Engineering Commons^™

Lna Integrates Fast Shutdown Function, Chin-Leong Lim

Chin-Leong Lim

To minimize dead time in time domain duplex (TDD) transceiver, reception should ideally commence as soon as transmission ends. However, the low noise amplifier (LNA), which is typically shutdown during transmission to prevent device damage and receiver overload, can exhibit a turn-on delay. In older implementations, the shutdown function is external to the LNA device. So, one way to reduce part count and to miniaturize this class of LNA is to integrate the LNA and shutdown function in a microwave monolithic integrated circuit (MMIC). The integration also allows the shutdown circuit to be connected to the LNA at an optimum …

Power Variation With Electret Surface Potential And Frequency Of Vibration In Vertical Vibration Based Cantilever-Electret Micro-Power Generation, Innovative Research Publications Irp India, Akin-Ponnle A.E, Ponnle A.A, Falaki S.O.

Innovative Research Publications IRP India

A cantilever-electret based electrostatic micro-power generator for energy harvesting was set up in which Cyclic Transparent Optical Polymer (CYTOP) was used as the electret, and the upper electrode was made in form of an Ashaped cantilever which was fabricated from materials of copper with embedded glass epoxy. The cantilever was vibrated in the vertical direction in close to contact point mode of operation. Experimental result showed that the average output power increases with increasing electret surface potential, and the minimum distance to contact point decreases with increasing electret surface potential. Also, variation of output power with frequency was investigated by …

Review Of Normal And Infrequent In-Feed Loss Risks In The Transmission System Of Oman, Omar H. Abdalla, Adil Al-Busaidi, Hilal Al-Hadi, Hisham A. Al-Riyami, Ahmed Al-Nadabi

Omar H. Abdalla

The paper presents technical studies performed to review the values of the Normal Infeed Loss Risk (NILR) and Infrequent Infeed Loss Risk (IILR) in the Transmission System Security Standard (TSSS). The objective is to facilitate the connection of the largest power station in Oman, which is Sur 2000 MW IPP, to the Main Interconnected Transmission System (MITS), while complying with the requirements of the TSSS. The full output of 2000 MW of Sur power plant is expected to available in 2015; therefore the MITS model of 2015 is used in the studies using the DIgSILENT professional software. The model includes …

Influence Of Oxygen On Electronic Properties Of Nanocrystalline Silicon, Shantan Kajjam

Shantan Kajjam

Nanocrystalline Silicon (nc-Si) is an important material for photovoltaic device applications. Its excellent absorption, low defect levels and many other interesting properties help build high efficiency solar cells. Its structure is very complex and is sensitive to contaminants and fabrication processes. It needs a careful study so that a maximum outcome can be attained from the material. Nc-Si is highly prone to be defective and oxygen is one of the major sources of the defects. In this thesis, systematic analysis of the fundamental properties of oxygen doped & boron compensated nc-Si are illustrated. Thin film solar cells were fabricated using …

Development Of Impedance Spectroscopy Based In-Situ, Self-Calibrating, On-Board Wireless Sensor With Inbuilt Metamaterial Inspired Small Antenna For Constituent Detection In Multi-Phase Mixtures Like Soil, Gunjan Pandey

Gunjan Pandey

Real time and accurate measurement of sub-surface soil moisture and nutrients is critical for agricultural and environmental studies. This work presents a novel on-board solution for a robust, accurate and self-calibrating soil moisture and nutrient sensor with inbuilt wireless transmission and reception capability that makes it ideally suited to act as a node in a network spread over a large area. The sensor works on the principle of soil impedance measurement by comparing the amplitude and phase of signals incident on and reflected from the soil in proximity of the sensor. The permittivity of the soil dielectric mixture which is …

Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim

Chin-Leong Lim

Compared to the PIN diode limiter, the Schottky-PIN limiter improves receiver protection, but has a higher insertion loss. Low cost, plastic packaged diodes can further worsen the loss. Diode stacking, mesa diode construction, and isolating the Schottky diode with a high-impedance quarter wave line or a directional coupler can reduce loss, but detrimentally raises the limiting threshold and/or adds bulk or cost. The PIN-Schottky limiter’s insertion loss can be improved by integrating the diodes’ parasitic capacitances into a low pass ladder network, but this solution requires the PIN diode to have two anode connections. Recently, the PIN-Schottky limiter was integrated …

From Verification To Implementation: A Model Translation Tool And A Pacemaker Case Study, Miroslav Pajic, Zhihao Jiang, Insup Lee, Oleg Sokolsky, Rahul Mangharam

Oleg Sokolsky

Model-Driven Design (MDD) of cyber-physical systems advocates for design procedures that start with formal modeling of the real-time system, followed by the model’s verification at an early stage. The verified model must then be translated to a more detailed model for simulation-based testing and finally translated into executable code in a physical implementation. As later stages build on the same core model, it is essential that models used earlier in the pipeline are valid approximations of the more detailed models developed downstream. The focus of this effort is on the design and development of a model translation tool, UPP2SF, and …

Optimal Design Of A Pv/Fuel Cell Hybrid Power System For The City Of Brest In France, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

This paper deals with the optimal design of a stand-alone hybrid photovoltaic and fuel cell power system without battery storage to supply the electric load demand of the city of Brest, Western Brittany in France. The proposed optimal design study is focused on economical performance and is mainly based on the loss of the power supply probability concept. The hybrid power system optimal design is based a simulation model developed using HOMER. In this context, a practical load demand profile of Brest city is used with real weather data.

Power Quality In Grid Connected Renewable Energy Systems: Role Of Custom Power Devices, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon

Dr. Shafiuzzaman Khan Khadem

This paper deals with the technical review of power quality problems associated with the renewable based distributed generation systems and how the custom power devices like STATCOM, DVR and UPQC play important role in power quality improvement. IEEE and IEC standard for the grid connected renewable energy systems are one of the critical point of interest for the selection of custom power devices. Special attention has been given on the compensation of reactive power, harmonic current and voltage fluctuation during the interconnected as well as islanding mode of operation. As the solar and wind are the most abundant resources therefore …

Parallel Operation Of Inverters And Active Power Filters In Distributed Generation System: A Review, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon

Dr. Shafiuzzaman Khan Khadem

In this paper a technical review of parallel operation of power electronics inverters for load sharing conditions in distributed generation (DG) network is presented. Emphasis is given to parallel operation of Active Power Filters (APFs) as they are widely used to mitigate load current disturbances into DG networks. Discussions on recent advances in control strategies as applied to APFs are presented.

Compact Lna Drives 2.5-Ghz Base Stations, Chin-Leong Lim

Chin-Leong Lim