Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

A heterostructure of MXene and MoS2 (Nb2CTx@MoS2) was synthesized and used for the ultrasensitive and selective detection of dopamine (DA). The composite was synthesized using a facile hydrothermal strategy and it was used to modify the carbon cloth (CC). The best composition of the material for DA detection was optimized by varying the content of MoS2 from 6.25 to 25 % while keeping the amount of Nb2CTx constant. From the electrochemical analysis, it was found that Nb2CTx@12.5MoS2 showed the best sensing characteristics owing to the optimum interaction between MoS2 and Nb2CTx. The Nb2CTx@MoS2 modified CC was able to detect DA linearly from 1 fM to 100 µM with a limit of detection (LOD) of 0.23 fM. The LOD of 0.23 fM is the lowest for DA detection in comparison with other MXene-based composites to the best of our knowledge. The developed sensor exhibited promising selectivity for determination of DA in presence of other interferents like uric acid and ascorbic acid. In addition, the developed sensor showed good repeatability, cyclic and storage stability, which shows the potential of this composite for developing flexible electrochemical sensors for the ultrasensitive and selective determination of DA. © 2023 Elsevier B.V.

World University root node

Biological Sciences and Engineering

Microchemical Journal

Ultrasensitive electrochemical detection of dopamine from human serum samples by Nb2CTx-MoS2 hetero structures

In this research, a novel multi-band reflecting polarization converter is proposed, which uses a single-layered substrate to convert between linear and circular polarization. The top FSS printed on the grounded dielectric spacer comprises an I-shaped metallic patch and an orthogonally connected inductive grid. For the y-polarized EM wave incidence, the design shows linear-cross polarization rotation with a Polarization Conversion Ratio (PCR) of a minimum of 90% from 15.28–17.86 GHz, 39.53–44.46 GHz, 55.46–56.26 GHz with 15.57%, 11.74%, and 1.43% Fractional Bandwidth (FBW). In addition, it also experiences linear-circular conversion with 3 dB minimum Axial Ratio (AR) from 12.06–14.04 GHz, 19.96–36.34 GHz, 47.08–54.74 GHz, and 56.60–57.06 GHz with 15.17%, 58.19%, 15.05%, and 0.81% FBW. Various oblique incidences in the design are studied, and the performance is stable up to 45°. Next, the proposed design is shorted at the end, replicating the diode ON condition mechanically, turning the proposed design into a perfect reflector in the operating range. The unitcell architecture is compact with a periodicity of 0.101 × 0.076 λL2, and overall thickness of 0.064 λL. The authors are certain that the design's small size and excellent angular stability make it ideal for applications calling for reflective type multi-band dual-polarized linear-circular and linear-cross polarization conversion, including reflector response. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Department of Electrical Engineering

Lecture Notes in Electrical Engineering

Multi-band Dual-Polarized Linear-Circular and Linear-Cross Obliquely Stable Reflective Type Polarizer with Mechanically Tunable Reflector Response for K-and Ka-Bands Applications

This work introduces an antenna added with a frequency selective surface (FSS) for breast tumor identification. The put forwared device is made on an FR4 substrate with relative permittivity 4.4 and thickness 1.6 mm. The developed antenna has a wide operating band from 2.9 - 13 GHz. An apex gain of 8.71 dBi is also achieved with the developed device. The impact of the antenna radiation on a developed breast phantom is also determined in this work, by calculating the Specific Absorption Rate (SAR) readings. © 2023 IEEE.

International Conference on Microwave, Antenna and Communication, MAC 2023

Monopole Antenna Loaded with Wind Mill shaped FSS for Breast Tumor Detection

This work demonstrates a novel, reflective-type, dual-polarized multiband polarization transformer for various C to Ku band applications. The design constitutes a top FSS printed on a thin FR-4 grounded dielectric substrate. A y/x-polarized incident wave experiences linear-circular conversion from 4.61 to 4.71 GHz (right-hand circular polarized (RHCP)/left-hand circular polarized (LHCP)), 5.44 to 7.68 GHz (LHCP/RHCP), 10.13 to 14.98 GHz (RHCP/LHCP), and 16.68 to 17.19 GHz (LHCP/RHCP) with 3.41, 34.15, 38.63, and 3.01% FBW, respectively. In addition, it performs linear-cross conversions with a minimum 90% polarization conversion ratio (PCR) from 4.92 to 5.18 GHz, 8.32 to 9.41 GHz, and 15.56 to 16.25 GHz with 5.15, 12.30, and 4.34% FBW. Multiple surface plasmonic resonances are responsible for these polarization conversions in different bands. The device performance is angular stable for both transverse electric (TE) and transverse magnetic (TM) incidences. The design novelty lies in compacted periodicity 0.112λL, low-profile thickness 0.037λL with a multi-conversion (switching the orthogonal circular rotation in consecutive bands), and stable angular response, which can potentially be used in real-time applications. © The Author(s), 2022. Published by Cambridge University Press in association with the European Microwave Association.

International Journal of Microwave and Wireless Technologies

Novel miniaturized arrow linked figure of eight square loop FSS-based multiband linear-circular and linear-cross reflective microwave polarizer

Frequency selective surface (FSS) gains significant interest in the wireless communication system for shielding against electromagnetic interference (EMI). This paper presents a novel multiband 2.5 D FSS with dual operations in the transmission and reflection modes. The FSS exhibits dual-band bandstop filtering in transmission mode to shield EMI at sub-6 GHz 5G, WLAN and WiMAX frequencies. In the proposed multilayer geometry, two stopband (SB) resonances (at 2.32 and 4.04 GHz) are generated using enhanced capacitance loaded modified Jerusalem cross (EC-MJC) and via connected meandered square loop (VC-MSL). FSS transmits the signal with a low insertion loss of &#x003C; 0.6 dB at pass-band frequency (2.98 GHz), existing between two reflection bands. The miniaturized unit cell size (&#x003C; 0.07 &#x03BB;L), polarization insensitive, and highly stable filter response at almost all incidence angles (up to 80&#x00B0;) are the attractive features of the designed FSS. In reflection mode, the 2.5 D FSS has been configured for multiband microwave absorbers at dual, triple, and quad-band resonances. The FSS and absorber are practically realized for the experimental validation of simulation results. The measured results are in good accordance with the numerical simulation for both operating modes, which establishes the design principle of the multifunctional FSS. IEEE

IEEE Transactions on Antennas and Propagation

Miniaturized Near All Angle Stable 2.5D FSS For Dual Band Shielding in Transmission Mode and Multiband Absorption in Reflection Mode

This article presents two ultra-broadband bandpass filter (BPF) designs for multi-standard applications, operating from 1–6 GHz and 6–10 GHz, with wide stopband characteristics. 1–6 GHz BPF (Filter 1) is based on the circuit model for an optimum distributed bandpass filter consisting of 3 shunt short-circuited stubs separated by non-redundant unit elements. By varying the length ratio between the unit elements and stubs and introducing stepped impedance in the unit elements, a 143% fractional bandwidth (FBW) is achieved, which is 20% higher than that obtained through the conventional optimum shunt short-circuited stub method. In addition, a stepped impedance elliptic lowpass filter was cascaded to achieve wide stopband characteristics from 7 GHz to 20 GHz. Filter 2 (6–10 GHz) is constructed by cascading a shunt short-circuited stub optimum high pass filter having a stepped impedance unit element with a stepped impedance low pass filter. The analytical model, transmission line equivalent circuit model and full wave electromagnetic simulated model are presented along with the measured results. The measured in-band return loss of Filter 1 and Filter 2 is >12 dB and the measured insertion loss is < 2 dB. The measured group delay of Filter 1 and Filter 2 is <0.8 ns. © 2023 IETE.

IETE Journal of Research

Stepped Impedance Optimum Short-Circuited Stub 1–6 GHz and 6–10 GHz Bandpass Filters for Multi-standard Radio

For microwave head imaging, a patch in the shape of a flower is created in this work using the CST Studio software. A matching performance of more than 10 dB is achieved between 1.59 to 5.2 GHz for the specified structure. When operating at 4.4 GHz, the antenna achieves an apex gain of 3.92 dBi. To determine the impact of the antenna on the human head, the SAR value of the designed antenna is examined. 7-layered human head model designed on software is used for this. The simulator is used to study each performance criterion for the proposed structure. Additionally, 11 copies of the intended antenna are positioned all around the designed head model to obtain sufficient data for imaging the embedded tumour. © 2023 IEEE.

Microwave Medical Imaging using a Compact Monopole Antenna for Brain Tumor Detection

This work introduces a monopole antenna based on metamaterials for breast cancer identification. The put forward antenna is built on an FR4 substrate with a dielectric constant of 4.4, loss tangent 0.025 and thickness of 1.6 mm. For gain enhancement, the designed antenna is equipped with a frequency selective surface (FSS) on its back side. The suggested antenna obtains a broad bandwidth (S11 > 10 dB) between 2.3 and 22.3 GHz, with a apex gain of 9.3 dBi at 12 GHz. The put forward work also achieves a maximum gain enhancement of 5 dBi with the addition of FSS at the back side of the antenna. The Specific absorption Rate (SAR) study of the antenna with a realistic homogeneous breast phantom modelled in the simulator is performed to assess the effect of radiation on the breast. It is observed that the suggested antenna agrees with the International limits when averaged over 1g of tissue. © 2023 IEEE.

2nd International Conference on Wireless, Antenna and Microwave Symposium, WAMS 2023

Monopole Antenna with Frequency Selective Surface for Microwave Breast Cancer Detection

Underwater acoustical 3D imaging is popular for underwater investigations due to its ability to give all the geometric information of the target. The computational complexity of the conventional time domain delay and sum beamforming (DAS) is a bottle neck for the real-time implementation of the acoustical 3D imaging. Many fast-beamforming techniques in frequency domain such as Chirp Zeta Transform beamforming (CZT) have been proposed to solve this problem. However, wideband pulse transmission for high resolution imaging makes frequency domain methods infeasible for the 3D acoustical imaging. In this work, we attempted to implement time domain delay and sum beamforming using software interpolation and compare it with the CZT beamforming. The simulation results show that software implementation of digital delay and sum beamforming is faster than CZT beamforming.

A Comparison of Time Domain Delay and Sum Beamforming and Chirp Zeta Transform Beamforming for Underwater 3D Acoustical Imaging

Photoplethysmography (PPG) signals play an important role for automatic measurement of pulse rate, blood pressure, non-invasive blood glucose level and respiration rate. Most of the PPG monitoring devices are prone to motion artifacts and noises under different PPG recording conditions. Thus, automatic assessment of PPG signal quality is most essential for discarding unacceptable PPG signals and reducing false alarms due to the noisy measurements. This paper presents a new PPG signal quality assessment (SQA) method by using the average degree feature extracted from the horizontal visibility graph (HVG) of the PPG signal and six different classifiers such as random forest (RF), Naive Bayes (NB), decision tree (DT), support vector machine (SVM), multilayer perceptron (MLP), convolutional neural network (CNN). On a wide variety of standard databases, evaluation results show that the CNN based SQA method had an overall accuracy of 99.24% that outperforms other five SQA methods in terms of overall accuracy. The NB based SQA method had an accuracy of 99.21% with lower memory space of 1 kB as compared to other SQA methods. © 2023 IEEE.