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PublicationA gain-enhanced multiband frequency and pattern reconfigurable antenna for Wi-Fi 6E and 5G new radio wireless standards(John Wiley and Sons Ltd, 2024-10)In this paper, a multiband hybrid reconfigurable antenna with enhanced gain is reported to support Wi‐Fi 6E, indoor WLAN, and 5G new radio (NR) wireless standards. The reported structure consists of a half‐hexagonal‐shaped radiating element along with two symmetrical rectangular single‐split resonators interconnected via two PIN diodes to achieve multiband frequency and pattern reconfigurability of the proposed antenna and a single‐layer frequency selective surface (FSS) to enhance the gain. By configuring these PIN diodes in three distinct modes, the reported antenna allows for independent reconfigurability to support multipurpose sub‐6GHz and Wi‐Fi 6E (3.3, 3.5, 5.1, 5.3, and 6.5 GHz) wireless standards, respectively. The results also showed that the antenna is capable of maintaining a frequency of 6.5 GHz in all modes while reconfiguring its radiation pattern in three different directions, namely, 265°, 13°, and 337° on the xz plane. The gain of the proposed hybrid reconfigurable antenna is enhanced by an FSS‐based reflector placed below the radiating structure at a distance of to the lowest operating frequency (3.3 GHz), and the gain is enhanced by 2–4 dBi as compared without FSS. The reported hybrid reconfigurable antenna is implemented on an FR‐4 substrate with a depth of 1.6 mm and a relative permittivity of 4.4. For validation of the proposed structure, the experimental results are compared with the simulated results.
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PublicationPerformance enhancement of LACO-OFDM BER and PAPR using a K-means algorithm for a VLC system(Optica Publishing Group, 2023)Layered asymmetrical clipped optical-orthogonal frequency division multiplexing (LACO-OFDM) enhances spectral efficiency by mandating the use of a K-means algorithm in LACO-OFDM (KLACO-OFDM), which enables efficiency gains to nearly double by modulating odd and even subcarriers. The traditional receiver is not sufficiently sophisticated enough to exploit the full potential of LACO-OFDM, thereby restricting its performance. In this paper, a K-means algorithm was used to increase the spectral efficiency of LACO-OFDM by integrating machine learning to cluster the inward signal such that the original locations of the received constellations can be retrieved. A K-means algorithm is used for assigning the received constellation points into their clusters of the ordinary quadrature amplitude modulator constellation points. The new mathematical framework in the proposed scheme is structured to analyze the PAPR and BER performance of LACO-OFDM systems that have been derived. The K-means algorithm development in LACO-OFDM (KLACO-OFDM) has also reduced the intersymbol interference, hence improving the spectral efficiency of LACO-OFDM compared with the conventional system in visible light communication (VLC) systems. BER gains were about 1.2–1.6 dB at 10−3 BER value, which rises from 1.4 to 2 dB for a 10−4 BER value because a lower BER facilitates precise estimation.
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PublicationTunable transparency and group delay in cavity optomechanical systems with degenerate fermi gas(MDPI, 2023)We theoretically investigate the optical response and the propagation of an external probe field in a Fabry–Perot cavity, which consists of a mechanical mode of trapped, ultracold, fermionic atoms inside and simultaneously driven by an optical laser field. We investigate the electromagnetically-induced transparency due to coupling of the optical cavity field with the collective density excitations of the ultracold fermionic atoms via radiation pressure force. Moreover, we discuss the variations in the phase and group delay of the transmitted probe field with respect to effective cavity detuning as well as pumping power. It is observed that the transmitted field is lagging in this fermionic cavity optomechanical system. Our study shall provide a method to control the propagation as well as the speed of the transmitted probe field in this kind of fermionic, ultracold, atom-based, optomechanical cavity system, which might have potential applications in optical communications, signal processing and quantum information processing.
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PublicationA compact 2.4 GHz L-Shaped microstrip patch antenna for ISM-Band Internet of Things (IoT) applications(MDPI, 2023)Wireless communication technology integration is necessary for Internet of Things (IoT)-based applications to make their data easily accessible. This study proposes a new, portable L-shaped microstrip patch antenna with enhanced gain for IoT 2.4 GHz Industrial, Scientific, and Medical (ISM) applications. The overall dimensions of the antenna are 28 mm × 21 mm × 1.6 mm (0.22λo × 0.17λo × 0.013λo, with respect to the lowest frequency). The antenna design is simply comprised of an L-shape strip line, with a full ground applied in the back side and integrated with a tiny rectangular slot. According to investigations, the developed antenna is more efficient and has a greater gain than conventional antennas. The flexibility of the antenna’s matching impedance and performance are investigated through several parametric simulations. Results indicate that the gain and efficiency can be enhanced through modifying the rectangular back slot in conjunction with fine-tuning the front L-shaped patch. The finalized antenna operates at 2.4 GHz with a 98% radiation efficiency and peak gains of 2.09 dBi (measured) and 1.95 dBi (simulated). The performance of the simulation and measurement are found to be in good agreement. Based on the performance that was achieved, the developed L-shaped antenna can be used in a variety of 2.4 GHz ISM bands and IoT application environments, especially for indoor localization estimation scenarios, such as smart offices and houses, and fourth-generation (4G) wireless communications applications due to its small size and high fractional bandwidth.
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PublicationAnalysis and design of dual-band folded-shorted patch antennas for robust wearable applications(IEEE, 2020)A flexible folded-shorted patch (FSP) antenna with dual-band functionality for wearable applications is presented. The proposed antenna is operational at 400 MHz and 2.4 GHz and can be considered compact for the lower operational frequency band (0.13λo × 0.13λo × 0.02λo). Flexible polydimethylsiloxane (PDMS) is used as the substrate due to its relatively low-cost as well as its robustness for wearable applications. A comparison of the fields radiated by the FSP, in terms of the TM010 and TM001 modes are also presented considering the cavity model which is actually related to the two noted operating bands. Equations needed to calculate the beam pattern and directivity for these modes are also derived and their results are compared to commercial full-wave simulations and measurements of a wearable PDMS prototype. An analysis was also performed to characterize the relevant dimensions that are important for independently controlling or tuning the resonant frequencies for these two radiating modes. The proposed antenna can be suitable for robust wearable applications such as military search and rescue operations, emergency response team units, and medical services.
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