Dual Feed Research Articles

4D printed electro-induced continuous carbon fiber reinforced shape memory polymer composites with excellent bending resistance

Four-dimensional (4D) printing technology of continuous carbon fiber reinforced shape memory polymer composites is a potential manufacturing process for lightweight and high-strength intelligent composite structures. In this study, a 3D printer with dual feed channels based on the fused deposition modeling (FDM) was designed to fabricate continuous carbon fiber reinforced shape memory poly(lactic acid)-based composites (CFRSMPC). The impact of various printing parameters on the bending strength and flexural modulus of 4D printed CFRSMPC was evaluated by the three-point bending test. Meanwhile, mathematical prediction models of bending strength and modulus based on the existing experimental data were established. The electro-induced shape memory effect of 4D printed CFRSMPC was investigated by the electric heating shape recovery test. The shape recovery rate of the specimens was more than 95%, indicating that the resistance heating method is stable and feasible. The quantitative effect of bending angle and temperature on the resistance of CFRSMPC during the programming and recovery process was further investigated. The results demonstrated that the real-time deformation of the CFRSMPC could be monitored by the resistance measurement method. It can be concluded that the CFRSMPC fabricated using the 4D printing method can serve as potential building blocks for electrically activated and deployable structures.

High port isolation of a dual polarized microstrip antenna array using DGS

ABSTRACTIn this paper, high port isolation in dual feed orthogonally polarized square patch antenna array is achieved by the use of Defected Ground Structure (DGS). A simple rectangular-headed cross DGS is implanted in the ground plane underneath the square patch in order to achieve high port isolation between two orthogonal ports at 2.95 GHz. The proposed design offers 58.55 dB port isolation between ports of single element patch and 45 dB that for two-element arrays. The port isolation of microstrip antenna with and without DGS has been studied and the result indicates better port isolation of the array with high cross polarization for two orthogonal polarizations owing to the effect of DGS. Finally, the two-element array is considered for MIMO application and mutual coupling between them is investigated. The simulated results of the proposed antennas are found to be in close agreement with the experimentally measured ones.

Patch Array Antenna Using a Dual Coupled Feeding Structure for 79 GHz Automotive Radar Applications

This letter proposes a novel design for a patch array antenna using a double indirect coupled feeding structure to achieve broad matching and gain bandwidths for automotive radar applications. The proposed radar antenna consists of a microstrip line, a rounded rectangular radiator, and a waveguide feeding structure. The indirect coupled feeding mechanism is first applied to the rounded rectangular radiator, which is placed at an adjacent distance from the microstrip line. To further improve the broad matching and gain characteristics, another indirect coupled feeding structure is applied to the transition between the microstrip line and the waveguide feeding network. To verify the proposed antenna performance, including impedance matching, bore-sight gain, and the radiation pattern, the proposed antenna is measured in a compact antenna test range chamber. The results confirm that the proposed patch array antenna using a double indirect coupled feeding structure is suitable for the 79 GHz radar array.

Beam scanning annular slot‐ring antenna array with via‐fence for wireless power transfer

Wireless power transfer has been the field of research for many decades, and with technological advancement and increase in wireless mobile devices, the future of wireless power transfer technology is very promising. The major requirement of wireless power transfer is an efficient and compact antenna array with high gain and flawless scanning performance. In this article, a 4 × 8 element array is proposed with a gain of 18 dB and scanning capability of ±45° in azimuth and elevation plane at 5.8 GHz. The overall size of the array is 100 mm × 200 mm. The element separation in the array is only 0.48 λ. There was strong mutual coupling due to smaller separation, which has been minimized with the application of via-fence around the antenna element. A dual feed circularly polarized annular slot-ring antenna is proposed and analyzed with via-fence to develop an array of 4 × 8 elements. The antenna array reflection coefficient obtained is less than 20 dB for different scan angles and the gain of the array obtained is also within 2 dB for ±45° scan angles.

Critical Section Channel Maintenance Evaluation Method for Double HVDC Feed-in Grid

In order to ensure stable operation of DC, the dual DC feed grid structure needs to ensure a certain grid strength, but it is necessary to study how to evaluate the impact of critical section maintenance on the AC system. Firstly, the strength evaluation index of the receiving power grid is analyzed. Secondly, an index that characterizes the effects of two DC couplings is proposed. Finally, a critical section channel maintenance evaluation method for double ultra-high voltage DC feed grid is proposed. The effectiveness of the proposed method is verified by the HN Power Grid simulation.

A Compact Dual-Polarized (CP, LP) With Dual-Feed Microstrip Patch Array for Target Detection

A planar antenna is designed to replace complex structures of many rat-races and 90° hybrids used in conventional target detection antennas for receiving radar signals. The proposed antenna has 2 × 2 microstrip patch antenna arrays with dual feeding to radiate symmetric polarizations in the 9.375 GHz ( X -band). The sum (Σ) pattern with circular polarization is implemented through a sequence feeding at port 1. The simultaneous feeding of port 2 radiates a difference (Δ) pattern in all linear polarizations. Thus, the proposed antenna is compact, planar, and has a simple comparator circuit. Measurement results verify the designed prototype, showing that the antenna has a null depth of over 34.5 dB in all polarizations, a peak sum gain 4.51 dB at 9.375 GHz, and a 3 dB axial-ratio bandwidth of 160 MHz.

Design and Analysis of dual feed patch antenna at 3.5 GHz Mid-band 5G Technology

A circularly polarised (CP) patch antenna with dual feed is presented. The antenna consists of a radiating patch, substrate and ground plane. A pair of feed is placed at TM10 and TM01 mode with sam...

Design Approach for a Microstrip Yagi Antenna With a Switched Beam Using Resonant TM10 and TM20 Modes

In this paper, a design approach for a microstrip Yagi antenna with a switched beam using resonant TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> modes is proposed. The antenna consists of a driven patch and two parasitic patches. Initially, a driven patch radiator with two symmetric probes is investigated to determine whether TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> or TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> mode of this patch can be generated by properly exciting the dual feeding ports. The operating bands of the dual modes are reallocated in close proximity to overlap with each other by introducing the shorting pins and narrow slots. Then, two smaller-sized parasitic patches are placed on the right side of the driver to achieve switchable tilted-beam radiation patterns. The results demonstrate that the smaller-sized parasitic patches act as either directors or reflectors when their TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode or TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> mode is excited, respectively. Therefore, the quasi-end-fire beams can be satisfactorily generated and steered in the E-plane by switching these two radiative modes by feeding probes. Finally, a proposed antenna is designed and measured. The measured results show that the antenna operating in TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> modes can achieve a common band of 3.03-3.19 GHz, and their beams are oriented at the directions of +27° and -42° in E-plane patterns, respectively. Most importantly, no RF switches are introduced in our design, thus significantly reducing the complexity and cost of the proposed antenna.

Dual‐port MIMO dielectric resonator antenna for WLAN applications

A dual-port multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) for 5 GHz IEEE (802.11a/h/j/n/ac/ax) is discussed in this article. Two prototypes of single feed DRA and dual feed MIMO DRA are fabricated and measured results are compared with the simulated data. The proposed single feed DRA and dual feed MIMO DRA exhibits wide impedance bandwidth (IBW). Antennas have been fabricated on Rogers RT Duroid substrate with Eccostock made DRA placed over the substrate. DRAs are excited by aperture coupled feed to achieve wide bandwidth and high efficiency. The measured IBW of uniport DRA and dual-port MIMO DRA are 26.6% (4.75-6.21 GHz) and 27.5% (4.7-6.2 GHz) respectively. Maximum gain of the antenna is 7.4 dBi. The results of the antennas are in good agreement with simulated data and they are suitable for WLAN applications. These antennas are also compact with area of substrate 32.8 cm2.

An efficient technique for improving methanol yield using dual CO2 feeds and dry methane reforming

Steam methane reforming (SMR)-based methanol synthesis plants utilizing a single CO2 feed represent one of the predominant technologies for improving methanol yield and CO2 utilization. However, SMR alone cannot achieve full CO2 utilization, and a high water content accumulates if CO2 is only fed into the methanol reactor. In this study, a process integrating SMR with dry methane reforming to improve the conversion of both methane and CO2 is proposed. We also propose an innovative methanol production approach in which captured CO2 is introduced into both the SMR process and the recycle gas of the methanol synthesis loop. This dual CO2 feed approach aims to optimize the stoichiometric ratio of the reactants. Comparative evaluations are carried out from a techno-economic point of view, and the proposed process is demonstrated to be more efficient in terms of both methanol productivity and CO2 utilization than the existing stand-alone natural gas-based methanol process.

Broadband and Efficient Full Wave Rectenna for Wireless Energy

This paper presents a novel approach to realize a broadband full wave rectenna for wireless energy transfer at 2.45 GHz ISM band. The full wave rectenna structure is designed using a center shorted dual edge feed microstrip patch antenna and two Schottky diodes. This antenna is inherently broadband in nature and can provide differential voltage at its two feed points. An optimized full wave rectenna is fabricated and tested. The proposed rectenna provides more conversion efficiency than a rectenna with similar antenna and conventional half wave rectifier.

Microstructural evolution and mechanical properties of deep cryogenic treated Cu–Al–Si alloy fabricated by Cold Metal Transfer (CMT) process

Cryogenic treatment is an effective route to obtain fine grained microstructure in materials. In this work, the effect of deep cryogenic treatment (DCT) on the microstructural evolution and mechanical properties of a copper-aluminum-silicon (Cu–Al–Si) alloy deposited by cold metal transfer (CMT) technology was investigated. Copper-rich Cu–Al–Si alloy with ~8.3% aluminum content was deposited on T2 copper substrate using an innovative dual wire feed system based on CMT technology. The deposited alloy was subjected to DCT for varying time duration (0, 6, 12 and 24 h). Evaluation of microhardness and tensile properties showed that the deep cryogenic treatment enhanced these properties. Microhardness increased about 10% with the increase in the DCT time duration. Under tensile loading conditions, the DCT conducted for 12 h provided the best properties, with an increase in both the tensile yield and ultimate strengths (~20% increase). Microstructural evolution and grain orientation were investigated using Electron Back Scattered Diffraction (EBSD). Microstructural studies revealed the formation of subgrains, fine grains and deformation twins due to DCT. Significant grain refinement was achieved due to the increase in the formation of high angle grain boundaries. It is summarized that the deep cryogenic treatment induces microstructural evolution: (i) grain refinement and (ii) texture randomization, and improves the mechanical properties of Cu–Al–Si alloy.

Zero-Sequence Voltage Elimination for Dual-Fed Common DC-Link Open-End Winding PMSM High-Speed Starter–Generator—Part I: Modulation

In this paper, a dual-fed (DF) common dc-link topology open-end winding permanent magnet synchronous motor for aircraft high-speed starter–generator application is considered. While on one hand the common dc bus configuration significantly simplifies and reduces the costs of the topology, on the other hand it allows the zero-sequence current (ZSC) to flow freely in the system. High-speed machines are characterized by low phase inductance, which implies low zero-sequence impedance. A small time constant of the zero-sequence circuit produces a high-frequency, high-intensity ZSC ripple with the risk of harming the switching devices. This paper presents a novel hybrid space vector pulsewidth modulation that allows to instantaneously eliminate the zero-sequence voltage (ZSV) produced by the two voltage source converters (VSCs) by square wave modulating one of the two VSCs. The non-sinusoidal machine back electromotive force (EMF) has been considered and the effect of the converters’ dead time on the ZSV has been analyzed. The square-wave-modulated VSC uses insulated-gate bipolar transistor (IGBT) devices, whereas the other uses Silicon Carbide (SiC) technology. The proposed topology is tested through both simulations and experiments.

Microstrip patch antenna feed for offset reflector antenna for dual band application

In this article, details of a dual band microstrip patch antenna (MPA) array feed for an offset reflector antenna is presented. The main objective of the proposed structure is to achieve low cross-polarization at Φ = 90° plane in the reflector pattern. Low cross-polar levels in the reflector pattern are achieved by illuminating the reflector with fields of the proposed dual band feed structure. A centered circular array as the dual band feed structure is proposed in which the central radiating element is a dual mode circular MPA operating at 6 GHz and the surrounding circular ring of eight circular MPA elements operating at 4 GHz in the dominant mode. The dual mode central antenna uses the concept of conjugate field matching for cross-polarization reduction. TM21 mode is excited at an appropriate ratio with the TM11 mode to achieve the proper field matching at 6 GHz. The radius of the surrounding circular array is varied to obtain cross-polarization better than −30 dB at both the resonant frequencies. The offset reflector gain is found to be better than 37 dB with a 2.5 m parabolic reflector and F/D = 0.8 at both the operating frequencies.

Design of compact dual-band patch antenna loaded with D-shaped complementary split ring resonator

ABSTRACTIn this paper, an inset-fed dual-band patch antenna with truncated corners is presented. The ground plane of the antenna is loaded with D-shaped complementary split ring resonator (D-CSRR) structures to obtain dual-band resonance and size miniaturization. The overall electrical size of the antenna is 0.29λ0 × 0.25λ0 and patch size is 0.14λ0 × 0.13λ0, where λ0 is evaluated at the lowest resonating frequency. The proposed planar antenna is low profile and does not need a dual feed or any external feeding mechanism for obtaining circular polarization. A size reduction of 66% is achieved as compared to the conventional patch antenna. The newly designed D-CSRR results in better miniaturization factor making proposed antenna suitable for modern wireless applications. The prototype of the antenna is fabricated and experimental findings are compared with electromagnetic and analytical results.

Development of Dual Band Feed

In this paper, Development of dual band feed operating in C and Ku bands to obtain high illumination and spill over efficiencies and high cross polarization discrimination, maximum gain and low side lobes for shaped Cassegrain Antenna of larger diameter is presented. The Design envisages a common aperture C and Ku band corrugated horn. Corrugated horn of suitable dimensions for the propagation of hybrid modes in both C and Ku bands having equal beam widths in principal planes (E&amp;H) and pattern of rotationally symmetric radiation will be illuminating the shaped sub reflector in modified Cassegrain geometry. The corrugated horn is designed to operate over a frequency range of C (3.4-4.8 GHz) and Ku (10.7-12.75 GHz) bands. CHAMP is used to simulate and analyze the designed model.

A dual feed PIN diode based switchable multiband planar meandered antenna for intelligent transportation system application

This article presents a dual feed switchable coplanar linearly polarized multiband meandered microstrip patch antenna. The antenna provides multiband functionalities with switching allowable at one of the nine adjacent frequencies. The proposed antenna, loaded with two symmetric PIN diodes, comprises dual-patch configuration and excited by coplanar microstrip feeds, it operates within 1 to 15 GHz frequency bands. The induced current of the antenna can be changed by switching the diodes, resulting in different operating frequency bands. The antenna has a nearly broadside radiation pattern and the impedance bandwidth is obtained up to 47% having a center frequency of 2.4 GHz for band range of 1 to 15 GHz. The measured gain of the antenna for 1.57, 2.4, 4.5, 4.71, 5.9, 6.53, 7.59, 10.8, and 11.87 GHz are 5, 5, 7, 6, 6.1, 4.4, 3.8, 3.5, and 1.87 dBi, respectively. The antenna has advantages of the simple biasing network, easy fabrication, and adjustment. It is suitable for many modern wireless communication systems like intelligent transportation system. This antenna is also useful in direct broadcast satellite applications.

The role of amino acids in the amplification and quality of DNA vectors for industrial applications.

In this study, we have demonstrated that the type and feeding regimen of amino acids have a significant impact on the quality as well as the quantity of DNA vectors produced. Nutrient pool and factorial design experiments were carried out in order to identify the amino acids involved in increased biomass and induction of plasmid amplification. Leucine, glycine, and histidine were responsible for increased biomass and leucine starvation in the presence of histidine was implicated in plasmid amplification. Supercoiling of the plasmid was optimized using a dual feeding strategy. As a result of this, a fed-batch fermentation strategy for the production of a 6.9 kb plasmid, pSVß, in Escherichia coli DH5α was developed. In batch fermentation, a maximum plasmid yield of 39.4 mg/L equivalent to 11.3 mg/g dry cell weight (DCW) was achieved with casein hydrolysate limitation. About 90% of plasmid was in the supercoiled (SC) form after 31 hr of fermentation but only remained so for a short period, leading to a very brief window for harvesting cells at scale. Subsequently, a fed-batch fermentation using a dual feeding strategy was employed. A mean maximum plasmid yield of 44 mg/L equivalent to 9.1 mg plasmid/g DCW was achieved. After 25 hr, 90% of plasmid was in the SC form and remained at this level for the remaining 10 hr of the fermentation, allowing adequate time for the harvesting of cells without the loss of supercoiling of product. This study emphasized that optimizing fermentation strategy and identifying the essential nutrients are beneficial for bioprocessing of plasmid DNA for therapeutic applications.

Development of a menaquinone-7 enriched functional food

There is increasing interest in the development of fortified foods enriched in menaquinone-7 as high dietary intakes may reduce the incidence of osteoporosis and cardiovascular calcification. In this work we explore the potential of using food ingredients as fermentation substrates for the development of such products. It was found that a combination of soy protein and glycerol was the most suitable for MK-7 production. The process was scaled-up; use of a dual feeding strategy was found to avoid foaming and improve MK-7 production. The MK-7 titre and productivity were 99mgL−1 and 2.1mgL−1h−1 respectively, amongst the highest values reported in the open literature. Finally, the resulting product was formulated into a food (soymilk); it was found that 75% of the MK-7 remained after 24 weeks of room temperature storage. These results clearly demonstrate an approach to utilise food ingredients for the production of MK-7 enriched functional foods.

A Novel Fault Classification Technique in Series Compensated Transmission Line using Ensemble Method

The paper presents a novel approach for classification of faults in Extra High Voltage (EHV) transmission line with series compensation. The proposed algorithm utilizes single end currents extracted from three phases of a transmission line given to a fault detection and classification system. A detailed model is constructed to analyze fault patterns occurring on a dual feed system with multiple series compensation provided on EHV transmission line. The algorithm uses a full cycle of post-fault currents. A Multiresolution Analysis Wavelet-based decomposition technique is used to provide a joint time frequency analysis. Extensive study is done by designing different fault classifiers using Support Vector Machine (SVM) with different feature vector groups. The SVMs with different parameters are compared to show performance of SVMs in given feature space of faults. A new algorithm is proposed with Ensemble method having group of different classifiers, namely, Artificial Neural Network (ANN), K-Nearest Neighborhood (KNN) and SVM. A combination of feature selection with Ensemble Classifiers is trained and tested on a wide range of fault patterns. A significant improvement in performance is obtained with different combination of features in Ensemble Classifier using subspace partition method.The proposed Ensemble Classifier provides an accuracy of 99.5%.