiofrequency Wave in phase with the electron beam. The results show that in the special frequency range the output power and gain are greater than conventional helix. In this paper, optimization results are presented in cold and hot tests on the new structure. The software CST is used in S-band frequency range.

A linearized relativistic field theory of a plasma-loaded helix Traveling-Wave tube is presented for a configuration where a solid electron beam propagate through a sheath helix enclosed within a loss-free wall in which the gap between the helix and the outer wall is filled with a dielectric. Numerical study of the effect of plasma density on the phase velocity and growth rate has been done. Numerical results show that the plasma have different behaviors in different density limits.

Using a Traveling Wave reduction technique, we have shown that Maccari equation, (2+1) -dimensional nonlinear Schrodinger equation, medium equal width equation, (3+1) -dimensional modified KdV–Zakharov–Kuznetsev equation, (2+1) -dimensional long Wave-short Wave resonance interaction equation, perturbed nonlinear Schro¨dinger equation can be reduced to the same family of auxiliary elliptic-like equations. Then using extended F-expansion and projective Riccati equation methods, many types of exact Traveling Wave solutions are obtained.With the aid of solutions of the elliptic-like equation, more explicit Traveling Wave solutions expressed by the hyperbolic functions, trigonometric functions and rational functions are found out. It is shown that these methods provide a powerful mathematical tool for solving nonlinear evolution equations in mathematical physics. A variety of structures of the exact solutions of the elliptic-like equation are illustrated.

The current study proposed a novel Traveling Wave (TW)-based protection algorithm for power transmission lines using intelligent systems. This algorithm is composed of two parts: the first part of the algorithm distinguishes the internal faults from the external ones, and the other one classifies the fault types and determines the faulted phases. In this research, first, Teager Energy Operator (TEO) was employed to extract TW signals and then, Hidden Markov Model (HMM) was utilized to distinguish the internal faults from the external ones according to the output of TEO. Of note, classification of the fault types and selection of the faulted phases are two important tasks in protection algorithms. In this regard, this study presented a very accurate and robust classification algorithm based on fuzzy systems. This algorithm took into account different ratios of the modal components of the faulted current signal as the input variable of fuzzy systems. The test system was then simulated in PSCAD software and the algorithm was applied in MATLAB. Testing the proposed algorithm with a large number of test signals under different fault conditions confirmed the robustness of both algorithms in terms of internal fault and fault type classifications.

In this paper, a Distributed Amplifier (DA) by using HEMT technology for ultra-wideband application is presented.Creation of Distributed integrated circuit has been investigated for approximately seventy years rapidly to developing semiconductor process technologies in the modern IC design. By using of this method, multiple parallel signals are combined and obtain to increase the bandwidth, enhanced power combining amplitude, and novel design capabilities for IC process. The circuit was designed and simulated in ED02AH technology by using ADS2010. The 4-stage design achieves 15.5 dB of power gain (± 0.5 dB) from 3.1 to 10.6 GHz. Reflected power of the input and output from loads matched to 50 Ohm are all below -10 dB over the bandwidth of the device, as is power transmitted from the output to the input. The device is stable for a wide range of input and output loads.

In this paper, a fully distributed model for a single pole single throw Traveling Wave switch is introduced and important parameters of the switch such as insertion loss, isolation, and reflection coefficient are presented based on the lossy transmission line model of switch. The results of fully distributed model are compared with the semidistributed model’s results and have good agreement with them. By applying the fully distributed model and calculating various switch’s parameters as a function of the switch length and operating frequency, the optimum switch length and operating frequency are obtained versus the parameters of switch, especially the reflection coefficient and isolation in OFF and ON conditions.