Showing 7 results for Coupled
H. Ghorbanzadeh, M. Khalaj Amir Hosseini,
Volume 8, Issue 1 (3-2012)
Abstract
The characteristics of dielectric backed planar conducting layers of arbitrarily shaped in a rectangular waveguide are calculated by means of coupled integral equation technique (CIET) which accurately takes higher order mode interactions. Equivalent structures for the accurate analysis whole structure are introduced in which magnetic surface currents are identified as the unknowns at the aperture parts of interfaces in all regions. Spectral dyadic green’s functions are derived for these equivalent structures. A coupled magnetic filed integral equation formulation is proposed which is solved using method of moment (MoM). Then one matrix equation that involves the all magnetic currents of non metallic parts (aperture parts) of discontinuities is derived. This single matrix formulation replaces the procedure of cascading individual GSM’s of each block. By dividing the area of cross section in discontinuities into a given number of subsections, it is possible to model any shape of metallic parts. In this method when the shape of metallic parts (in a given structure) changes, the related coupled integral equations can be extracted from the pre-computed general matrices in a given frequency and there is not need to repeat the all of process. The proposed technique permits modeling of a variety of structures such as cavity-backed micro strip antenna, frequency selective surfaces (FSS’s), waveguide filters with printed irises and generally multilayered media with printed circuits embedded between dielectric layers in a waveguide.
The usefulness of the proposed method and its performance are verified by calculating and simulating of a given structure.
M. Khalaj Amirhosseini,
Volume 9, Issue 3 (9-2013)
Abstract
In this article, three new green's functions are presented for a narrow strip line (not a thin wire) inside or on a homogeneous dielectric, supposing quasi-TEM dominant mode. These functions have no singularity in contrast to so far presented ones, so that they can be used easily to determine the capacitance matrix of multi-layer and single-layer homogeneous coupled microstrip lines. To obtain the green’s functions, the Laplace’s equation is solved analytically in Fourier integral or Fourier series expressions, taking into account the boundary conditions including the narrow strip. The validity and accuracy of three presented green’s functions are verified by some examples.
F. Khamin Hamedani, Gh. Karimi,
Volume 14, Issue 4 (12-2018)
Abstract
A novel dual-band bandpass filter (DB-BPF) with controllable parameters in design process and a compact structure is introduced in this paper. The total structure includes open-circuited and short circuited coupled-lines, leading to a compact circuit. The resonance frequencies, insertion loss and quality factor can be independently controlled by adjusting the coupled lines. In order to eliminate the magnetic and electric coupling effects, the virtual grounds are placed in coupled complementary hairpin resonator. To verify the validity of the design approach, a DB-BPF centring, at 3.5 and 5 GHz with respective insertion losses of 0.7 and 0.58dB for WIMAX (IEEE 802.16 band) and WLAN (IEEE 802.11 band) applications has been designed and fabricated, whose the measured results confirm the electromagnetic simulation.
M. Sanatgar, M. R. Alizadeh Pahlavani, A. Bali Lashak,
Volume 15, Issue 3 (9-2019)
Abstract
This paper presents the control approach for single inverter dual coupled brushless DC motors (DCBLDC) drive system. One of the basic requirements of such systems, is the power balance between two motors and on the other hand, minimizing mechanical fluctuations in order to avoid mechanical equipment damage especially in the state of mechanical resonance. This paper also presents an improved form of the conventional direct torque control (IDTC) for the DCBLDC, which can be used on nine-switch inverters (NSIs). The conventional approaches used in the coupled motors are considered, and then a combination of torque and velocity control is proposed for DCBLDC. After theoretical analysis and drive modeling, whose performance has been simulated by MATLAB/Simulink in terms of dispatching balanced power as well as dealing with transient phenomena owing to malfunctioning of the mechanical connection line. Finally, experiments with the 120W BLDC motors are executed to verify the feasibility of the proposed approach.
S. Pourjafar, H. Shayeghi, H. Madadi Kojabadi, M. Maalandish, F. Sedaghati,
Volume 16, Issue 1 (3-2020)
Abstract
In this work, a non-isolated high step up DC-DC converter using coupled inductor and voltage multiplier cell is proposed. The proposed converter conversion ratio is efficiently extended by using a coupled inductor. An interleaved configuration of two diode-capacitor cells is applied to step up the voltage conversion ratio and decrease the voltage stress across the switches. Also, in the suggested converter high voltage gain is provided by low turn ratio of the coupled inductor which decreases the volume of cores. Moreover, the reverse recovery problem of output diode is diminished by recycling the leakage inductance energy of the coupled inductor. It causes to increase the overall system efficiency. Furthermore, the voltage multiplier cells lead to clamp the voltage spikes through the switch, when the switch turns off. The comparison between the suggested converter and similar converters is provided to verify its advantages. To validate the effectiveness of the suggested converter, a 200W laboratory prototype with 20V input and 150V output voltages operating at 25kHz switching frequency is carried out and experimental test consequences are given.
Robab Kazemi, Zohreh Asadollahzadeh-Zia, Reza Masoumi,
Volume 19, Issue 4 (12-2023)
Abstract
In this work, a broadband dual-channel differential phase shifter is developed with a small phase deviation across a wide frequency range. The design consists of two main lines for 45° and 90° phase shifts, along with a reference line. A prototype is fabricated and measured to validate the performance of the design. Phase shifts of 45° ± 5° and 90° ± 5° over a frequency range of 1.26 GHz - 4 GHz (bandwidth of 104%) are achieved from the channels. The transmission losses of the three lines are less than 0.35 dB and the isolation between the adjacent ports is better than 20 dB. The area of this dual-channel differential phase shifter is 
(14.7 mm × 66.15 mm), where 
is the guided wavelength at the center frequency.
Ali Jabbari, Hassan Moradzadeh, Rasul Lotfi,
Volume 19, Issue 4 (12-2023)
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.
