Md. Masud Rana

Peak to Average Power Ratio Analysis for LTE Systems

The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SCFDMA) scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. SCFDMA uses DFT spreading prior to OFDMA modulation to map the signal from each user to a subset of the available subcarriers i.e., single carrier modulation. The efficiency of a power amplifier is determined by the peak to average power ratio (PAPR) of the modulated signal. In this paper, we analyze the PAPR in 3GPP LTE systems using root raised cosine based filter. Simulation results show that the SCFDMA subcarrier mapping has a significantly lower PAPR compared to OFDMA. Also comparing the three forms of SCFDMA subcarrier mapping, results show that interleave FDMA (IFDMA) subcarrier mapping with proposed root raised cosine filter reduced PAPR significantly than localized FDMA (LFDMA) and distributed (DFDMA) mapping. This improves its radio frequency (RF) power amplifier efficiency and also the mean power output from a battery driven mobile terminal.

DNA Hybridization Detection Based on Resonance Frequency Readout in Graphene on Au SPR Biosensor

This paper demonstrates a numerical modeling of surface plasmon resonance (SPR) biosensor for detecting DNA hybridization by recording the resonance frequency characteristics (RFC). The proposed sensor is designed based on graphene material as biomolecular recognition elements (BRE) and the sharp SPR curve of gold (Au). Numerical analysis shows that the variation of RFC for mismatched DNA strands is quiet negligible whereas that for complementary DNA strands is considerably countable. Here, graphene is used to perform faster immobilization between target DNA and probe DNA. The usage of graphene also changes the RFC that ensure hybridization of DNA event by utilizing its optochemical property. In addition, proposed sensor successfully distinguishes between hybridization and single-nucleotide polymorphisms (SNP) by observing the variation level of RFC and maximum transmittance. Therefore, the proposed frequency readout based SPR sensor could potentially open a new window of detection for biomolecular interactions. We also highlight the advantage of using graphene sublayer by performing the sensitivity analysis. Sandwiching of each graphene sublayer enhances 95% sensitivity comparing with conventional SPR sensor.

An effective compact-FDTD wideband modeling of graphene conductivity

This paper demonstrates a competent rational polynomial method for efficient computational modelling of graphene surface conductivity using compact framework in the finite-difference time domain (FDTD) method that shape out graphene conductivity. The update equations of graphene surface conductivity using the proposed model in compact-FDTD (C-FDTD) method are developed. Numerical identity is presented to show the accuracy of the proposed approach and validation is obtained by comparing with exact formulism.

Performance of sub-carrier mapping in single carrier FDMA systems under radio mobile channels

Single carrier-frequency division multiple access (SC-FDMA) utilizes single carrier modulation at the transmitter and frequency domain equalization at the receiver. It has almost similar performance and essentially the same overall structure of an orthogonal frequency division multiple access (OFDMA) system with low peak to average power ratio (PAPR). Recently, the SC-FDMA has drawn great attention as an attractive alternative to OFDMA, in the uplink communications where lower PAPR greatly benefits the mobile terminal in terms of manufacturing cost as well as transmit power efficiency. Such power efficiency can provide considerable performance improvements in future wireless communication networks. This article outlines the basic principles of SC-FDMA systems with different types of sub-carrier mapping schemes. Simulation results demonstrate the performance of different sub-carrier mapping schemes under ideal and pedestrian channel condition.

An effective modified modeling of graphene interband conductivity

This paper proposes a modified mathematical model of graphene interband conductivity. The proposed modified model is similar to Drude model that can be easily applied for wideband modelling up to optical frequency range. This model can easily be superimposed with various computational methods especially in the finite difference time domain method (FDTD) for wideband applications. The effect of biasing chemical potential on the performance of modified conductivity model is analyzed. Validation of modified approach is also presented comparing with other existing interband conductivity models.

Enhancing the performance of rectangular patch antenna using E shaped slot technique for 5.75 GHz ISM band applications

This paper addresses the numerical simulations of rectangular patch and E shaped patch antennas for improving the performance of 5.75 GHz industrial, scientific and medical (ISM) band applications. The proposed antennas are directly feed by probe coaxial connector and the feed points are effectively controlled for the required operation. Significant performance enhancement can be realized when the E-shaped patch is used instead of the conventional rectangular microstrip patch antenna. The operating frequency of the patch antenna along with conventional rectangular microstrip patch and E shaped patch antennas are 5.75 GHz. All the simulation is done by using High Frequency Simulation Software (HFSS). In the comparison of E shaped patch antenna with the conventional rectangular microstrip patch antenna, improvement has been achieved in the overall antenna return loss by 50.72%, bandwidth by 25.76% and gain by 8.95%.

A comparative performance analysis of inverted F antenna using different substrates

This paper presents a comparative performance analysis of Inverted F antenna using various substrates. Natural cork, Plastic and Wood plastic are used as its substrate and the results are compared with the results of using FR4 substrate. This antenna is simulated using Ansofts HFSS software. The antenna performances are also analyzed using different widths of its radiating surface. It is designed with capacitive element so that the phase variation be minimum in current flow and enhances the radiation efficiency. The designed antenna covers the ISM band, WLAN (2.4-2.484 GHz), LTE2300, LTE2500 applications and also 6.96-7.20 GHz for private use.

Hand motion capture system in piano playing

It is important to measure the dexterous finger movements for piano education. But there are some problems to measure accurately of finger movements with angular position due to the complex finger bones construction. In this research, the complex and soft hand movements of a professional pianist were observed using different melodious music as an example, though it can measure any types of finger movements using magnetic motion capture (MoCap) system. The system can measure the complex finger movements with six degrees of freedom (6DOF). From the measured data, we calculated the finger height in space while playing the piano. We have investigated the hand/fingers status during playing the piano. The knowledge of finger movements of an expert pianist is useful for the skill learning. The data and knowledge of finger movements can be applicable in various fields where dexterous movements are essentials such as piano, computer typing, writing, different games etc.

EBG Based Microstrip Patch Antenna for Brain Tumor Detection via Scattering Parameters in Microwave Imaging System

A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S-parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain.

DEVELOPMENT OF GRAPHENE BASED TAPERED SLOT ANTENNAS FOR ULTRA-WIDEBAND APPLICATIONS

In this paper, three different types of graphene based tapered slot antennas are designed for ultra-wideband (UWB) applications. The taper profiles for three antenna types are linear, exponential, and constant width. A single layer graphene sheet of 35 μm thickness is used to model the radiating element and feeding structure of the designed antennas. To feed the antennas, microstrip to slotline transition technique is adopted. An approximate analytical theory based on conical transmission line model is considered to authenticate the design of graphene based tapered slot antennas. Better impedance matching over 2–20 GHz is obtained by designing a balun in the form of a radial stub. Return loss, bandwidth, radiation pattern, and directive gain are the considered antenna performance parameters. Time domain solver of CST MWS software is used to evaluate the performances of linearly tapered slot antenna (LTSA), exponentially tapered slot antenna (Vivaldi), and constant width slot antenna (CWSA). The results obtained from CST are compared with that from HFSS to further validate the design. Simulation results with extensive parametric study confirm that the novel 2-D material graphene can be considered as a promising one to model UWB tapered slot antennas. Furthermore, the effectiveness of designed graphene based tapered slot antennas is revealed by comparing their performances with other existing UWB antennas. Moreover, as a UWB application, Vivaldi antenna shows promising results in microwave brain tumor detection.