Effect of Plasma Antenna Shape on the Antenna Performance Using Plasma Computer Simulation Technology (CST)

The manipulation of fluorescent lamps in terms of size and shape was done to investigate the performance of the fluorescent-based plasma antenna. In order to fully utilize different types of commercially available fluorescent lamps, this research dealt with the effects of different shapes and types of fluorescents lamp available in the market. The aim of this research is to test the performance of fluorescent lamps with three basic shapes, namely tubular, 2U and 3U as plasma antennas by means of return loss, gain, directivity and radiation pattern. The electrical properties were determined using the current and voltage probes connected to a digital oscilloscope. Glomac programming was used to generate the average electron density and electron temperature values, using the measured electrical properties. Those parameters are crucial for calculating the plasma parameters i.e., collisions and plasma frequencies. Plasma parameter values were used in Computer Simulation Technology (CST) to simulate antenna performance. From the s-parameter or return loss results, this kind of plasma antenna radiated best at frequencies ranging from 3 to 5 GHz with the best at -41 dB using the 2U type. The gain was within the range of 0.6 dB to 2.3 dB allowing the tubular type to have the best result. The best radiation pattern was shown by tubular shaped lamp due to its uniform and symmetric main lobes in the lower and upper planes. The physical parameters of the fluorescent lamp influenced the amount of current needed to ionize the gas in the lamp. This caused the production of many electrons which altered the average electron density and its temperature. As a result, it can be concluded that by varying the shape of lamps, the plasma and collision frequencies will be affected, and consequently affecting the plasma antenna performance

A Patternless Piezoelectric Energy Harvester for Ultra Low Frequency Applications

This paper presents a pattern less piezoelectric harvester for ultra low power energy applications. Usually patterned cantilevers are used as vibration energy harvester which results additional fabrication process. Hence, to reduce the process, a four layer cantilever configuration is used to design the harvester with Aluminum, Silicon and Zinc Oxide. The device dimension is settled to 12×10×≈0.5009 mm3 with ≈300 nm deposition thickness for each layer. The modeling and fabrication processes are demonstrated in detail. The induced voltage by the cantilever is obtained through the analytical and practical measurements. From the measurements, it is found that, the maximum induced voltage is 91.2 mV from practical measurement with voltage density of 1.517 mV/mm3. It is evident from the results that, this pattern less model can be useful for next generation vibration energy harvester with simpler technology

Development of Low Cost HF Antenna for Amplitude Observation at Equatorial Region

In this paper the development of low cost antenna for High Frequency (HF) has been proposed. The proposed antenna is designed to operate from 3 MHz until 30 MHz for space weather observation. The antenna consists of small loop with primary and secondary loop. The primary and secondary purpose for radiating element while a lumped element being placed in series with the secondary loop for frequency tuning. Circumference size is taken from the 1/10 or 10% of wavelength, with circumference of 2.14 M and diameter of 0.64 M and able to capture the frequency at 15.21 and 15.34 MHz respectively. 4nec2 software has been used to bear out the simulation results. The antennas prototype has been designed, constructed and measured. The return loss measurement of antenna is -30dB, at 14 MHz. An omni directional radiation pattern measurement has been carried out at 15 MHz for signal transmitting

Association mapping of stigma and spikelet characteristics in rice (Oryza sativa L.)

Stigma and spikelet characteristics play an essential role in hybrid seed production. A mini-core of 90 accessions developed from USDA rice core collection was phenotyped in field grown for nine traits of stigma and spikelet and genotyped with 109 DNA markers, 108 SSRs plus an indel. Three major clusters were built upon Rogers’ genetic distance, indicative of indicas, and temperate and tropical japonicas. A mixed linear model combining PC-matrix and K-matrix was adapted for mapping marker-trait associations. Resulting associations were adjusted using false discovery rate technique. We identified 34 marker-trait associations involving 22 SSR markers for eight traits. Four markers were associated with single stigma exsertion (SStgE), six with dual exsertion (DStgE) and five with total exsertion. RM5_Chr1 played major role indicative of high regression with not only DStgE but also SStgE. Four markers were associated with spikelet length, three with width and seven with L/W ratio. Numerous markers were co-associated with multiple traits that were phenotypically correlated, i.e. RM12521_Chr2 associated with all three correlated spikelet traits. The co-association should improve breeding efficiency because single marker could be used to assist breeding for multiple traits. Indica entry 1032 (cultivar 50638) and japonica entry 671 (cultivar Linia 84 Icar) with 80.65 and 75.17% of TStgE, respectively are recommended to breeder for improving stigma exsertion

Investigation on the effect of impurities in xenon based dielectric barrier discharge lamps

International audienceIn any discharges, the existence of impurities could give a severe change or bring a negative or positive effect to the discharge and plasma characteristics. The authors purposely added a few kinds of impurities and their effect on the discharge was investigated. The common and typical impurities of H 2, N 2, CO 2 and CH 4 were applied in varying concentration percentages into a xenon DBD lamp. Their discharge condition, emission spectra and electrical characteristics were studied. The plasma generation differs from one type of impurity to another. With two different concentrations of hydrogen, at 5% concentration it would stabilize the discharge and at 0.5% concentrations it would give an additional collision process where a strong peak of atomic lines were observed. Nitrogen with two types of concentration i.e., 1% and 0.1% gives two kinds of characteristics in emission spectroscopy. From the electrical parameters, the voltage across the gap shows the lamps with impurities have a higher value compared to the pure xenon lamp

Reconfigurable Plasma Antenna Array by Using Fluorescent Tube for Wi-Fi Application

This paper presents a new design of reconfigurable plasma antenna array using commercial fluorescent tube. A round shape reconfigurable plasma antenna array is proposed to collimate beam radiated by an omnidirectional antenna (monopole antenna) operates at 2.4GHz in particular direction. The antenna design is consisted of monopole antenna located at the center of circular aluminum ground. The monopole antenna is surrounded by a cylindrical shell of conducting plasma. The plasma shield consists of 12 commercial fluorescent tubes aligned in series containing a mixture of Argon gas and mercury vapor which upon electrification forms plasma columns. The plasma behaves as a conductor and acts as a reflector in radiation, in the condition where plasma frequency,ωp is higher than operating frequency. From this concepts, when all plasma elements are activated or switched to ON, the radiation signal from monopole antenna will trapped inside the plasma blanket and meanwhile when one or more plasma elements is deactivated (switched OFF), the radiation from monopole antenna will escape. This antenna has the capability to change its patterns with beam direction at 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° at frequency 2.4 GHz. The proposed antenna has been successfully fabricated and measured with conclusive results

Characterisation of a thermionic plasma source apparatus for high density gaseous plasma antenna applications

none8noneAlexander Daykin-Iliopoulos, Franco Bosi, Fabio Coccaro, Mirko Magarotto, Athanasios Papadimopoulos, Paola De Carlo, Cristian Dobranszki, Igor Golosnoy and Steve GabrielDaykin-Iliopoulos, Alexander; Bosi, FRANCO JAVIER; Coccaro, Fabio; Magarotto, Mirko; Papadimopoulos, Athanasios; DE CARLO, Paola; Dobranszki, Cristian; Golosnoy and Steve Gabriel, Igo