Mandeep Jit Singh

A New Metasurface Superstrate Structure for Antenna Performance Enhancement

A new metasurface superstrate structure (MSS)-loaded dual band microstrip line-fed small patch antenna is presented in this paper. The proposed antenna was designed on a ceramic-filled bioplastic sandwich substrate with a high dielectric constant. The proposed 7 × 6 element, square-shaped, single-sided MSS significantly improved the bandwidth and gain of the proposed antenna. The proposed MSS incorporated a slotted patch antenna that effectively increased the measured operating bandwidth from 13.3% to 18.8% and from 14.8% to 23.2% in the lower and upper bands, respectively. Moreover, the average gain of the proposed MSS-based antenna was enhanced from 2.12 dBi to 3.02 dBi in the lower band and from 4.10 dBi to 5.28 dBi in the upper band compared to the patch antenna alone. In addition to the bandwidth and gain improvements, more directive radiation characteristics were also observed from the MSS antenna compared to the patch itself. The effects of the MSS elements and the ground plane length on the reflection coefficient of the antenna were analyzed and optimized. The overall performance makes the proposed antenna appropriate for RFID and WLAN applications.

Evaluating the academic trend of RFID technology based on SCI and SSCI publications from 2001 to 2014

Radio frequency identification (RFID) is one of the most influential technologies of the twenty-first century. Today, RFID technology is being applied in a wide array of disciplines in science research and industrial projects. The significant impact of RFID is clearly visible by the rate of academic publications in the last few years. This article surveys the literature to evaluate the trend of RFID technology development based on academic publications from 2001 to 2014. Both bibliometric and content analyses are applied to examine this topic in SCI-Index and SSCI-Index documents. Based on the bibliometric technique, all 5159 existing RFID documents are investigated and several important factors are reviewed, including contributions by country, organizations, funding agencies, journal title, authors, research area and Web of Science category. Moreover, content analysis is applied to the top 100 most cited documents and based on their contents, these top 100 documents are classified into four different categories with each category divided in several sub-categories. This research aims to identify the best source of the most cited RFID papers and to provide a comprehensive road map for the future research and development in the field of RFID technology in both academic and industrial settings. Six key findings from this review are (1) the experimental method is the most popular research methodology, (2) RFID research has been a hot area of investigation but will branch out into related subset areas, (3) South East Asia is positioned to dominate this research space, (4) the focus of research up to now has been on technical issues rather than business and management issues, (5) research on RFID application domains will spread beyond supply chain and health care to a number of different areas, and (6) more research will be related to policy issues such as security and privacy.

Large area few-layer graphene with scalable preparation from waste biomass for high-performance supercapacitor

Carbonaceous materials with high surface area and a sheet-like structure promote fast ion-transport kinetics, making them an ideal choice to be used in supercapacitors. Few-layer graphene (FLG)-like nanosheets with abundance of micro as well as mesopores are achieved via mechanical exfoliation method from an agricultural waste biomass: peanut shell (PS). A well-known elementary method of probe-sonication, for the achievement of FLG sheets from renewable sources, is introduced in this study for the very first time. The Peanut shell-derived FLG (PS-FLG) possesses remarkably high specific surface area (2070 m2 g−1) with a sufficiently large pore volume of 1.33 cm3 g−1. For the fabrication of a binder-free supercapacitor, the PS-FLG-based electrodes exhibited a high specific capacity of 186 F g−1 without the use of any binder in 1 M H2SO4 as supporting electrolyte. The highest energy density of 58.125 W h Kg−1 and highest power density of 37.5 W Kg−1 was achieved by the material. Surprisingly, the working potential increased to 2.5 V in an organic electrolyte leading to an obvious increase in the energy density to 68 W h Kg−1. Solid-state-supercapacitor was fabricated with this material for the possible use of low-cost, high energy promising energy storage device.

GPS water vapor monitoring and TroWav updated for ENSO studies

The GPS receiver and the meteorology sensors have been installed at Universiti Malaysia Sabah (UMS), Kota Kinabalu (UMSK: 6.03°N, 116.12°E and 63.49 m) for study a climate condition that has associated with El Niño Southern Oscillation (ENSO). The atmospheric precipitable water vapor (PWV) derived from GPS technique was used as an indicator of ENSO detection. In the processing, the Niell Mapping Function (NMF) used to map the atmospheric delay from zenith to the line-of-site was updated using the Vienna Mapping Function (VMF). With GPS antenna co-located with meteorological sensors, the comparison of GPS PWV with time-dependent surface pressure and sea surface temperature (SST) during the first ten weeks observation found that surface pressure is opposed to the PWV changes.

Proposed Rain Attenuation Model Revised from ITU Used for Prediction in Tropical Climates

A model for predicting rain attenuation on earth-to-space is developed by using the measured data obtained from tropical and equatorial region. The proposed rain attenuation model uses the complete rainfall rate cumulative distribution as input data. It is shown that significant improvements in terms of prediction error over existing attenuation model are obtained

Extending birthday paradox theory to estimate the number of tags in RFID systems.

The main objective of Radio Frequency Identification systems is to provide fast identification for tagged objects. However, there is always a chance of collision, when tags transmit their data to the reader simultaneously. Collision is a time-consuming event that reduces the performance of RFID systems. Consequently, several anti-collision algorithms have been proposed in the literature. Dynamic Framed Slotted ALOHA (DFSA) is one of the most popular of these algorithms. DFSA dynamically modifies the frame size based on the number of tags. Since the real number of tags is unknown, it needs to be estimated. Therefore, an accurate tag estimation method has an important role in increasing the efficiency and overall performance of the tag identification process. In this paper, we propose a novel estimation technique for DFSA anti-collision algorithms that applies birthday paradox theory to estimate the number of tags accurately. The analytical discussion and simulation results prove that the proposed method increases the accuracy of tag estimation and, consequently, outperforms previous schemes.

Efficient and low complexity STBC-OFDM scheme over fading channel

In this paper, a new trend of Space Time Block Code-Orthogonal Frequency Division Multiplexing (STBC-OFDM) was proposed. First, introduce brief description of the conventional (STBC-OFDM) scheme. Second, introduce the efficient and low complexity scheme of a STBC-OFDM, where both encoder and decoder lay in the time domain. This scheme does not require channel knowledge either at the transmitter or receiver. The decoding algorithm is based on generalized maximum-likelihood sequence estimation. The performance of the proposed scheme was investigated over two-tap Rayleigh fading channels. The simulation results show the performance of proposed STBC-OFDM scheme definitely outperforms conventional STBC-OFDM scheme on fading channel for different Doppler frequency (fD).

A 10GHz PHEMT Dielectric Resonator Oscillator

In all microwave systems, oscillators represent the basic microwave energy source. The main problem in oscillator design is the phase noise. This paper will discuss the design and fabrication of a 10GHz parallel feedback type GaAs PHEMT dielectric resonator oscillator. It incorporated an E2000 series dielectric resonator from Tekelec Temex with a quality factor of 5000 at 10GHz. The coupling gap between the resonator and the microstrip lines can be adjusted to optimize the ratio of the loaded to the unloaded quality factor to give a better phase noise, where it can be achieved when an insertion loss of 9.5dB is obtained. Phase noise measurement and analysis on the effect of frequency pushing and pulling towards the oscillator has been done using a spectrum analyzer. The dielectric resonator oscillator was measured and exhibited an oscillation at 9.845 GHz with a phase noise of -115.5 dBc/Hz at 100 kHz

Electromagnetic Performances Analysis of an Ultra-wideband and Flexible Material Antenna in Microwave Breast Imaging: To Implement A Wearable Medical Bra.

In this paper, we report a compact and ultra-wide band antenna on a flexible substrate using the 5-(4-(perfluorohexyl)phenyl)thiophene-2-carbaldehyde compound for microwave imaging. In contrast to other microwave based imaging systems, such as an array of 16 antennas, we proposed a bi-static radar based imaging system consisting of two omnidirectional antennas, which reduces complexity and the overall dimension. The proposed compact antennas are 20 × 14 mm2 and designed for operating at frequencies from 4 to 6 GHz. To allow for implantation into a bra, the electromagnetic performances of the antennas must be considered in bending conditions. In comparison with the recently reported flexible antennas, we demonstrated both electromagnetic performance and imaging reconstruction for bending conditions. For the proof of concept, the electromagnetic performances both at flat and bending conditions have been verified using a homogeneous multilayer model of the human breast phantom. Our results demonstrate that the antenna, even at bending conditions, exhibits an excellent omni-directional radiation pattern with an average efficiency above 70% and average gain above 1 dBi, within the operational frequency band. The comprehensive aim of the realized antenna is to design a biodegradable and wearable antenna-based bra for early breast cancer detection in the future.

Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags

A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919–923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for ‘place and tag’ application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP).