Radiation Efficiency Research Articles

A four-element metasurface loaded high gain MIMO antenna for X-band applications

This research presents a novel four-port metamaterial-backed Multiple Input Multiple Output (MIMO) antenna system designed for X-band applications. Each modified circular-shaped antenna element is meticulously printed on a 1.6 mm thick FR4 substrate, resonating within the 9.2 to 9.9 GHz frequency range, encompassing a significant portion of the X-band spectrum. To enhance overall gain, a tilted square-shaped 4 × 4-unit cell is strategically printed on the ground plane of the substrate. The proposed MIMO antenna achieves a maximum gain of up to 8 dBi across the operating spectrum, coupled with an impressive radiation efficiency of up to 80%. Fabrication of the designed antenna is performed, and comprehensive parameter measurements validate its performance, exhibiting a close correlation with simulated results. Essential MIMO parameters such as ECC (<0.01), TARC (>10 dB), CCL (<0.3), and diversity gain are calculated to affirm the antenna’s proficiency further. The results show that the proposed antenna could be a suitable contender for X-band applications.

Design and Implementation of a Printed Circuit Model for a Wideband Circularly Polarized Bow-Tie Antenna

A crossed bow-tie antenna design for S- and C-Band (2.44–7.62 GHz) with a peak gain of 7.29 dBi is presented to achieve wideband radiation efficiency greater than 90% and circular polarization with a single feed point. The polarization of the antenna is modeled by the input admittance of crossed bow-ties, and the model predictions are validated by experiments. A wideband matching network is designed to be tightly integrated with the antenna and produce a 103% impedance bandwidth. The matching network is decomposed into an equivalent circuit model, and an analysis is presented to demonstrate the principles of the matching network design. A prototype of the optimized antenna design is fabricated and measured to validate the analysis.

Asymmetric Structural Engineering of Hot-Exciton Emitters Achieving a Breakthrough in Non-Doped BT.2020 Blue OLEDs with a Record 9.5% External Quantum Efficiency.

High-efficiency non-doped deep-blue organic light-emitting diodes (OLEDs) meeting the standard of BT.2020 color gamut is desired but rarely reported. Herein, an asymmetric structural engineering based on crossed long-short axis (CLSA) strategy is developed to obtain three new deep-blue emitters (BICZ, PHDPYCZ, and PHPYCZ) with a hot-exciton characteristic. Compared to 2BuCz-CNCz featuring a symmetric single hole-transport framework, these asymmetric emitters with the introduction of different electron-transport units show the enhancement of photoluminescence efficiency and improvement of bipolar charge transport capacity. Further combined with high radiative exciton utilization efficiency and light outcoupling efficiency, the non-doped OLED based on PHPYCZ exhibits the best performance with an excellent current efficiency of 3.49%, a record-high maximum external quantum efficiency of 9.5%, and a CIE y coordinate of 0.049 approaching the BT.2020 blue point. The breakthrough obtained in this work can inspire the molecular design of deep-blue emitters for high-performance non-doped BT.2020 blue OLEDs.

Designing an ultra-wideband directional antipodal Vivaldi antenna with U-slots for biomedical applications using an optimized attention network

Abstract This research introduces a compact Ultra-Wideband (UWB) antipodal Vivaldi antenna with a U-slot tailored for biomedical applications. Utilizing an elliptical tapered patch variation on a 50*32 mm2 substrate achieves its compact design. Parameter optimization, employing the Multi-Layer Stacked Shallow Attention Neural Network (MLSSANN) with Adaptive Gannet Optimization Algorithm (AGOA), ensures accurate predictions and efficient exploration of the design space. Performance analysis includes metrics like gain, directivity, reflection coefficients, return loss and radiation efficiency. The U-slot variant exhibits higher gain peaking at 24.5 GHz (10 dB) compared to the standard variant peaking near 37 GHz (13.7 dB). The U-slot antenna also shows improved directivity and return loss, with a 13.89 % enhancement in return loss at 3.7 GHz. Moreover, the addition of the slot shifts the lower cut-off frequency from 1,580 MHz to 740 MHz, reducing the antenna size by 41 % while maintaining acceptable radiation characteristics.

Molecular Design Motifs of Non‐Fullerene Acceptors for Mitigating All Inherent Non‐Ideal Energy Losses in Organic Photovoltaics

AbstractNon‐fullerene acceptors (NFAs) have demonstrated a great potential for the transcendence of performance limits in organic photovoltaics. Despite the tremendous efforts, however, synthetic control of non‐ideal recombination losses on the photovoltage are still elusive and thus lag far behind the inorganic counterparts. Here, a rational design strategy of non‐fullerene acceptors is presented to overcome the limitations derived from the inherent excited state properties of organic molecules. Spectroscopic studies on a series of chemical analogs of ladder‐type fused acceptors reveal that the radiative efficiency of non‐fullerene acceptors is predominantly determined by the inherently strong electron‐vibration coupling of their bound excited states, rather than the redistribution of molecular orbitals itself. In this sense, regardless of intramolecular charge transfer characteristics, the incorporation of rigid, and planar moiety with wide π plane is found to promote the dominance of long‐lived and weakly‐bound excited states in the photophysical process, in which the mitigated non‐radiative decays of NFAs can be directly translated into that of charge‐transfer states. Furthermore, the incorporation of such chemical moiety can minimize the evolution of subgap broadening in the bulk heterojunction blends, lowering the contribution of non‐ideal radiative losses. As a result, the model systems demonstrate the non‐radiative loss down to 180–190 meV, without sacrificing photocurrent generations, reaching that of inorganic counterparts.

The influence of radiation modeling on flame characteristics and emissions prediction in microcombustors with Ammonia/Hydrogen blends

This study advances numerical methodologies for designing microcombustor-based thermophotovoltaic systems by incorporating comprehensive analyses of radiation models and absorption coefficients. It examines the impact of non-premixed hydrogen-ammonia-air fuel blends on the micro combustion process using three-dimensional CFD simulations on a Y-shaped microcombustor under atmospheric conditions.Key to this research is modeling radiative heat transfer from multiple species, including ammonia (NH3), nitric oxide (NO), and water vapor, ensuring accurate predictions and optimization of thermal behavior and efficiency. Three modeling approaches were compared: a multispecies Planck-mean approximation radiation model (PMAC), a narrowband model for water vapor, and a scenario excluding radiation effects.The PMAC model, incorporating the absorption coefficients of ammonia and its products, consistently produced lower errors in flame length compared to the NB method across all equivalence ratios, with errors ranging from 0 % to 7 % for PMAC and 10 % to 30 % for NB, with the lowest error observed at Φ = 1.0. Additionally, the prediction of laminar burning velocity (LBV) differed by approximately 4 % between the two models.Considering different fuel blends, two scenarios were compared: constant input thermal power and constant fuel flow rate. Efficiency in the constant input thermal power scenario maintained higher radiation efficiency, in the range of 32–38%. Additionally, radiation efficiency initially increased with increasing H2 content but subsequently decreased for high H2 values due to effects on flame area, flame position, and temperature.

Transparent and flexible fish-tail shaped antenna for ultra-wideband MIMO systems

Abstract The article presents an innovative transparent, flexible antenna design tailored specifically for ultra-wideband multiple-input multiple-output (MIMO) systems. Using polyethylene terephthalate substrates as the base material, we enhance the antenna’s radiation performance, transparency, and flexibility. Broadband impedance matching is achieved through a hollow ground plane fed by a fish-tail radiator and coplanar waveguide. Additionally, significant MIMO antenna isolation in ultra-wideband scenarios is achieved through the vertical arrangement of units and neutral lines. The MIMO antennas we manufactured exhibit minimum transparencies of 71.1% and 85.9% with and without reflectors, respectively. Measurement results demonstrate that the antenna operates within the 3–20 GHz frequency range, with over 24 dB of isolation, 2 ± 2 dBi of peak gain, and 45% ± 5% of radiation efficiency, suitable for applications in wearable devices, vehicle intelligence, and other fields.

Offset-fed Slotted Antenna Practically Loaded with Split Ring as Water Quality Sensor for X-Band Industrial Applications

This article communicates an offset-fed split ring loaded slotted-antenna design, testing, and analysis for different water quality sensor. The antenna was designed to resonate at 10GHz on a low-cost FR-4 substrate of dimensions 0.621λo×0.467λo×.053λo, where λo is the free space wavelength. The measured antenna parameters are found in excellent agreements. The antenna achieves a gain of 7.61dBi with nearly unidirectional radiation pattern and a radiation efficiency of 76% at 10GHz. Further, the research is explored to use the antenna as a water sample sensor. Different water samples are tested with the antenna by dipping the antenna into the water samples and in the second case contactless measurements at 10mm apart from the upper water level in the container. The quality of water is examined by observing the shift in the resonant frequency (fr), antenna quality factor with different total dissolved solvents (TDS) water samples, and changes in the reflection coefficient (S11) values in the water samples. It is observed that the antenna shows less than 1.5% numerical sensitivity (NS) with fr and high NS with the S11. The S11 and bandwidth of the antenna vary with different water samples. This antenna is suitable for X-band industrial and microwave laboratory applications.

CSRR and EBG loaded wideband THz dielectric resonator MIMO antenna for nano communication and bio-sensing applications

In this paper, a wideband Graphene-inspired dielectric resonator THz MIMO antenna is designed. The antenna has dimensions of 56 × 56 × 3.6 μm³ and is designed on a Rogers RO3035 substrate with a relative permittivity of 3.6 and loss tangent of 0.0015. This antenna works in the range of 6.0 THz-12.5 THz (70.76 %) with a peak gain of 7.68 dBi and radiation efficiency (>70 %) is suitable for use in medical imaging and THz wireless near-field applications. A CSRR is loaded to obtain band notch characteristic for avoiding interference between nearby wireless devices in the range of 10.6–10.8 THz. EBG was also introduced with a patch antenna to reduce surface wave loss and improve isolation, resulting in a high front-to-back ratio (FBR) in the range of 10–12.5 THz. Without the graphene disk, the silicon-based DRA did not achieve significant gain. At a chemical potential of 0.5 eV and a relaxation time of 0.1 ps, the proposed DRA demonstrated good antenna properties. By varying the chemical potential and relaxation time, frequency agility was easily achieved. A Graphene disk having a height of 3 μm is placed on a Silicon (εr = 11.1) based cylindrical DRA to provide high gain and improve the impedance bandwidth, achieving wide bandwidth from 6.0 THz to 12.5 THz. The proposed two element antenna performance is evaluated by parameters such as gain, return loss, isolation between two antenna elements, and diversity parameters like Envelope correlation coefficient ECC<0.1, Directive Gain >9.5 dB, Total Active reflection Coefficient >10 dB and Avg. Channel capacity loss <0.35bps/Hz so that the proposed antenna is suitable for wideband nano/optical communication in IoT-6G. Furthermore, the antenna is suitable for biological sensing applications due to its average sensitivity and FOM for hemoglobin and urine of 805.33GHz/RIU and 805.55GHz/RIU, respectively, and 3.37 and 10.55.

Solution combustion derived color-tunable Eu3+ doped Ca8ZnBi(VO4)7 nano sample for luminous devices and latent fingerprinting applications

Eu3+ doped Ca8ZnBi(VO4)7 host lattice have been produced through an environmentally friendly, economical, and energy-efficient solution combustion synthesis. The trigonal phase with the R 3c space group of the constructed series was verified by x-ray diffraction and Rietveld refinement technique. The elemental and morphological study was done by using energy dispersive X-ray analysis (EDAX) and scanning electron microscope (SEM), transmission electron microscope (TEM) respectively. In the excitation spectra, the intense band at 334 nm indicates the transfer of energy occur between VO43- → Eu3+. The color-tunable features of the generated nanosample are indicated by the emission (617 nm, 5D0→7F2) color of the nanophosphor, which lies in the yellow, orange, and red regions for varying doping amounts. The band gap was determined using Tauc’s hypothesis for both host lattice (3.18 eV) and Eu3+ doped nanomaterials (3.13 eV) which lie in the range of semiconductors. The use of Dexter’s theory and the Inokuti-Hirayama (I-H) model verified the existence of dipole–dipole (d-d) type interlinkages as a genuine phenomenon for concentration quenching. Additionally, Auzel’s system was used to study radiative lifetime (0.6510 ms), quantum efficiency (59.51 %), and non-radiative rates (621.8 s−1). The CIE coordinates (0.5164, 0.4703), lower value of correlated colour temperature (CCT) (2459 K) and color-tunable phenomena made it a possible choice for warm white light emitting luminous devices. The optimized nanophosphor has been investigated for latent fingerprinting and has been successful in identifying all of the fingerprint’s levels-1, 2 and 3.

Unveiling the Versatility of Coumarin-Integrated with Phenanthroline/Thiabendazole-Based EuIII Complexes for Smart LEDs, Vapoluminescence, and Bioimaging Applications.

Narrow band red-emitting phosphors based on organo-Eu(III) complexes prove their energetic features with surprising performance in smart red/white LEDs, sensing, and biological fields. In this report, a series of unique Eu(III) complexes have been synthesized with coumarin integrated with a class of phenanthroline(Phen)/thiabendazole(TBZ) based ancillary ligands and dibenzoyl methane (DBM)/2-theonyl trifluoroacetone (TTA) as an anionic ligand. The computational study reveals that the TBZ/Phen-based neutral ligands are superior energy harvesters to those other reported analogue neutral ligands. All the Eu-complexes demonstrated outstanding red emission due to electric dipole (ED) transition (5D0 → 7F2) in solid, solution, and thin film with high quantum yield (QY). Theoretical analysis (TD-DFT) and experimental findings describe that the energy transfer (ET) from the ligand's triplet level to the Eu(III) ion is completely occurring. The Eu(III) complexes can potentially be used to fabricate intense hybrid white and red LEDs. All of the fabricated red LEDs revealed high luminous efficiency of radiation (LER) values. The fabricated blue LED based hybrid white LEDs displayed remarkable performance with a low correlated color temperature (5634 K), high color rendering index 88%, and CIE values (x = 0.33; y = 0.342) for 3Eu. By interaction with acid-base vapors, Eu-complexes displayed effectively alterable on-off-on luminescence. Further, cellular imaging shows that Eu-complexes can be a potential biomarker for cancer cell lines.

A Wideband Millimeter-Wave Dual-Beam Dielectric Resonator Antenna with Substrate Integration Capability.

A wideband dual-beam dielectric resonator antenna (DRA) with substrate integration capability was proposed for millimeter-wave (mm-wave) applications. The four rows of air vias along the x-direction and two extended rectangular patches could shift the undesirable radiation mode upward and move the conical-beam radiation mode downward, respectively. Thus, the TE211 mode and the TE411 mode of the patch-loaded perforated rectangular substrate integrated dielectric resonator (SIDR) supporting the dual-beam radiation can be retained in the operating band, and their radiation can be improved by the air vias along the y-direction. The T-shaped line coupled dual-slot structure could excite the above two modes, and a dual-slot mode supporting dual-beam radiation could also work. Then, a wideband DRA with a stable dual-beam radiation angle can be achieved, and its impedance matching can be improved by two air slots on two sides. Compared with the state-of-the-art dual-beam antennas, the proposed antenna shows a wider bandwidth, a higher radiation efficiency, and the substrate integration capability of DRA, making it more suitable for mm-wave applications. For demonstration, a 1 × 4 array was designed with the 10 dB impedance matching bandwidth of 41.2% and the directions of the dual beams between ±30° and ±35°.

Using a metasurface to enhance the radiation efficiency of subterahertz antennas printed on thick substrates

This study investigates the possibility of increasing the radiation efficiency of printed antennas and arrays by suppressing their inherent surface waves using a metasurface made of quad-split rings (QSR). A symmetrical resonant microstrip dipole and a four-element series-fed dipole array printed on an infinite grounded dielectric layer (layer thickness: 0.2 mm; relative permittivity: 9.4; tanδ: 0.0005) were simulated with FEKO 2022 software. Conducted at 100–116 GHz, the numerical results revealed extremely low radiation efficiencies of approximately 31% and 40% for the studied dipole and dipole array, respectively, which resulted from the presence of surface waves in the dielectric. However, placing only one QSR near each dipole arm triggered an increase in radiation efficiency by 2.5 times (up to 75%). The use of a metasurface in the form of two small QSR arrays triggered a pronounced improvement in radiation efficiency, reaching 93.6% and 95.8% for the studied dipole and dipole array, respectively. Analysis of the electric field distribution images showed that this enhancement resulted from surface wave suppression.

Design and Simulation of 1x4 Patch Array for Enhanced Gain

In contemporary wireless communication systems, antenna design plays a crucial role in achieving better performance metrics like gain, directivity, radiation efficiency, and appropriate impedance matching. In this work, a 1x4 array antenna operating at 2.4 GHz is designed and simulated. With an emphasis on single patch antennas and linear arrays with 1x2 and 1x4 components, beam steering in antenna array investigates the design, simulation, and analysis of antenna arrays at 2.4 GHz using CST Microwave Studio. In order to maximize performance, the project starts with the design of a single patch antenna. Important factors such as substrate material, patch dimensions, and feed mechanisms are examined. To improve gain, directivity, and bandwidth, 1x2 and 1x4 linear arrays are designed as an extension of the single patch design. The antennas are simulated using CST Microwave Studio, which offers comprehensive insights into their radiation patterns, impedance matching, and overall performance. Based on the simulations, it can be observed that a 1x4 array has substantially better gain and directivity when compared to a single patch. As a result, these arrays are more appropriate for applications that need more concentrated beams and greater coverage. Performance comparisons between the single patch, 1x2, and 1x4 arrays are included in the project's thorough study, along with a discussion of the trade-offs between design complexity, physical size, and performance advantages. The findings demonstrate the advantages of antenna arrays in improving 2.4 GHz wireless communication systems and provide insightful guidance for the creation of effective and high-performing antennas in this frequency range. The suggested antenna array exhibits encouraging performance in terms of parameters like gain, directivity, and efficiency, which qualifies it for use in particular applications including Internet of Things (IoT), wireless communication systems, and radar systems

Dual-band dual-truncated R-slot loaded monopole patch antenna using a single-layer bandstop FSS reflector for gain enhancement

New reflector structure (RS) based on ultra-wide stopband single-layer frequency selective structure (FSS) for mid-band sub-6 GHz 5G applications is designed. The proposed RS is arranged into array of 7 × 7-unit cell of FSS elements for antenna gain and front-to-back ratio enhancement. The single antenna element of volume 30 × 20 × 1.6 (in mm3) consists of a dual-quarter-circular truncated edge-fed rectangular slot (R-slot) loaded rectangular patch (R-patch) antenna with degraded ground structure (DGS) to operate at 3.6 GHz mid-band sub-6 GHz 5G and 5.8 GHz WBAN band. The proposed unit cell FSS element, the RS of volume 55.5 × 55.5 × 13.2 (in mm3) and the associated antenna are designed on lossy thin FR-4 substrate material and investigated numerically using commercial computer simulation technology microwave studio (CST-MS) software. The studied dual-structure based RS made with array of single-layer FSS and monopole R-patch antenna is fabricated and measured. The measured impedance bandwidth (IBW) of 48.28% (3.06–4.85 GHz) and 86.20% (5–10 GHz), peak gain of 5.36 and 7.45 dBi, radiation efficiency of 67.11% and 80.16%, and front-to-back ratio of 12.23 dB and 22.84 dB are achieved at the resonant frequencies 3.5 and 5.8 GHz respectively. The FSS reflector associated with the dual-band monopole R-patch antenna performances are in good agreement with the portable wireless applications requirements.

Bilateral rectangular shape dielectric resonator antenna coupled with offset microstrip lines for wideband circular polarization

SummaryIn this work, an offset microstrip line coupled bilateral rectangular‐shaped dielectric resonator antenna (RDRA) is designed for broadband circular polarization (CP), which is fabricated and experimentally verified. The vertical microstrip is added in an offset position to generate orthogonal modes and the fundamental modes TEx111 and TEy111. The generation of orthogonal modes designates the antenna structure as a CP antenna with orthogonal modes. Moreover, the location of the microstrip feed arrangement is used to control the polarization state in the proposed work. In the proposed design, the simulated and hand‐measured input impedance bandwidth(|S11| ≤ −10 dB) obtained is 32.6% (3.53–4.9 GHz) and 33.2% (3.56–4.98 GHz), respectively, whereas the simulated and measured axial ratio (AR ≤ 3 dB) shows 16.1% (3.71–4.36 GHz) and 17.03% (3.7–4.39 GHz) of axial ratio bandwidth, respectively. This design shows a consistent radiation pattern and good average gain, with acceptable agreement between simulation and hand‐measured results. The simulated result shows 94% radiation efficiency in the working frequency range.

Sodium yttrium fluoride doped with Er3+ ions for thermally and non-thermally coupled nano-thermometry and IR detection applications

Microwave-assisted combustion synthesis approach was adopted to prepare sodium yttrium fluoride doped with erbium (NaYF4: Er3+) nanoparticles. Powder x-ray diffraction study confirmed the formation of mixed phase of NaY1-xF4: xEr3+ (x = 1, 3, 5, 7 and 9 mol%) sample with cubic and hexagonal phases (predominant). Three characteristic emission peaks appearing at 526, 546 and 670 nm were attributed to the transitions 2H11/2, 4S3/2 and 4F9/2 to 4I15/2 respectively which are characteristic emissions of Er3+ ions when excited with 980 nm radiation. The optimal dopant concentration was determined as 7 mol% of Er3+ ions in yellowish-green region, and the asymmetric ratio was also calculated. The synthesized up-converting sample follows two-photon process for excitation which was confirmed by power law by varying pump-power in the range of 49–143 mW. The thermally and non-thermally coupled levels attributed to the transitions (2H11/2 and 4S3/2), (2H11/2 and 4F9/2) of Er3+ ions were employed to study the temperature sensing which was recorded in 300–550 K and the relative sensitivities were evaluated to be 0.92 and 0.58 %K−1 correspondingly. The significant thermal sensitivity of the synthesized phosphor materials promises its possibility in optical thermometry applications. The synthesized sample when excited with 980 nm laser radiation produced emission in the visible region which facilitates the utilization of sample as infrared (IR) detector. In the purview of solid-state lighting, the luminous efficiency and luminous efficacy of radiation were evaluated as 23.57 % and 161 lm/Wop respectively. The optical thermometry, IR detection and light generation capabilities of the hexagonal-phased sodium yttrium fluoride doped with erbium (NYF:Er) ions are demonstrated with the obtained results.

Calculation of relative luminescent efficiency of TL/OSL detectors to cosmic radiation spectrum in cis-lunar space

In the MARE experiment onboard the NASA Artemis 1 mission of the ORION spacecraft to lunar orbit, two anthropomorphic female phantoms, equipped with a large number of active and passive radiation detectors were flown. Among the detectors were both LiF:Mg,Ti and LiF:Mg,Cu,P TL detectors as well as Al2O3:C OSL detectors. In order to correctly interpret the measured doses, the effective relative TL/OSL efficiency for cosmic radiation of these detectors was calculated by combining simulated radiation spectra for the cis-lunar space conditions with the efficiency functions based on experimental data for different ions and on a microdosimetric model.The obtained results show that for the ORION shielding conditions, the relative efficiency of LiF:Mg,Ti is close to unity (0.95), while the remaining detectors show somewhat smaller efficiency: 0.90 for Al2O3:C and (0.81–0.86) for LiF:Mg,Cu,P. The analysis of the influence of the shielding thickness on the relative TL/OSL efficiency revealed, that for low shielding conditions, the relative efficiency may be more significantly decreased, reaching values between 0.71 (LiF:Mg,Cu,P) and 0.85 (LiF:Mg,Ti) for 1 g/cm2.

Atmospheric chemistry of CF3CHFCF2OCH3 (HFE-356mec3) and CHF2CHFOCF3 (HFE-236ea1) initiated by OH and Cl and their contribution to global warming.

The kinetic study of the gas-phase reactions of hydroxyl (OH) radicals and chlorine (Cl) atoms with CF3CHFCF2OCH3 (HFE-356mec3) and CHF2CHFOCF3 (HFE-236ea1) was performed by the pulsed laser photolysis/laser-induced fluorescence technique and a relative method by using Fourier Transform infrared (FTIR) spectroscopy as detection technique. The temperature dependences of the OH-rate coefficients (kOH(T) in cm3s-1) between 263 and 353K are well described by the following expressions: 9.93 × 10-13exp{-(988 ± 35)/T}for HFE-356mec3 and 4.75 × 10-13exp{-(1285 ± 22)/T} for HFE-236ea1. Under NOx-free conditions, the rate coefficients kCl at 298K and 1013mbar (760Torr) of air were determined to be (2.30 ± 1.08) × 10-13 cm3s-1and (1.19 ± 0.10) × 10-15 cm3s-1, for HFE-356mec3 and HFE-236ea1, respectively. Additionally, the relative kinetic study of the Cl + CH2ClCHCl2 reaction was investigated at 298K, as it was used as a reference reaction in the kinetic study of the Cl-reaction with HFE-356mec3 and discrepant rate coefficients were found in the literature. The global atmospheric lifetimes were estimated relative to CH3CCl3 at the tropospheric mean temperature (272K) as 1.4 and 8.6years for HFE-356mec3 and HFE-236ea1, respectively. These values combined with the radiative efficiencies for HFE-356mec3 and HFE-236ea1 derived from the measured IR absorption cross sections(0.27 and 0.41 W m-2 ppv-1) yield global warming potentials at a 100-yrs time horizon of 143 and 1473, respectively. The contribution of HFE-356mec3 and HFE-236ea1 to global warming of the atmosphere would be large if they become widespread increasing their atmospheric concentration.

Integrating deep convolutional surrogate solvers and particle swarm optimization for efficient inverse design of plasmonic patch nanoantennas.

Plasmonic nanoantennas with suitable far-field characteristics are of huge interest for utilization in optical wireless links, inter-/intrachip communications, LiDARs, and photonic integrated circuits due to their exceptional modal confinement. Despite its success in shaping robust antenna design theories in radio frequency and millimeter-wave regimes, conventional transmission line theory finds its validity diminished in the optical frequencies, leading to a noticeable void in a generalized theory for antenna design in the optical domain. By utilizing neural networks, and through a one-time training of the network, one can transform the plasmonic nanoantennas design into an automated, data-driven task. In this work, we have developed a multi-head deep convolutional neural network serving as an efficient inverse-design framework for plasmonic patch nanoantennas. Our framework is designed with the main goal of determining the optimal geometries of nanoantennas to achieve the desired (inquired by the designer) S 11 and radiation pattern simultaneously. The proposed approach preserves the one-to-many mappings, enabling us to generate diverse designs. In addition, apart from the primary fabrication limitations that were considered while generating the dataset, further design and fabrication constraints can also be applied after the training process. In addition to possessing an exceptionally rapid surrogate solver capable of predicting S 11 and radiation patterns throughout the entire design frequency spectrum, we are introducing what we believe to be the pioneering inverse design network. This network enables the creation of efficient plasmonic antennas while concurrently accommodating customizable queries for both S 11 and radiation patterns, achieving remarkable accuracy within a single network framework. Our framework is capable of designing a wide range of devices, including single band, dual band, and broadband antennas, with directivities and radiation efficiencies reaching 11.07 dBi and 75 %, respectively, for a single patch. The proposed approach has been developed as a transformative shift in the inverse design of photonics components, with its impact extending beyond antenna design, opening a new paradigm toward real-time design of application-specific nanophotonic devices.