Performance Analysis of a Monopole Antenna with Fluorescent Tubes at 4.9GHz Application.

This paper presents of analysis the performance monopole antenna with fluorescent tubes. The antenna was designed at the operating frequency which is 4.9 GHz. The commercially fluorescent tubes consist of a glass tube filled with mixture mercury vapor and argon gas. After get sufficient voltage the gas inside the fluorescent tube will ionize to plasma and formed plasma column. The plasma frequency is equal to 5.634e11 Hz. The plasma is highly conducting and acts as a reflector. When all of the tubes surrounding the antenna are electrified, the radiation is trapped inside when the plasma frequency is greater than radio frequency. An accomplishment of the design has been carried out using CST microwave studio software. The developed antenna has potential in military application. To conclude, antenna’s performance was analyzed in terms of return loss, radiation pattern and gain. Keywords : Plasma, monopole antenna, return loss, radiation pattern, gain

Performance analysis of photovoltaic and wind turbine grid-connected systems under LVRT conditions

The integration of grid-connected renewable energy systems has gained significant attention and introduces several challenges and considerations. One of these challenges is ensuring the reliable and stable operation of these systems under various grid conditions. For example, faults at the grid could lead problems such as DC-link over-voltage and AC over-current that may cause disconnection or damage to inverter. This paper presents a comprehensive analysis of the performance of photovoltaic (PV) and doubly-fed induction generator (DFIG) wind turbine grid-connected systems under low voltage ride-through (LVRT) conditions. The study aims to investigate their behavior, and stability during LVRT events and provide insights for enhancing their grid integration capabilities. The PV and DFIG systems are modelled and simulated using MATLAB Simulink under three difference conditions, with and without using reactive current injection and DC chopper circuit. Various performance parameters, including grid voltage, grid current, DC-link voltage, active power, and reactive power, are analyzed to assess the system's behavior and compare their responses. The principal results reveal distinct performance characteristics of the PV and DFIG systems. The PV system shows higher overshoot currents, over-voltage, and significant drops in active power during fault occurrences, while the DFIG system exhibits lower overshoot currents and better stability in the DC-link voltage. Reactive power responses differ between the systems, with the PV system demonstrating a higher capability for support. The implementation of DC chopper shows more effective in the reduction of DC-link voltage and overshoot grid current in the PV system compared to the DFIG system

Morphological and electrical characterization of hybrid thin-film composed of titania nanocrystals, Poly (3-hexylthiophene) and Piper Betle Linn

In this research, the effect of scan numbers of titania nanocrystals (TiO2 NCs) on the morphological and electrical characteristics of hybrid thin-films is investigated. These hybrid thin-films consist of a combination of organic (Piper Betle Linn extraction and Poly (3-hexytlthiophene) (P3HT)) and inorganic TiO2 NCs (anatase structure) materials. These hybrid thin-films are fabricated in bilayer heterojunction of ITO/TiO2 NCs/P3HT/Piper Betle Linn via electrochemistry method using Electrochemical Impedance Spectroscopy (EIS). The scan numbers of TiO2 NCs are varied by 1, 3 and 5 number of scans. The morphological characterization is carried out via Field Emission Scanning Electron Microscopy (FESEM) meanwhile the electrical characteristic of the hybrid thin-film is measured by using four point probes. FESEM image indicates the particle size was found to be around 17-34 nm. The increment of scan number of TiO2 NCs from one to five scan numbers of TiO2 NCs in bilayers thin films showed that the atomic percentage of titanium decrease from 5.23% to 2.20%. This result indicates that as the thickness of thin films increases, the electrons required more energy to excite into conduction band of TiO2. Meanwhile, the electrical conductivities of hybrid solar cell increase from 0.385 Scm-1 to 0.389 Scm-1 as the scan numbers of TiO2 increase from one to three, however the electrical conductivity decrease to 0.346 Scm-1 at five scan numbers. As a conclusion, this study shows that the morphological and electrical properties of hybrid thin-films can be significantly affected by the scan number of TiO2 NCs

The impact of deflection on the sensing response of Fiber Bragg gratings bonded to Graphene and PMMA substrates

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