Parallel Feed Research Articles

Design of Compact Reconfigurable Antenna Array for WLAN Applications

In this communication, a compact design of a reconfigurable antenna array operating in the band IEEE 802.11a is presented. The proposed antenna array contains four radiating elements excited by a hybrid parallel-series-feed network. The hybrid feed technique is used to avoid the main beam squint due to frequency changes compared to series and parallel array feed topologies. Each of the four radiating elements consists of straight narrow strip inductor in parallel with an interdigital capacitor. The antenna resonant frequency is electronically controlled by placing PIN diodes switches at the resonant element's inputs. The antenna permits reconfigurable switching frequency bands between 5.25 and 5.82 GHz. The results of the return loss and pattern radiation are shown. The size of the whole antenna structure is about 64 × 18 mm2 and can potentially be used in wireless systems.

5G dual-band slotted SIW array antenna

A dual-band slotted substrate-integrated waveguide four-element array antenna for the 5G communication system is presented in this manuscript. Two longitudinal slots are responsible for generating frequency bands of 28 and 38 GHz. The proposed antenna is designed on the substrate duroid 5880/Rogers having a loss tangent and dielectric constant of 0.003 and 2.2, respectively. The developed single-element design at 28 GHz provides 6.35 dBi gain, while at 38 GHz it provides 7.3 dBi gain and the simulation is carried out with CST Microwave Studio, 2018. To accomplish high gain, an optimized four-element array antenna is designed with a parallel feeding network on the same substrate that covers 28 GHz (27.6–28.1 GHz) and 38 GHz band (37.9–38.69 GHz). The designed antenna array attains the radiation efficiency of 88.08% with 12.7 dBi gain at 28 GHz and the efficiency of 84.44% with 15.5 dBi gain at 38 GHz band.

Design and fabrication of screw feeding device in additive manufacturing

Wire arc additive manufacturing (WAAM) is a new manufacturing technique in which large metal components can be fabricated layer by layer. A method is related apparatus for fabricating a three-dimensional object under a computer-aided design of the object in a layer-by-layer but not point-by-point fashion. Providing a work surface lying substantially parallel feeding a first layer of a first powder to this work surface by screw feeding. Feeding a second layer of a second powder onto the first layer, repeating the feeding, spraying and directing steps to build successive layers along the Z-direction in a layer-wise fashion under the design for forming multiple layers of the object; the main objective of the paper is screw feeding setup and experimenting the microstructure, grain size & hardness of the manufactured composites with different reinforcement ratios.

OpenDSS를 이용한 국내 전기철도 급전계통 모델링

Commercial Electomagnetic Transient Programs show accurate transient results by solving differential equations with respect to the circuit, but are not suitable for fast, data-based analysis. The open source distribution simulator is an open program developed for planning and analysis of the distribution system, and provides a strong linkage function with external programs and fast processing speed. In this paper, a process of modeling through an open source distribution simulator was proposed by considering the double-track parallel feeding system applied to the domestic high-speed railway system as a representative. The proposed modeling method was verified by simulating the target system under the equal conditions with a transients program and comparing the results. Modeling and utilizing the railway system through flexible and simple text-based open software can contribute to future artificial intelligent-based analysis, or energy efficiency in terms of operational aspects.

An infrared energy harvesting device using planar cross bowtie nanoantenna arrays and diode-less rectification based on electron field emission

ABSTRACT In this paper, we present a rectification process through electron emission from sharp tips under a high electric field of 109–1010 V/m based on the Fowler–Nordheim theory. A large planar array of 104–105 nanoantennas is proposed to achieve the required electric field for electron emission in the nanoantenna gap. Spatial coherence of the incident wave is a prohibitive issue in using large antenna arrays, and it is overcome by choosing proper size for the array. The design starts with a single-element nanoantenna, for which, five different types are considered, namely dipole, spiral, cross bowtie, sinuses and square spiral. Full-wave simulations show that cross bowtie has the highest field enhancement. Moreover, two array configurations, i.e. series and parallel feed networks, are considered and their field enhancement are compared. Moreover, field enhancement in large array configurations is predicted using proposed equations based on curve fitting.

A Millimeter-Wave Spoof Surface Plasmon Polaritons-Fed Microstrip Patch Antenna Array

A novel spoof surface plasmon polaritons (SSPPs)-fed microstrip patch antenna with a simple low-profile geometry is proposed. The method of inserting an open-ended planar single-conductor SSPPs section into the supporting substrate under the rectangular patch is investigated originally to excite the required TM10 mode and to achieve the promising impedance matching simultaneously. An impedance bandwidth of 8.2%, stable linearly polarized unidirectional radiation, and a gain of around 6 dBi are confirmed by a fabricated prototype. A planar single-conductor parallel feed network consisting of the SSPPs power dividers is then analyzed, which has a simulated insertion loss of around 8 dB. By combining the feed network with the patch elements, a $1\times 4$ SSPPs-fed microstrip patch antenna array is designed in the Ka -band. The measurement verifies the stable radiation with an enhanced gain of about 12 dBi across the operating band. Due to the planar configurations with low cost and promising performance, the presented SSPPs-fed patch antenna and array may find potential applications in future millimeter-wave wireless systems.

Integration of multi effect evaporation and membrane distillation desalination processes for enhanced performance and recovery ratios

This work focuses on the integration of multiple effect evaporation (MEE) and membrane distillation (MD) processes. The MEE brine is treated by the MD allowing at the same time a preheating of the MEE feed water. Different structures of integration are assessed theoretically. Simulation models based on the heat and mass transfer balances are developed for the parallel feed (PF), parallel cross (PCF), forward feed (FF)-MEE, and direct contact MD (DCMD) configurations. The main performance parameters such as the performance ratio, recovery ratio, and specific energy consumption are investigated via simulation of various MEE-MD configurations and operating parameters. The results show that hybrid MEE and MD structures outperform the standalone MEE systems. The performance ratio increased by more than 25% when hybrid structure is used as compared to standalone MEE. The results revealed also that the hybrid parallel PF-MEE-MD configuration yields the best performance compared to other hybrid configurations. It also outperforms the standalone PCF-MEE which is widely adopted and used in practice. Besides, the performance of the hybrid configurations is especially sensitive to the feed temperature's variation in both MEE and MD units. Increasing MD feed temperatures has a positive impact on the recovery ratios of the combined systems.

Analytical Estimation of Radiation Mode Radar Cross Section (RCS) of Phased Arrays

A novel analytical method has been proposed to compute radiation mode RCS of phased arrays. The array RCS is computed by tracing the path of an impinging EM signal as it travels through the array system. The scattered field contribution from each component of array and its feed network is expressed in terms of the reflection and transmission coefficients. The individual contributions are then coherently superimposed to arrive at total array RCS. The proposed method can be used to obtain the radiation mode RCS of any conventional phased array or low profile patch array with high impedance surface (HIS)-based substrate or superstrate. Results are shown for dipole array with parallel feed network, corporate-fed patch array with conventional metallic ground plane and HIS-based hybrid ground plane. This approach is applicable for estimation and control of radiation mode RCS of any type of phased array.

Novel sea water desalination unit utilizing solar energy heating system

A conventional parallel cross feed flow multi-effect desalination plant was simulated and optimized by the use of multi-goal algorithm MATLAB language programming together with engineering equation solver. An analysis of the overall performance of the plant was executed. A new design of solar desalination plant inclusive of solar parabolic collectors, steam generator, and MED unit has been proposed to commute the conventional plant. Further, an implementing was carried out on the subject of oblique steam production true more than one thermal oil which include THERMINOL VP1, THERMINOL 66, THERMINOL 59, THERMINOL SP, THERMINOL 55 and DOWTHERM A in addition to water. Via the simulation, it became clear that THERMINOL VP1 had 1.025% greater desalinated water than others. Additionally, the operation cost of distillate production by the usage of mazut or natural gas is a lot extra than using solar energy.

A new ultra‐wideband miniaturized antenna with a double‐branch radiator

AbstractThe antenna proposed in this study is a double‐branch radiator antenna. The radiator of this antenna is neither a conventional single‐branch radiator nor is it just a simple combination of 2 radiator branches. Moreover, a parallel resonance wideband feeding technology is used on the feed structure of the proposed antenna. The reference antenna in this study was a conventional single‐branch radiator antenna, which also uses the parallel resonance wideband feeding technology. A total of 3 resonant current modes are generated with the proposed antenna. The operating mechanisms of the 3 modes were analyzed in detail. The results showed that the impedance bandwidth was significantly enhanced with the simple modification. The impedance bandwidth reached 210 MHz (0.83‐1.04 GHz), which is 2 times that of the reference antenna and approximately 4 to 5 times that of a conventional planar inverted‐F antenna (PIFA).

A Microwave/Millimeter Wave Dual-Band Shared Aperture Patch Antenna Array

This paper describes the design of microwave/millimeter wave dual-band patch antenna array with shared aperture. The antenna array is designed of stack structure of three printed circuit boards. The Ka-band patches are fed directly with microstrip lines of the Ka-band power divider network and the E-band patches are coupling fed by the E-band power divider network through slots cut in the antenna ground. An antenna unit is studied, fabricated and measured firstly to verify the feasibility of the shared aperture structure. Finally, a shared aperture antenna array consists of a $2\times 4$ Ka-band array and an $8\times 16$ E-band array is designed based on the antenna unit. The E-band and the Ka-band feeding network are carefully designed to reduce the reflections, and the Ka-band feeding network combines series feed and parallel feed in order to save space. The shared aperture antenna array is fabricated and measured, and the results are presented. In order to measure the E-band array, the main port of the E-band power divider is connected to a standard WR12 waveguide through an antipodal fin-line waveguide to microstrip transition.

Modelling and Simulation of the Multi-effect/Thermal Vapor Compression Distillation Process

The Multi-effect distillation (MED) associated with thermal vapor compression (TVC) process has recently been applied for a number of desalination plants in the GCC countries and emerged as a strong competitor to the multistage flash distillation (MSF) process. The MED/TVC desalination process is characterized by low power consumption compared to the MSF process. It is currently operated at low TBT of 65°C to avoid scale formation compared to MSF technology which operate at top brine temperature of 110°C, this lead to lower tendency to scale formation and less fouling risk. The use of more efficient pretreatment to MED/TVC desalination plants such as nano-filtration or high performance additive antiscalant would allow operating MED at higher TBT which allow increasing the performance ratio. A simulation steady-state program has been established to analyze the thermodynamic behavior of parallel feed flow MED/TVC unit at a wide range of TBT from 65°C up to 125°C and different number of effects with different condition of motive steam pressure on the performance ratio, and specific heat transfer and therefore the best design of MED for the future different design options were considered to optimize the operational of MED system to enhance the economics and performance of MED technology.

Design and Analysis of High Gain Linear Rectangular Microstrip Array Antenna at 20.2 GHz of Ka Band

Day by day user demand for high data transmission with uninterrupted service leads to usage of high frequency. To fulfill the demands ISRO launched GSAT-14 with two Ka-Band BECONS at 20.2 GHz and 30.5 GHz. Through this design and analysis of one, two (1 × 2), four (1 × 4) and eight (2 × 4) element linear rectangular shaped microstrip array antennae at a frequency of 20.2 GHz is done to attain high frequency access, high gain and directivity. The substrate material used is identical for the one, two (1 × 2), four (1 × 4) and eight (2 × 4) element i.e. “Rogers RT/Duroid 5880” with thickness and Relative permittivity of 0.254 mm and 2.2 mm is considered. The antenna elements placed linearly with equal distance and the feed network applied here is a corporate or parallel feed network. The RF Wilkinson power divider is used for impedance matching and to excite the number of elements (n) from a single source to drive all elements uniformly with loss less resistive network. The proposed array antennae are simulated using HFSS software and fabricated observations are analyzed.

Thermodynamic, economic and environmental impact studies on various distillation units integrated with gasification-based multi-generation system: Comparative study and optimization

Abstract This research proposes four scenarios for a multi-generation system to produce power, pasteurized milk, biofuel and fresh water for the northern areas of Iran. In all scenarios, power, pasteurized milk and biofuel are produced by a similar arrangement of a supercritical CO2 (S–CO2) Brayton cycle, a biomass gasifier and a milk pasteurization unit while the portable water is produced by a brine recirculation multi-stage flash (BR-MSF) in scenario 1, by forward, backward and parallel feed schemes of multi-effect distillation (BF, FF and PF-MED) in scenarios 2, 3 and 4, respectively. A comparative study is conducted for the exergy, exergoeconomic and exergoenvironmental performances of all scenarios with various stages and effects using Engineering Equation Software (EES). The optimum performances of all scenarios are found by applying the fast and elitist non-dominated sorting genetic algorithm (NSGA-II) and using linear programming technique for multi-dimensional analysis of preference (LINMAP), technique for order of preference by similarity to ideal solution (TOPSIS) and Shannon entropy decision makers. According to the results, the maximum distillate water with capacity of 400.6 m3/day is obtained for scenario 1 through Shannon entropy method. Moreover, scenario 4 gives the maximum exergy efficiency with a value of 44.16% using LINMAP method and scenario 2 with the lowest total cost and environmental impact (EI) rates of 77.15 $/h and 33.35 mPts/s, respectively obtained from TOPSIS method is the best layout from the economic and EI aspects.

Compact and wideband planar loop antenna with microstrip to parallel strip balun feed using metamaterials

In this paper, a small size, wideband and high gain planar loop antenna with a new feed is presented. The antenna consists of a printed rectangular loop with two gaps, a corrugated reflector in order to reduce the antenna size and a dipole. In addition, a parasitic strip and metamaterials are also used in the antenna structure. Corrugating the reflector will extend the current path, it means the effective electrical length increases and resonance frequency decreases and therefore, the current on the reflector flows over a longer path which results in a size reduction. Compared to the originally printed loop antennas, the size of the proposed antenna is reduced by 50.1%. The parasitic strip and metamaterials act as a director for a quasi-Yagi-Uda in high frequency, and also improve the main directivity. In addition, using the metamaterials improve the antenna gain and impedance matching. To demonstrate the capability of the proposed design method, the antenna has been fabricated and its parameters measured. Measured results show that the fabricated antenna has a wide fractional bandwidth of 53% from 2.01 to 3.478 GHz with return loss of better than 10 dB and a measured peak gain of 5.4 dBi.

Linearized Discrete Charge Balance Control with Simplified Algorithm for DCM Buck Converter

In this paper, a linearized discrete charge balance (LDCB) control strategy is proposed for buck converter operating in discontinuous conduction mode (DCM). For DC-DC power converters, discrete charge balance (DCB) control is an attractive approach to improve the output voltage transient response. However, as a non-linear control strategy, the algorithm is complex, which is difficult for implementation. To reduce the complexity, this paper proposes the LDCB control strategy that is derived through linearizing conventional DCB controller. By deriving the differential functions of the DCB control algorithm, the small signal relationship between the input and output of DCB controller is explored. Furthermore, based on the relationship, the LDCB controller is formed through three parallel feed loops to the duty ratio. As a linear control approach, the achieved LDCB controller is greatly simplified for implementation. This not only saves the hardware cost, but also reduces the calculation lag, which provides potential to improve the switching frequency. Besides, since the LDCB controller shares the same small signal model as that of DCB controller, it achieves similar control loop bandwidth and transient performance. Effectiveness of the proposed LDCB control is verified by zero/pole plots, transient analyses and experimental results.

Miniaturized dual‐band loop‐type ground radiation antenna with enhanced bandwidth for mobile devices

AbstractIn this article, a miniaturized wide‐band and dual‐band loop‐type ground radiation antenna for mobile devices is proposed. The antenna feed structure, which consists of two shunt capacitors and a shunt inductor, enhances the bandwidth in both bands by generating an additional parallel feeding resonance in each band. Compared to the reference dual‐band loop‐type ground radiation antenna with a single loop feed that only uses a capacitor in series, the bandwidth of the proposed antenna is 1.6 and 2.13 times wider in the low and high bands, respectively under a 3:1 voltage standing wave ratio. The measured results indicate that the proposed antenna provides good radiation performance.

Effect of Nut Consumption on Erectile and Sexual Function in Healthy Males: A Secondary Outcome Analysis of the FERTINUTS Randomized Controlled Trial.

Lifestyle risk factors for erectile and sexual function include smoking, excessive alcohol consumption, lack of physical activity, psychological stress, and adherence to unhealthy diets. In the present study, we evaluated the effects of mixed nuts supplementation on erectile and sexual function. Eighty-three healthy male aged 18–35 with erectile function assessment were included in this FERTINUTS study sub-analysis; a 14-week randomized, controlled, parallel feeding trial. Participants were allocated to (1) the usual Western-style diet enriched with 60 g/day of a mixture of nuts (nut group; n = 43), or (2) the usual Western-style diet avoiding nuts (control group; n = 40). At baseline and the end of the intervention, participants answered 15 questions contained in the validated International Index of Erectile Function (IIEF), and peripheral levels of nitric oxide (NO) and E-selectin were measured, as surrogated markers of erectile endothelial function. Anthropometrical characteristics, and seminogram and blood biochemical parameters did not differ between intervention groups at baseline. Compared to the control group, a significant increase in the orgasmic function (p-value = 0.037) and sexual desire (p-value = 0.040) was observed during the nut intervention. No significant differences in changes between groups were shown in peripheral concentrations of NO and E-selectin. Including nuts in a regular diet significantly improved auto-reported orgasmic function and sexual desire.

Designing Microwave Filters Using Metamaterials

The possibility to use the split ring resonator – SRR in a microwave filter design is investigated. SRR is made from non-ferrous metals, is one of the variants of the inclusions in the metamaterial. The periodic SRR structure modifies the permittivity and permeability of the source material, to obtain a negative refractive index. These unique properties are widely used in microwave technology, because they allow to create devices with improved performance and extended functionality. Microstrip line with etched SRR on ground plane is considered. The equivalent circuit model for SRR is shown. The paper presents calculation and comparison of the return and transmission responses for SRR structure with series coupling feed lines and with parallel coupling feed lines. The basic relationships for calculating the S-parameters (the return S11(F) and transmission responses S21(F)) are given. S-parameter calculation is made. When the reflection coefficient S11(F) reaches the maximum value, and the transmission coefficient S11(F)- the minimum, the filter operates at the resonance frequency Fp. Simulation are made using the software of Microwave Office. The results are presented in graphs. The dependence of the resonant frequency of the filter from the value of the permittivity of the substrate is found. The effect of the type of metal (copper, gold, silver), from which made the SRR on the resonance frequency of the filter is defined. It is concluded that the increase in the value of the permittivity of the substrate causes a decrease in the value of the resonant frequency of the filter. While the type of metal material of the SRR, on the resonance filter properties do not have a significant influence. The research results will reduce the time spent on the design and optimization of the design parameters.

Recent Progress in Synaptic Devices Paving the Way toward an Artificial Cogni‐Retina for Bionic and Machine Vision

In article number 1900003, Dan Berco and Diing Shenp Ang review recent progress in artificial synaptic devices in light of a futuristic visual perception platform. A cogni-retina (“thinking eye”) has the potential to perform image recognition tasks within sub-nanosecond delays whereas software AI algorithms require millions of cycles. It is based on an artificial neural network that captures images as an imprint directly onto an array by altering the bitwise synaptic weights. Image processing can be done by parallel feed forward through successive layers of the same network.