A. H. M. Zahirul Alam

High-rate reactive deposition of indium oxide films on unheated substrate using ozone gas

Abstract The effectiveness of ozone incorporation in reactive gas of oxygen for producing indium oxide films by DC reactive magnetron sputtering employing a metal target has been investigated. It was found that 4% volume concentration of O 3 in addition to oxygen greatly enhanced the reactivity of the sputtered particles on the substrate of growing surface without substrate heating. The deposition rate of stoichiometric oxide film is found much greater in ozone added environment than that of growing in only oxygen environment.

Analysis of CNT electronics structure to design CNTFET

In this paper, graphene electronic structure of carbon nanotubes has been analyzed and validate with past theoretical and experimental results. The energy dispersion relation, effective mass and intrinsic carrier concentration of graphene have been analyzed to build diverse carbon nanotubes. The electronics properties of graphene are subject to change with the different diameters and wrapping angles of carbon nanotubes. Different chiral vector (n, m) of a graphene allows to design carbon nanotube for a wide range of applications, which can be achieved from the analyzed carrier concentration calculation. The proposed calculations set a higher boundary for a wide range of applications including the integration of carbon nanotube internal architecture and carbon nanotube field effect transistors.

Design and analysis of UWB rectangular patch antenna

In this paper a simple structure of Ultra Wideband (UWB) antenna is proposed. The antenna offers excellent performance for UWB system, ranging from 3.7 GHz to 13.8 GHz. The antenna exhibits a 10 dB return loss bandwidth over the entire frequency band. The antenna is designed on FR4 substrate and fed with 50 ohms microstrip line. It is found that the frequency band depends on the width of the partial ground width, the width of the feedline and position of the feedline.

Properties of indium tin oxide films with indium tin modulation layers prepared by nano-scale controlled reactive magnetron sputtering

Abstract A new preparation method for tin-doped indium oxide (ITO) films containing nano-scale indium tin (IT) sandwich layer(s) by the combined use of reactive and non-reactive d.c. magnetron sputtering is proposed. The film properties vary markedly with the number of IT layers and the thickness ratio m of the IT layer to the ITO layer. The lowest resistivity of a 100 nm film is 5.8 × 10−4 Ω cm with IT layers, but 9.8 × 10−4 Ω cm without IT layers. The transparency of the film is greater than 90% in the visible region.

An activity monitoring system for senior citizens living independently using capacitive sensing technique

With the continual increase of senior citizens more resources are required for providing care centers services. The quality of such services can be enhanced by remotely monitoring senior citizens living independently in their homes. The monitoring can be performed using various types of sensors, but the solution presented in this paper is simple, cost effective as well as easy to implement compared to most of the existing systems. The proposed system uses capacitive based sensor to monitor the daily activities of an elderly living alone. The monitoring system works on the principle of measuring the disturbance in the electromagnetic field when a human body approaches the sensor. This proposed sensor is fundamentally based on electric field sensing using sensors are in the form of thin planar electrodes. The Arduino-based board in combination with CapSense library acquires the sensed data. The detection system is embedded on the care-center floor surface, making the system to be non-intrusive as well as maintaining the privacy of the user. The data so obtained is perceived as information on a PC, which can be used in generating an automatic alarm system. A notification can be sent to the cell phones of the caregivers for assistance. The important thing in the alarms is that no user input is required from the person under monitoring and no devices need to be worn. A prototype sensor is described in detail and preliminary results are presented based on simulation and experimental procedure.

Parametric analysis for designing low voltage and low frequency energy harvester booster

This work presents an ultra-low voltage DC-DC boost converter vibration-based energy harvesting. A switching gate controlled concept is used which is well suited for low vibration-based frequency and voltage applications. The 0.1-0.5 V input voltage range is linearly increased with the increase of output voltage range, 4-22 V. The transient analysis is simulated to verify the optimum value of the inductive resistance, switching rise and fall times circuit under test. The 10 kΩ load circuit is using 160 μH inductor and 10 μF load capacitor. This voltage converter is suitable for energy harvesting applications in automotive, buried electronic devices for broadband frequency range from 1 kHz to 10 kHz.

Modeling of small band-gap CNT for designing of faster switching CNTFET

This paper suggests the modeling phenomena of small band-gap Carbon Nanotube (CNT). Device physics of CNT is studied and do the calculation of sub-band for zigzag CNT to model small band-gap tubes. Each carbon nanotube is described as a graphene sheet rolled into a cylindrical shape so that the structure is one dimensional with axial symmetry. A comparison is made with the current literature to show that the proposed chirality CNT with small band-gap which makes faster switching Carbon Nanotube Field Effect Transistor (CNTFET).

Design and Development of a Simulator for Modelling Carbon Nanotube

In this paper, a Matlab simulator is developed for modelling of carbon Nanotubes (CNTs). First electronics structure is derived and discussed to facilitate the analysis and modelling of the simulator. Then a calculation is done for electron energy dispersion relations for single-wall zigzag CNTs with different tube indexes. From the analysis of energy dispersion relation, it is derived an analytical models for CNT parameters such as the mobility and the intrinsic carrier concentration. Once obtain the CNT parameters, and then import them to the developed simulator. The simulator is based on the semiconductor equations and quantum effects. Finally the simulator produces the result for optimum modelling of CNT for electronic device application.

Design of a low noise amplifier with GaAs MESFET at ku_Band

A Ku-Band low noise amplifier has been designed with the gain of 8.90 dB and 2.19 dB noise figure for satellite receiver. The parameters are optimized by using Microwave Office Simulator (AWR) Ver. 2006. The size of the monolithic chip is 0.316mm2. The LNA is designed to operate at 12GHz.

Designing an UWB patch antenna with band notched by using L-shaped slot and unsymmetrical feedline

An ultra-wideband (UWB) antenna with band-notch characteristic of size 32mmtimes28.1 mm is proposed. This antenna is designed to cover the Federal Communication Commission (FCC) bandwidth for UWB applications (3.1-10.6 GHz) and have a notch filtering at the IEEE 802.11a frequency band (5.15-5.825 GHz). This notch-filter effect is obtained by introducing a resonant L-shaped slot at this frequency. The design parameters and the performance of the proposed antenna are analyzed by using high frequency structured simulator HFSS.