Gaurav Kumar Pandey

Bio: Gaurav Kumar Pandey is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Monopole antenna & Antenna (radio). The author has an hindex of 14, co-authored 49 publications receiving 567 citations. Previous affiliations of Gaurav Kumar Pandey include Indian Institute of Technology Delhi & Indian Institute of Technology (BHU) Varanasi.

A Quad-Band Compact Diversity Antenna for GPS L1/Wi-Fi/LTE2500/WiMAX/HIPERLAN1 Applications

Abstract: In this letter, a low-profile quad-band antenna array for multiple-input-multiple-output (MIMO) application has been presented. The proposed two-antenna array operates at GPS L1/Bluetooth/Wi-Fi/LTE2500/WiMAX/HIPERLAN1 frequency bands. Each antenna element has an area of 25×10 mm2 over a small ground plane of the size 100×60 mm2. To maintain the small size of the antenna element, folded patch is used. A rectangular slot is etched on the main radiator to utilize the higher-order mode. A quarter-wavelength resonator is integrated at the edge of folded patch to get an additional resonance for quad-band operation. An antenna prototype is fabricated, and measured results are in good agreement with simulated results. Radiation characteristics and diversity performance of the proposed structure are presented.

Compact antipodal Vivaldi antenna for UWB applications

Abstract: A novel compact end-fire antipodal Vivaldi antenna is proposed for ultra-wideband (UWB) applications such as in radars, microwave imaging and in high data rate wireless systems. To make the antenna compact, a bending feed line structure and sinusoidal modulated Gaussian tapered slot is used. The proposed antenna has a reflection coefficient of less than −10 dB from 2 GHz to more than 12 GHz (more than 166% fractional bandwidth). The radiation characteristics show an end-fire radiation pattern in the operating frequency band with peak realised gain values in the range of 1.5−5.2 dBi. Time domain analysis shows that the antenna has good pulse handling capability with a high system fidelity factor.

Low Mutual Coupling Between MIMO Antennas by Using Two Folded Shorting Strips

Abstract: This paper presents a compact dual-band multiple input multiple output (MIMO) antenna with low mutual coupling, operating in the 2.4GHz band (2.4{2.485GHz) and 5.5GHz band (5.15{ 5.85GHz). The proposed antenna system consists of two antenna elements located at the top two corners of FR4 substrate (PCB). Each element dimension is reduced substantially by employing a folded structure and slots on the top patch plate, so that it takes up a small volume of 12 £ 9 £ 6mm 3 . To enhance port-to-port isolation and e-ciency of each antenna, an additional non-radiating folded shorting strip is connected between each antenna element and ground plane of PCB. The measured isolation values are lower than i28dB over the lower WLAN band (2.4{2.485GHz) and better than i26dB (i30dB in most of the band) across the higher WLAN band (5.15{5.85GHz). The improvement in antenna's e-ciency caused to raise up 1dB of efiective diversity gain of MIMO system. Furthermore, S-parameters, radiation patterns and diversity performance characteristics are provided.

Metamaterial-based UWB antenna

Abstract: A metamaterial-based novel compact microstrip antenna is presented for ultra-wideband (UWB) applications. The antenna consists of two layers of metamaterials made by etching a π-shaped slot and crossed-shaped slots, on the radiating patch and the ground plane, respectively. The series capacitance and shunt inductance developed due to the patterned radiating patch and ground plane lead to the left-handed behaviour of the metamaterial. The proposed antenna has a compact size of 30.8 × 27.6 × 0.8 mm3 and is fed by a 50 Ω microstrip line. The impedance bandwidth (−10 dB) is from 3 GHz to more than 14 GHz with maximum radiation in the horizontal plane and tends towards a directional pattern as the frequency increases.

A printed high gain UWB vivaldi antenna design using tapered corrugation and grating elements

Abstract: A compact Vivaldi antenna is proposed with high gain over the ultrawideband UWB using novel combination of corrugation and grating elements. As it is very intricate to improve the radiation characteristics such as gain throughout the UWB using single technique, therefore, corrugation at the flares and grating elements in the area of tapered slot are used to improve gain over the UWB. Due to the corrugation, the gain and front-to-back ratio improved significantly over 3-8 GHz whereas the effect of grating elements is observed over 8 GHz. The antenna operates for 2.9 GHz to more than 12 GHz with S11<-10 dB and is designed on 0.8-mm thick low cost FR4 substrate 40 mm × 45 mm. The proposed antenna shows nearly stable unidirectional radiation patterns, peak realized gain more than 5 dBi, and front-to-back ratio better than 10 dB over the UWB. Furthermore, the time domain study of the antenna is carried out which shows good pulse handling capability with nearly flat group delay. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:610-618, 2015.

Bending and On-Arm Effects on a Wearable Antenna for 2.45 GHz Body Area Network

Abstract: Three types of flexible textile antennas for 2.45 GHz body area network (BAN) are compared in this letter. Two types of conducting materials are used to form radiation patch and ground plane; they are called copper foil tape (CFT, 0.05 mm thickness) and Shieldex (SH, 0.13 mm thickness, 0.009 Ohm surface resistivity). The substrate is a thin felt with relative permittivity of 1.2 and the thickness of 2 mm. In order to satisfy these requirements of small frequency shifting when the antenna is bent and placed on human body, two shorting probes are used to connect the radiation patch and ground plane. Compared to the antenna without shorting probes, the size of proposed antenna is reduced from 96 ×47 to 70 ×25 mm 2 , and the measured minimum value of S11 in free space is also decreased from -14.59 to -33.30 dB. Furthermore, an antenna with smaller size of 46 ×25 mm 2 is designed by modifying the proposed structure, and it can act as a wearable antenna as well.

A Low Cost and Portable Microwave Imaging System for Breast Tumor Detection Using UWB Directional Antenna array

Abstract: Globally, breast cancer is a major reason for female mortality. Due to the limitations of current clinical imaging, the researchers are encouraged to explore alternative and complementary tools to available techniques to detect the breast tumor in an earlier stage. This article outlines a new, portable, and low-cost microwave imaging (MWI) system using an iterative enhancing technique for breast imaging. A compact side slotted tapered slot antenna is designed for microwave imaging. The radiating fins of tapered slot antenna are modified by etching nine rectangular side slots. The irregular slots on the radiating fins enhance the electrical length as well as produce strong directive radiation due to the suppression of induced surface currents that radiate vertically at the outer edges of the radiating arms with end-fire direction. It has remarkable effects on efficiency and gain. With the addition of slots, the side-lobe levels are reduced, the gain of the main-lobe is increased and corrects the squint effects simultaneously, thus improving the characteristics of the radiation. For experimental validation, a heterogeneous breast phantom was developed that contains dielectric properties identical to real breast tissues with the inclusion of tumors. An alternative PC controlled and microcontroller-based mechanical MWI system is designed and developed to collect the antenna scattering signal. The radiated backscattered signals from the targeted area of the human body are analyzed to reveal the changes in dielectric properties in tissues. The dielectric constants of tumorous cells are higher than that of normal tissues due to their higher water content. The remarkable deviation of the scattered field is processed by using newly proposed Iteratively Corrected Delay and Sum (IC-DAS) algorithm and the reconstruction of the image of the phantom interior is done. The developed UWB (Ultra-Wideband) antenna based MWI has been able to perform the detection of tumorous cells in breast phantom that can pave the way to saving lives.

MIMO antennas with diversity and mutual coupling reduction techniques: a review

Abstract: Multiple input multiple output (MIMO) antenna is at core of the presently available wireless technologies. The design of MIMO antennas over a limited space requires various approaches of mutual coupling reduction, otherwise gain, efficiency, diversity gain, and radiation patterns will be severely affected. Various techniques have been reported in literature to control this degrading factor and to improve the performance of the MIMO antennas. In this review paper, we have carried out an extensive thorough investigation of diversity and mutual coupling (correlation) reduction techniques in compact MIMO antennas.

Recent developments and research needs in modeling lane changing

Abstract: This paper comprehensively reviews recent developments in modeling lane-changing behavior. The major lane changing models in the literature are categorized into two groups: models that aim to capture the lane changing decision-making process, and models that aim to quantify the impact of lane changing behavior on surrounding vehicles. The methodologies and important features (including their limitations) of representative models in each category are outlined and discussed. Future research needs are determined.

A reduced size dual port MIMO DRA with high isolation for 4G applications

Abstract: © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:495-501, 2015. © 2014 Wiley Periodicals, Inc.A dual-port reduced size multiple input multiple output (MIMO) Dielectric Resonator Antenna (DRA) has been studied and proposed. The MIMO antenna consists of a Rectangular Dielectric Resonator antenna, which is fed by two symmetrical feed lines for orthogonal mode excitation. The proposed antenna is suitable for operation over various long term evolution (LTE) bands. A measured bandwidth of 264 MHz for |S 11 | <-10dB and isolation of 18 dB at 1.8 GHz has been obtained. Besides, the Envelope Correlation Coefficient, Mean Effect Gain and Diversity Gain have been studied for the presented MIMO DRA using the S-parameters. Based on these results, it can be concluded that the proposed antenna can be a suitable candidate for MIMO applications.