Mohammad Sadegh Soltani Gishini, Alireza Ganjovi, Majid Taraz, Masoud Saeed,
Volume 12, Issue 1 (1-2018)
Abstract
In this work, applicability of Particle in Cell-Monte Carlo Collisions (PIC-MCC) simulation method for better understanding of the plasma physical mechanisms and real important aspects of a plasma column driven by surface wave plasma discharges that is used in plasma antennas is examined. Via the implementation of geometry and physical parameters of the plasma column to an Object Oriented PIC-MCC code, the plasma density, electrical conductivity, plasma kinetic energy and electric field inside the plasma column as its essential properties are obtained. The gas within the plasma column is taken to be argon which is kept at the low operational background pressures. The radial increasing and axial decreasing of the electric field in the plasma column is observed. Moreover, the plasma density reduces radially, while it is maximized along the axial positions. It is seen that, the density of charged particles and their corresponding current densities are maximized at the positions closer to the surface wave launcher.
Mohammad Amin Bani, Majid Nazeri, Ahmad Sajedi Bidgoli,
Volume 15, Issue 2 (7-2021)
Abstract
In this paper, the frequency response of a detector antenna is investigated when a layer of dielectric is placed on it. For this purpose, the surface wave theory has been used to explain the propagation of the current pulses in the antenna electrodes. Examinations are also performed of the propagation spectra of two types of terahertz antennas, bow-tie and dipole (with LT-GaAs substrates), on which the dielectrics of gallium arsenide and silica are located. These antennas are simulated through the CST software (FDTD method). The simulations show that the presence of a surrounding dielectric on the surface of an antenna affects the velocity of the current pulse propagation on the electrodes. It is also shown that the change in the thickness and position of the surrounding dielectric have a negative effect on quality of detector antenna by shift its spectral response to lower frequencies.
