Faculty Publications

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    An integrated cascode DE power amplifier for RF calibration system towards measurement of bio-sensor applications
    (John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2019) Kumar, R.; Kumar Kanaujia, B.K.; Dwari, S.; Kumar, S.; Song, H.
    The integrated cascode DE power amplifier for RF calibration system toward measurement of bio-sensor applications is presented in this paper. The proposed architecture includes cascode class-D and class-E amplifier stages that could provide better calibration accuracy in terms of wide bandwidth, power efficiency, high gain, minimum group delay, and lowest calibration system. The achieved high performance of proposed amplifier overcomes conventional measurement issues toward bio-sensor application. The inductive ?-shape matching network drives RF input to class-D stage and provides wide bandwidth of operation. While class-E stage with T-shape matching network maintains stable gain and high efficiency in desired band of operation. The performance of the CMOS proposed amplifier is executed in RF ADS simulator along with fabricated chip using commercial TSMC 65 nm manufacturing process. The simulated and measured data achieves Ku band (12 GHz to 18 GHz) with almost flat gain of 30 dB. The DE amplifier provides an output and saturated power of 17 dBm with highest power efficiency of 45%. The measured calibration factor at maximum resonant frequency of 13.5 GHz achieves best value of less than 2 dB within input power range of ?50 dBm to 0 dBm. The lowest calibration factor provides best accuracy along with the other parameters and could be beneficial toward bio-sensor measurement in the various applications. The calculated area of the fabricated chip is as 0.45*0.45mm2 where class-E consuming area of 38% and class-D of 44%. The fabricated chip consumes less power consumption of 3.2 mW under power supply of 1 V. © 2018 Wiley Periodicals, Inc.
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    Investigation of CMOS Based Integration Approach Using DAI Technique for Next Generation Wireless Networks
    (Springer New York LLC barbara.b.bertram@gsk.com, 2019) Roy, G.M.; Kanuajia, B.K.; Dwari, S.; Kumar, S.; Song, H.
    This research work investigates a CMOS based low noise amplifier (LNA) using differential active inductor with eight-shaped patch antenna for next generation wireless communication. The proposed work conceded into three different phases. The first phase proposes LNA architecture which includes multistage cascode amplifier with a gate inductor gain peaking technique. The ground approach for this architecture employs active inductor technique that includes two stages of differential amplifier. The proposed novel technique leads to give incremental in inductance by using of common mode feedback resistor and lowers the undesirable parasitic resistance effect. Additionally, this technique offers gain enhanced noise cancellation and achieves a frequency band of around 5.7 GHz. The proposed architecture includes single stage differential AI and enhances the bandwidth up to 6.8 GHz with peak gain of 21 dB at 7.8 GHz. The noise figure and stability factor are achieved which is reasonably good at 1 dB. The proposed architecture is design and optimized on advanced design RF simulator using 0.045 µm CMOS process technology. While in second phase, a narrow band eight-shaped patch antenna is designed which provides operating band range from 5.8 to 6.5 GHz with 6.2 GHz resonating frequency. Highest peak gain of 15 dB and maximum radiation power of 42.5 dBm is succeed by proposed antenna. The final phase provides integration strategy of LNA with antenna and achieves desired gain of nearly 21 dB with minimum NF of 1.2–1.5 dB in the same band. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
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    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.
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    A highly robust RF 65 nm CMOS power amplifier design using Quasi-Newton control algorithm for wireless system
    (Elsevier B.V., 2023) Kumar, K.; Kumar, S.; Kumar Kanaujia, B.K.
    This article reports a novel robust approach towards CMOS power amplifier (PA) using Quasi-newton (QN) control algorithm in 65 nm CMOS process which provides best performance parameters over redundant wide bandwidth ranging from 2.4 to 16.4 GHz frequency band. Each stage are designed and optimized using QN algorithm to get desired goals such as high linearity, small group delay variations and high PAE across the entire frequency band of interest. Moreover, pole-zeros compensation technique is adopted and derived to get better stability of the proposed PA. The simulation and measurement results of PA achieved a small signal power gain of 10.5–16.8 dB with input return loss of better than 10 dB over the frequency band of 2.4 GHz to 16.4 GHz. A small group delay variation of ±58 ps over full frequency band of operation is achieved by optimizing the design parametric analysis. It is also observed that within the frequency of 6.5 to 14.6 GHz, an excellent small group delay variation of only ±11 ps is achieved and this is due to stage-2 tuning compensation technique. It also demonstrates the achieved input power in 1 dB compression points are −3.1 to 4.3 dBm, leading to maximum power added efficiency of 36.3%, respectively. The proposed PA consumes a lower DC power of 20.5 mW under supply voltage of 1.5. In addition, Process, voltage and temperature (PVT) analysis is executed at different conditions in order to achieve a robustness of the proposed PA over the entire band of operation. © 2023 Elsevier B.V.
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    Analytical modelling of ultra-small group delay variation of ultra-broadband RF power amplifier using NSGA-II algorithm
    (John Wiley and Sons Ltd, 2024) Kumar, K.; Kumar, S.; Kumar Kanaujia, B.K.
    This paper proposes a ± 9.4 ps ultra-small group delay (GD) variation of fully integrated 65 nm complementary metal oxide semiconductor (CMOS) power amplifier (PA) over 6.5–17 GHz broadband for wireless application. The proposed CMOS PA is realised by using broadband stage, RLC inter-stage and power stage topologies. The non-dominated sorting genetic algorithm (NSGA-II) is employed for PA parameter optimisation to ensure a small GD variation of ±9.4 ps over broadband with an excellent small signal gain flatness of 23.65 ± 1.85 for 6.5–17 GHz. The small GD variation of ±9.4 ps and ± 11.05 ps are attained under two cases of DC supply voltages of 2.4/1.2 V and 1.2/1.2 V, respectively. To the best of author's knowledge, the achieved GD variations are lowest among all CMOS PAs as reported so far. In addition, an analytical modelling of GD is derived to validating the minimum GD variation using zero-pole compensation. With supply voltages of 2.4/1.2 V at 6.5 GHz, the large signal power gain, Psat and OP1dB are 26 dB, 19.3 dBm and 17.94 dBm, respectively, while peak power added efficiency (PAE) is 38.196%. At reduced supply voltages of 1.2/1.2 V, the PA achieves maximum power gain of 17.7 dB and peak PAE of 35% at 6.5 GHz. The CMOS PA occupies an area of 0.206 mm2. © 2023 John Wiley & Sons Ltd.
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    An Ultra-low Noise, Highly Compact Implantable 28 nm CMOS Neural Recording Amplifier
    (Institute of Electronics Engineers of Korea, 2024) Akuri, N.G.; Naik, D.N.; Kumar, S.; Song, H.; Kar, A.
    An ultra-low noise, Tera-ohm input impedance two-stage front-end neural amplifier (FENA) in the 28 nm CMOS process is presented in this work. As per the author’s best knowledge, the proposed FENA is implemented on a 28 nm CMOS process for the first time. The proposed FENA consists of an operational transconductance amplifier integrated low-pass filter (LPF) technique. This technique effectively removes the noise current density by using the LPF transfer function and FENA circuit to achieve the best performances, such as ultra-low input-referred noise, ultra-high input impedance, and high gain. The proposed mathematical technique is employed to optimize the dimensions of the neural amplifier in the 28 nm lower node, which results in a noise-free biasing current and ultra-low input referred noise of 18 fV/√Hz at 10 KHz. The ultra-low input referred noise of FENA is achieved by reducing the gate-distributed resistance method. The FENA achieves an ultra-high input impedance of 0.2 Tera-ohm, while a splendid measured gain of 60 dB has succeeded. FENA occupies a chip area of 0.0023 mm2, which consumes a lower power consumption of 1 µW under supply voltage of 1.2 V. The FENA is found to be less prone to PVT variations as 1 mHz of high-pass corner frequency towards robust design. The best performance parameters of FENA could be beneficial for deep exploration neural recording in wireless neural monitoring systems. © 2024, Institute of Electronics Engineers of Korea. All rights reserved.
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    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.