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In this letter, a circularly polarized (CP) metal-tolerant tag antenna with long reading distance (RD) is proposed for the ultra-high frequency (UHF) radio-frequency identification (RFID) systems. In order to realize CP radiation and high gain, a cross slot is etched on top patch to provide two orthogonal polarizations, whereas the meandered strip on central copper layer is used to obtain 90o phase difference between adjacent ports. An equivalent circuit model (ECM) is established to better understand the operating mechanism and impedance characteristic. A prototype mounted on a 200 mm 200 mm metal plate has been manufactured and measured to verify the design, and shows an impedance bandwidth of 8 MHz (918-926 MHz) and axial ratio bandwidth of 1.3 MHz (921.6-922.9 MHz). Also, a maximum gain of 2 dBi at 922 MHz and a maximum RD of about 22.4 m have been demonstrated.

In this paper, an attitude independent liquid dielectric resonant antenna (DRA) is proposed. The design combines the technique of hemispherical DRA and the attractive features of liquid antennas (like the gravity correlation fluidity and the transparency) to achieve attitude independent characteristics. The great advantage of this design is to passively control the maximum beam pointing by using the gravity correlation of the liquid, without using any active components. The simulations and measurements are compared to verify the rationality of the antenna performance. A prototype covering the 430 MHz to 448 MHz band (S11 70%) and maximum gain of 4 dBi. The antenna has great potentials in aviation applications.

A low-cost differentially-fed dual-mode multiple-input- multiple-output (MIMO) antenna is proposed for enhanced isolation and filtering response based on the substrate-integrated suspended line (SISL) platform. Stacked patches are placed above the driven patches to realize dual-mode performance and filtering response in the upper band. The stacked patches are widened and notched to enhance the isolation and the filtering response in the lower band. Eight metal stripes are set at both sides of the feed lines to enhance the frequency selectivity further. Compared with the conventional MIMO antenna based on patch elements, the isolation is enhanced by 7.6 dB, and the out-of-band suppression with 17.6 dB is achieved. To verify the design, a prototype is fabricated and measured. In a operating band of 4.8-4.96 GHz, maximum gain of 8.3 dBi, and isolation of 31.3 dB are realized. The filtering response is achieved by three broadside radiation nulls at 4.36 GHz, 4.62 GHz, and 5.08 GHz.

The function of passive wide-angle beam scanning is desired by the base station antenna to provide “green” cellular services. In this communication, such function is realized by designing a compact phase-controlled pattern-reconfigurable dielectric resonator antenna (DRA). The proposed DRA has a compact structure with a side length of $0.38 \boldsymbol {\lambda }_{\text {c}}$ and excites the fundamental TE and TM modes by diverse ports. By assigning phase between diverse ports, E-plane tilted patterns are synthesized with ±66° scan angles. Its pattern-reconfigurable capability makes contributions for increasing array beam scanning angle and minimizing gain fluctuation. A passive four-element array is verified to have an enhanced beam scanning angle of ±81° with a gain fluctuation of 1.25 dB. The maximum gain of the scanning beam is located on the off-axis angle of ±66° and achieves a wide 3 dB scan coverage of ±105°. Good agreements have been shown between the measured and simulated results. The proposed phase-controlled pattern reconfigurable DRA and DRA arrays have an impedance bandwidth of 3.33% (2.95–3.05 GHz) for a sub-6 GHz wireless system. They enable the wide-angle beam scanning for base station antenna and provide a cost-effective passive system for “green” communications.

In this letter, a planar inverted-F antenna (PIFA) working at 401.8 MHz is optimized for microsatellites (MicroSats) omnidirectional communication and omnidirectional communication is achieved by antenna layout optimization. Some parameters of the antenna are analyzed for investigating the influences to the resonant frequency and the gain. The PIFA occupies a small volume of 85 × 85 × 31 mm3, which is 0.011 λ × 0.011 λ × 0.004 λ and has a maximum gain of 5.37 dBi after optimized. An omnidirectional, highly isolated dual-antenna communication satellite receiving system is realized by layout optimization simulation analysis. The effectiveness of the antenna and the layout optimization is verified by comparison between simulation and experimental results. The antenna has potential applications in MicroSats omnidirectional communications as the antenna has a small size and it can be quickly redesigned and manufactured.

Onset of green revolution emerged as boon for the growing population by producing enormous crops. Complete reliance on the chemicals have led to mammalian toxicity, development of insecticide resistance and bio-magnification of pesticides etc. The negative impact of pesticides necessitates the concerted efforts to evolve new innovative pest-resistive, eco-friendly smart nano-pesticides. Nanotechnology with its unique properties offers an alternative that include diversity in nano-formulation and encapsulation methods. Nano-pesticides offer sustained release kinetics, solubility efficient enhanced permeability, and stability to achieve increased pest-control efficiency over longer durations and to prevent degradation of the encapsulated molecules under adverse environmental conditions to achieve maximum gain. Nanoparticles (NPs) can act as ‘magic bullets’ that can be loaded with insecticides, pesticides, herbicides, fungicides etc. and can be released to the target site. Smart delivery of nano-pesticides is quintessential to minimize pesticide dosage to achieve increased efficacy. This review summarizes the importance of nano-pesticides especially metallic NPs for Insect Pest management.

India being a developing country, tones of industrial waste byproducts are generated every year and the quantity of waste keeps on escalating with time. In recent times, improving the subgrade strength by using soil reinforcement such as geosynthetics and by utilizing industrial wastes which if left unutilized pollutes the environment, is gaining lot of importance. In the present work, an experimental investigation has been carried out to improve the soil strength by adding fly ash (FA) and by reinforcing the soil using geonet. Locally available soil used in the experimental work was classified as SC soil (Clayey Sand) based on its index properties. Soil was mixed with variable percentages of FA, 10%, 14%, 18%, 22% and 26% to decide the ideal percentage of FA for which maximum gain in soil strength was witnessed in Unconfined Compression test and soaked CBR test. Geonet was placed at varying depths of one fourth the depth (H/4), half the depth (H/2) and three fourth the depth (3H/4) from top of soil specimen to determine the ideal depth of placement of geonet for which the soil exhibited maximum gain in strength in soaked CBR test. Based on the experimental results, soil with 18% FA showed maximum increase in UCC strength of 156.19 kPa and soaked CBR value increased by approximately 2.55 times that of control specimen. Soil reinforced with geonet placed at three fourth depth from top showed maximum strength gain in soaked CBR test.

This letter presents a double-layer 45° linearly polarized (LP) wideband and highly efficient transmitarray antenna (TA). The proposed element is composed of two multi-resonant dipoles and four metal vias. The dipoles are placed on the diagonal of the unit cell and printed on both sides of the dielectric substrate. The metal vias which penetrate the substrate and connect the upper and lower dipoles are used to improve the transmission efficiency and obtain the large phase shift range of the proposed element. The proposed element realizes a full 360° phase shift range with a smooth slope in the band, and the magnitude loss is less than 1.5 dB at 20 GHz. The proposed TA is designed, manufactured, and measured. The measurement and simulation results are consistent. Measurement results indicate that the proposed TA has a maximum gain of 26.9 dBi at 20 GHz and an aperture efficiency of 53.5% with a 1 dB gain bandwidth of 12% (18.8–21.2 GHz). The proposed double-layer 45° LP TA shows enhanced bandwidth and simple design. Using a double-layer structure opens possibilities for TA design.

The International Thermonuclear Experimental Reactor (ITER) tokamak can generate fusion energy in an acceptable method. In this study, the particle and energy equations were developed for $${\text{T}}\left( {{\text{D}},n} \right){}^{4}{\text{He}}$$ , $${\text{D}}\left( {{\text{D}},n} \right){}^{3}{\text{He}}$$ , $${\text{D}}\left( {{\text{D}},p} \right){\text{T}}$$ , and $${}^{3}{\text{He}}\left( {{\text{D}},p} \right){}^{4}{\text{He}}$$ fusion reactions and optimum conditions were determined to achieve the maximum gain using differing mixtures of fuel. Also, the particle and energy equations were solved using the zero-dimensional model, and the ITER90H-P plasma parameters were calculated by the numerical methods. The possibility regarding the presence of impurities was ignored in all our calculations.

A high-gain superstrate antenna array is designed at 60 GHz. The proposed antenna array is extremely low in cost and possesses high performance metrics. The proposed structure can be integrated easily into many modern millimeter-wave/5G transceivers. The array boresight gain is 19.4 dBi, the relative bandwidth is 10.7%, and the maximum gain variation is 1.7 dB within the operating bandwidth.

A novel wideband circularly polarized (CP) dielectric reflectarray operating at Ka -band is proposed. Each element consists of a cross-shaped dielectric block and a metal ground. The two arms of the cross element are arranged along the diagonal of the square metal floor. For ease of the design, the dimensional scaling factor is used to obtain the reflection phase. The dielectric reflectarray of the size 15 × 15 and dielectric constant 9.8 is designed. Genetic algorithm (GA) is applied to optimize the element size. It is found that the maximum gain is 24.2 dBi, and 1 dB gain bandwidth is 10.7%, respectively. A broad 3 dB axial ratio (AR) bandwidth of 19.3% can also be obtained. The proposed CP antenna is fabricated using the high-precision 3-D printing technology. Relatively good agreement between the simulated and measured results is achieved.

In this paper, a simple and efficient method to increase the gain and bandwidth of the wearable antennas used in several medical/communications systems is presented. To increase the gain and bandwidth simultaneously, the triple transmission lines (TTLs) method has been used. With this method, the frequency ranges of 1.7–2.5 and 5.4–5.95 GHz are covered with dual-band responses. Also, the simulated maximum gain at 2 and 5.8 GHz is equal to 8.26 and 9.86 dB, respectively. Using the TTLs method, the second frequency band (5.4–5.95 GHz) is achieved. Also, the gain improvement in operating frequencies is more than 4 dB compared to the conventional antenna. The dimensions of the proposed wearable high-gain antenna are 80 × 92 × 2 mm3 or 0.57 × 0.67 × 0.01 λg3 at 2 GHz. Finally, a dual-band sample antenna for use in medical systems was fabricated with a flexible felt substrate and its characteristics were measured. There is a good fit between the measurement and simulation results.

In this work, a compact two-element triple-band multiple-input multiple-output (MIMO) antenna loaded with reflective type metasurface (MS) for enhancing the gain, isolation and impedance bandwidth (IBW) is presented. The two-element radiator antenna consists of a microstrip feed line on the upper side of the substrate and defected ground structure (DGS) on the backside on which multiple slots are etched for obtaining triple-band antenna performance. Due to DGS loading, the entire dimensions of the single radiator antenna are reduced to 22 × 22 × 1.6 mm3 with smaller electrical dimensions of 0.17λ 0 × 0.17λ 0 × 0.012λ 0 at the first resonating frequency. The proposed two-port MIMO antenna with MS operates at 2.36–2.50, 3.43–3.50 and 5.15–5.88 GHz with percentage bandwidths of 5.76, 2.02 and 13.22% for the three operating bands. Due to MS loading, a gain improvement of 5.49, 4.57 and 0.80 dBi is noticed with a maximum gain of 3.98, 5.25 and 2.66 dBi is obtained at the three operating frequencies of 2.46, 3.51 and 5.32 GHz, respectively. The intended antenna is appropriate for working in IEEE 802.11 b/g/n (2.4–2.484 GHz) WLAN, IEEE 802.11 a/h/j (5.15–5.825 GHz) WLAN, and IEEE 802.16e (3.4–3.5 GHz) WiMAX wireless applications.

The study designed and implemented quadrifilar helix antenna (QHA) for weather satellite signal reception. The antenna design and optimization were done by varying the element diameter, the radial lengths, the axial lengths, and element materials on adopted model. The simulated QHA has far-field radiation pattern in the upper hemisphere with maximum gain of 4.14dBi at 0o and omnidirectional coverage, half-power beamwidth of 140o, bandwidth of 6.5MHz, and VSWR of 1.13. The implemented QHA has major lobe in conformity with the simulated QHA with maximum gain of 10.75dB at 0o, and half-power beamwidth of 104o.

Ultra-low loss (ULL) fibers allow high-quality signal transmission and are expected to become important candidates for new deployment of fiber links in an optical network. In our previous study, we investigated strategies for selecting network links to be deployed with ULL fibers in a single stage, subject to an annual operational budget. As a step further, this study considers such deployment in multiple stages, which corresponds to a scheduling problem of ULL fiber deployment. To this end, we cannot simply adopt a repetition of our previous single-stage deployment approach since it cannot tell which set of links are to be deployed with ULL fibers in each stage. Rather, we need to jointly consider the set and the order of links to be deployed in each stage so as to get a maximum overall gain in terms of time-weighted frequency slot (FS) usage. Also, the time taken for deploying each fiber link and the interval between neighboring deployment stages should be considered. To achieve a global optimization, we develop a mixed integer linear programming (MILP) model and look at three scheduling strategies which are physical length (PL), shortest route traversed (SRT), and maximum deployment gain (MDG) based strategies. We evaluate the performance of these strategies through simulations and find that the proposed MDG strategy performs best in terms of the total time-weighted FS usage. Results also show that there is an optimal number of deployment stages which provides maximum gain of spectrum usage while requiring few network re-optimizations.

This study presents a linear-to-circular polarization conversion metasurface (PCM) based on a novel unit cell for a circularly polarized (CP) Fabry-Perot (FP) antenna. The unit cell consists of a bottom linear-polarization patch and a top circular-polarization patch, which are separated by a metalized plane and connected by a metalized via. The bottom patch receives the power and transfers it to the top layer through the metalized via; the top layer then transmits the power into space. The metasurface is designed to have high reflectivity and an appropriate reflection phase to compose a resonate cavity with the ground plane. The capability of linear to circular polarization conversion is provided to the PCM by adjustment of the transmission magnitude and phase. A slot coupled patch antenna is used as the feeder due to its stable broadside radiation. The linearly polarized wave emitting from the feeder resonates in the cavity and then is converted into a CP wave when it comes out of the cavity. A prototype antenna is fabricated and measured. The measurement results show that the antenna has good circular polarization performance within the band of 9.8–10.2 GHz. The maximum gain of the antenna reaches 17.8 dBic at 10 GHz, with an aperture efficiency of 53%. The proposed antenna outperforms most of the previously reported CP FP antennas due to its low profile, high gain, and relatively high efficiency.

A packaged microstrip line feed network on a single substrate surface is presented in the Ka-band for a 4 × 4 dual-polarized array with a capability to be expanded to higher order 2N × 2M, where N and M are integer numbers larger than 1. A dual-polarized aperture-coupled magneto-electric dipole antenna is designed as a single element with 20% bandwidth of −10 dB reflection coefficients, ports’ isolation better than 35 dB, cross polarization less than −25 dB within the main beam view-range of 30°, and gain of 8 dBi. A 4 × 4 array is implemented that maintains a bandwidth of 16.7% at 30 GHz with a maximum gain of 19.3 dBi.

Effectively resource management in the cloud environment can improve the utilization of resource and reduce resource costs and overheads.Task scheduling and optimization within the cloud computing environment are one of the main concerns that need to be handled to increase resource utilization and QoS (Quality of Service). Although there are some algorithms have been proposed to handle the problem of task scheduling, existing methods mainly focus on reducing the task execution time while ignoring the other factors such as workload balance and QoS. In this paper, we put forward a novel algorithm named ITSA (Improved Task Schedule Algorithm), which is based on the gain value of task swap and performs “task pair” scheduling by utilizing the greedy strategy. The main idea of ITSA can be concluded as follows: Firstly, we present the concept of the gain value of task swap; then, we bind task with the minimum gain value and task with the maximum gain value together to form a “task pair”, and perform scheduling by adopting the greedy strategy. Finally, we evaluate the proposed algorithm by extensive experiment, and the data obtained from the experiment shows that the proposed algorithm has a better performance compared with other algorithms in terms of the workload balance and QoS.

A novel scheme is proposed for the enhancement of the gain and output power of terahertz (THz) traveling-wave tube (TWT) amplifiers. The scheme combines a slow-wave structure (SWS) and multigap resonant cavities, resulting in a complementary hybrid of traveling-wave and standing-wave elements, thus offering a compact circuit length. The idea has been verified by a specific design of a 220-GHz TWT amplifier by means of particle-in-cell (PIC) simulations. For an electron beam with a voltage of 21 kV and a current of 200 mA, a maximum gain of 42.22 dB and a 3-dB bandwidth of 6.5 GHz has been achieved while the overall circuit length is only 38 mm. For an input power of 11.25 mW, the CW peak power is predicted to be 187.5 W at 220 GHz, corresponding to an electronic efficiency of 4.47%. These simulation results predict a performance that well exceeds that reported for conventional TWTs, along with a significant reduction of the input power and circuit length.

This paper discussed the design of 32 × 32 left-hand circularly polarized (LHCP) phased array antenna at Ku-band for satellite communications. In this paper, planar phased array antenna principle, single radiating element structure and analysis and simulation of antenna array are presented. The array is compact and the whole front-end of this array can be placed on the same multilayer printed circuit board (PCB). Thus, this array is easy to be carried by satellites. With 33.43dB maximum gain, good axial radio performance and scanning range from 0 to 60, the array provides superb performance for satellite communication systems.

A dual band planar inverted-F antenna (PIFA) for wearable applications is proposed. The design utilizes the slots on the radiating plate and the ground plane to realize dual band and wire band characteristics. To verify the design, a prototype was fabricated and measured, which covers two working bands of LoRa applications, namely 433 MHz and 868 MHz. The proposed design has total radiation efficiencies above 70% across the operating bands, and a maximum gain of 1.25 dBi. The SAR of the proposed design is evaluated, which meets the European standards. The textile antenna can be a promising candidate for LoRa (Long Range) applications.

A millimeter-wave wideband circularly polarized antenna with an improved gain is designed in this paper. The gain enhancement of 5 dB at 35 GHz is achieved by loading the CP antenna with FSS superstrate. The simulation results show that the proposed antenna has a wide -10 dB impedance bandwidth of 58.2%, a 3-dB AR bandwidth of 35%, a 3-dB gain bandwidth of 30%, and a maximum gain of 11.9 dBic at 35 GHz.

The problem in this research is learning rarely uses media in learning,  students' mathematical understanding ability is still low in mathematics learning flat-build material, lack of learning media. This study aims to determine the relationship of the development of Macromedia Flash-assisted mathematics learning media related to flat material. This research method uses research and development (Research and Development). The 4-D device development model consists of 4 stages of development, namely Define, Design, Develop and Disseminate or adapted into a 4-D model, namely defining, designing, developing and disseminating. In the field trials the average pretest score is 68.24 while the average posttest score is 86.76. An average increase of 18.52. The minimum gain value is 0.62 while the maximum gain value is 1.00. In the test of the spread of the average pretest value is 60.33 while the average posttest score is 81.33. An average increase of 21. The minimum gain value is 0.77 while the maximum gain value is 0.83. Based on these data, the development of mathematics learning media assisted by macromedia flash has experienced a significant increase in students' mathematical understanding abilities.

Esta investigación permite dar a conocer los riesgos físicos en las tareas de mantenimiento de una estación de radio base de telefonía celular. A pesar de que hasta la fecha las investigaciones realizadas anteriormente no presentan evidencia científica importante para indicar que estas radiaciones afectan al ser humano, estos análisis han determinado la existencia de límites de exposición a radiaciones no ionizantes, los cuales deben ser respetados por los trabajadores que realizan este tipo de trabajos. Las mediciones de densidad de potencia (s), densidad de campo eléctrico (e), densidad de campo magnético (H) realizadas para alturas (h) de 2 hasta 5 m en el lóbulo principal del emisor o antena donde existe la máxima ganancia determinaron un 32 % de los puntos medidos sobrepasan el límite permisible. Con estos valores se establecieron las distancias de seguridad y, por lo tanto, se determinó que: la altitud es inversamente proporcional a la densidad de campo magnético, eléctrico y de potencia.

In this letter, a salty water antenna with beam-steering characteristics is proposed. The antenna combines the idea of the electronically steerable parasitic array radiator (ESPAR) antenna and the water antenna to realize a 360° beam steering. The unique features of water antennas, such as transparency, reconfigurability, and liquidity, are fully utilized. Both the computer simulations and measurements are conducted to validate the performance. The proposed design has a frequency range from 334 to 488 MHz ( S 11 60%), 13 different working states, and a maximum gain of 5.8 dB. Compared with existing pattern-reconfigurable liquid antennas, this new antenna has a wider bandwidth, more working states, and better invisible ability. It is, therefore, a promising candidate for a range of very high-frequency or ultrahigh-frequency applications, such as Internet of Things and maritime applications.

Two identical homemade prototypes are used to monitoring the tide levels on two strategic points of the Serinhaém estuary. This monitoring was realized along a period close to the new moon phase. From the analysis of the experimental results, the average height of the tide is determined between each period of high-tide and low-tide. These estimations show discrepancies minors than half order of magnitude, compared to the theoretical predictions of the static and dynamic oceanic tide models. Also the amplification effects of the tide in the estuary head can be quantified exhibiting a maximum gain 1.33, which is observed in the new moon phase.

This paper presents new single-ended-fed planar aperture antennas (SPAAs) using low-temperature co-fired ceramics (LTCC) process technology. The SPAA element is proposed first, which not only inherits the merits of the aperture antennas including high gain and wide bandwidth but also exhibits advantages of low profile and compact size. The aperture is excited by a cross-shaped patch, and a loop-shaped balun structure placed below the patch is introduced to convert the single-ended signal into differential one to drive the patch. In this way, the energy can propagate on the patch in a traveling waveform and illuminate the aperture with uniform E-field distributions. Therefore, the antenna achieves good electrical and radiation performances, which are comparable to its balanced-fed counterparts, while processing a simplified structure. Measured results demonstrate that the impedance bandwidth of the antenna covers the 60 GHz license-free band (57–64 GHz), and the maximum gain can reach 11.5 dBi with a cavity area of only about 27 mm2. Furthermore, the element is successfully extended to a $4\,\,\times \,\,4$ element array using a substrate-integrated-waveguide based feeding network to further increase the gain up to 20.4 dBi. The measured results show that the impedance bandwidth of the array is from 57.5 to 65.7 GHz and the radiation performances are very stable over the operating frequency band.

OBJECTIVE: We retrospectively investigated a series of patients with carbon monoxide (CO) poisoning transported by a physician-staffed helicopter (DH) to seek evidence supporting the daily management of patients with CO poisoning. STUDY DESIGN: Subjects were divided into two groups: the carboxyhemoglobin saturation (SpCO) (+) group, which included patients who had a pulse CO-oximeter attached during transportation; and the SpCO (-) group, which included all other patients. We compared the level of SpCO before and after transportation when the level was noted. RESULTS: The subjects were predominantly middle-aged and male. Seventeen subjects (53.1%) received a diagnosis of CO poisoning based on the situation in which the subjects were found, without the carboxyhemoglobin level being measured. No subjects show deterioration of their condition after transportation, and none ultimately died. The frequency of male gender, normobaric oxygen treatment and return to the base hospital in the SpCO (+) group was significantly greater than in the SpCO (-) group. The SpCO levels after transportation were significantly lower than they had been before transportation. CONCLUSION: This is the first study to show the results of the analysis of patients with CO poisoning transported by the DH. All patients with CO poisoning were safely transported.