Browsing by Author "Kumar, S."

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3D printing of functionally graded nanocomposites: An investigation of microstructural, rheological, and mechanical behavior
(John Wiley and Sons Inc, 2024) Kumar, S.; Rajath, S.; Shivakumar, N.D.; Ramesh, M.R.; Doddamani, M.
Manufacturing functionally graded material through 3D printing is challenging owing to the deposition of different materials with different thermal properties in each layer, leading to a higher thermal gradient between deposited and depositing layers, resulting in improper bonding between them and, hence, reduced mechanical properties. This study focuses on 3D printing of functionalized multi-walled carbon nanotubes (MWCNTs)/high-density polyethylene (HDPE)-based lightweight functionally graded nanocomposites (FGNCs) and their investigation for microstructural, rheological, physical, and mechanical properties. Functionalized MWCNTs (0.5% → 5%) are initially compounded with widely utilized HDPE to develop nanocomposites (H0.5→H5 pellets) for extruding filaments for 3D printing. 3D-printed FGNC samples are investigated through scanning electron microscopy (SEM), rheology, density, tensile, and flexural tests. SEM and rheology confirm the homogeneous dispersion of the filler in HDPE and the processing parameters suitability in blending, extrusion, and 3D printing. Complex viscosity (η*), loss modulus (E″), and storage modulus (E′) of FGNCs increase, while the damping decreases with the MWCNTs rise in the graded layers. Density results revealed the highest weight saving potential (~12%) of FGNC-2 (H1–H3–H5), showing great weight saving potential. Tensile and flexural properties rise when the MWCNTs content rises in the graded layer. The FGNC-2 showed the highest tensile strength and moduli, 37.12% and 90.41% higher than HDPE. Flexural strength and moduli are also found to be the highest for FGNC-2, 28.57%, and 26.83% higher than HDPE. The highest specific moduli and strength are found for FGNC-2, 46.16% and 44.14% higher than HDPE, respectively. Experimental findings are found to be strongly in agreement with numerical findings. 3D-printed FGNC-2 demonstrated the best flexural and tensile characteristics with the lowest weight and hence can be used to make practical parts and structures that need variable stiffness. Highlights: FGNCs functionally graded n anocomposites are concurrently 3D printed. FGNC-2 exhibited the highest weight saving potential of 12%. FGNC-2 showed 90.41% and 37.12% enhanced tensile modulus and strength. FGNC-2 displayed 28.57% and 26.83% improved flexural strength and modulus. FGNCs exhibited better mechanical performance than the homogeneous NCs. © 2024 Society of Plastics Engineers.
4D printing of heat-stimulated shape memory polymer composite for high-temperature smart structures/actuators applications
(John Wiley and Sons Inc, 2024) Kumar, S.; Ojha, N.; Ramesh, M.R.; Doddamani, M.
High temperature shape memory polymers (HT-SMPs) have great utilization in self-deployable hinges/morphing structures for space/aerospace, and high-temperature sensors/actuators for electronics. However, HT-SMPs have many drawbacks, such as low stiffness, strength, thermal stability, and dynamic mechanical properties. This work aims at improving these properties of highly utilized space grade HT-SMP, PEKK (polyether ketone ketone), by reinforcing it with low-cost carbon fibers (CFs), and developing its composite via additive manufacturing. The additively manufactured CF/PEKK composites are annealed at 200 °C (CF/PEKK-A200) and 250 °C (CF/PEKK-A250), and for the first time, investigated for shape memory effect (SME). The shape fixity and the shape recovery of the CF/PEKK-UNA (un-annealed), CF/PEKK-A200, and CF/PEKK-A250 are noted to be 95.97%, 88.95%, and 86.40%, and 88.70%, 92.70%, and 95.19%, respectively with a significant weight saving potential of ?21%. Dispersion of CFs in PEKK and suitability of processing parameters (blending, extrusion, and 3D printing) are confirmed through scanning electron microscopy (SEM). Thermal degradation temperature ((Formula presented.)) of the printed CF/PEKK composite (?568 °C) is found to be ?3.5% higher than PEKK (?549 °C). CF/PEKK-A250 exhibited the highest storage modulus (4438.23 MPa), ~158% higher than PEKK (1722.3 MPa), while CF/PEKK-A200 demonstrated the highest tensile modulus (10.9 GPa), which is 138.5% higher than PEKK (4.57 GPa) and 312.88% higher than CF/PEKK-UNA (2.64 GPa). Moreover, CF/PEKK-A200 exhibited 237.46%, 138.51%, 127.08%, 61.48%, 32.93%, and 50.35% higher tensile modulus than PEEK, PEKK, PEK, CF/PEK, CF/PEEK, and CF/PEKK composites, respectively, showing great potential to replace them. Highlights: Printed CF/PEKK composites are investigated for shape memory behavior. The printed composites exhibited outstanding shape memory properties. Printed-A200 exhibited 138.51% enhanced tensile modulus than pure PEKK. Also, the printed-A200 showed 313% enhanced modulus than printed-UNA. (Formula presented.) (568 °C) of the printed composites is found ?4% greater than pure PEKK. © 2024 Society of Plastics Engineers.
A 0.15 μm GaN HEMT device to circuit approach towards dual-band ultra-low noise amplifier using defected ground bias technique
(Elsevier GmbH, 2023) Gupta, M.P.; Kumar, S.; Elizabeth Caroline, B.; Song, H.; Kumar, V.; Gorre, P.
This work presents a GaN HEMT device to circuit approach towards low noise amplifier (LNA) using defective ground bias (DGB) technique. This is the first MMIC GaN HEMT LNA design to offer dual-band of operation in both L and S-bands to the author's best knowledge. The proposed 0.15-μm GaN HEMT device fabrication achieves a high output power of 20 W using slot radiation phenomenon. The proposed DGB technique consists of gate and drain biasing topologies which achieves a dual-band of operation using microwave approach. The DGB technique is incorporated into GaN HEMT LNA which achieves high input and output power with good stability. To achieve an optimal noise, high I/O power, and almost flat gain at both L and S-bands, the defective ground structure of bias topologies is modeled and optimized. An artificial ground defect is created to offer resonant properties for the DGS of a microstrip line, which utilizes frequency-selective properties to improve the performance of the LNA circuit by suppressing the harmonics and scaling the size. The dedicated LNA shows the benefits of compact size, extremely low noise figure of 0.74/1.6 dB, high output power of 44 dBm and nearly flat gain of 14/11 dB at 1.17/2.49 GHz with the unique methodologies suggested. The compact GaN HEMT LNA could overcome the weak signal strength received by RF receiver for smart rail transport system. © 2023 Elsevier GmbH
A 0.5–5 Gb/s Wide Range, 160 fJ/Pulse Fully Integrated 13th-Order CMOS IR-UWB Transmitter for Wireless Capsule Endoscopy Systems
(John Wiley and Sons Ltd, 2025) Akuri, N.; Kumar, K.; Kumar, S.; Nikhil, K.S.; Song, H.
This paper proposes a novel technique based fully integrated 13th-order derivative CMOS impulse-radio ultrawideband (IR-UWB) transmitter with wide range of adaptive data rates for wireless capsule endoscopy systems (WCE). The proposed IR-UWB transmitter involves BPSK modulator-integrated RF power amplifier (PA) approach for WCE in first time as per author's best knowledge. The CMOS BPSK modulator with resonator technique generates 13th-order Modulated Gaussian pulse without the pulse generator. It has a peak-to-peak value of 25 mV and PSD level of ?72.60 dBm/MHz, data rate variability from 500 Mbps to 5 Gbps. The BPSK modulator with resonator is designed by time constant analysis in first time. In addition, a proposed CMOS PA is designed using four stacked transistors, which achieves a high output power as well as high efficiency for entire frequency band of operation from 3 to 16 GHz and wide impedance matching. The PA achieved an excellent gain of 16.55 dB with gain ripple of 0.25 dB only. Moreover, the PA achieved the saturated output power of 18.2 to 19.3 dBm with OP1dB of 15.96 to 16.72 dBm across entire bandwidth. Without violating FCC guidelines, PA strengths both peak-to-peak values, and PSD level of BPSK modulated signal to 80 mV and ?46.42 dBm/MHz. An IR-UWB transmitter has been implemented and fabricated using 65-nm CMOS Process, which consumes of only 160 fJ/pulse for generating Gaussian pulses order ranging from third-order to more than 13th-order at various data rates. © 2025 John Wiley & Sons Ltd.
A 1-V, 8.6-nA Resistor-less PTAT Current Reference with Startup Circuit
(Institute of Electrical and Electronics Engineers Inc., 2018) Kumar, S.; Rao, H.G.; Rekha, S.
A low voltage, low current, Proportional To Absolute Temperature (PTAT) current reference circuit is proposed. The conventional PTAT circuit is exploited to operate with a supply voltage of 1 V with suitable modifications in the circuit. Resistor has been replaced by an active circuit. All the devices are operating in weak inversion region. Zero static power startup circuit has been proposed to conform the proper initialization of the circuit. This PTAT current generator generates 8.6 nA of current at 1 V supply at room temperature. It is observed that the supply voltage sensitivity is as low as 7 percent per volt. Â© 2018 IEEE.
A 2.71-pA/√Hz ultra-low noise, 70-dB dynamic range CMOS transimpedance amplifier with incorporated microstrip line techniques over extended bandwidth
(John Wiley and Sons Ltd, 2023) Gorre, P.; Vignesh, R.; Kumar, S.; Song, H.; Roy, G.M.
Recent advancements in the area of telemedicine have focused on remote patient monitoring services as a new frontier in medical applications. The present work reports a 65-nm complementary metal–oxide–semiconductor (CMOS)-based transimpedance amplifier (TIA) in an optical radar system for non-contact patient monitoring. A T-shaped microstrip line (MSL) integrated with variable gain common source TIA using MSL peaking technique and off-chip post-amplification integration is a newly proposed architecture to achieve a ultra-low noise, high dynamic range (DR) and high figure of merit over broadband than a traditional TIAs. First, the integrated T-shaped MSL develops an additional resonant frequency that resonates with a photodiode capacitance improving the bandwidth performance at higher Q values. Second, the shunt MSL peaking technique that introduces an additional conjugate pole-pair that cancels the effect of input capacitance helps to further improve the bandwidth of the TIA. Finally, an active feedback concept achieves a wide linear dynamic range enabling high TIA detectability. The proposed TIA realizes an impedance bandwidth of 770 MHz ranging from 7.12 to 7.89 GHz with a transimpedance gain of 105.1 dBΩ and ultra-low input-referred noise (IRN) density of 2.71 pA/√Hz. A high linear DR of 70 dB is achieved by employing a variable gain control scheme with a low group delay variation of 0.81 ns. The proposed work demonstrates a 1-Gb/s data rate while a bit-error rate less than 10−12 is achieved. The TIA consumes a power of 0.82 mW under the supply voltage of 1.2 V. © 2022 John Wiley & Sons Ltd.
A 28 nm CMOS low-noise amplifier with novel redundant noise cancellation technique beyond ultra-wideband for 6G-based wireless systems
(Elsevier GmbH, 2024) Naik, D.N.; Gorre, P.; Prasad Gupta, M.; Kumar, S.; Al-Shidaifat, A.; Song, H.
In the current scenario, almost 5G-based wireless systems have been deployed everywhere but still performance trade-offs of RF amplifiers in the sub-nanometer regime are challenging. In this work, a high-performance low-noise amplifier (LNA) is realized in a 28 nm CMOS process with a novel redundant noise cancellation technique (RnC). The proposed technique improves the noise figure (NF) beyond the ultra-wideband of a low-noise amplifier (LNA) and minimizes the trade-off in the 28 nm process. An ultra-low NF is achieved in two approaches; Firstly, a current mirror network is employed in the primary path to cancel the thermal noise of the dominant transistor of a common gate-common source (CG-CS) without an extra power supply. Secondly, an auxiliary amplifier stage is introduced here to reduce the noise which contributes to the current mirror circuit and cancels the distortion in CG-CS topology without violating the traditional noise cancellation condition. In addition, an analytical approach is followed to optimize the input impedance, gain bandwidth and noise figure. Hence, the proposed RnC LNA benefits in achieving good tradeoffs among gain, bandwidth, NF, and power consumption in 28 nm technology node. The proposed RnC LNA is analyzed and fabricated using CMOS 28 nm technology, occupying an area of 0.011 mm2. The proposed design achieves an optimum performance: nearly flat gain of 15.3 dB, minimum NF of 1.7 dB over 1.7 to 12.52 GHz, and an IIP3 of − 2.6 dBm at 6.5 GHz. The proposed LNA consumes ultra-low power consumption of 1.8 mW under the power supply of 1 V. © 2023
A 28-32GHz CMOS LNA with broadband approach for 5G Mm-wave communication cells
(Institute of Electrical and Electronics Engineers Inc., 2019) Vignesh, R.; Gorre, P.; Kumar, S.; Song, H.
This paper first time reports a wideband low noise amplifier (LNA) with achievable minimum atmospheric absorption frequency band for 5G millimeter wave communication cells. A novel suspended substrate line based parallel-series network is optimized and analyzed that demonstrates a wideband response. The proposed LNA consists of two stage Cascode topology with incorporated parallel-series network and microwave components that provides broadband ranging from 28GHz to 32GHz. A full of two stage Cascode LNA overcoming the traditional mismatching constraints with consideration of suspended substrate lines (SSL) and Tee-junction in the proposed design. It is observed that suspended lines reduce parasitic and bulk effects of devices and enables LNA to provide broadband communication for 5G macro and micro cells. The proposed design is realized using RF 65nm Magna Hynix CMOS process with layout cell. The simulation results reveals that 28GHz-32GHz wide band with maximum forward gain of 25dB. The minimum noise figure of 2.5dB is achieved with optimization of passive components. The input impedance (real and imaginary) and smith chart realization for LNA provides satisfactory performance. Â© 2019 IEEE.
A 61.2-dB?, 100 Gb/s Ultra-Low Noise Graphene TIA over D-Band Performance for 5G Optical Front-End Receiver
(Springer, 2021) Gorre, P.; Vignesh, R.; Song, H.; Kumar, S.
This work reports in first time a 100-Gb/s, ultra-low noise, variable gain multi-stagger tuned transimpedance amplifier (VGMST-TIA) over the D-band performance. The whole work is binding into two phases. The first phase involves the modeling and characterization of graphene field-effect transistor (GFET) with an optimized transition frequency of operation. While in the second phase, a TIA design employs a T-shaped symmetrical L-R network at the input, which mitigates the effect of photo diode capacitance and achieves a D-band of operation. The proposed work uses a VGMST to establish TIA, which realizes optimum noise performance. The high gain 3-stage VGMST-TIA effectively minimizes the white noise and illustrates a sharp out-of-band roll-off to achieve considerable noise reduction at high frequencies. The active feedback mechanism controls the transimpedance gain by tuning the control voltage which results better group delay. Besides, an L-C circuit is employed at the output to enhance bandwidth. The full TIA is implemented and fabricated using a commercial nano-manufacturing 9-nm graphene film FET on a silicon wafer using 0.065-?m process. The TIA achieves a flat transimpedance gain of 61.2 dB? with ± 9 ps group delay variation over the entire bandwidth. The proposed TIA measured an impedance bandwidth of 0.2 THz with ultra-low input-referred noise current density of 2.03 pA/?Hz. The TIA supports a 100-Gb/s data transmission due to large bandwidth; therefore, a bit-error-rate (BER) less than 10?12 is achieved. The chip occupies an area of 0.92 * 1.34 mm2 while consuming power of 21 mW under supply of 1.8 V. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
A 64 ?dB?, 25 ?Gb/s GFET based transimpedance amplifier with UWB resonator for optical radar detection in medical applications
(Elsevier Ltd, 2021) Gorre, P.; Vignesh, R.; Song, H.; Kumar, S.
This work reports a novel Graphene Field Effect Transistor (GFET) based transimpedance amplifier (TIA) for optical radar detection in medical applications. Design-I includes a microstrip line (MSL) based UWB resonator circuit which enables the TIA design to operate in UWB range of frequency with high Q-factor. Design-II comprises MSL UWB resonator integrated stagger-tuned CR-RGC TIA which enhances the transimpedance limit and mitigates the effect of photodiode capacitance results in higher bandwidth performance. The proposed TIA realizes a 2.6 times lesser noise compared to the conventional CR-RGC TIA. A flat transimpedance gain of 64 ?dB? and ultra-low input-referred noise current density of 8.9 pA/?Hz are achieved using gain and noise optimization methods. Additionally, a dynamic range of 49 ?dB with a group delay variation (GDV) of ±25 ps is achieved over the entire UWB range. The TIA demonstrates a 25 ?Gb/s data rate while a bit-error-rate (BER) less than 10?10 is achieved. The chip occupies an area of 0.67?0.72 ?mm2 while consuming power of 19 ?mW under the supply voltage of 1.8 ?V. © 2021 Elsevier Ltd
A 73% PAE, Highly Gain Inverse Class-F Power Amplifier for S-Band Applications
(Springer Science and Business Media Deutschland GmbH, 2021) Naik, J.D.; Gorre, P.; Kumar, R.; Kumar, S.; Song, H.
This paper proposes a continuous-mode inverse Class F power amplifier (PA) achieving wide bandwidth, high output power, and high efficiency. This work includes transmission line-based output/input matching networks and single-ended topology. The main focus of the work is to achieve a high gain with wide bandwidth. The proposed structure incorporates a termination of even and odd harmonics to deliver voltage and current waveform isolation with minimal matching network (MN) design complexities. The analyses simulated in Keysight Technologies Advanced Design System (ADS), which results in a wideband PA design. The results are quantified by using high power-added efficiency (PAE) and output power. PAE of 72.6% and output power more than 41Â dBm obtained over wide bandwidth 2â€“4.2Â GHz at âˆ’3Â dB gain compression. The proposed PA could overcome the traditional performance and utilize for green communication. Â© 2021, Springer Nature Singapore Pte Ltd.
A 8–12 GHz, 44.3 dBm RF output class FF?1 DPA using quad-mode coupled technique for new configurable front-end 5G transmitters
(Springer, 2021) Kumar, R.; Dwari, S.; Kumar Kanaujia, B.K.; Kumar, S.; Song, H.
This paper presents a high-efficiency Class FF - 1 DPA using the quad-mode coupled technique for new configurable front-end 5G transmitters. The proposed DPA consists of carrier PA, main PA, input–output matching network and hybrid power network (HPN). The HPN includes a quad-mode coupled technique which is four-section U-shaped transmission line. The HPN is used for even–odd mode impedance analysis to ensures the high-selectivity of output power and achieve a wideband response in the presence of harmonic control conditions. The optimum harmonic impedance is analyzed for the desired band to achieve high output power and efficiency. The DPA circuit is fabricated by using 0.25 µm GaN HEMT on silicon nitride monolithic microwave integrated circuit die process. At maximum output power level of 44.3 dBm, the delivered power-added efficiency (PAE) of 64.3–67.3% and drain efficiency (DE) of 71.7–73.7% at even–odd mode operation are achieved with a gain of 13.0–14.3 dB. For the output power level of 39.045 dBm corresponding to 9 dB output back-off (OBO), the drain efficiency lies between 55–62% with 73% fractional bandwidth. All the demonstrated transmission parameters are working in the band of 8–12 GHz. The size of the chip is 2.8 × 1.9 mm2 and it occupies less die area as compared to the existing DPAs. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
A compact and efficient graphene FET based RF energy harvester for green communication
(Elsevier GmbH, 2020) Singh, N.; Kumar, S.; Kumar Kanaujia, B.K.; Beg, M.T.; Mainuddin, M.; Kumar, S.
This paper presents a graphene field effect transistor (FET) based rectenna with substrate-integrated waveguide (SIW) broadband approach for RF energy harvesting application. The proposed structure of integrated rectenna consists of a graphene FET rectifier and an SIW antenna operating in the (S11 < ?10 dB) range of 29–46 GHz. The peak gain of the SIW antenna observed is 8.12 dBi. In addition, a new matched circuit consisting of microstrip line and butterfly stub (without using any lumped elements) is designed. The matched circuit provides a miniaturized block by reducing the size and eliminating parasitic reactance in the integrated rectenna. The proposed rectenna is implemented and fabricated using two superimposed layers: RT/duroid 5880 and graphene substrate with a compatible approach. A measured conversion efficiency of 80.32% is obtained. The dimensions of the proposed antenna and rectifier are 3.2 × 3.2 × 0.4 mm3 and 3.2 × 10 × 0.4 mm3, respectively. The proposed rectenna covers Ka- and Q-band applications and could be a potential candidate for contemporary energy harvesting systems. © 2019 Elsevier GmbH
A compact broadband GFET based rectenna for RF energy harvesting applications
(Springer, 2020) Singh, N.; Kumar, S.; Kumar Kanaujia, B.K.; Beg, M.T.; Mainuddin, M.; Kumar, S.
In this paper, a compact GFET-based rectifier integrated with a monopole antenna is proposed for wireless energy harvesting applications. The GFET increases impedance bandwidth of the rectifying circuit, thus covering a range of 22.5–27.5 GHz. The sensing antenna is a triangular monopole with truncated corners for realizing circular polarization at the frequencies 24.25 GHz and 27 GHz. By the help of ?/4 transformer, the sensing antenna is matched with the proposed GFET rectifier. The RF-DC conversion efficiency realized is 80% at 5 dBm for the load of 5 K?, and the output DC voltage observed is 6.8 V. The modified ground plane triangular monopole antenna shows a peak gain of 7.8 dBi. The designed rectenna prototype is fabricated and found simulated and measured results are in good agreement. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
A Compact Design of UWB Monopole Antenna with Dual Notched Bands for WiMAX Applications
(Sumy State University, 2022) Gupta, S.; Rawat, S.; Kumar, S.
A compact conformal coplanar waveguide-fed (CCF) ultra-wideband (UWB) monopole antenna with dual notched bands at 3.25-3.85 GHz and 5.25-5.85 GHz for worldwide interoperability for microwave access (WiMAX) applications is presented in this paper. The evolution of the proposed antenna structure is presented in a stepwise manner with the incorporation of a parasitic element and a PIN diode. In the proposed structure, the bandwidth enhancement and band notch are realized by an asymmetric design, which has two I-shaped stub lines parallel to the feed line and two semicircles on both sides of the feed line. The notch is achieved by applying the parasitic element parallel to the patch and placing a PIN diode between the parasitic element and the antenna patch. The volumetric size of the antenna is 24×22×0.035 mm3. The proposed structure attains an operating band (VSWR ≤ 2) ranging from 3.1 to 10.6 GHz with a gain close to 3.95 dBi, along with significant efficiency and symmetrical radiation patterns. Parasitic elements are used to improve directivity or gain and reduce the back lobe. By choosing the parasitic elements, different resonant modes can be excited nearby each other, which can provide a wider bandwidth. The proposed antenna is low profile and is designed to be used as a transceiver in UWB communication for WiMAX applications. © 2022 Sumy State University
A Compact Dual-band Hat-Shaped Antenna with Band-Specific Behavior Using Harmonic Mixer for Passive Neural Monitoring
(Institute for Ionics, 2024) Gopavajhula, D.S.; Kumar, S.; Narasimhadhan, A.V.; Song, H.
This work proposes a hat-shaped dual-band antenna with band-specific behavior using a harmonic mixer for the passive wireless neural monitoring system. The antenna is designed to work in coherence with a harmonic mixer of 2nd order. The antenna covers a volume of 16 × 16 × 1.6 mm3. The performance of the antenna is found to be satisfactory by conducting experiments using both homogeneous and heterogeneous media mimicking human tissue after covering it with a biocompatible PDMS layer. The lower and higher resonant bands extend from 3.75 to 3.9 GHz and 7.05 to 8.2 GHz, respectively, supporting communication at high data rates up to 20 Mbps. A directive gain of 1.29 dB in the lower band and 1.39 dB in the higher band makes it a good choice for implantable medical devices. A six-layer head model was considered for SAR evaluation with a penetration depth of 10 mm for safe operation as per IEEE C95.1-1999 standard. Based on this simulation, the maximum input power that can be fed to the antenna for safe operation is found to be 8.46 mW. The link budget analysis reveals that a satisfactory communication link may potentially be established up to a distance of 7 and 1.5 m between implantable and interrogator antennae with corresponding data rates of 1 Mbps and 20 Mbps, respectively. © The Author(s), under exclusive licence to Shiraz University 2023.
A Comparative Study onÂ End-to-End Learning forÂ Self-Driving Cars
(Springer Science and Business Media Deutschland GmbH, 2024) Kumar, S.; Pir, M.A.; Rajan, J.; Talawar, B.
Autonomous vehicle technology has advanced in recent years. The self-driving car is one of the most attractive research fields, and automakers are fast focusing on it. There have been a number of attempts made in this field, such as lane recognition, the detection of objects on roadways, and the reconstruction of three-dimensional models; however, the focus of our study is on models that directly transform the camera input images into steering angles. In this paper, we performed a comparative study of some of the popular end-to-end CNN models pertaining to autonomous vehicles. We used four different data sets for model training and validation. Only one of the data sets was gathered from the real world; the other three were created using software simulations. For evaluating the performance of different models, we used the mean squared error (MSE) metric. It was interesting to see that certain models fared better than others when applied to diverse data sets. When considering real-world datasets, both pre-trained VGG-16 and pre-trained VGG-19 using transfer learning exhibit comparable performance, achieving an MSE value of 21.4 which is better than all other considered models. However, in the case of simulated datasets, pre-trained VGG-19 outperforms the majority of the other models. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
A comprehensive characterization of 3D printable poly ether ketone ketone
(Elsevier Ltd, 2024) Ojha, N.; Kumar, S.; Ramesh, M.R.; Balan, A.A.S.; Doddamani, M.
The current work focuses on the comprehensive characterization of a 3D printable biomaterial, polyether ketone ketone (PEKK). The PEKK granules are first characterized and then utilized for extrusion of the PEKK filaments. The extruded PEKK filaments are characterized for crystallinity, quality, and printability, wherein they exhibit amorphous nature, good quality, and appropriate printability. Utilizing the filaments, the samples are printed with the appropriate printing parameters, which are further characterized for layer adhesion, voids, and crystallinity, wherein they showed seamless layer adhesion, improper beads consolidation, and the amorphous nature. The as printed samples are further annealed at different temperatures (200 and 250 °C). The scanning electron microscopy (SEM) of the annealed samples (A-200 and A-250) revealed better void consolidation, while the X-ray diffraction (XRD) revealed better crystallinity compared to the un-annealed sample. The printed samples are also investigated for dynamic mechanical analysis (DMA), shape memory, and tensile properties. The storage moduli of the annealed samples are observed to be better than the un-annealed sample. The annealed samples exhibited better shape memory properties: shape fixity and shape recovery ratio of A-200 and A-250 samples, 90.28 and 90.75%, and 99.16 and 94.73%, respectively, compared to the un-annealed samples. The highest shape fixity ratio and the shape recovery ratio are noted for A-250 (90.75%) and A-200 (∼ 100%). The A-200 and A-250 samples showed enhanced tensile modulus and strength, 4.16 and 49.67%, and 36.61 and 35.06%, respectively compared to the un-annealed sample. The highest modulus is noted for A-250, while the strength is comparable (36.61 and 35.06%) for A-200 and A-250. © 2023 Elsevier Ltd
A Comprehensive Survey on Breast Cancer Diagnostics: From Artificial Intelligence to Quantum Machine Learning
(Institute of Electrical and Electronics Engineers Inc., 2025) Reddy, M.R.V.S.R.S.; Kumar, S.; Bhowmik, B.
Breast cancer remains a leading cause of mortality among women worldwide, where early detection significantly improves survival rates. Traditional diagnostic methods like mammography, biopsy, and ultrasonography face challenges like diagnostic errors and low sensitivity. Recent advancements in Artificial Intelligence (AI), including deep learning for image analysis and natural language processing for patient data interpretation, have shown promise in enhancing diagnostic capabilities. The integration of these AI techniques with Quantum Machine Learning (QML) leverages quantum parallelism to process high-dimensional medical data and extract intricate imaging patterns more efficiently. This paper provides a comprehensive overview of cancer, its subtypes, symptoms, and the limitations of conventional diagnostics while highlighting the transformative potential of QML in improving diagnostic accuracy and efficiency for breast cancer detection and prognosis. Â© 2025 IEEE.
A Conceptual Investigation at the Interface between Wireless Power Devices and CMOS Neuron IC for Retinal Image Acquisition
(MDPI, 2020) Al-Shidaifat, A.; Kumar, S.; Chakrabartty, S.; Song, H.
In this paper, a conceptual investigation of the interface between wireless power devices and a retina complementary metal oxide semiconductor (CMOS) neuron integrated circuit (IC) have been presented. The proposed investigation consists of three designs: design-I, design-II, and design-III. Design-I involves a slotted loop monopole antenna as per American National Standards Institute (ANSI) guidelines, which achieve an ultra-wide band ranging from 3.1 GHz to 10.6 GHz. The biocompatible antenna is made on silicon-nitride substrate using on-wafer packaging technology and it is used as a receiver device. The performance of antenna provides a wideband, sufficient power to receive, and low losses due to the avoidance of printed circuit board (PCB) fabrication. A CMOS based multi-stack power harvesting circuit achieves the output power ranging from 4 mW to 2.7 W and corresponds from the selected Radio Frequency (RF) bands of loop antenna is exhibited in design-II. The power efficiency of 40% to 82%, with respect to output powers of 4 mW to 2.7 W, is achieved. Design-III includes a CMOS based retina neuron circuit that employs a dynamic feedback technique and support to achieve the number of read-out spikes. At the end of the interface between wireless power devices and a CMOS retina neuron IC, 50 mV read-out spikes are achieved, with varying light intensity, from 0 mW/cm2 to 2 mW/cm2. The proposed design-II and design-III are implemented and fabricated using commercial CMOS 0.065 µm, Samsung process. The antenna and RF power harvesting IC could be placed on a contact lens platform while retina neuron IC can be implanted after ganglions cells inside the eye. The antenna and harvesting IC are physically connected to the retina circuit in the form of light. This conceptual investigation could support medical professionals in achieving an interfacing approach to restore the image visualization. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.