Laboratory Applications Research Articles

Enhancing Rice Bran Soluble Dietary Fiber Yield Through Sequential Ultrasound–Xylanase Treatment

The main aim of this study was to enhance the content of soluble dietary fiber (SDF) derived from rice bran (RB) through various treatments, including physical methods (ultrasound and alternating magnetic field (AMF)) and enzymatic approaches (cellulase and xylanase), applied individually or in combination. The results revealed that AMF treatment was the most effective single modification technique for increasing SDF yield, followed by treatments with xylanase, cellulase, and ultrasound. Notably, among the combined approaches, the sequential ultrasound–xylanase treatment (U-X) demonstrated the highest potential for enhancing SDF yield. Further optimization experiments revealed that under the conditions of a xylanase addition of 4.3 mg/g sample, a material-to-liquid ratio of 50 mL/g, and an ultrasonic power of 72 W, the yield of U-X-SDF significantly increased from 1.03% to 18.4%. Compared to unmodified samples, the modified SDF groups exhibited marked enhancements in water holding capacity (42.5–86.4%) and water solubility (21.0–30.6%), while the unmodified SDF displayed superior oil holding capacity than the modified groups. In summary, the sequential ultrasound–xylanase treatment not only improves the SDF yield but also enhances the functional properties of RB-derived SDF, positioning it as a valuable health-promoting food additive with potential benefits for both laboratory and industrial food applications. The optimized treatment process can contribute to the development of new functional food ingredients from RB, thereby promoting health and wellness in consumers.

Formation of a nitrobenzoxadiazole-based yellow fluorophore for the selective spectrofluorimetric determination of the antifungal drug pimaricin in ophthalmic pharmaceutical formulations

Pimaricin (PMR) is a polyene antifungal drug commonly used as the primary medicine for treating fungal keratitis. In this study, a selective and novel spectrofluorimetric method was designed, optimized, and validated to determine pimaricin in its ophthalmic preparations. The method based on the formation of a nitrobenzoxadiazole-based yellow fluorophore upon the reaction of pimaricin with 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl). The fluorescence intensity of the fluorophore was measured at the emission wavelength of 538.5 nm (excitation = 473.5 nm). The factors affecting the reaction (reagent volume, alkalinity, reaction temperature, heating time, volume and type of buffer solution, and the dilution solvent) were investigated and optimized. The calculated linear range was 0.25–1.5 µg/mL, and the limits of detection and quantitation for the method were 0.047 and 0.143 µg/mL, respectively. The selectivity of the method for PMR in the presence of the pharmaceutical additive benzalkonium chloride was proved. The established method was successfully applied to determine PMR in its pharmaceutical ophthalmic preparation (Natamycin® ophthalmic drops) with an accuracy of 103.79 ± 1.83%. The proposed method is practical and valuable for its routine application in quality control laboratories for analysis of PMR in its ophthalmic pharmaceutical preparation.

The Exploitation of Nanotechnology in Herbicides and Bioherbicides: A Novel Approach for Sustainable Weed Management

The growing global demand for food security requires a paradigm shift towards sustainable agricultural practices, particularly in weed management. Nanotechnology is emerging in agriculture as a useful tool to reduce the dosage and the negative effects of herbicides on the one side and to improve the bioherbicides efficiency on the other side. This review provides an in-depth analysis of the literature available on the topic, with particular reference to the main characteristics of nanoparticles for weed control and the main nanoformulations for herbicides and bioherbicides. Nanoformulations such as nanoemulsions, nanocapsules, nanospheres, silver nanoparticles and organic materials protect the active ingredients from environmental degradation and enable their controlled release, enhance foliar adhesion and facilitate the penetration into plant tissues while at the same time minimizing the off-target effects. The last paragraph reviews the recent advancements in the field of nanobioherbicides. Moreover, examples of nanoherbicide and nanobioherbicide application in laboratory, greenhouse and field conditions are collected and discussed. This review highlights the increasing efficiency and diffusion of nanoherbicides and nanobioherbicides, suggesting their introduction into sustainable and integrated weed management strategies. However, further research is still required to assess their effectiveness under natural conditions, improve their stability over time and study their bioaccumulation and toxicity toward non-target organisms.

Recent advances in rapid detection of Helicobacter pylori by lateral flow assay.

Infection with H. pylori (Helicobacter pylori) is the most prevalent human infection worldwide and is strongly associated with many gastrointestinal disorders, including gastric cancer. Endoscopy is mainly used to diagnose H. pylori infection in gastric biopsies. However, this approach is invasive, time-consuming and expensive. On the other hand, serology-based methods can be considered as a non-invasive approach to detecting H. pylori infection. The LFA (lateral flow assay) serves as a rapid point-of-care diagnostic tool. This paper-based platform facilitates the detection and quantification of analytes within human fluids such as blood, serum and urine. Due to ease of production, rapid results, and low costs, LFAs have a wide application in clinical laboratories and hospitals. In this comprehensive review, we examined LFA-based approaches for detection of H. pylori infection from human fluids and compare them with other high-sensitivity methods like ELISA (Enzyme-linked immunosorbent assay). Furthermore, we reviewed methods to elevate LFA sensitivity during H. pylori infection including, CRISPR/Cas system and isothermal amplification approaches. The development and optimization of novel labeling agents such as nanozyme to enhance the performance of LFA devices in detecting H. pylori were reviewed. These innovations aim to improve signal amplification and stability, thereby increasing the diagnostic accuracy of LFA devices. A combination of advances in LFA technology and molecular insight could significantly improve diagnostic accuracy, resulting in a significant improvement in clinical and remote diagnostic accuracy.

A DIY Bioreactor for in Situ Metabolic Tracking in 3D Cell Models via Hyperpolarized 13C NMR Spectroscopy.

Nuclear magnetic resonance (NMR) spectroscopy is a valuable diagnostic tool limited by low sensitivity due to low nuclear spin polarization. Hyperpolarization techniques, such as dissolution dynamic nuclear polarization, significantly enhance sensitivity, enabling real-time tracking of cellular metabolism. However, traditional high-field NMR systems and bioreactor platforms pose challenges, including the need for specialized equipment and fixed sample volumes. This study introduces a scalable, 3D-printed bioreactor platform compatible with low-field NMR spectrometers, designed to accommodate bioengineered 3D cell models. The bioreactor is fabricated using biocompatible materials and features a microfluidic system for media recirculation, ensuring optimal culture conditions during NMR acquisition and cell maintenance. We characterized the NMR compatibility of the bioreactor components and confirmed minimal signal distortion. The bioreactor's efficacy was validated using HeLa and HepG2 cells, demonstrating prolonged cell viability and enhanced metabolic activity in 3D cultures compared to 2D cultures. Hyperpolarized [1-13C] pyruvate experiments revealed distinct metabolic profiles for the two cell types, highlighting the bioreactor's ability to discern metabolic profiles among samples. Our results indicate that the bioreactor platform supports the maintenance and analysis of 3D cell models in NMR studies, offering a versatile and accessible tool for metabolic and biochemical research in tissue engineering. This platform bridges the gap between advanced cellular models and NMR spectroscopy, providing a robust framework for future applications in nonspecialized laboratories. The design files for the 3D printed components are shared within the text for easy download and customization, promoting their use and adaptation for further applications.

LittleFaceNet: A Small-Sized Face Recognition Method Based on RetinaFace and AdaFace.

For surveillance video management in university laboratories, issues such as occlusion and low-resolution face capture often arise. Traditional face recognition algorithms are typically static and rely heavily on clear images, resulting in inaccurate recognition for low-resolution, small-sized faces. To address the challenges of occlusion and low-resolution person identification, this paper proposes a new face recognition framework by reconstructing Retinaface-Resnet and combining it with Quality-Adaptive Margin (adaface). Currently, although there are many target detection algorithms, they all require a large amount of data for training. However, datasets for low-resolution face detection are scarce, leading to poor detection performance of the models. This paper aims to solve Retinaface's weak face recognition capability in low-resolution scenarios and its potential inaccuracies in face bounding box localization when faces are at extreme angles or partially occluded. To this end, Spatial Depth-wise Separable Convolutions are introduced. Retinaface-Resnet is designed for face detection and localization, while adaface is employed to address low-resolution face recognition by using feature norm approximation to estimate image quality and applying an adaptive margin function. Additionally, a multi-object tracking algorithm is used to solve the problem of moving occlusion. Experimental results demonstrate significant improvements, achieving an accuracy of 96.12% on the WiderFace dataset and a recognition accuracy of 84.36% in practical laboratory applications.

Water Treatment Technologies: Development of a Test Bench for Optimizing Flocculation-Thickening Processes in Laboratory Applications

This study introduces an automated test bench designed to optimize flocculation-thickening processes in the wastewater treatment industry. Addressing current challenges in operational efficiency and cost reduction, the test bench employs Model-Based Systems Engineering (MBSE) principles, leveraging SysML modeling within the CESAM framework. By integrating advanced technologies, including PLC programming and a closed-loop control system, this bench provides precise and efficient testing under varying operational conditions. Economic implications are explored, demonstrating the cost-effectiveness of optimized flocculation processes, which reduce chemical use and operational expenditures while enhancing water clarity and sludge management. The system’s 3D modeling enables detailed simulations, aiding in both research and pedagogical applications. This platform highlights the potential of MBSE in creating scalable, robust solutions that contribute to sustainable water management.

Discriminating Analysis of Metal Ions via Multivariate Curve Resolution-Alternating Least Squares Applied to Silver Nanoparticle Sensor.

Heavy metals are life-threatening pollutions because of their great toxicity, long-term persistence in nature and their bioaccumulation in living organisms. In this work, we performed multivariate curve resolution-alternating least squares analysis of UV-Vis raw spectra received by a colorimetric sensor constructed on mercaptoundecanoic acid functionalized silver nanoparticles (AgNPs@11MUA) to detect Cd2+, Cu2+, Mn2+, Ni2+, and Zn2+ in water. This combined approach allowed the rapid identification and quantification of multiple heavy metals and showed adequate sensitivity and selectivity, thus representing a promising analytical and computational method for both laboratory and field applications such as environmental safety and public health monitoring.

Step-by-step verification of particle-in-cell Monte Carlo collision codes

The particle-in-cell (PIC) method with Monte Carlo collisions (MCC) is widely used in the simulation of non-equilibrium plasmas for electric propulsion and laboratory applications. Due to the simplicity of the basic PIC algorithm and the specific modeling needs of the different research groups, many codes have been independently developed. Verification of these codes, i.e., ensuring that the computational code correctly implements the intended mathematical models and algorithms, is of fundamental importance. Different benchmark cases, such as one from Turner et al. [Phys. Plasmas 20, 013507 (2013)], Charoy et al. [Plasma Sources Sci. Technol. 28, 105010 (2019)], and Villafana et al. [Plasma Sources Sci. Technol. 30, 075002 (2021)], have been published in recent years. These have consisted of a complex physical setup, in which many computation modules interact to yield the final result. Although this approach has the advantage of testing the code in a realistic case, it may hide some implementation errors. Moreover, in the case of disagreement, the previous works do not provide an easy way to identify the faulty code modules. In this work, we propose a step-by-step approach for the verification of PIC-MCC codes in a 2D-3V electrostatic setup. The criteria for the test cases are (i) they should highlight possible implementation errors by testing the modules separately, whenever possible (ii) they should be free from physical instabilities to avoid chaotic behavior, and (iii) the numerical result should be accompanied by analytical calculations, for confirmation purposes. The seven test cases identified all show excellent agreement between the authors' codes.

Advanced mechanisms and applications of microwave-assisted synthesis of carbon-based materials: a brief review.

The interaction of microwave radiation with carbon-based materials induces rapid, instantaneous heating. When combined with the plasma excitation capabilities of microwaves, this property presents novel avenues for synthesizing carbon-based materials that require high temperatures and catalytic activity. This review investigates the response of carbon-based materials to microwave radiation, analyzes the dielectric loss mechanism responsible for heat generation, and details the microwave plasma excitation mechanisms employed in the synthesis and processing of carbon-based materials. Furthermore, the structure of microwave reactors is discussed, followed by a discussion of their diverse applications in both laboratory and industrial settings. Lastly, the review addresses the challenges associated with the practical implementation of microwave technology and explores future development prospects, with a particular focus on the application of microwaves in carbon-based material synthesis.

Real‐Time Reverse Transcription Multienzyme Isothermal Rapid Amplification for Rapid Detection of African Horse Sickness Virus

African horse sickness (AHS) is an acute infectious disease of equids caused by the AHS virus (AHSV), which can cause up to 90% mortality in naive horses. Reliable and rapid diagnosis is crucial for the surveillance and control of AHSV. As one of the AHSV detection methods recommended by World Organization for Animal Health (WOAH), the RT‐qPCR assay has the drawbacks such as complex operation, expensive instruments, and long detecting time, which limit its application in simple laboratories or outdoors. In this study, a real‐time reverse transcription multienzyme isothermal rapid amplification (RT‐MIRA) assay was established to detect AHSV. Primers and exo‐probes were designed, synthesized, and screened based on the conserved regions of the AHSV Seg-7 gene. A series of experiments were conducted to evaluate the performances of the established real‐time RT‐MIRA for detecting AHSV. The valid testing results showed that this method was highly specific for the detection of AHSV, without exhibiting any cross‐reactivity towards other equine viruses or other Orbivirus; its limit of detection (LOD) was 10 copies/μL, which was consistent with that of RT‐qPCR, meaning it had good sensitivity for detecting AHSV. Furthermore, the real‐time RT‐MIRA for AHSV performed good repeatability, and its standard curve exhibited good linearity with a correlation coefficient of R2 = 0.9898, which indicated that the established method could be used for the quantitative detection of ASHV. As no AHS infection cases have been reported in China, 120 simulated clinical samples were tested by the real‐time RT‐MIRA and RT‐qPCR for AHSV, which results showed there was a significant correlation between the two assays, with a κ value of 0.966 and an R2 value of 0.9576. Parallel detection of 396 equine blood samples and 1760 Culicoides by this method and the RT‐qPCR showed that all samples were negative for AHSV. Furthermore, the results of the real‐time RT‐MIRA could be judged by naked eyes under a portable equipment with blue light (480 nm). In conclusion, the real‐time RT‐MIRA for AHSV was specific and sensitive and had the advantages of convenient operation, visualization, no need for special equipment, and could be a reliable tool for rapid screening and detection of AHSV in field or border ports.

8th Grade Students' Opinions on 3D Virtual Laboratory Applications

Experimental applications in science education make learning more meaningful, and learning without experimenting cannot be fully absorbed. However, increasing costs, time constraints and risk factors that may occur during the application make hand-made experiment activities difficult. The aim of this study is to examine the effect of the 3D virtual laboratory application prepared for science education on students, unlike traditional plain lecture teaching, and to reveal the opinions of students who are taught with the application. In this context, the research was conducted on 5 8th grade students in Konya province in the 2021-2022 academic year with the 3D virtual laboratory application prepared for the science unit "Matter and Industry". After the research, a semi-structured interview was conducted in which open-ended questions were asked to the students about the applications and the process, and the students' verbal opinions were taken. During the interview, student conversations were recorded on the computer and then transcribed and examined. As a result of the interviews with the students, it was seen that the effects of 3D virtual laboratory applications on students were very positive. In addition, considering cost, time and risk factors, it can be suggested that virtual laboratory applications may be preferred to handmade activities.

DETERMINATION OF THE FLOW RATE AND TEMPERATURE OF THE LIQUID WHEN IT IS FORCED THROUGH THE THROTTLE OPENINGS

The article presents laboratory findings from studies conducted on a specially developed setup for analyzing liquid flow through throttle holes. The liquid flow rate depends on various factors, such as hole diameter, upstream pressure, liquid viscosity, and the channel’s length and shape. As the liquid passes through the throttle, pressure drops, velocity increases, and kinetic energy rises, subsequently converting to thermal energy due to molecular friction. This throttling process raises the liquid’s temperature, making it suitable for heating applications in industrial, laboratory, and heating systems. This throttling process increases the liquid's temperature through molecular friction, making it a practical solution for heating applications across industrial and laboratory systems.

Lactobacilli-Derived Postmetabolites Are Broad-Spectrum Inhibitors of Herpes Viruses In Vitro.

Herpes viruses are highly contagious agents affecting all classes of vertebrates, thus causing serious health, social, and economic losses. Within the One Health concept, novel therapeutics are extensively studied for both veterinary and human control and management of the infection, but the optimal strategy has not been invented yet. Lactic acid bacteria are key components of the microbiome that are known to play a protective role against pathogens as one of the proposed mechanisms involves compounds released from their metabolic activity. Previously, we reported the anti-herpes effect of postmetabolites isolated from Lactobacilli, and here, we confirm the inhibitory properties of another nine products against the phylogenetically distant human Herpes simplex virus-1 (HSV-1) and fish Koi Herpes virus (KHV) in cell cultures. Cytotoxicity, cytopathic effect inhibition, virucidal effect, the influence on the adsorption stage of the virus to the cells, as well as the protective effect of the postmetabolites on healthy cells were evaluated. The inhibitory effect was more pronounced against HSV-1 than against KHV at all studied viral cycle stages. Regarding the intracellular replicative steps, samples S7, S8, and S9 (Mix group) isolated from Ligilactobacillus salivarius (vaginal strain) demonstrated the most distinct effect with calculated selective indices (SIs) in the range between 69.4 and 77.8 against HSV-1, and from 62.2 to 68.4 against KHV. Bioactive metabolites from various LAB species significantly inhibit extracellular HSV-1 and, to a lesser extent, KHV virions. The blockage of viral adsorption to the host cells was remarkable, as recorded by a decrease in the viral titer with Δlg ≥ 5 in the Mix group for both herpes viruses. The remaining postmetabolites also significantly inhibited viral adsorption to varying degrees with Δlg ≥ 3. Most metabolites also exerted a protective effect on healthy MDBK and CCB cells to subsequent experimental viral infection. Our results reveal new horizons for the application of LAB and their postbiotic products in the prevention and treatment of herpes diseases.

The Validity and Reliability of the My Jump Lab App for the Measurement of Vertical Jump Performance Using Artificial Intelligence.

The countermovement jump (CMJ) is a widely used test to assess lower body neuromuscular performance. This study aims to analyze the validity and reliability of an iOS application using artificial intelligence to measure CMJ height, force, velocity, and power in unloaded and loaded conditions. Twelve physically active participants performed 12 CMJs with external loads ranging from 0% to 70% of their body mass while being simultaneously monitored with a pair of force platforms and the My Jump Lab application. The scores for jump height, mean propulsive force, velocity, and power between devices were compared for validity and reliability purposes. The force platform and the application showed a high association (r > 0.91, p < 0.05) for measuring CMJ height, force, velocity, and power. Small and no statistically significant differences (p < 0.05) were observed in most loading conditions. Both instruments showed high reliability (Cronbach's α > 0.93, Coefficient of variation < 6%) for measuring the different trials performed by each participant. The My Jump Lab application was shown to be valid and reliable for measuring CMJ height, force, velocity, and power in both loaded and unloaded jumps, eliminating the problems associated with the cost and portability of force plates for daily practice.

Assessing Habitat Suitability for the Invasive Species Lantana camara on Bali Island: A Model Using the Biodiversity and Climate Change Virtual Laboratory (BCCVL)

Indonesia, known for its high biodiversity, is threatened due to alien plants that invade local plant species in forest areas. West Bali National Park is overgrown with invasive exotic plants, such as Lantana camara L., known locally as the kembang telek. The research aims to predict the distribution of L. camara using species distribution models (SDMs) and analysis variable contribution in the model featured in the biodiversity climate change virtual laboratory (BCCVL) application. L. camara distribution prediction model in Bali used the Bioclim data input by identifying areas of low, medium, and high habitat suitability. Central mountainous regions, including parts of Buleleng, Jembrana, Bangli, Karangasem, and Tabanan, show the highest suitability. Response curves demonstrated the correlation between climate variables and occurrence probability, highlighting the specific condition of rainfall and temperature ranges favoring Lantana's growth. The model showed a reliable AUC value of 0.89, indicating realibility. Potential improvements through additional environmental parameters were suggested. While L. camara has some potential benefits as a medicinal plant in Balinese culture, its invasive nature poses significant threats to native ecosystems. The predictive map offers valuable insights for authorities to implement initiative-taking strategies for preventing and controlling Lantanas spread in vulnerable areas of Bali.

Introduction to Generative Artificial Intelligence: Contextualizing the Future.

Generative artificial intelligence (GAI) is a promising new technology with the potential to transform communication and workflows in health care and pathology. Although new technologies offer advantages, they also come with risks that users, particularly early adopters, must recognize. Given the fast pace of GAI developments, pathologists may find it challenging to stay current with the terminology, technical underpinnings, and latest advancements. Building this knowledge base will enable pathologists to grasp the potential risks and impacts that GAI may have on the future practice of pathology. To present key elements of GAI development, evaluation, and implementation in a way that is accessible to pathologists and relevant to laboratory applications. Information was gathered from recent studies and reviews from PubMed and arXiv. GAI offers many potential benefits for practicing pathologists. However, the use of GAI in clinical practice requires rigorous oversight and continuous refinement to fully realize its potential and mitigate inherent risks. The performance of GAI is highly dependent on the quality and diversity of the training and fine-tuning data, which can also propagate biases if not carefully managed. Ethical concerns, particularly regarding patient privacy and autonomy, must be addressed to ensure responsible use. By harnessing these emergent technologies, pathologists will be well placed to continue forward as leaders in diagnostic medicine.

Design and Implementation of a Cost-Effective, Safe, and Precise Lean-Rich Generating System for NOX Storage Reduction Catalyst Evaluation: Performance Analysis, Statistical Modeling, and Multiple Response Optimization – A Guideline for Future Research and Application

Mixing is a critical factor in chemical reaction engineering, particularly in the development of new catalysts for pollutant removal, such as NOx storage reduction catalysts. Comprehensive performance evaluation in laboratory experiments requires high-quality test gases. Several techniques have been developed for generating these gases, each with specific advantages and limitations. This research presents a simple, safe, and cost-effective gas generation system for laboratory applications, including evaluating adsorbents and catalysts, particularly NOx storage reduction catalysts, and for toxicological studies using precise dynamic methods like gas stream mixing and evaporation. Components of the dynamic system—including gas cylinders, connections, mixing chambers, rotameters, the quartz reactor with preheating chamber, bubbler systems, and tubular heaters—are comprehensively described. Statistical modeling and optimization were employed to determine the optimal operating conditions. The optimal conditions were identified as NO (924 ppm), O₂ (15%), CO (9999 ppm), and a space velocity of 105,921 h⁻¹. Additionally, the system's ability to generate various mixtures of gases (NO, O₂, and CO) and vapors (toluene and water) was assessed. The system was further evaluated under fan-on and fan-off modes to assess its performance under varying turbulent conditions. A detailed analysis was performed to determine the relative errors, time to reach steady-state conditions, and actual concentrations produced under different expected concentrations (NO: 100-200 ppm, O₂: 3-15%, CO: 500-10000 ppm, toluene: 64-8999 ppm, relative humidity: 0.14-22.69%), space velocity (70,000-140,000 h⁻¹), bubbler flow rates (10-600 mL/min), and saturator temperatures (5-20°C). Fundamental equations for calculating conversion, selectivity, and yield of a component of interest, carbon-messing, and carbon balance in the mixture are also provided.

A practical, reproducible laboratory method for assessing soil aggregate stability

AbstractSoil aggregate stability is an important soil physical measurement that is closely related to a range of soil health functions. It is defined by its analytical method and often within‐method variability and inter‐method comparability have not been addressed and quantified. The current Natural Resources Conservation Service Kellogg Soil Survey Laboratory (KSSL) method for analyzing aggregate stability uses non‐standardized equipment and hand‐sieving techniques and is not easily scalable. The objective of this study was to evaluate and modify an alternative method that uses a single sieve mechanical wet sieving apparatus (MWS method) to produce results comparable to the current KSSL method and evaluate another alternative method that uses multiple sieves in a custom‐fabricated Yoder‐type apparatus. The two methods were evaluated for efficiency, repeatability, and scalability. The MWS method uses standardized equipment and methods, which should be scalable and reproducible in different laboratories. Sample preparation, pretreatment, and sieving parameters of the MWS method were adjusted to produce analytical results which most closely matched the KSSL method. Repeated analysis of soil sample standards showed that within‐method variability of the MWS method was slightly less than in the KSSL method. In a comparison of 90 samples of widely varying properties, Lin's concordance correlation coefficient was 0.927, indicating a moderate strength of agreement between the MWS method and KSSL method. Results from a modified Yoder method were not comparable to the KSSL method, and the greater time requirements, procedural complexity, and large equipment footprint were identified as practical limitations for use in large‐scale laboratory applications.

Gain and bandwidth enhancement using superstrate loaded 2×2 circular-array antenna for X-Band and RADAR applications

ABSTRACT This article demonstrates the fabrication, and measurements of a corporate offset-fed 2 × 2 array electromagnetically coupled patch (EMCP) circular-antenna based on the Fabry-Perot cavity principle. Single element antenna has a low gain of 6.28 dBi and is enhanced to 13.45dBi by loading the array with a superstrate. The antenna parameters −10 dB fractional bandwidth (FBW) and gain are improved by an air gap with 4-stacked circular patches and 4 stubs in the proposed design. The peak gain of the 2 × 2 array without superstrate was 8.88 dBi at 8.19 GHz, which is enhanced to 13.82 dBi at 9.55 GHz by parasitic loading and superstrate. The FBW of the proposed array antenna was enhanced by arranging four stubs between the 4-circles in the superstrate structure. The −10 dB FBW without stubs was 24.82% (7.62–9.73 GHz) and with stubs it became 38.47% (7.73–11.0 GHz). Adjustment of the height of the superstrate at 2.0 mm not only enhanced the gain and bandwidth but also advancement in the unidirectional radiation patterns. The array is prototyped is measured to validate the reflection coefficients and radiation characteristics and they found an excellent match with simulated results. The suggested array is most suitable for energy launchers in transitions, RADAR, military, satellite, X-band communications, and microwave laboratory applications.