238 research outputs found

    Broadband Analysis of Microwave Structures by Enhanced Finite-Element Methods

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    The paper deals with the broadband modeling of microwave structures by finite-element methods. The attention is turned to original enhancements of accuracy, efficiency and stability of finite-element codes. The partial improvements are based on novel approximations both in the spatial domain and in the time one, in the adoption of complex frequency hopping, fast frequency sweep and envelope finite-element techniques. In the paper, a possible hybridization of approaches is discussed. Proposed finite-element schemes are applied to the analysis of canonical longitudinally homogeneous transmission lines in order to demonstrate their advantages

    Modeling of Microwave Semiconductor Diodes

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    The paper deals with the multi-physical mode-ling of microwave diodes. The electrostatic, drift-diffusion and thermal phenomena are considered in the physical model of the components. The basic semiconductor equati-ons are summarized, and modeling issues are discussed. The simulations of the Gunn Effect in transferred electron devices and the carrier injection effect in PIN diodes are investigated and discussed. The analysis was performed in COMSOL Multiphysics using the finite element method

    Transmission Line on Semiconductor Substrate with Distributed Amplification

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    In order to compensate losses in metal strips, an active microstrip line on a semiconductor substrate is proposed, and its finite element model is presented. The active medium is provided by A3B5 semiconductor in highintensity electric field. The simple model of the active media is developed and used for calculation of the propagation properties of the fundamental mode and for the thermal analysis of the device. The problem of system self-oscillation is discussed and empirical stability criteria are introduced. A proper heat-sink is proposed to provide the operation in a continuous regime

    Synthesizing Sierpinski Antenna by Genetic Algorithm and Swarm Optimization

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    The paper discusses the synthesis of the Sierpinski antenna operating at three prescribed frequencies: 0.9 GHz, 1.8 GHz (both GSM) and 2.4 GHz (Bluetooth). In order to synthesize the antenna, a genetic algorithm and a particle swarm optimization were used. The numerical model of the antenna was developed in Zeland IE3D, optimization scripts were programmed in MATLAB. Results of both the optimization methods are compared and experimentally verified

    Time-Domain Finite Elements for Virtual Testing of Electromagnetic Compatibility

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    The paper presents a time-domain finite-element solver developed for simulations related to solving electromagnetic compatibility issues. The software is applied as a module integrated into a computational framework developed within a FP7 European project High Intensity Radiated Field – Synthetic Environment (HIRF SE) able to simulate a large class of problems. In the paper, the mathematical formulation is briefly presented, and special emphasis is put on the user point of view on the simulation tool-chain. The functionality is demonstrated on the computation of shielding effectiveness of two composite materials. Results are validated through experimental measurements and agreement is confirmed by automatic feature selective algorithms

    Analisis Penggunaan Metode Risk Profile, Good Corporate Governance, Earning, and Capital (Rgec) Dalam Mengukur Kesehatan Bank Pada Bank Umum Syariah Di Indonesia Periode 2012-2014

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    This research aims to analyze the USAge of Risk Profile, Good Corporate Governance, Earning and Capital (RGEC) method to measure bank health on Islamic Banks in Indonesia between 2012-2014. This research used RGEC method which is an innovation from Capital, Asset, Management, Earning, Liquidity and Sensitivity to Market Risk (CAMELS) method to analyze and measure bank health by using composite rank calculation on financial report. Total Islamic banks in this research are 11 banks, which are Bank Syariah Mandiri, BNI Syariah, Bank Muamalat Syariah, Bank Mega Syariah, BRI Syariah, BCA Syariah, Bank Syariah Bukopin, Bank BJB Syariah, Bank Panin Syariah, Bank Maybank Syariah and Bank Victoria Syariah. The result during 2012-2014 period showed that bank with the healthiest predicate in 2012 was Bank Muamalat Syariah, and in 2013 were Bank BNI Syariah and Bank Mega Syariah 2013 also in 2014 were bank Bank Panin Syariah and Bank BNI Syariah

    Parametric Study of Mushroom-like and Planar Periodic Structures in Terms of Simultaneous AMC and EBG Properties

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    In the paper, the parametric analysis of a mushroom-like and a planar metallo-dielectric periodic structure with square unit cell and metallic patch is presented. First, the angular stability for different unit cell settings was studied. Second, restrictions for simultaneous behavior as artificial magnetic conductor (AMC) and electromagnetic band gap (EBG) are briefly discussed. Finally, main differences between the mushroom-like and the planar structure are specified and conclusions are formulated

    Kredit Usaha Rakyat dan Perkembangan UMKM di Kabupaten Simeulue Pasca Covid-19

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    Abstract : People's Business Credit (KUR) is a form of government program in increasing access to financing for Micro Small and Medium Enterprises (MSMEs) with low-interest rates, this program is channeled through financial institutions with guarantee patterns. KUR funds are given to people who have productive businesses with varying amounts to the business conditions involved, but during the covid-19 pandemic, the MSME sector also experienced the difficulty of installment returns, so this study was conducted to answer two fundamental questions, are: how KUR funds in the review of sharia economic law and how the fate of MSMEs during the covid-19 pandemic in Simeulue Regency. This research is qualitative research and data collection techniques using observation, interview, and documentation, while data analysis uses descriptive techniques. Based on the results of research it can be concluded that in the incarnation of Sharia economic law regarding KUR there are two opinions, first declaring the law haram because it includes riba, while the second opinion asserts that the legal KUR can and does not include riba. The difference lies in whether or not the interest of the KUR. Then the influence of covid-19 on MSMEs in Simeulue Regency is bad for the development of community businesses due to the lack of buyer interest so that the weakening of their income and the effect on delayed installment payments beyond the due date

    Insight from Molecular, Pathological, and Immunohistochemical Studies on Cellular and Humoral Mechanisms Responsible for Vaccine-Induced Protection of Rainbow Trout against <em>Yersinia ruckeri</em>

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    The immunological mechanisms associated with protection of vaccinated rainbow trout, Oncorhynchus mykiss, against enteric redmouth disease (ERM), caused by Yersinia ruckeri, were previously elucidated by the use of gene expression methodology and immunochemical methods. That approach pointed indirectly to both humoral and cellular elements being involved in protection. The present study correlates the level of protection in rainbow trout to cellular reactions in spleen and head kidney and visualizes the processes by applying histopathological, immunohistochemical, and in situ hybridization techniques. It was shown that these cellular reactions, which were more prominent in spleen than in head kidney, were associated with the expression of immune-related genes, suggesting a Th2-like response. Y. ruckeri, as shown by in situ hybridization (ISH), was eliminated within a few days in vaccinated fish, whereas nonprotected fish still harbored bacteria for a week after infection. Vaccinated fish reestablished normal organ structure within a few days, whereas nonprotected fish showed abnormalities up to 1 month postinfection. Protection in the early phase of infection was mainly associated with the expression of genes encoding innate factors (complement factors, lysozyme, and acute phase proteins), but in the later phase of infection, increased expression of adaptive immune genes dominated. The histological approach used has shown that the cellular changes correlated with protection of vaccinated fish. They comprised transformation of resident cells into macrophage-like cells and increased occurrence of CD8α and IgM cells, suggesting these cells as main players in protection. Future studies should investigate the causality between these factors and protection
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