F. Hojjat Kashani, A. A. Lotfi Neyestanak, K. Barkeshli,
Volume 1, Issue 2 (April 2005)
Abstract
A modified circular patch antenna design has been proposed in this paper, the
bandwidth of this antenna is optimized using the genetic algorithm (GA) based on fuzzy
decision-making. This design is simulated with HP HFSS Program that based on finite element
method. This method is employed for analysis at the frequency band of 1.4 GHz- 2.6 GHz. It
gives good impedance bandwidth of the order of 15.5% at the frequency band of 1.67GHz-
1.95GHz and 10.6% at 2.23GHz- 2.48GHz. It means that impedance bandwidth increases above
4.9% than the impedance bandwidth of ordinary circular patch antennas and band width rise
from 1.78GHz- 1.98GHz (10.6%) to 1.67GHz- 1.95GHz (15.5%) and 2.23GHz- 2.48GHz
(10.6%). The antenna fabricated with two slots on circular patch antenna. The measured results
of the optimized antenna validate a high compatibility between the simulation and the
measurements.
Ali Jabbari, Hassan Moradzadeh, Rasul Lotfi,
Volume 19, Issue 4 (December 2023)
Abstract
Along with the development of hybrid electric vehicles, researchers are trying to reduce existing limitations such as noise and environmental concerns and improve the efficiency and reliability of these systems. The use of magnetic gear technology is one of the solutions that have been recently proposed to remove these limitations and achieve higher benefits. In this paper, a mechanically coupled magnetic geared (MCMG) machine has been introduced. An accurate analytical model based on the subdomain method is presented to calculate the magnetic machine performance. To do this, first, a pseudo-Cartesian coordinate system is specified, and then the constitutive equations, i.e. Laplace’s and Poisson’s equations are rewritten for different regions of the machine. The separation of variables method was used to determine the general solution of the equations. Then by applying appropriate interface and boundary conditions, the Fourier coefficients of the equations were determined. To verify the analytical results, the performance of the proposed magnetic machine is numerically simulated using the finite element method in commercial software, and then a prototype is built and tested in three distinct modes. By comparing the analysis results with numerical simulation results and experimental tests, the high accuracy of the proposed analytical model can be confirmed.
