Gain Pattern Research Articles

Miniaturized circularly polarized wearable array antenna for medical device applications

Antenna miniaturization is essential for healthcare applications, and numerous studies have tackled the challenge of presenting miniaturized, reliable designs while maintaining performance. This paper presents a small circularly polarized (CP) sequential wearable array antenna with overall dimensions of only 110 mm × 95 mm × 1.8 mm. It comprises four novel designs of circular-shaped elements arranged sequentially in an array configuration measured only 24 mm×24 mm×1 mm. It is fed by a separate cascade feeding network incorporating a single rat-race and two branch-line couplers. The antenna is designed for medical device applications within the 2.4 GHz Industrial Scientific Medical (ISM) frequency band. The proposed design is fabricated and experimentally tested, demonstrating wide impedance bandwidths of 21.24% (2.2–2.72 GHz) and an Axial Ratio (AR) bandwidth (AR < 3 dB) covering the entire 2.4 GHz ISM frequency band. At 2.43 GHz, the antenna achieves a gain of -14.9 dBi. Both simulation and experimental results confirm excellent performance in impedance matching, gain pattern, and circular polarization, making it promising for wearable wireless communication in medical applications. The link margin was calculated, and the specific absorption rate of the antenna was analyzed, the result revealing that it aligns with the safety limits of IEEE C95.1-1999 standards.

The deleterious effect of orally administered aqueous extract of &lt;i&gt;Acalypha wilkesiana&lt;/i&gt; (Red Acalypha) on female reproductive organs in Sprague Dawley rats

Acalypha wilkesiana is a herbaceous plant that has been traditionally used to treat and/or manage a variety of illnesses, including respiratory issues, diabetes, jaundice, hypertension, fever, diarrhea, and inflammation of the liver. The effects of taking Acalypha wilkesiana orally on the uterus and ovaries were examined in this study. Twenty (20) adult female Sprague-Dawley rats (165±20g) were purchased and given a two-week period to get used to the laboratory environment. Aqueous extract of Acalypha wilkesiana was given orally for four weeks at concentrations of 0, 100, 200, and 400 mg/kg of BW following acclimatization. Groups A-D provided as the control, low, medium, and high doses, respectively. The rats' weight gain and behavioral patterns were periodically examined. Following their euthanasia, blood was drawn via the ocular sinuses to measure hormonal parameters, and the uterus and ovaries were exercised to examine histology and oxidative stress markers. Significantly lower levels of FSH, LH, estrogen, and progesterone were observed in the treatment groups, while significantly lower levels of SOD and CAT and higher levels of MDA were observed. In both the 40 and 80 mg/kg groups, histological sections of the ovaries and uterus revealed vascular congestion in the ovaries and moderate to severe damage within the uteri. The findings demonstrated that long-term use of Acalypha wilkesiana increased levels of oxidative stress, altered hormone levels, and negatively affected the histoarchitecture of the uterus and ovaries.

A low-profile dual-band millimeter wave patch antenna for high-speed wearable and biomedical applications

This paper presents a low-profile, dual-band patch antenna designed for the mmWave frequency range. The antenna, fed by a microstrip line, is fabricated on a thin, flexible substrate (Rogers 3003) with dimensions of 12 × 3 × 0.25 mm³. The radiating patch includes two circular slots, enabling dual-band operation at 28 GHz and 38 GHz. Key performance metrics, including realized gain, efficiency, and radiation patterns, are analyzed across these frequency bands, with measured results compared to simulations performed using CST Microwave Studio. Furthermore, the antenna's parameters are evaluated in a bent configuration, demonstrating its suitability for wearable applications. The study also assesses the antenna's impact on human tissues, calculating average SAR values of 0.914 W/Kg and 1.140 W/Kg at 28 GHz, and 0.720 W/Kg and 1.360 W/Kg at 38 GHz, for 1/10 gm tissue. Furthermore, the link margin is calculated to verify effective wireless communication over distances up to 80 m. This antenna effectively covers key millimeter-wave frequency bands, making it ideal for high-speed 5 G and biomedical applications.

The Current High Bird Colonisation Rate in a Major Mediterranean Island is Consistent With a More Intense Past Defaunation Compared to Nearby Mainland

ABSTRACTAimWe expand here previous own biogeographic work on the determinants of avian colonisation of a major land‐bridge Mediterranean island. So far we have explained mechanistically the high current rate of colonisation of the island which proceeds by overflow of mainland species with growing population trends and with prior experience as winter visitors. However, here we focus on the historical factors that have led to such a high colonisation rate.LocationMajorca Island and a nearby Iberian mainland coastal region with equivalent characteristics (Alicante province).Time PeriodTwenty‐five years (1991–2015).Major Taxa StudiedBirds.MethodsWe compared the pattern of species gain and loss in Majorca and Alicante during the study period.ResultsWe found that while Alicante only gained eight new species and lost one, Majorca lost none and gained 21 species as breeders (odds ratio 2.6). The process of species gains in 5‐year periods since 1991 showed a nonlinear pattern in both regions, with an abrupt decline in Alicante starting in 2006–2010 and final stagnation during 2011–2015, but just a smooth and recent pattern of slowdown in Majorca (2011–2015 on). Taxonomic diversity of colonising species at the family level, as well as habitat of colonisation, were quite similar between regions, but larger body size species were more common in Majorca.Main ConclusionsWe conclude that current differential colonisation rates between both regions are consistent with a more intense past defaunation of the resource‐poor region (Majorca) prior to modern rural flight that happened simultaneously in both regions. While Alicante could be approaching a theoretical carrying capacity in the number of species, Majorca is farther from it. We predict that the island will continue gaining species in the next few decades. Worldwide, further research on comparing wildlife recovery rates between regions with differential intensity of past wildlife defaunation is badly needed to understand biodiversity recovery processes.

Overview of Vivaldi Antenna Selection for Through-Wall Radar Applications

This paper analyzes broadband antennas, with a special focus on Vivaldi antennas, for their suitability for through-wall radar applications. It assesses various antenna designs, emphasizing high gain, wide impedance bandwidth, and effective wall penetration capabilities. Vivaldi antennas are superior due to their broad bandwidth, high gain, and directional radiation patterns. This study further explores structural optimizations, feeding techniques, and performance enhancement strategies to refine Vivaldi antenna designs for through-wall radar systems. Through a comparative analysis and technical evaluation, this paper highlights Vivaldi antennas’ potential for improving through-wall radar systems’ imaging and sensing capabilities. This presents a pathway for future ultra-wideband advancements.

Weight gain in pregnancy and impact of obesity on the obstetric outcome: A retrospective study in a secondary care hospital in South India

ABSTRACT Objective: To evaluate the patterns of weight gain in pregnancy and the outcomes of pregnancy in overweight and obese mothers. Materials and Methods: A retrospective cohort study was performed on 1,352 mothers between October 2020 and August 2021. All pregnant women who presented for antenatal checkups from 20 weeks or earlier, with a singleton pregnancy, were included in the study. Details such as comorbidities, total duration of labor, complications during labor, and neonatal complications were included. Results: At the first antenatal visit, 16% of mothers were underweight, 51% of mothers were normal weight, and 33% of mothers were overweight or obese. Women with poor weight gain were two times more prone to give birth to a child with low birth weight than those with adequate weight gain. Excess weight gain in pregnancy in women with a normal body mass index (BMI) had an association with the development of pre-eclampsia. The odds of overweight/obese pregnant women developing gestational diabetes mellitus (GDM) were 2.1 times higher than in pregnant women with normal BMI. The odds of pregnant overweight/obese women undergoing cesarean section were 1.6 times higher than in pregnant women with normal BMI. Conclusion: Overweight/obese pregnant women had increased odds of developing GDM and undergoing a cesarean section. Excess weight gain was also seen in overweight/obese women. It is therefore important for physicians to educate women on acceptable weight gain during their pregnancy.

A Compact and Flexible Monopole Antenna with Controllable Bandwidth

In this paper, a compact antenna with flexible and controllable bandwidth characteristics is proposed. To ensure wide coverage along with an omnidirectional radiation pattern, a monopole structure was utilized as the primary radiating element of the proposed antenna. The monopole was fed using a coplanar waveguide technique to achieve a single-layer design. To alter the operating bandwidth, defined by a reflection coefficient of less than -10 dB, a single stub was directly connected to the feeding transmission line. By controlling the stub's length, matching performance in the high-frequency range was found to undergo significant degradation, indicating that the operating bandwidth could be controlled. Furthermore, for validation, two antenna prototypes were fabricated and measured under different circumstances. In the unbending mode, the design without the stub achieved a wideband of 51.6%, while the other design with the stub exhibited a narrower band of about 19.6%. Additionally, the antennas worked efficiently when operating in bending mode. It is also worth noting that the antenna gain and radiation pattern remained stable across the entire operating bandwidth.

H-Shape Microstrip Patch Antenna: Design, Simulation, and Characterization

This paper presents the design, simulation, and characterization of an H-shape microstrip patch antenna intended for high-frequency applications. The proposed antenna is modeled using Computer Simulation Technology (CST) Microwave Studio, a powerful tool for simulating electromagnetic fields and optimizing antenna parameters. The H-shaped configuration is chosen to enhance the antenna's radiation characteristics, bandwidth, and gain, while minimizing size and surface wave effects. The design process involves parameter optimization, including substrate selection, patch dimensions, and feed point configuration, to achieve superior performance. Detailed simulation results are presented, demonstrating the antenna's return loss, VSWR, gain, and radiation pattern. The antenna operates efficiently with stable resonance, offering low return loss and high radiation efficiency. The simulation results confirm that the H-shape microstrip patch antenna is well-suited for various wireless communication systems, showing potential for integration in compact, high-performance devices. This paper serves as a step towards further optimization and practical implementation of H-shape microstrip antennas in advanced RF systems.

Predicted future range expansion of a small carnivore: swift fox in North America

ContextSmall carnivores are declining globally due to a complex suite of threats. Conservation of these species requires an understanding of their distributions and potential responses to future land-use and climate change.ObjectivesWe modelled species-environment relationships of swift fox (Vulpes velox), a species of concern across their range. We developed spatial projections of current and future distribution to aid in conservation planning.MethodsWe assembled swift fox occurrence data from managers and community science sources to develop ensemble distribution models. In addition to landscape and climatic predictors, we developed a model of red fox distribution to represent effects of competition. We forecasted spatial predictions into the year 2070 under two climate change scenarios representing high (SSP 5–8.5) and low (SSP 1–2.6) emissions scenarios.ResultsPercent cover by grassland, mean annual precipitation, and minimum temperature of the coldest quarter were the three most important variables for swift fox distribution. Current suitable habitat for swift fox extends across 16 North American states and provinces. Future projections of swift fox distribution suggest an overall increase in area of swift fox suitable habitat under both emissions scenarios of > 56.9%, though patterns of gain and loss vary spatially.ConclusionsThe expansion of suitable habitat in future scenarios reflects swift fox adaptability to multiple land uses in a period following multi-organizational conservation efforts. Our spatial projections can be used in conservation planning and can serve as a case study of a small carnivore species likely to recover under future change scenarios provided that threats are addressed and landscape-scale conservation efforts continue.

Variability in rat weight gain during development.

The rat is one of the most employed animal models in biomedicine. Traditionally, weight gain has been utilized to gauge development and compare across species. Numerous studies have conducted longitudinal analyses of rat development, with emphasis on weight gain analysis. Given the high variability in these patterns, experimental data from a single laboratory may not be reliable for generalized estimation. This study aimed to analyze the effect of different factors on the pattern of weight gain during rat development. A literature survey was conducted to compile a database comprising nearly 300 data points of age and weight from 15 longitudinal studies. The database comprised both pre- and postnatal data. Utilizing the Gompertz equation, the data was analyzed to formulate a comprehensive model describing rat development. Differences in growth patterns became increasingly evident at later developmental stages, when significant differences in the maximum asymptote between sexes and strains were reached.

The effect of kangaroo mother care on weight gain pattern in low birth weight premature babies at a tertiary care hospital

Abstract Background: Premature infants are at high risk of death. They need specialized incubatory care which is very costly and requires skilled workforce and specialized equipment. Kangaroo mother care (KMC) does the same job with no cost and does not require set-up as for incubatory care. It can prevent mortality and morbidity and also promotes bonding between mother and child. Objective: The objective of the study was to study the effect of KMC on weight gain pattern in low birth weight premature babies compared to incubatory care. Materials and Methods: A nonrandomized experimental study was carried out among 200 premature infants. They were divided into two groups of 100 each. Randomization was not done. One group was given KMC. The second group was given incubatory care. The weight of babies in both groups was measured with a digital weighing machine. Both groups were followed till the 9th day with a follow-up frequency of days – 1, 3, 5, 7, and 9. On each follow-up day, weight was recorded. Results: Both groups were comparable for gender, birth weight, and gestational age. In the KMC group, there was significant weight gain on day 2 compared to day 1 and on day 7 compared to day 6. But weight gain on day 3 compared to day 2 and on day 9 compared to day 8 was not significant. In the non-KMC group, there was significant weight gain on day 3 compared to day 2 and on day 9 compared to day 8. From 2nd day to 9th day, each day weight gain in the KMC group was higher compared to the non-KMC group. Conclusion: We conclude that the KMC significantly improved weight gain on a daily basis. The KMC also improved the weight gain compared to that of the non-KMC group. Hence, we recommend to create awareness among the community at all health-care levels and among health-care professionals on the benefits of KMC/the importance of KMC.

Analysis of the Borreliaceae Pangenome Reveals a Distinct Genomic Architecture Conserved Across Phylogenetic Scales.

The family Borreliaceae contains arthropod-borne spirochetes that cause two widespread human diseases, Lyme disease and relapsing fever. Lyme disease is a subacute, progressive illness with variable stage and tissue manifestations. Relapsing fever is an acute febrile illness with prominent bacteremia that may recur and disseminate, particularly to the nervous system. Clinical heterogeneity is a hallmark of both diseases. While human clinical manifestations are influenced by a wide variety of factors, including immune status and host genetic susceptibility, there is evidence that Borreliaceae microbial factors influence the clinical manifestations of human disease caused by this family of spirochetes. Despite these associations, the spirochete genes that influence the severity and manifestations of human disease are, for the most part, unknown. Recent work has identified lineage-specific expansions of lipoproteome-rich accessory genome elements in virulent clones of Borrelia burgdorferi. Using publicly available genome assemblies, it is shown that all Borreliaceae lineages for which sufficient sequence data are available harbor a similar pattern of strongly structured, lineage-specific expansions in their accessory genomes, particularly among lipoproteins, and that this pattern holds across phylogenetic scales including genera, species, and genotypes. The relationships among pangenome elements suggest that infrequent episodes of marked genomic change followed by clonal expansion in geographically and enzootically structured populations may account for the unique lineage structure of Borreliaceae. This analysis informs future genotype-phenotype studies among Borreliaceae and lays a foundation for studies of individual gene function guided by phylogenetic patterns of conservation, diversification, gain, and/or loss.

The velocity-space signature of transit-time damping

Transit-time damping (TTD) is a process in which the magnetic mirror force – induced by the parallel gradient of magnetic field strength – interacts with resonant plasma particles in a time-varying magnetic field, leading to the collisionless damping of electromagnetic waves and the resulting energization of those particles through the perpendicular component of the electric field, $E_\perp$ . In this study, we utilize the recently developed field–particle correlation technique to analyse gyrokinetic simulation data. This method enables the identification of the velocity-space structure of the TTD energy transfer rate between waves and particles during the damping of plasma turbulence. Our analysis reveals a unique bipolar pattern of energy transfer in the velocity-space characteristic of TTD. By identifying this pattern, we provide clear evidence of TTD's significant role in the damping of strong plasma turbulence. Additionally, we compare the TTD signature with that of Landau damping (LD). Although they both produce a bipolar pattern of phase-space energy density loss and gain about the parallel resonant velocity of the Alfvénic waves, they are mediated by different forces and exhibit different behaviours as the perpendicular velocity $v_\perp \to 0$ . We also explore how the dominant damping mechanism varies with ion plasma beta $\beta _i$ , showing that TTD dominates over LD for $\beta _i &gt; 1$ . This work deepens our understanding of the role of TTD in the damping of weakly collisional plasma turbulence and paves the way to seek the signature of TTD using in situ spacecraft observations of turbulence in space plasmas.

Evolutionary Dynamics of Satellite DNA Repeats across the Tettigoniidae Family: Insights from Genomic Analysis.

Satellite DNA repeats are repetitive DNA sequences found in eukaryotic genomes, typically consisting of short DNA motifs repeated in tandem arrays. Despite the vast body of literature on satellite DNA repeats in other taxa, investigations specifically targeting Tettigoniidae remain conspicuously absent. Our study aims to fill a critical gap in our understanding of satellitome evolutionary processes shaping Tettigoniidae genomes. Repeatome analysis revealed that the Meconema thalassinum genome comprises 92%, and Phryganogryllacris superangulata had the lowest value of 34%, with an average of 67% in other Tettigoniidae species. The analysis reveals significant variation in the number of satellite DNA repeats across species of the Tettigoniidae family, with M. thalassinum exhibiting the highest count, 246, reported in insects to date and the lowest count, 10, in Pholidoptera griseoptera. Ruspolia dubia and Ruspolia yunnana, which are congeneric species, showcase distinct counts of 104 and 84 families, respectively. Satellite DNA repeats in R. dubia exhibit the highest abundance, constituting 17.2% of the total genome, while the lowest abundance was reported in P. griseoptera, at 5.65%. The genome size correlates weakly with the satellite DNA family count (rs = 0.42, p = 0.29), but a strong correlation exists between satellite abundance and family number (rs = 0.73, p = 0.03). Moreover, the analysis of satellite DNA gain and loss patterns provides insights into the amplification and homogenization of satellite DNA families within the genome, with species-specific repeats exhibiting a positive trend toward amplification. The chromosomal distribution in M. thalassinum displayed that the highest accumulation was observed on Chr12, Chr01, and Chr04, constituting 17.79%, 17.4%, and 17.22% of the total chromosome size, respectively. The chromosome-specific propagation of satellite DNA families was evident, with MthSat01 solely on chromosome 1 and MthSat170 on chromosome 2, sharing 1.64% and 2.33%. The observed conservation and variations in satellite DNA number and abundances, along with distinct patterns of gain and loss, indicate the influence of potentially diverse evolutionary processes shaping the genomic landscape of these insects, which requires further investigation. Furthermore, the differential accumulation of satellite DNA on specific chromosomes implies that potential chromosome-specific functions or structural features influence the retention and proliferation of satellite sequences.

Dual Polarized Reconfigurable MIMO Antenna for Multi-Band Functioning

This work presents the development, fabrication, and measurements of a new Ultra-wideband sensing multi-band frequency reconfigurable MIMO Active Integrated Antenna (AIA). The proposed antenna has two frequency reconfigured (switching element PIN diodes) planar inverted F-shape antennas (PIFA) using meandered line (ML) structures and a Mirror-shape UWB sensing antenna. The Mirror-shape UWB sensing antenna is integrated with 2x2 MIMO Meandered line PIFA elements for spectrum sensing. PIN diodes (BAR 6402V) are used to provide all digital switching on/off combination modes to attain frequency reconfigurability. Varactor diodes are used for tuning over the wide band. The proposed antenna senses a wide frequency band from 0.5GHz-3GHz and provides frequency reconfigurability over the five bands based on BARP6402V switching modes (0.78GHz-1.01GHz, 1.34GHz-1.62GHz, 1.85GHz-2.18GHz, 2.44GHz-2.67GHz, and 2.76GHz-2.80GHz). All the measured resultant performance parameters are compared with simulation software results. The antenna system is fabricated on an FR4 substrate of size 120mmX65mmX1.6mm. The proposed method used to achieve frequency reconfigurable ultra-wideband MIMO provides a high gain 6.15dBi at a frequency of 1.75GHz. The research also analyzed and investigated all 2x2 MIMO resultant parameters like Total Active Reflection Coefficient (TARC), Isolation coefficient, Envelope correlation Coefficients (ECC), Diversity Gain (DG), Multiplexing efficiency, etc. The proposed antenna is applicable for sensing, communication, &amp; UWB sensing, and cognitive radio (CR) applications since it exhibits stable excellent gain and Omni-directional radiation pattern over the desired bands. Because of its reconfigurable nature, the same antenna also supports use in multiple general-purpose applications like GPS tracing, LTE, UMTS, GSM1800, rescue operation, Wi-Fi/Bluetooth/ISM/WLAN, CDMA, etc applications.

Unraveling resilience amidst degradation: Recurring loss of freshwater marshes in the Paraná River Delta, Argentina

Wetland ecosystems have experienced several ecological and hydrological impacts in recent decades determined by human activities and natural disturbances. The Lower Delta of the Paraná River, one of the most important wetland ecosystems of South America, has seen significant losses in both the structural and functional components of wetland vegetation. These losses promoted not only a widespread conversion of freshwater marshes into grasslands between 1997 and 2013, but also a decline in ecosystem functional diversity between 2001 and 2015. These processes manifested as abrupt shifts in long-term vegetation dynamics, a distorted, transient, spatially heterogeneous relationship with the hydrologic regime, and altered plant communities. However, recent field observations (2015–2023) have partially challenged previous findings and assumptions. Thus, we ask whether previously observed wetland losses are part of a long-term periodic process, rather than a permanent change. To address this question, we studied land use and land cover conversions through an object-based supervised classification of yearly Landsat composites between 1985 and 2023, trained on 935 ground-truth points. To study the spatial and temporal patterns of wetland gain and loss, we implemented an Intensity Analysis (IA), as well as analyses that capture frequency-specific variations and identify significant shifts in linear trends. We produced a total of 39 land cover maps. The IA revealed non-stationarity at all levels of analysis: interval, category, and transition. The study area exhibited resilient patterns through significant and increasingly short-term, periodic dynamics guiding the gain and loss of freshwater marshes. On the opposite, long-term, negative trends depicted an absolute, sustained loss. These contrasting patterns suggest that despite experiencing absolute loss and degradation, wetland ecosystems thrive by exhibiting transient recovery or adaptation mechanisms. Our study unraveled the complexity of wetland ecosystem dynamics, emphasizing how resilience and degradation interplay in the context of land use intensification.

Trajectories of BMI before and after diagnosis of type 2 diabetes in a real-world population.

Few studies have examined the clinical characteristics associated with changes in weight before and after diagnosis of type 2 diabetes. Using a large real-world cohort, we derived trajectories of BMI before and after diabetes diagnosis, and examined the clinical characteristics associated with these trajectories, including assessing the impact of pre-diagnosis weight change on post-diagnosis weight change. We performed an observational cohort study using electronic medical records from individuals in the Scottish Care Information Diabetes Collaboration database. Two trajectories were calculated, based on observed BMI measurements between 3 years and 6 months before diagnosis and between 1 and 5 years after diagnosis. In the post-diagnosis trajectory, each BMI measurement was time-dependently adjusted for the effects of diabetes medications and HbA1c change. A total of 2736 individuals were included in the study. There was a pattern of pre-diagnosis weight gain, with 1944 individuals (71%) gaining weight overall, and 875 (32%) gaining more than 0.5 kg/m2 per year. This was followed by a pattern of weight loss after diagnosis, with 1722 individuals (63%) losing weight. Younger age and greater social deprivation were associated with increased weight gain before diagnosis. Pre-diagnosis weight change was unrelated to post-diagnosis weight change, but post-diagnosis weight loss was associated with older age, female sex, higher BMI, higher HbA1c and weight gain during the peri-diagnosis period. When considering the peri-diagnostic period (defined as from 6 months before to 12 months after diagnosis), we identified 986 (36%) individuals who had a high HbA1c at diagnosis but who lost weight rapidly and were most aggressively treated at 1 year; this subgroup had the best glycaemic control at 5 years. Average weight increases before diagnosis and decreases after diagnosis; however, there were significant differences across the population in terms of weight changes. Younger individuals gained weight pre-diagnosis, but, in older individuals, type 2 diabetes is less associated with weight gain, consistent with other drivers for diabetes aetiology in older adults. We have identified a substantial group of individuals who have a rapid deterioration in glycaemic control, together with weight loss, around the time of diagnosis, and who subsequently stabilise, suggesting that a high HbA1c at diagnosis is not inevitably associated with a poor outcome and may be driven by reversible glucose toxicity.

Design of Y-shaped tri-band rectangular slot DGS patch antenna at sub-6 GHz frequency range for 5G communication

This paper presents the design and development of a rectangular slot DGS patch antenna fed by a microstrip line, designed to operate across three distinct frequency bands at 4.0 GHz, 4.9 GHz, and 5.5 GHz for 5G wireless communication applications. The antenna design outlined in this study is implemented on a Fr-4 substrate with dimensions measuring 50.5 × 41.12 × 1.5 mm3. The antenna gains at three frequency bands are 2.69 dBi, 7.27 dBi, and 11.37 dBi having impedance bandwidths of 9%, 8.9%, and 5.1%, respectively. The attained bandwidths are 356 MHz, 443 MHz, and 287 MHz for the respective frequency bands. The radiation efficiencies of the proposed antenna are 90%, 82%, and 79% of the three respective frequencies. Antenna 1 in this study exhibits single-band behavior, effectively covering the single frequency band which is 5.5 GHz (5.3578–5.9519 GHz) 5G unlicensed band 5-GHz WLAN IEEE 802.11a frequency. On the other hand, Antenna 2 demonstrates dual-band characteristics spanning the S-band 3.7 GHz (3.5619–3.8544 GHz) and C-band range 5.1 GHz (4.8496–5.2008 GHz) suitable for mid-band 5G applications. Antenna 3 proposed antenna exhibits a tri-band functionality within the C-band spectrum. The results highlight multiple-band operation, consistent high gain, high directivity, and favorable directional radiation patterns.

Compact Ultra Wide band Modified Circular Robo type Antenna for C – V2X application

This document focuses on the Ultra-Wideband Modified Circular Robo structure Antenna (UWCRSA) with partial ground for the sub-7 GHz band (4.17 GHz to 7 GHz). The overall geometry of the proposed antenna is 12×18×0.8 mm3. The designed structure is obtained by placing a simple modified circular robotic structure patch with dielectric constant (ɛr) and dissipation factor (tanδ) of 4.4 and 0.02, respectively, on the FR4 substrate. In this document, we examine the design technique, complexity, overall geometric parameters, substrate used, feed technique and performance analysis of the proposed antenna. The semi-grounded radiating patch design is primarily suitable for cellular vehicle applications and anything below 7 GHz (C – V2X) (IEEE 802.11p standard) and WIFI enhanced 3rd version (IEEE 802.11ac standard). Simulation results for the proposed antenna were generated with a Radio Frequency Structure Simulator (HFSS) and measurements were obtained with a Rohde and Schwarz ZNB 20 network analyzer. Simulation and measurement results are measured in terms of S11, VSWR, bandwidth, gain, directivity, efficiency and radiation pattern. Antenna results show good agreement and can be used for C – V2X, WIFI Extended 3rd Version and satellite communications.

Enhanced Gain Dual-Port Compact Printed Meandered Log-Periodic Monopole Array Antenna Design with Octagonal-Ring Shaped FSS for Broadband 28 GHz Applications

In this article, we propose a microstrip-fed printed meandered log-periodic monopole array (PMLPMA), and its dual-port configuration incorporating an octagonal ring frequency selective surface (FSS) layer. The dual-port PMLPMA antenna system has a compact structure with a total dimension of 18.75 × 18.75 mm2 and is designed to operate in the 5G n257 (28 GHz) band. The proposed PMLPMA radiator consists of five log-periodic monopole array elements, and the dual-port antenna system comprises two identical PMLPMAs placed vertically next to each other. Additionally, an octagonal ring-shaped single-layer FSS was implemented on the proposed antenna system to increase the gain across the operational band. Simulation results demonstrate that the dual-port PMLPMA antenna achieves a peak gain of about 3.5 dBi without the FSS layer, while a peak gain of 7.35 dBi is achieved when the FSS layer is augmented on the antenna. Moreover, isolation levels exceeding 30 dB are obtained for both cases between the 26.5–29.5 GHz frequency ranges. To verify the simulation results, the dual-port PMLPMA antenna system, and the octagonal ring-shaped FSS layer are also prototyped. The measurements align closely with the simulations in terms of performance criteria such as gain, bandwidth, and radiation patterns. Thus, the 28 GHz band antenna system exhibits great potential for 5G mobile applications.