Iranian Journal of Electrical & Electronic Engineering
http://ijeee.iust.ac.ir
Iranian Journal of Electrical and Electronic Engineering - Journal articles for year 2016, Volume 12, Number 2Yektaweb Collection - http://www.yektaweb.comen2016/6/12A New Implementation of Frequency Selective Surface Cloak for Cylindrical Structures
http://ijeee.iust.ac.ir/browse.php?a_id=906&sid=1&slc_lang=en
<p dir="ltr" style="text-align: justify;">The main purpose of this paper is to design, implement and measure a new sample of mantle cloak. A new method called mantle cloak is introduced by cloaking an object by a single, conformal meta-surface which can drastically suppress the scattering of the desired object. In this paper, a grid lattice is placed around a dielectric object as the cloaking structure. Previously, this FSS has been utilized for the cloaking of PEC object; but, since this structure has inductive equivalent circuit on the dielectric, it can be used for cloaking of dielectric cylinder. Numerical simulations of near field and far field of the designed structure are derived to prove the effectiveness of our meta-surface cloak. Also, measurement results of S<sub>11</sub> and S<sub>21</sub> related to cloaked structure and their comparison with single dielectric proves suitable performance of the designed cloak. The results show more than 20% bandwidth for this structure. This means that this structure is suitable for broadband operations.</p>
A. AbdolaliA New Shearlet Framework for Image Denoising
http://ijeee.iust.ac.ir/browse.php?a_id=903&sid=1&slc_lang=en
<p style="text-align: justify;">Traditional noise removal methods like Non-Local Means create spurious boundaries inside regular zones. Visushrink removes too many coefficients and yields recovered images that are overly smoothed. In Bayesshrink method, sharp features are preserved. However, PSNR (Peak Signal-to-Noise Ratio) is considerably low. BLS-GSM generates some discontinuous information during the course of denoising and destroys the flatness of homogenous area. Wavelets are not very effective in dealing with multidimensional signals containing distributed discontinuities such as edges. This paper develops an effective shearlet-based denoising method with a strong ability to localize distributed discontinuities to overcome this limitation. The approach introduced here presents two major contributions: (a) Shearlet Transform is designed to get more directional subbands which helps to capture the anisotropic information of the image; (b) coefficients are divided into low frequency and high frequency subband. Then, the low frequency band is refined by Wiener filter and the high-pass bands are denoised via NeighShrink model. Our framework outperforms the wavelet transform denoising by %7.34 in terms of PSNR (peak signal-to-noise ratio) and %13.42 in terms of SSIM (Structural Similarity Index) for ‘Lena’ image. Our results in standard images show the good performance of this algorithm, and prove that the algorithm proposed is robust to noise.</p>
E. EhsaeyanSingular Perturbation Theory in Output Feedback Control of Pure-Feedback Systems
http://ijeee.iust.ac.ir/browse.php?a_id=883&sid=1&slc_lang=en
<div style="text-align: justify;">This paper studies output feedback control of pure-feedback systems with immeasurable states and completely non-affine property. Since availability of all the states is usually impossible in the actual process, we assume that just the system output is measurable and the system states are not available. First, to estimate the immeasurable states a state observer is designed. Relatively fewer results have been proposed for pure-feedback systems because the cascade and non-affine properties of pure-feedback systems make it difficult to find the explicit virtual controls and actual control. Therefore, by employing the singular perturbation theory in back-stepping control procedure, the virtual/actual control inputs are derived from the solutions of a series of fast dynamical equations which can avoid the “explosion of complexity’’ inherently existing in the conventional back-stepping design. The stability of the resulting closed-loop system is proved by Tikhonov’s theorem in the singular perturbation theory. Finally, the detailed simulation results are provided to demonstrate the effectiveness of the proposed controller, which can overcome the non-affine property of pure-feedback systems with lower complexity and fewer design parameters.</div>
H. Toossian ShandizPlasmonic Adder/Subtractor Module Based on a Ring Resonator Filter
http://ijeee.iust.ac.ir/browse.php?a_id=839&sid=1&slc_lang=en
<p dir="ltr" style="text-align: justify;">A four port network adder-subtractor module, for surface plasmon polariton (SPP) waves based on a ring resonator filter is proposed. The functionality of module is achieved by the phase difference manipulation of guided SPPs through different arms connected to the ring resonator. The module is designed using the concepts of a basic two-port device proposed in this paper. It is shown that two port network eliminates odd, and transmits even SPP modes of a single source. Moreover, in the case of four-port adder (with two individual sources), it is elucidated that according to the location of each output port, one can achieve the consequent added or subtracted outputs, correspondingly. Two distinct peaks are observed in the transmission spectrum of adder and subtractor outputs, where increasing the individual source phase difference, leads to a red shift in the adder output, and a blue shift in the subtractor output peaks. The proposed module can be used as the building block for implementing arithmetic operations in plasmonic integrated circuits. The transmission line theory verifies the numerical simulation results, and demonstrates the functionality of the adder/subtractor module. </p>
M. A. KaramiA Concurrent Dual-Band Low Noise Amplifier for GNSS Receivers
http://ijeee.iust.ac.ir/browse.php?a_id=880&sid=1&slc_lang=en
<p dir="ltr" style="text-align: justify;">In this paper, a new design of concurrent dual-band Low Noise Amplifier (LNA) for multi-band single-channel Global Navigation Satellite System (GNSS) receivers is proposed. This new structure is able to operate concurrently at frequency of 1.2 and 1.57 GHz. Parallel and series resonance parts are employed in the input matching in order to achieve concurrent performance. With respect to used pseudo-differential structure, LNA is basically a single-ended-to-differential conversion and it consequently has no need to balun. In addition, an inductively degenerated cascode approach is employed to have better simultaneous matching and Noise Figure (NF). Simulations are performed with TSMC 0.18 μm technology in ADS software. Results analysis present that LNA achieves input matchings of -11.024 and -13.131 dB, NFs of 2.315 and 2.333 dB, gains of 26.926 and 27.576 dB, P<sub>-1dB</sub> of -15.3 and -13 dBm, IIP3 of -0.9 and 2.2 dBm at 1.2 and 1.57 GHz, respectively. Besides, LNA consumes 8.32 mA DC current from a 1.8 V supply voltage.</p>
M. R. MosaviTHD Minimization of the Output Voltage for Asymmetrical 27-Level Inverter using GA and PSO Methods
http://ijeee.iust.ac.ir/browse.php?a_id=743&sid=1&slc_lang=en
<p style="text-align: justify;">Multilevel voltage source inverters have several advantages compare to traditional voltage source inverter. These inverters reduce cost, get better voltage waveform and decrease Total Harmonic Distortion (THD) by increasing the levels of output voltage. In this paper Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) methods are used to find the switching angles for achieving to the minimum THD for output voltage waveform of the Cascaded H-bridge Multi-Level Inverters (MLI). These methods are used for a 27-level inverter for different modulation indices. Result of two methods is identical and in comparison to other methods have the smallest THD. To verify results of two mentioned methods, a simulation using MATLAB/Simulink software is presented.</p>
J. S. MoghaniA New Topology of Bidirectional Buck-Boost dc/dc Converter with Capability of Soft Switching and input Current Ripple Cancellation
http://ijeee.iust.ac.ir/browse.php?a_id=902&sid=1&slc_lang=en
<p style="text-align: justify;">In this paper, a new bidirectional buck-boost dc-dc converter with capability of soft switching and zero input current ripple is proposed. The coupled inductor is used in the proposed converter to eliminate the input current ripple. In the proposed converter, zero voltage switching (ZVS) and zero current switching (ZCS) can be obtained for the main and auxiliary switches, respectively. In addition, the proposed topology is analyzed in all operating modes and all equations of voltage and current for components are obtained. Moreover, the required conditions for soft switching operation and also achieving zero input current ripple are calculated. Finally, the acuracy performance of the proposed converter is reconfirmed through simulation results in EMTDC/PSCAD software program.</p>
E. BabaeiGraphene Nano-Ribbon Field Effect Transistor under Different Ambient Temperatures
http://ijeee.iust.ac.ir/browse.php?a_id=960&sid=1&slc_lang=en
<p style="text-align: justify;">This paper is the first study on the impact of ambient temperature on the electrical characteristics and high frequency performances of double gate armchair graphene nanoribbon field effect transistor (GNRFET). The results illustrate that the GNRFET under high temperature (HT-GNRFET) has the highest cut-off frequency, lowest sub-threshold swing, lowest intrinsic delay and power delay product compared with low-temperature GNRFET (LT-GNRFET) and medium-temperature GNRFET (MTGNRFET). Besides, the LT-GNRFET demonstrates the lowest off-state current and the highest ratios of Ion/Ioff, average velocity and mobile charge. In addition, the LT-GNRFET has the highest gate and quantum capacitances among three aforementioned GNRFETs.</p>
M. Akbari EshkalakEvaluation of Price-Sensitive Loads' Impacts on LMP and Market Power using LMP Decomposition
http://ijeee.iust.ac.ir/browse.php?a_id=856&sid=1&slc_lang=en
<p style="text-align: justify;">This paper presents a novel approach for evaluating impacts of price-sensitive loads on electricity price and market power. To accomplish this aim an analytical method along with agent-based computational economics are used. At first, Nash equilibrium is achieved by computational approach of Q-learning then based on the optimal bidding strategies of GenCos, which are figured out by Q-learning, ISO's social welfare maximization is restated considering demand side bidding. In this research, it was demonstrated that Locational Marginal Price (LMP) at each node of system can be decomposed into five components. The first constitutive part is a constant value for the respective bus, while the next two components are related to GenCos and the last two parts are associated to Load Serving Entities (LSEs). Market regulators can acquire valuable information from the proposed LMP decomposition. First, sensitivity of electricity price at each bus and Lerner index of GenCos to the bidding strategies and maximum pricesensitive demand of LSEs are revealed through weighting coefficients of the last two terms in the decomposed LMP. Moreover, the decomposition of LMP expresses contribution of LSEs to the electricity price. The simulation results on two test systems confirm the capability of the proposed approach.</p>
H. Rajabi MashhadiA Grid-Connected PV Inverter with Compensation of Load Active and Reactive Power Imbalance for Distribution Networks
http://ijeee.iust.ac.ir/browse.php?a_id=884&sid=1&slc_lang=en
<p style="text-align: justify;">Load balancing is an important issue in distributed systems. In addition, using distributed generation sources such as photovoltaic is increasing. Power electronic converters are main interfaces between the sources and the grid. In this paper, a method has been proposed to reduce the load imbalancing in distribution networks using PV Grid Interface Converter. Two DC/DC and DC/AC converters have been utilized for connecting PV to the grid. A control strategy is presented which enables the converter to compensate the load imbalancing by injecting power of solar cells to the load and grid. Simulation results by MATLAB/SIMULINK software indicate the ability of the proposed control method to reduce the load imbalancing.<br>
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M. A. Shamsi Nejad