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In this paper, a Substrate-Integrated Waveguide (SIW)–based Cylindrical Dielectric Resonator Antenna (CDRA) is designed for 6G THz applications. This antenna provides a Quad-band response at 2.14 THz, 3.41 THz, 5.61 THz, and 9.02 THz respectively. The unique feature of the proposed SIW-CDRA is its ability to exhibit Circular Polarization (CP) behavior across three frequency bands. Graphene material is added onto the top of the proposed CDRA to achieve tunability in the antenna's resonant frequency. CP tuning is also achieved by varying the graphene potential of the antenna. Furthermore, this proposed antenna shows both Right Hand Circular Polarization (RHCP) and Left Hand Circular Polarization (LHCP) behavior at different resonant frequencies. The antenna exhibits a maximum gain of 6.97 dB and a maximum radiation efficiency of 84.53%. Notably, the antenna showcases a 3 dB Axial Ratio (AR) bandwidth of 11.05% (1.968–2.195 THz), 4.58% (5.483–5.734 THz), and 5.22% (8.843–9.313 THz) is achieved. Moreover, the CDRA generates two higher-order modes, specifically HEM11δ at 5.61 THz and HEM12δ at 9.02 THz. Additionally, the antenna exhibits a unique feature of converting multiband response to wideband response by changing the length of the aperture slots. All these results show that the proposed multiband SIW with CDRA is unique and suitable for THz applications. [ABSTRACT FROM AUTHOR]

A new ultra-wideband two-port MIMO Dielectric Resonator Antenna (DRA) based on defected ground structure is introduced for Terahertz (THz) frequency applications. The antenna utilizes two silicon-based Dielectric Resonators (DRs) as radiators. It exhibits an ultra-wideband response with a bandwidth of 14.5 THz (9.5 THz–24 THz) and offers high isolation of ≤ − 20 dB across the operating frequency range. Additionally, it achieves dual-band circular polarization with a 3-dB Axial Ratio (AR) Bandwidth (ARBW) of 37.55% (9.82 THz–14.36 THz) and 30.87% (16.9 THz–23.07 THz) respectively. The antenna demonstrates a high radiation efficiency of 95.02% and a peak gain of 8.76 dB. By varying the feed lengths, the antenna enables polarization reconfigurability, which is advantageous for future THz wireless systems. Moreover, the antenna exhibits improved MIMO diversity performance, characterized by parameters such as CCL < 0.5 bps/Hz, MEG ≤ − 3 dB, TARC ≤ − 10 dB, DG ≈ 10 dB, and ECC < 0.01. To enhance its performance, the DRA is coated with graphene, enabling tunability in frequency response and axial ratio (AR) response, thereby increasing the Impedance Bandwidth (IBW). These unique characteristics make the proposed MIMO DRA well-suited for various THz Nanodevice applications, including Terahertz wave Radar, Health care, Astronomical radiometric applications, and future THz wireless communication. [ABSTRACT FROM AUTHOR]

This study employed a simulation-based approach for probing the performance-limiting parameters. Comparative observation of performance parameters with corresponding Shockley–Queisser limit values highlight a significant deficit in fill factor and open-circuit voltage (VOC) of perovskite solar cells (PSCs). This work identifies parameters such as carrier concentration, sheet resistance, and internal recombination responsible for these FF deficits in contemporary PSC. Simulation of illumination-dependent FF for these design parameters gives insight into the optimal range of parameters, which ought to be crucial to stabilize and enhance the device's performance. PSCs are sensitive toward shunt resistance and experimental PSC devices must have RSh above 5 K Ω cm2 for optimal FF and VOC values. We observed that FF is optimal in mid-carrier concentration around the range of ~ 1016 cm−3. This optimal FF could be due to the interplay between resistivity, Shockley–Read–Hall recombination and Auger recombination at these carrier densities. We summarize pathways such as shunt resistance values, carrier concentration, and back contact optimization work function to maximize FF in PSC. The optimized device with the derived design parameters has achieved a Voc, Jsc, FF and PCE of 1.3248 V, 22.93 mA/cm2, 79.39% and 23.22% respectively. [ABSTRACT FROM AUTHOR]

Recent studies show that the increased demand for energy in industries influences the research interest in environmental and energy issues. This demand leads to more intense research on renewable energy sources via solar cells, wind energy and piezo electric materials. This review article provides insights on the dye-sensitized solar cells (DSSCs), explicitly DSSCs, emphasizing perovskite solar cells (PSCs). In the last decade, due to their remarkable properties, researchers have investigated metal halide perovskite solar cells (MHPSCs) in photovoltaic technologies. These include defect tolerance, high absorption coefficients, low cost, and long lifetime with feasible processing methods. The MHPSCs have achieved a power conversion efficiency of around 25% with a bandgap of ~ 1.6 eV. In this perspective, we emphasize the study of diverse nanomaterials of low cost, which can be integrated into the perovskite structure to form solar cells. Initially, a basic overview of the perovskite solar cell evolution from DSSC is highlighted with an emphasis on the need for solid-state devices. Further, numerous nanomaterial applications in DSSCs and PSCs are reviewed and demonstrated. Eventually, a forecast and prospects for the subsequent research directions of different nanomaterials for perovskite solar cells are presented. [ABSTRACT FROM AUTHOR]

In this paper, two identical Cylindrical Dielectric Resonator Antennas (CDRA) are stacked together to achieve Circular Polarization (CP). Ultra wideband impedance bandwidth and wide axial ratio bandwidth is achieved by three factors: stacking of similar DRs, stepped conformal microstrip feed line which will generate orthogonal modes and new partial ground plane with circular rings. Measurement results show that the proposed stacked Cylindrical CPDRA achieves an Impedance Bandwidth (IBW) of (S11 < −10 dB) of 72.48% (3.65–7.8 GHz) and Axial Ratio Bandwidth (ARBW) (AR <3 dB) of 44.12% (4.38–6.86 GHz), respectively. In addition, the proposed antenna shows dominant Left Hand CP with gain ranges from 1.4 to 6.5 dBic with maximum radiation efficiency of 93.3%. The advantages and novel points of proposed research work is as follows: (i) The novel configuration of stacking CDRA's along with stepped microstrip feed enhances ARBW, (ii) New proposed partial ground plane with two circular rings provides enhancement in IBW, (iii) Simple design and small height of DRs produces enhanced IBW, ARBW, Gain and Efficiency. Furthermore, by changing the position of circular rings on ground plane, the proposed antenna provides dominant LHCP to RHCP conversion and achieves polarization reconfigurability. The proposed antenna configuration covers the frequency range of applications of C‐band and military satellite communication. [ABSTRACT FROM AUTHOR]

A Cylindrical Dielectric Resonator antenna (CDRA) along with silicon based Rectangular Dielectric Resonator (RDR) slab is proposed in this paper for terahertz (THz) applications. This antenna provides multi-band response at different resonant frequencies. Unique feature of the proposed antenna is, it provides Circular Polarization (CP) behaviour at quad band in the field of THz dielectric resonator antennas and also CP tuning is achieved by varying graphene potential of the antenna. Furthermore this antenna shows both Right Hand CP (RHCP) and Left Hand CP (LHCP) behaviour at different resonant frequencies. A rectangular slab is incorporated with CDRA knows CPDRA to achieve CP response. Results show that a maximum gain of 6.67 dB, maximum radiation efficiency of 89%, 10 dB Impedance Bandwidth (IBW) of 4.66% (8.59-9THz), 2.98% (10.88–11.21THz), 4.83% (14.19–13.52THz) and 5.86% (15.88–16.84), Axial Ratio Bandwidth (ARBW) of 1.83% (8.66–8.82 THz), 2.16% (10.94–11.18), 3.84% (13.26–13.78 THz) and 4.8% (16.04–16.83 THz) is achieved by the combination of CDRA and Rectangular slab. For antenna tunability, the upper layer of CDRA is layered with graphene material and CP performance of antenna is analyzed for different values of graphene chemical potential. This new approach for the tuning and obtained results make the proposed Quad band CP DRA as unique and is suitable for THz applications. [ABSTRACT FROM AUTHOR]

The length and width of the metallic gate layer are kept identical to the graphene patch when the external voltage is applied, ensuring that the fermi level is maintained consistently [[9], [34], [46]]. HT ht Graph (16)where HT ht is the Fermi-Dirac distribution given by HT ht . Keywords: antenna; circular polarization; impedance bandwidth; MIMO; terahertz EN antenna circular polarization impedance bandwidth MIMO terahertz 273 285 13 05/09/22 20220601 NES 220601 1 Introduction For the next generation communication system, Terahertz (THz) frequency spectrum is becoming choice of many wireless applications because of its wider bandwidth and high data rates [[1]], [[2]], [[3]]. [Extracted from the article]

Mucormycosis is a progressive, opportunistic fungal infection with high risk of mortality. Rampant use of steroids in the treatment coronavirus disease 2019 creates a fertile environment for mucor growth. Perioperative challenges for the anesthesiologist in a patient having post-coronavirus disease mucormycosis include increased risks of arterial and venous thromboembolism, poor glycemic control and myocardial dysfunction, adrenal insufficiency from corticosteroid use, pulmonary dysfunction, and residual neuromuscular weakness. So, a complete biochemical workup of renal functions, hypothalamic-pituitary-adrenal axis, electrolyte, coagulation profile, optimization of blood glucose, and pulmonary function should be done. [ABSTRACT FROM AUTHOR]

This paper describes the development and characterization of a wireless pressure monitoring system (WPMS) using an integrated radio frequency (RF) transceiver for applications such as monitoring of exerted vapor pressure variations of gases, volatile organic compounds (VOCs), and water vapor. Parametric sensing and environment detection using integrated approach are the key drivers for modern sensor technology. Our WPMS has an operating frequency band of 2.3152–2.6478 GHz. It has been developed using a pressure transducer, voltage-controlled oscillator, amplifier, and transmit/receive filtennas (filtering antennas). Transmitting antenna has been used for radiating RF signal (conditioned pressure information), while reflecting the undesired harmonics. Filtering antenna at the receiver side has been used to detect the desired RF signal, while filtering out the undesired signal. Experiments have been performed for monitoring a pressure variation of 0–50 kPa for a distance of 3 m from the transmitter. The pressure sensitivity of the system is 6.4 MHz/kPa with a good linearity response. Wireless temperature monitoring using our constructed RF sensor has also been demonstrated. The temperature sensitivity of wireless temperature monitoring system is about −662.2 kHz/°C between −55 °C and 130 °C. Calibration curve and polynomial fitting equations have been provided for evaluating pressure and temperature variations. The main advantages of this integrated system are integrated design, high-pressure/high-temperature sensitivity response, good linearity response, lower cost, less complexity, handheld, compact size, increased flexibility, and indigenous subsystems. The proposed system is suitable for wireless pressure/temperature monitoring applications in gas/oil industry, VOC industry, and steam industry. [ABSTRACT FROM AUTHOR]

Abstract: Design and development of a tunable dual‐band filtering LNA has been presented in this paper. The center frequency of the lower band is continuously tuning with applied dc voltages. The center frequency of lower band has a tuning range of 2.0–2.5 GHz; while that of upper band is fixed at 5 GHz. Power consumption of our circuit is 28 mW. Overall size of proposed device is 0.96λg × 0.34λg, where λg is the guided wavelength at lower frequency. One ATF36163 GaAs HEMT is used as the active device in our circuit. Measured per stage gain of lower band is varying from 8 to 1.6 dB; while that of upper band is 5.4 dB. Measured noise figure of lower band is 2.4–3.4 dB; while that of upper band is 2.5 dB. Proposed filtering LNA has improved selectivity and spurious harmonic suppression with measured stopband attenuation of 45 dB. To author's knowledge, the investigation of tunable multiband and multifunctional device for highly improving the level of integration of the multiband RF front‐end design is reported for the first time. [ABSTRACT FROM AUTHOR]

We report a varactor-loaded tunable microstrip bandpass filter (BPF) with reconfigurable center frequency and bandwidth. The effects of loading varactors at intercoupled stepped-impedance resonator (SIR) resonator and at tapped input/output port coupled-lines are studied. Tuning elements are properly loaded at the middle of the coupled-line sections for achieving tunable center frequency and bandwidth performance. Initial BPF (without loading varactors) is based on a half-wavelength (λg/2-) coupled stepped-impedance resonator (CSIR) structure. For the validation of the proposed concept, a hardware prototype is fabricated and characterized. A total of three varactors are used as the tuning elements. Only two dc control voltages are used for tuning the center frequency and bandwidth. [ABSTRACT FROM AUTHOR]

ABSTRACT This article reports the development and characterization of a robust RF transceiver system for wireless monitoring of the pressure variation in a gas pipeline installed in an industry. Proposed system consists of a monolithic silicon pressure sensor for converting applied pressure information to a DC voltage output, a varactor-based voltage controlled oscillator (VCO) for converting DC voltages to RF signal, a power amplifier for amplifying the transmitting RF signal, and two wideband microstip fed filtering antennas used in transmitter and receiver modules. Transmitting antenna is used for radiating the selected RF signal (conditioned pressure information) while reflecting the undesired harmonics. Filtering antenna (Filtenna) at the receiver side is used to detect the desired RF signal while filtering out the undesired signal. Operating frequency band of proposed wireless pressure monitoring system is 2.2565-2.5804 GHz covering lower ISM band (2.4-2.5 GHz). As a proof of concept, experiment has been performed for monitoring of a pressure variation in the range 0-50 kPa and for a distance of 2 m between transmitting and receiving antennas. The measured pressure sensitivity of the proposed gas pressure monitoring system is 6.4786 MHz/kPa with a good linearity response. Calibration curve and curve fitting equations are provided for evaluating the pressure variation in a gas pipeline by detecting the received RF signal at the receiver end. Proposed system can be used for wirelessly monitoring the pressure of a gas pipeline installed in an industry. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2237-2242, 2016 [ABSTRACT FROM AUTHOR]

ABSTRACT This article reports the design and analysis of a quint-band resonator using an internally coupled multimode stepped-impedance resonator along with meandered λ/2 resonators. Resonance frequency of the fundamental even- and odd-mode along with the first higher order mode of the proposed resonator has been selected to obtain resonances at first, second, fourth, and fifth pass band while other λ/2 resonator controls the occurrence of third pass band. This resonator has been used in the design of a miniaturized quad-band bandpass filter where transmission zeros have been used to obtain quad-band filter response for better selectivity. Full wave simulation results along with the measured characteristics of the resonator and filter are also presented. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:708-712, 2016 [ABSTRACT FROM AUTHOR]