Design of Multilayer Substrates Microstrip Patch Antenna for Fuze Application

A precise layer alignment is crucial to ensure performance repeatability of multilayer microstrip antennas. We introduce a novel lab-scale construction process for multilayer microstrip textile patch antennas that consists in combining an alignment method, based on laser-cut wood frames to perform accurate layer alignment, with a fast intralayer attachment method, based on thermally activated adhesive sheets. This lab-scale construction process is validated with an electromagnetically coupled microstrip rectangular patch textile antenna operating in the 2.45 GHz ISM band. It has been reproduced eight times to validate the proposed construction process. The differences between desired simulated versus measured average values of the resonant frequencies, impedance bandwidths, gains, and total efficiencies equal 6.25 MHz, 21.5 MHz, 0.6 dBi, and 4.45%, respectively. Moreover, the standard deviations of measured resonant frequencies, impedance bandwidths, gains, and total efficiencies equal 24.54 MHz, 14.02 MHz, 0.15 dBi, and 3.57%, respectively. These results confirm that the novel lab-scale construction process provides good performance repeatability of multilayer microstrip textile patch antennas.

This paper reports a multilayer textile microstrip patch antenna for integration into protective clothing for professional workers since it is made out of a high performance aramid fabric. It is designed to operate in the 2.45 GHz industrial, scientific and medical (ISM) band for short range communication to transmit vital signs, activity and environmental conditions to a nearby base station. Electrotextiles are used for the antenna patch and ground plane. Integration of the textile antenna into the protective clothing requires a finite ground plane and reliable operation in the vicinity of the body. Furthermore the patch may bend. A rectangular ring topology is proposed to preserve the antenna characteristics in real-life applications. This research paves the way for a new generation of protective clothing. (5 pages)

The modified Wolff model (MWM)‐based cavity model is presented for the simple and accurate computation of the input impedance of a probe‐fed multilayer rectangular microstrip patch antenna. Results of the MWM are compared with both the experimental data and data of the MoM, with agreement within 1.5% for resonance frequency and within 0.15 for normalized input impedance. Further results are presented on the input impedance of a suspended rectangular microstrip patch antenna with a two‐layer superstrate. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 237–239, 2001.

This article presents the experimental results and verification of design expressions of multilayer rectangular and circular microstrip patch. Three rectangular and circular microstrip patch of different dimension have been fabricated on substrates er2 = 4.3, thickness 1.53 mm and er2 = 2.2, thickness 0.787 mm. The measurements have been carried out for simple microstrip patch, covered microstrip patch, space dielectric patch and microtrip patch with two superstrate. The experimental results obtained have been compared with reported design expression of multilayer rectangular and circular Microstrip patch in (Kumar and Malathi, Microwave Opt Technol Lett (2007), 2946-2950; Microwave Opt Technol Lett 40 (2008), 3206-3212). The experimental resonant frequency is in close agreement with the calculated resonant frequency. Such experimental validation and results may prove to be more useful for design engineers and further investigation. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:352–356, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25735

P-Type Chemical Doping-Induced High Bipolar Electrical Conductivities in a Thermoelectric Donor–Acceptor Copolymer

Delineation of site-specific productivity zones using soil properties and topographic attributes with a fuzzy logic system

BACKGROUND: There is little information available concerning the effect of sanitizing agents, including ultraviolet (UV‐C) light, on nutritional composition of fresh‐cut produce. In this study, the influence of UV‐C light irradiation (3.2–19.2 kJ m−2) on the nutritional quality of fresh‐cut tomato cv. Durinta grown under either low (2.4/2.8 dS m−1) or high (4.9/7.7 dS m−1) electrical conductivity (EC) of the hydroponic nutrient influx/efflux solution was investigated.RESULTS: When grown under low EC UV‐C light treatment reduced development of microbial population of fresh‐cut tomato, increased phenolic content and delayed degradation of vitamin C after 7 days of storage at 4–6 °C. UV‐C light irradiation had no significant effect on appearance, color or lycopene content of fresh‐cut tomato. In recently harvested intact tomatoes, the lycopene and vitamin C contents were 30% higher in tomatoes irrigated with high EC, whereas the phenolic content was unaffected by the salt treatment. After fresh‐cut processing, phenolic and vitamin C contents of fresh cuts produced from tomatoes treated with high EC decreased by > 10%. This decline was initially accelerated in tomato treated with UV‐C light irradiation.CONCLUSIONS: Our results revealed that fresh‐cut tomatoes are affected dissimilarly by UV‐C treatments, depending on the degree of salt stress undergone by plants before harvest. We determined the impact of a sanitizing procedure on nutritional composition, an effect often overlooked but with great significance to ensure overall quality of fresh produce. Our findings revealed the need for more nutritional studies addressing the effect of multiple stress factors from pre‐harvest to post‐processing stages. Copyright © 2008 Society of Chemical Industry

Recent efforts have extended fluid dynamic modeling to include low-electrical-conductivity (wavelike) electromagnetic field effects in plasmas. Here, we present results of a new study to explore and illustrate the capability of resolving such effects in the development of plasma instabilities. Recent work[1, 2] has explored the development of an efficient numerical procedure for simulating the coupled fluid dynamic and full electromagnetic (Maxwell) equations. This system of equations is more general than the resistive magnetohydrodynamic (MHD) model. The physical advantage to this system is that the inclusion of the displacement current and charge separation effects extends fluid dynamic modeling of plasmas to include regions of extremely low (or zero) electrical conductivity, where the electromagnetic fields possess a wave nature. Capturing the correct physical behavior of plasma instabilities in the limit of extremely low electrical conductivity is of significance for modern aerospace applications, including energy bypass arrangements for scramjet propulsion using magnetohydrodynamic augmentation, due to the extremely low electrical conductivity of the aerospace environment. The results depicted in this paper illustrate the potential for the numerical method realized in Ref. 1 to effectively resolve this behavior in cases where the MHD approximation may not be valid due to an exceedingly low electrical conductivity. A new study was initiated to explore more fully the capabilities to resolve regions of both low and high electrical conductivity using this numerical scheme. The problem selected for this study was the classic MHD KelvinHelmholtz instability. The initial and boundary conditions are provided in Ref. 2. A periodic box is initialized with two fluids of different density moving in opposite directions. An initial small perturbation is applied to the interfaces between the fluids, seeding an instability. A 256x256 grid size using a Roe solver for the coupled system of Navier-Stokes and full Maxwell equations was used, as detailed in [1, 2]. Three cases were explored: Case A was assigned a zero electrical conductivity, σ = 0 (purely hydrodynamic), Case B was given a small electrical conductivity of σ = 1, and Case C was given a very high conductivity of σ = 10 6 . Case A provides a hydrodynamic benchmark. Case B permits an investigation of a simulation that includes the effects of electromagnetic wave propagation in the plasma evolution. Case C effectively realizes the magnetohydrodynamic approximation. Results for the simulations are presented in a unique fashion in Fig. 1. For each subfigure, three spacetime isosurfaces of the density (blue, green and orange corresponding to the color range) have been depicted. Isosurfaces are the same for all three presented subfigures. Time flows from right (initial conditions) to left (final solution). For Case A, the fluid achieves a highly chaotic solution. The propagation of the initial disturbance at the interfaces between the two fluids is clear, as well as their development into a highly turbulent flow. Case B possesses an extremely low electrical conductivity, and therefore is not subject to the magnetic diffusion approximation of MHD. In fact, electromagnetic wave propagation was visible in this solution. The presence of a finite electrical conductivity provides some diffusion, but it does not match very well to the MHD prediction. However, the conductivity is large enough to abate the low-wavelength instabilities somewhat, and provide stability to the flow. Case C realizes the magnetohydrodynamic limit, where the magnetic field tends to stabilize the flow and strongly suppresses low-wavelength instabilities. A much more organized series of flow structures evolve through time to the final state. The magnetic field is effectively “frozen” to the fluid with such a large electrical conductivity, and the field strongly diffuses with little wave propagation.

A variational method in the spectral domain is used to determine the quasistatic capacitance of a patch antenna within a nonhomogeneous multilayer structure. The patch is modelled both by a one dimensional analysis using a segment of an infinite transmission line and by a full two-dimensional representation. A new technique is presented for determining the relative permittivity of an equivalent single-layer structure, from which the frequency-dependent effective permittivity is obtained. Results for a number of different antenna structures are given and show good agreement with measured values.

Tomato plants were grown in peatmoss-based substrate and supplied with nutrient solution of high (4.5 mS·cm–1) or low (2.3 mS·cm–1) electrical conductivity (EC) under high (95%) or low (55% of capillary capacity) substrate water content (SWC) to examine the effects of high EC and low SWC on growth and physiology. Salts were allowed to accumulate in the substrate for 7 weeks. Both high EC and low SWC significantly decreased dry matter production (DMP) and fruit yield (FY). Fruit harvest index was lower in high EC- or low SWC-treated plants. Decrease in marketable FY was attributed to both the decrease in total FY and the increase in small and abnormal (cracked and rot) fruits. Both high EC and low SWC decreased photosynthesis (PN) and leaf water potential (ΨL). However, chlorophyll content and respiration were increased by high EC under both high and low SWC. Water consumption based on both whole plant and unit of leaf area was decreased by high EC and low SWC. ΨL and transpiration were depressed by high EC and low SWC, especially at midday. There was a significant positive correlation between fruit yield and water consumption. The effects of high EC and low SWC were additive on most of the variables. Decreases in ΨL might ultimately account for water consumption reduction, PN depression, and FY decrease.

Graphene has a two-dimensional honeycomb structure consisting of a single layer of carbon atoms with a sp2-bonding configuration and has recently attracted significant attention owing to its unique properties, which include an exceptionally high specific surface area and high electrical and thermal conductivities as well as mechanical and chemical stability. However, graphene sheets exhibit an extreme tendency to agglomerate or restack. This leads to a surface that is electrochemically less effective, low electrical conductivity, and an interlayer spacing that hinders access to electrolyte ions, thus limiting the use of the sheets in supercapacitor applications. Introducing carbonaceous materials such as metal oxide, carbon nanotubes (CNTs) between the graphene sheets is a viable strategy for preventing the sheets from agglomerating.In this study, we report the scalable fabrication of a high-quality hierarchical interconnected carbon nanostructure, combining two-dimensional graphene nanosheets and one-dimensional graphene nanoscrolls from graphite by a simple hightemperature molten salt method. The electrode using the prepared material exhibited high reversible specific capacitance, excellent rate capability, and good cyclability because of their unique interconnected networks of carbon nanostructures with high electrochemically active surface area and high electrical conductivity. More details on the synthetic procedure, electrochemical and structural properties will be presented at the meeting.

Although 750 μ mho/cm is the limit for the electrical conductivity (EC) in the “Standard of Taiwan Irrigation Water Quality,”; the EC of irrigation water is usually over limit, resulted from the pollution dumped into the rivers, streams, and creeks. It will be a damage to agricultural crop using polluted irrigation water. The basic principle of dilution can neutralize high EC of polluted water using pure or low EC water. With the increasing quantity of clean water, the polluted water will drop its EC to a certain extent. Therefore, the purpose of this study is to determine the relationship between dilute water quantity and its EC. As results shown in this study, pure water or water of low EC mixing with water of high EC can be a basic principle for diluting. The practical principle can be used in the farms and the results meet the irrigation water standard. Moreover, the better quality of dilute water is, the less its quantity is; the worse the quality the more the quantity is. Furthermore, the electrolyte effect and the principle of Le Chatelier in aquatic chemistry are resulted in solubility of salt and EC of mixed water solution increase. All the precipitation, coagulation, and flocculation will decrease free ions’ content and EC in mixed water solution.

This paper describes a flexible microstrip patch antenna that incorporates a novel multi-layer construction consisting of a liquid metal (eutectic gallium indium) encased in an elastomer. The combined properties of the fluid and the elastomeric substrate result in a flexible and durable antenna that is well suited for conformal antenna applications. Injecting the metal into microfluidic channels provides a simple way to define the shape of the liquid, which is stabilized mechanically by a thin oxide skin that forms spontaneously on its surface. This approach has proven sufficient for forming simple, single layer antenna geometries, such as dipoles. More complex fluidic antennas, particularly those featuring large, co-planar sheet-like geometries, require additional design considerations to achieve the desired shape of the metal. Here, a multi-layer patch antenna is fabricated using specially designed serpentine channels that take advantage of the unique rheological properties of the liquid metal alloy. The flexibility of the resulting antennas is demonstrated and the antenna parameters are characterized through simulation and measurement in both the relaxed and flexed states.

Tomato fruits of high quality and yield are of interest to greenhouse growers. As potassium (K) and calcium (Ca) have been associated with fruit quality, we studied the effect of the balance between such cations and the electrical conductivity (EC) on fruit yield and quality. Plants were fertigated with K (Kext) and Ca (Caext) balances in the nutrient solution varying from 0.54–1.22 and 0.69–1.44 at ECs of 2.3 ± 0.1 dS m−1 and 2.7 ± 0.1 dS m−1, respectively. Optimum balance for fruit yield was 0.82–0.85, and it was associated with high fruit K internal (Kint) concentration (~ 200 mmol kg−1). Higher EC increased firmness when the balance was ≤ 1.00, with the optimum at 0.85; firmness was correlated with Caint when EC was 2.3 dS m−1; however, at 2.7 dS m−1, increasing Kext increased firmness and intensified the effect of Caext. Increasing a* values were associated with high lycopene and uniform maturation when that balance was 0.82 and 1.00 at low and high EC, respectively. Highest a* values were observed when Kint in the fruit was ~ 200 mmol kg−1, while 91 to 130 mmol kg−1 were associated with lower a* values. Fruits contained higher starch (+ 20%), total (+ 12%), and reducing sugars (+ 29%) at high EC. The optimum K and Ca balance, 0.82–0.85, is independent of their concentration and was associated with high yield and firmness, improved fruit color, and increased lycopene and sugar concentrations.

Salinity is an abiotic factor that affects plant growth and development. However, some halophyte species develop mechanisms to tolerate saline conditions. The objective was to evaluate morphophysiological and biochemical characteristics, and mineral accumulation of Suaeda edulis Flores Olv. & Noguez. The experiment was conducted in a floating-root hydroponic system with a completely randomized design with a factorial arrangement. The first factor was three S. edulis ecotypes that were subjected to a second factor consisting of salinity stress (seawater diluted with Oreochromis niloticus wastewater) with four electrical conductivities (2.5, 10.0, 15.0, 30.0 dS m-1). The variables evaluated were growth parameters, chlorophyll content, water potential, protein content, ether extract and crude fiber, and mineral content. The results showed that most of the variables showed significant differences in the interaction of the factors. There is a differential response of the ecotypes to stress treatments, observing a polynomial (cubic/quartic) trend in the variables, which showed low values at low electrical conductivities, a maximum positive response at intermediate levels of electrical conductivity, suggesting optimal conditions for growth, and at high electrical conductivity, a decrease was observed in most of the variables. The differential accumulation of sodium and potassium indicates exclusion and tolerance mechanisms that vary between ecotypes. These findings highlight the potential of S. edulis to grow in environments with moderate salinity and provide information on its adaptive physiology.