Conventionally, diplexers are designed by connecting two filters of different frequencies using a transmission T‐line junction which acts as a distribution network serving the individual filters. Here, a novel diplexer has been proposed and designed to utilize a directly coupled resonator as the distribution network. The directly coupled resonator is designed using two square open‐loop resonators of the same resonant frequency of 1.95 GHz. Coupling of the two resonators is achieved using a λ/4 transmission line to directly couple them. This process made the resonator pair to possess a dual‐mode resonator function, resonating at 1.85 and 2.05 GHz. Two bandpass filters are then designed in the corresponding modes of the resonator pair with 5% fractional bandwidth and coupled accordingly. This technique allowed the resonator pair to contribute to the resonant poles of the diplexer while functioning as the distribution network.
The challenges involved in the application of fuzzy logic in wireless sensors networks often stem from the limitation in processing and storage capabilities of the nodes . This anomaly can be overcome by using a centralized data sink, equipped with more storage and processing capabilities and which can also serve as the decider on the occurrence or otherwise of the event of interest based on selected readings of a subset of the deployed nodes. It is known that selecting a finite subset of a universal set can be intractable especially with relatively large size of the problem space. In this paper, we propose the application of T-norm Fuzzy Logic(TFL) to address the sensor selection problem and compare its performance to that of a standard Genetic Algorithm (GA). Extensive simulation results reveal the usefulness of this approach and how it is closely related to the GA technique.
Light Emitting Diode (LED) applications are increasingly used in various microelectronic devices due to their efficient light generation. The miniaturisation of the LED and its integration into compact devices within the weight limit have resulted in excessive heat generation, and inefficient management of this heat could lead to the failure of the entire system. Passive and/or active heat sinks are used for dissipating heat from the system to the environment to improve performance. An ANSYS design modeller and transient thermal conditions were utilised in this study to design and simulate the LED system. The modeller performs its function by utilising the Finite Element Method (FEM) technique. The LED system considered in this work consists of a chip, thermal interface material, and a cylindrical heat sink. The thickness of the Cylindrical Heat Sink (CHS) fins used in the investigation is between 2 mm and 6 mm, whilst ensuring the mass of heat sinks is not more than 100 g. The input power of the LED chip is between 4.55 W and 25.75 W, as required by some original equipment manufacturers (OEMs). A mesh dependency study was carried out to ensure the results were synonymous with what can be obtained practically. The simulation results suggest that the power ratings did not affect the thermal resistance of the CHS. In addition, the thermal resistance increased with the increased thickness of the CHS fin. The efficiencies of the heat sink were found to increase with an increased thickness of the cylindrical fin and the accuracy between the calculated and simulated thermal efficiency ranges from 84.33% to 98.80%. Evidently, the CHS fin of 6 mm thickness is more efficient than the other CHS fins, as depicted in this study.
A volume integral equation known as Fredholm Integral Equation (FIE) approach for solving plane electromagnetic (EM) waves scattering by small dielectric particles is presented. In this paper we adapted FIE method published in previous work by (A.R. Holt, N.K. Uzunoglu and B.G. Evans, IEEE Trans., 26, 706-712, 1978) to solve scattering of plane EM waves by homogeneous dielectric ellipsoidal scatterers. In contrast to previous work, the basis of numerical integration are not represented as an expansion in a set of polynomials (Gegenbauer polynomial) but as a direct spatial integration. We assume discretization of the scattering particle into grid or cell points of unit cube in a regular lattice field. The homogeneous dielectric scatterer is modelled by assuming general ellipsoid equation centred at the origin of the regular lattice field which aligns with the Cartesian coordinate system axes. The first and second Born approximation terms are evaluated for a cell in the regular lattice field, while the contributions for all other cells weighted according to content are evaluated efficiently applying Fourier Shift Theorem.Preliminary results indicate similar agreement is observed with what was previously achieved by implementing Mie theory and other established numerical algorithms for homogeneous spherical or ellipsoidal dielectric scatterers. The strength of our model is that the main integration and equations solved are in the spatial frequency domain. As a result, the angular scattering pattern is strongly connected to the Spatial Fourier Transform of the scatterer; hence, for electrically small particles the angular spectrum is relatively smooth, the number of pivots required (in k-space) and complexity of the linear equations solved are relatively low as evident.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.