Advanced Electromagnetics (E-Journal)
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299 research outputs found
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Design and Fabrication of a Novel Quadruple-Band Monopole Antenna Using a U-DGS and Open-Loop-Ring Resonators
No full textIn this Article, a novel quadruple-band microstrip patch antenna is proposed for the systems operating at quad-band applications. The antenna structure is composed of modified rectangular patch antenna with a U-shaped defected ground structure (DGS) unit and two parasitic elements (open-loop-ring resonators) to serve as a coupling-bridge. The proposed antenna with a total size of 31×33 mm2 is fabricated and tested. The measured result indicates that the designed antenna has impedance bandwidths for 10 dB return loss reach about 180 MHz (4.4–4.58 GHz), 200 MHz (5.4–5.6 GHz), 1100 MHz (7.2–8.3 GHz), and 700 MHz (9.6–10.3 GHz), which meet the requirements of the wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX), C and X bands applications. Good agreement is obtained between measurement and simulation results
Compact Dual Band Antenna Design for Ku / Ka Band Applications
No full textThis communication proposes a compact 16 GHz / 30 GHz dual band antenna design for Ku / Ka band applications. The antenna consists of two layers with lower layer having the fed patch and the upper layer having non-periodic element array. The antenna has been designed to operate at two different frequencies with compact dimensions of (8mm x 8mm) using Rogers RT 5880. The compact size of this proposed antenna also makes it suitable for integration with the microwave and millimeter wave circuits. The proposed antenna provides high radiation efficiency and a peak gain of about 8 dB at the resonant frequencies with reduced side lobe levels
On the reduction of the third-order harmonic losses in low–voltage power cables used for feeding large LED and CFL lighting loads
No full textAn experimental investigation of diversity factors of CFL (compact fluorescent lamps) in combination with LED (light emitting diode) lamps is presented in this paper. Attention was paid to the reduction of low–order harmonic currents, especially the third one; which is mainly responsible for the strong increase in power losses in the neutral conductor of low–voltage installations. The harmonic currents drawn by several LED and CFL lamps with nominal powers < 25 W were first measured to investigate the electrical characteristics of individual lamps. In addition, a series of experiments was conducted in which LED lamps were powered between lines through small autotransformers thus avoiding the use of the neutral conductor. The results showed in both cases a sensible reduction of the harmonic current of third order and therefore a marked reduction of the power losses associated with them
Applying the Retarded Solutions of Electromagnetic Fields to Transmission Line RLGC Modeling
No full textThe RLGC model, and its variations, is one of the most common techniques to simulate Transmission Lines. The RLGC model uses circuit network elements consisting of Resistance R, Inductance L, Conductance G and Capacitance C (per unit length) to represent a small segment of the Transmission Line, and then cascades multiple segments to simulate the Transmission Line of arbitrary length. Typically the parameters in RLGC model are extracted from the propagation constant and characteristic impedance of the transmission line, which are found using numerical simulation methods. These resulting RLGC parameters for multi-GHz signaling are usually frequency-dependent. This paper introduces an analytical approach to extract RLGC parameters to simulate transmission line, which results in a different model, the RLGC(p) model
Trapping of light with angular orbital momentum above the light cone
No full textWe consider bound states in the radiation continuum (BSC) above the light cone in an one-dimensional periodic array of dielectric spheres in air. The BSCs are classified by orbital angular momentum m, Bloch wave vector β directed along the array, and polarization. The most simple symmetry protected BSCs have m = 0, β = 0 and occur in a wide range of the radius of spheres and dielectric constant. More sophisticated BSCs with m ̸= 0, β = 0 exist only for a selected radius of the spheres at a fixed dielectric constant. We also show the existence of robust Bloch BSCs with β ̸=0, m = 0. The BSCs with m = 0 can be easily detected by the collapse of Fano resonance in scattering of a plane wave. In response to a plane wave with circular polarization the BSCs with m ̸= 0 give rise to Poynting vector spiralling around the array
Optimum Design of Thin Wideband Multilayer Electromagnetic Shield Using Evolutionary Algorithms
No full textThis paper describes the method of optimum design of multilayer perforated electromagnetic shield using Evolutionary algorithms, namely Particle Swarm Optimization Algorithm (PSO) and Genetic Algorithm (GA). Different parameters which are inherently conflicting in nature corresponds to the multilayer structure of the electromagnetic shields have been considered. The goal is to minimize the overall mass of the shield with respect to its shielding effectiveness and cost. Three different models are considered and synthesized using evolutionary algorithms. Numerical optimal results for each model using different algorithms are presented and compared with each other to establish the effectiveness of the proposed method of designing
Design and Fabrication of Tri-Stopband Bandstop Filters Using Cascaded and Multi-Armed Methods
No full textIn this paper, we proposed a compact C-open-loop ring resonator and its equivalent circuit. The second cascaded BSF are designed using this simple C-ring resonator. The double ring BPF consists of two cascaded C-ring resonators, which are placed on the RO4003 substrate, while the other triple BSF structure consists of tree cascaded C-ring resonators, which are connected with input and output through microstrip feed lines. The both filters are simulated, optimized and partially realized using MWR simulator and Anritsu E5072A vector network analyzer VNA. In order to reduce the size and to improve the filter characteristics, novel compact filter topologies are designed basing on the previous structures. The proposed multi-band bandstop filters consist of several open-loop ring resonators placed vertically overlapping (coupled multi-armed ring resonator). Using this idea, the filter topologies with design flexibility, close size and excellent results are reached. The novel compact multi-band bandstop filters produce several stopband along a frequency range from DC to 9 GHz, in which each separate band exhibits an acceptable and useful bandwidth. Each stopband has regenerated two reflexion zeros, what leads to a good sharpness factors in the transition domains. Good agreement between the experimental results, full-wave simulation has been achieved. This new filter idea can be very attractive for the nowadays multilayer and compact radio frequency integrated circuit design
Review on Computational Electromagnetics
No full textComputational electromagnetics (CEM) is applied to model the interaction of electromagnetic fields with the objects like antenna, waveguides, aircraft and their environment using Maxwell equations. In this paper the strength and weakness of various computational electromagnetic techniques are discussed. Performance of various techniques in terms accuracy, memory and computational time for application specific tasks such as modeling RCS (Radar cross section), space applications, thin wires, antenna arrays are presented in this paper
Energy Tunneling Behavior in Geometrically Separated Wave Guides
No full textIn this paper, characteristics of energy tunneling channel between the waveguides geometrically separated by a coaxial cable are studied. The novel aspect of design is use of coaxial channel to connect the waveguides while maintaining the energy tunneling phenomena. As anticipated the tunneling frequency depends upon the length of wire inside the waveguide and the length of the coaxial cable. The tunneling frequency also depends upon the dielectric constant of the material inside the waveguide and coaxial cable. At tunneling frequency the field strength (E and H) in the channel is extremely high, making the channel extremely sensitive to small change in permittivity of dielectric occupying the channel. The advantage of the proposed design is, its ability to tune to desired tunneling frequency just by changing the length of the coaxial cable without the need to redesign the waveguide height to accommodate the long tunneling wires. This structure can be used as dielectric sensor both for solid or liquid dielectrics just by placing the sample in coaxial cable cavity, contrary to previously report work where the sample has to be placed inside the waveguide
Electromagnetic and material contributions to stress, energy, and momentum in metamaterials
No full textWe demonstrate modeling of the field-kinetic and material response subsystem for various media and extend the models to dispersive negative index metamaterials. It is shown that neither the Minkowski or Abraham models are universally correct, as demonstrated to describe metamaterials under both the field-kinetic and wave SEM models for various applications such as negative refraction, perfect lensing, and invisibility cloaking