Faculty Publications
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Item Simulation of Radio over Fiber System for Microwave Signal Generation using Sub- Carrier Modulation Technique(Institute of Electrical and Electronics Engineers Inc., 2023) Singh, V.; Meena, K.S.R.; Singh, M.Nowadays, Radio over fiber (RoF) technology is used in a variety of applications, including wireless communication systems, satellite communication systems, and radar systems. In this paper, we reported a sub-carrier modulation with Amplitude Shift Keying (SCM-ASK) system which supports the transmission of various signals across a single-mode fibre with enhanced encryption efficiency. The quality of the received signal is usually poor in RoF systems, a number of factors may contribute to this problem, such as high bit error rates (BER), low Q-factor values, and the receiver may not be working in a high data rate network. To overcome this, the Q-factor needs to be raised while BER should be brought down to assured values. Using Opti-System software, SCM-ASK is investigated at various channel spacings and fibre lengths. Also, the RoF system performance is analyzed in terms of BER, Q-factor, and the eye diagram patterns. © 2023 IEEE.Item MIMO based radio-over-fiber link for millimeter wave generation using external optical modulator(American Institute of Physics, 2024) Meena, K.S.R.; Rao, A.; Singh, M.In this paper, photonically assisted millimeter wave signal generation techniques are proposed for modern space applications. For this, two designs are investigated with different optical modulators, namely, amplitude modulator and Dual Drive-Mach Zehnder Modulator (DD-MZM). A 2*2 Wavelength Division Multiplexing (WDM) transmitter with a 100 GHz frequency spacing is used to broadcast Multiple-Input Multiple-Output (MIMO) signals, and it encodes the signals using a 1Gbps pseudo-random bit sequence with return-to-zero coding. The Electrical Constellation Visualizer is used to examine the distortion in the proposed Radio over Fiber (RoF) links. The opti-system software simulation for DD-MZM design confirms a high-frequency millimeter wave signal with 60 dBm optical sideband suppression ratio (OSSR) and radio-frequency spurious suppression ratio (RFSSR) 72 dBm. Whereas Amplitude Modulator based architecture produces mm-wave signals with high Q-factor and low loss. Therefore, the merging of MIMO and RoF technology is a better solution for generating mm-wave signals for next-generation communication systems. © 2024 Author(s).Item An Approach to Increase the Efficiency of Uricase by Computational Mutagenesis(Iranian Chemical Society, 2023) Nelapati, A.K.; Meena, K.S.R.Uricase is widely used to treat hyperuricemia and gout. Its clinical use is limited due to side effects such as severe allergy, hypersensitivity, and anaphylactic reactions in some patients. Uricase from Arthrobacter globiformis (Ag) and Bacillus fastidious (Bf) was chosen to improve enzyme binding energy by reducing the deleterious effects in treatment. To reduce the adverse effects of uricase, enzyme should be modified. For this purpose, we performed in silico mutagenesis on uricase. We altered the active site of amino acids of uricase from both sources using f PyMOL. The ligand uric acid was docked with mutated uricase using Autodock 4.0. It was found that mutation of Val64 with Alanine in Ag uricase, and mutation of Gly42 with Isoleucine in Bf uricase improved the binding energy of the enzyme up to 50%. The binding affinity of native Ag uricase docked with uric acid was -8.414 kcal mol-1, while for the mutated enzyme, it was -8.570 kcal mol-1. Binding energies for Bf uricase were -5.221 and 5.389 kcal mol-1 for native and mutated enzymes, respectively. We showed that our in silico model with improved uricase binding energy can facilitate making a potent drug by protein mutagenesis, leading to a drug development with minimum adverse effects to treat hyperuricemia © 2023. Physical Chemistry Research.All Rights Reserved.Item Microwave Photonics Based Millimeter-Wave Signal Generation Technique for 5G Systems(Institute of Electrical and Electronics Engineers Inc., 2024) Meena, K.S.R.; Singh, M.We report a novel millimeter-wave (mm-wave) signal generation scheme with microwave photonics (MWP) technology for advanced 5G optical links. This work combines two parallel Mach Zehnder modulators with a series Mach Zehnder modulator for better tunability and efficient bandwidth. The experiments confirm a 35-GHz mm-wave signal of highest power and a 60-GHz mm-wave of lowest power from a 15-GHz electrical drive input signal. The optical sideband suppression ratio (OSSR) and the radio frequency sideband suppression ratio (RFSSR) over a 0.5-km standard single-mode fiber link are 27 and 66 dBm, respectively. The harmonic suppression is also studied with modulation depth (m) and filter attenuation (a) parameters. The system s performance is evaluated in terms of eye patterns, quality factor ( Q), output power spectrum, and margin. In addition, the suggested photonic link plays a crucial role in developing 5G communication systems for generating high-frequency, ultrafast speed, and low-noise mm-wave signals © 1963-2012 IEEE.Item Widely-tunable optoelectronic oscillator using a microfiber coupler Sagnac loop(Springer, 2025) Meena, K.S.R.; Thayaba Nausheen, A.; Singh, M.An optoelectronic oscillator (OEO) integrating a Microfiber Coupler Sagnac loop and a parallel optical amplifier is proposed for the generation of wide-range, stable microwave signals. Unlike conventional OEOs that rely on dual-loop configurations, fixed optical delay lines, or bulky and lossy external filters, our design offers a solution capable of generating RF signals over a broad frequency range of 5–20 GHz. Sagnac loop provides high-resolution spectral filtering and substantial side-mode suppression, while the parallel optical amplifier enhances the loop gain and facilitates the stable oscillation across the entire tuning bandwidth. Our results confirm multi-tone microwave signal generation with a side-mode suppression ratio exceeding 50 dB. The single sideband phase noise of about ? 125 dBc/Hz at 10 kHz offset frequency is achieved for 10 GHz oscillation frequency. This hybrid architecture leads to highly stable, tunable, and pure microwave signal generation, making it suitable for radar systems, high-speed communication, and advanced sensing applications. © The Author(s), under exclusive licence to The Optical Society of India 2025.