Advanced Electromagnetics (E-Journal)
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A Hybrid Approach for Antenna Optimization Using Cat Swarm based Genetic Optimization
No full textThe aim of the paper is to introduce the hybrid technique for the multiobjective optimization of antennas. The goal of the antenna optimization is typically minimising the reflection coefficient through a frequency band. To minimize the energy consumption is essential consideration of energy efficient transmission schemes that is used for the data transfer in wireless sensor networks. In our proposed work the efficient and low-cost multi objective technique CSGO (Cat Swarm based Genetic optimization) approach was used. The Cat Swarm Optimization approach is combined with genetic algorithm (GA) to optimize the bandwidth and return loss of the antenna. CSGO approach is to improve the Optimization efficiency and computational .This hybrid optimization approach will reduce the side lobe level and provide improvement in the Directivity. CSGO applied to the design of a miniaturized multiband antenna, showing better diversity and significant savings of overall optimization cost compared with the previously reported design methods
Design of Non-Uniformly Spaced Circular Arrays of Parasitic Dipoles for Lower Side Lobe Level with Maximum Directivity
No full textThis paper presents a new approach for circular array of parasitic dipoles composed by one active dipole for reduction of side lobe level with maximum directivity including mutual coupling. The desired goal is obtained by changing the spacing between the parasitic elements and length of the parasitic elements while the position and length of driven element is fixed. In addition to it, reflection coefficient (RC) of the driven element is kept closer to the specified value. Matlab based method of moment code is used to evaluate the performance of circular antenna designs generated by QPSO algorithm. Two examples are presented to show the effectiveness of this proposed approach.  
Numerical treatment of floating conductors based on the traditional finite element formulation
No full textA method to model a conductor with undefined potential (commonly known as floating conductor), is sometimes required in the electric field analysis. This paper presentsand compares the main methods to deal with such issue, based on the traditional finite element formulation. The purpose is to guide the reader in the selection of a method under the following criteria: Accuracy, implementation and simplicity. The accuracy of each method was evaluated against the analytic solution of the capacitance matrix for a system of parallel cylindrical conductors. Based on the results of the simulations, the characteristics of the methods and this paper’s criteria, a qualification of each method performance is done. Additionally, particular cases in which a specific method could be the most suitable option to deal with floating conductors, are analyzed. In general, the Virtual Permittivity method exhibits the best performance. However, it is shown that the method’s accuracy is influenced by the rounding errors. This paper proposes an additional consideration on the method formulation in order to verify the accuracy of the results
A Compact ACS-Fed Tri-band Microstrip Monopole Antenna for WLAN/WiMAX Applications
No full textThis paper proposes a novel small asymmetric coplanar strip (ACS) fed tri-band monopole antenna for WLAN and WiMAX applications. To tune and create multiple resonant frequencies, the exciting strip of monopole antenna is connected to two different arms which are a J-shaped directed toward the asymmetric ground plane and an open stub. The proposed monopole antenna with a total size of 14.6 x17.5 mm2 is fabricated and tested. The measured results indicate that the antenna has impedance bandwidths for 10-dB return loss reach about 500 MHz (2.01-2.52 GHz), 230 MHz (3.48-3.71 GHz) and 1.2GHz (5.59-6.72 GHz) which cover widely the 2.4/5.8 GHz WLAN bands and the 3.5GHz WiMAX band. The simulated radiation patterns of the proposed antenna at the three resonant frequencies have a dipole-like radiation pattern in both E-and H-Planes. The compact size, the simple structure and good radiation performances of the proposed antenna makes it well-suited forthe intended applications
PCB access impedances extraction method of in-situ integrated circuit
No full textThis article describes an extraction technique of input and output impedances of integrated circuits (ICs) implemented onto the printed circuit boards (PCBs). The feasibility of the technique is illustrated with a proof-of-concept (POC) constituted by two ICs operating in a typically transmitter-receiver (Tx-Rx) circuit. The POC system is assumed composed of three different blocks of emitter signal source, load and interconnect passive network. This latter one is assumed defined by its chain matrix known from its electrical and physical characteristics. The proposed impedance extraction method is elaborated from the given signals at the transmitter output and receiver input. The terminal access impedances are formulated in function of the parameters of the interconnect system chain matrix. The feasibility of the method is checked with a passive circuit constituted by transmission lines driven by voltage source with RL-series network internal impedance and loaded at the output by the RC-parallel network. Good correlation between the access impedance reference and calculated is found
Design of High Gain Novel Dielectric Resonator Antenna Array for 24 GHz Short Range Radar Systems
No full textin this work we present a 16x1 array’ elements of a high gain Novel shape designed Dielectric Resonator Antenna (NDRA), having a low dielectric constant value of 18, for wide band (WB) and narow band (NB) 24 GHz automotive Short Range Radar (SRR) applications. The proposed NDRA array is feed by an efficient microstrip network feeding mechanism and presents wide impedance bandwidth (426 MHz), high gain (20.9 dBi), high efficiency (96%) and directional radiation pattern at 24 GHz with narrow angular beam-width of 6.4°. Computed NDRA array results allow the proposed design to be practical for the next automotive radar generations. Parametric studies have been analyzed using the Finite Difference Time Domain (FDTD) method of the CST-MW time domain solver and results, of the optimal structure, have been validated by the Finite Element Method (FEM) used in HFSS electromagnetic (EM) simulator
Design of dual and Wideband Rectangular Patch Antenna for C and X Band Applications
No full textIn this paper, we resolve two issues of microstrip antennas, which are miniaturization and efficiency behavior. For that, a rectangular patch antenna with 16×18×1.6 mm3 dimensions with dual-band characteristics, was designed, fabricated and characterized. In order to improve the problem of narrow bandwidth in microstrip antennas, we implement in this study the slot technique, allowing us to achieve our purpose. This technique, lead to a good reflection coefficient and VSWR. The characteristics of the fabricated antenna were measured and analyzed by Vector Network Analyzer. The results show two resonance frequencies that define two bandwidths defined by a return loss less than -10 dB and are respectively; 7.47 GHz at a frequency of 400 MHz, and 11.01 GHz at a frequency of 790 MHz. Also, the obtained gain has a good value and it’s very remarkable according to the small size of the structure, with a peak value of 6.1 dB at 12.5 GHz. The small size and good characteristics enlarged the applications domains of our structure, from telecommunications and especially Radar, satellite communications to medical and wireless applications
Design and Simulation of Temperature Sensor based on Long Period Grating in Liquid Filled Photonic Crystal Fiber
No full textIn this paper, a high sensitivity temperature sensor based on photonic crystal fiber long period grating (PCF-LPG) filled with ethanol is proposed and simulated by full vector finite element method. The relationship between the resonant wavelength shift, and the temperature was analyzed. The results show that the resonant wavelength of the ethanol filled photonic crystal fiber long period grating is proportional linearly with temperature and the highest sensitivity of was achieved, which is 90 times higher than that of conventional LPG temperature sensors
Two-layered Dual-band Perfect Metamaterial Absorber at K band Frequency
No full textThis paper presents a study of a novel absorber structure based on two-dielectric-layers, two perfect absorption frequency bands at K band (f1 = 26.5 GHz and f2 = 28.6 GHz) go under observance. The study of the dependence of absorption and frequency on relative distance between the layers of material and the material structure parameters are discussed. 
Bandwidth Enhanced MIMO antenna for LTE bands using Split Ring Resonators and Stubs
No full textIn this work, an array of circular patch antenna loaded with a partial split ring and a pair of stubs each with same dimensions, on each of the antenna. Patch of the radius (r) = 7.5mm. The split ring is of the width 1.35mm. the split ring not only accounts for a newer operating band, but also tend to reduce the isolation and the stubs are tends to increase the bandwidth which results in change by 44.92% compared to array of antennas without split rings. The substrate dimensions are 55´30´0.8mm3 and the ground of 55´9mm2. The proposed antennas are simulated using high frequency structural simulator and the results compared with the circular patch antenna without split ring resonators. The results obtained clearly show that, bandwidth of circular micro strip antenna without split ring can be enhanced. The proposed antennas may find applications in LTE band 1, 2, 3, 4, 7, 9, 10, 11, 15, 16, 21, 22, 23, 24, 25, 30, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43 GHz covering a broadband width of 2500MHz