Search

AbstractIn this paper, a novel one-dimensional (1D) phononic crystal fiber with conical entrance has been proposed for energy harvesting application. The cladding part of the phononic fiber is 1D phononic crystal which is included 4 layers of steel and 3 layers of epoxy resin materials. Also, an epoxy resin rod has been considered as core. The energy harvesting working frequency is 50 kHz, so in the first step, we focus on designing the 1D phononic crystal. Next, optimized 1D phononic crystal has been selected as phononic crystal cladding. The most important parameter to adjust the working frequency of phononic fiber is the radius of core. For obtaining the electrical output, a piezoelectric film is considered at the end of phononic crystal fiber. A conical entrance is designed to couple the acoustic wave from environment to core region. Simulation of structure has been done by finite element method. Achieved results show that incident acoustic waves can confine in the core region. The comparison of output voltage with the bare case shows a 70 times enhancement for the proposed structure. [ABSTRACT FROM AUTHOR]

AbstractBackgroundAims/ObjectivesMaterials and MethodsResultsConclusions and SignificanceThe Vibrant Soundbridge Implant provides multiple options for coupling the Floating Mass Transducer (FMT) to the ossicles. A parametric evaluation in clinical trials is difficult.We studied the vibratory output of the FMT with three couplers—short process, former long process, and current long process—in an acoustic-mechanical middle ear model (AMEM) under simulated impaired coupling conditions.The AMEM, with life-sized ossicles, was tested via acoustic and electrical (FMT-) stimulation. Simulated impairments included accidental bone-contact, cable tension, and insufficient connection. Stapedial footplate vibrations were measured using Laser Doppler.Acoustic stimulation generally fulfilled the ASTM standard. With normal coupling, SP- and LP-couplers performed comparable to temporal bone data. Impaired coupling led to various effects: bone-contact reduced the transmission up to 20 dB, cable tension minimally affected SP and current LP couplers but reduced the sound transmission for the former LP coupler. Connecting the SP-coupler with only two of four titanium legs caused a single frequency dip without affecting overall magnitude, whereas off-axis LP fixation reduced the output by 15-20 dB around 1000 Hz.The AMEM generated reproducible, ASTM-compliant measurements. SP and current LP couplers showed resilience to potential FMT implantation impairments in most frequencies. [ABSTRACT FROM AUTHOR]

This paper presents a novel optimization-based procedure for designing a multi-band branch-line coupler with arbitrary output power division ratios and phase differences that are distinct at each of arbitrarily-allocated design frequencies. The procedure aims to find the optimal parameters of the design that result in the best possible performance while maintaining the deviation from the desired specifications within a predefined tolerance level. This procedure uses the analytical S-parameters of the proposed coupler which are derived using even-odd mode analysis. A tri-band (1.5/2.4/4.2 GHz) and a quad-band (1.5/2.4/3.5/4.2 GHz) microstrip prototypes are developed using the proposed procedure to have band-distinct power division ratios and phase differences. For validation, both prototypes are simulated, fabricated, and measured. At all operating frequencies, the measured deviations from the desired power division ratios and phase differences are within 1 dB and 10$^\circ$, respectively. Also, the measured matching and isolation are $< $ −11 dB at all design frequencies. The achieved measurement results and the agreement between measured results and theoretical expectations demonstrate the applicability of the proposed design procedure in practice. The proposed coupler is a candidate for use in analogue multi-band multi-beam antenna arrays, and the proposed design procedure can be applied in designing other multi-band microwave devices.

Wireless power transfer (WPT) technology applied to underwater environments has the advantages of no electrical contact, high safety, and high applicability. Underwater capacitive power transfer (UCPT) technology shows great potential in the field of underwater wireless power transfer as it has more advantages compared to underwater inductive power transfer (UIPT) technology. This paper begins with the system principles of UCPT and explains the advantages of UCPT technology for underwater applications. It then reviews the coupler and equivalent circuit models currently used for UCPT in various underwater environments, which indicates the direction for the design of underwater couplers in the future. In addition, compensation networks currently applied in UCPT systems are summarized and compared. Furthermore, different application examples of UCPT are introduced, and the key factors constraining UCPT development are pointed out. Research directions for future development of UCPT technology are also investigated. [ABSTRACT FROM AUTHOR]

In this paper, we present the current stage of development of the INM-CM Earth system model family by the Marchuk Institute of Numerical Mathematics of the Russian Academy of Sciences. The major change from the previous model version INM-CM5 is a new computational platform for the Earth System modelling. We describe the main parts of this digital platform, such as ocean-atmosphere coupling, version control, compilation/configuration, and automated testing subsystems. We also discuss major modifications of the physical parts of the climate model whereby the model simulations of observed climate were significantly improved as well as the model computational performance. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Key Clinical Message: Topical papaverine is an effective vasodilator that can be used for dilating small veins to accept venous couplers for thumb replantation. This technique corrects size mismatches for successful venous anastomosis and minimizes postoperative complications. Thumb replantation is a complex microsurgical procedure used to restore function and appearance after amputation. A successful venous anastomosis is essential in replantations; however, venous couplers can mismatch the size of veins and lead to obstacles. A 26‐year‐old male presented with a left thumb amputation caused by an electric saw injury. The amputated thumb was preserved and replantation surgery was performed 9 h post‐injury. The digital artery and veins were repaired but a size mismatch was found between the only salvageable superficial vein (0.7 mm) and the smallest available venous coupler (1 mm). The vein was dilated to accept the coupler by a series of applications of topical papaverine (1 mg/mL). This allowed venous anastomosis to be accomplished in 25 min. Postoperative follow‐up showed good thumb function, sensation, and circulation. Venous anastomosis is vital in thumb replantation to avoid venous congestion hence survival of the replanted thumb. Venous couplers shorten operative time and decrease the risk of postoperative complications. Papaverine is a vasodilator and facilitates venous anastomosis when veins and couplers are mismatched. This case demonstrates how papaverine, a vasodilator, may be used to improve surgical outcome during thumb replantation when small veins prevent venous coupler use. [ABSTRACT FROM AUTHOR]

In this paper, we propose an ultra-wideband magic-T operating in the frequency band from 1.2 to 4 GHz with a relative bandwidth of 108%, which is based on an interlayer coupling 3 dB directional coupler and a branch-loaded 90° phase shifter. Compared to traditional magic-T structures, it can operate within an ultra-wideband range and has the advantages of a simple structure and easy processing. Simulation and experimental results demonstrate excellent amplitude and phase stability. When the input is at the sum port, the phase error at each output port is less than 2.8°. For the difference port input, the phase error at each output port is less than 7.6°. Furthermore, the overall amplitude imbalance is less than 2.1 dB, the transmission coefficient is below -7.4 dB, and the isolation is greater than 11 dB. It can be used in ultra-wideband phased array systems to generate sum-and-difference beams for direction finding. [ABSTRACT FROM AUTHOR]

This paper introduces a modified continuous mode class‐GF power amplifier (PA) incorporating a phase shift parameter to modify the drain voltage waveform. This modification significantly boosts the overlap area between the fundamental impedance and the second harmonic impedance, thereby providing increased flexibility in designing a broadband matching network. Additionally, a straightforward modified coupler network is proposed to effectively accommodate the expanded impedance design space. Experimental validation was conducted with a PA operating within the frequency range of 0.5–3.5 GHz. The results affirm the efficacy of the proposed approach, with the saturated output power ranging from 40.0 to 42.5 dBm, accompanied by a gain exceeding 10 dB. Furthermore, a remarkable drain efficiency ranging from 59% to 76.2% is achieved within the targeted frequency band. [ABSTRACT FROM AUTHOR]

The ANTHEM (Advanced Technologies for Human-centered Medicine) Radio-Frequency Quadrupole (RFQ) will employ eight coaxial power couplers, which will be magnetically coupled to the device through a loop antenna. The coupler design can support up to 140 kW in continuous wave operation. This paper presents the design of the cavity used for high-power testing, with the primary objectives of both optimizing the coupling between the couplers and ensuring operations at the designated operating frequency. Furthermore, the paper encompasses thermal and structural assessments conducted through numerical simulations. [ABSTRACT FROM AUTHOR]

Synthetic aperture radar (SAR) is a powerful tool in remote sensing applications that can produce high-resolution images and operate in any weather condition. It is composed of many RF components, such as the IQ mixer, which mixes the base chirp signal (IF) with the carrier signal (LO) and increases the bandwidth of the transmitted signal to twice the maximum frequency of the base chirp signal, reducing the workload of Programmable Field Gate Arrays (FPGA) and increasing the resolution of the SAR system. This research proposes a power combiner–splitter design that will be used as a supporting component to construct the IQ mixer in SAR applications based on a rat-race coupler. The measurement results show that the coupler has good S-parameter values.  S 11 ,  S 22 , and  S 33  have a low reflection value below −17 dB,  S 13  has a high isolation value below −22 dB, and  S 21  and  S 31  have a low attenuation value below −4 dB with amplitude unbalance below 0.1 dB and phase unbalance below 1 ° . The 150 MHz requirement bandwidth for the RF signal is also achieved. [ABSTRACT FROM AUTHOR]

The deployment of power line communication (PLC) has gained tremendous attention in recent times because of the dawn of the internet, the increasing need for fast connectivity, and it does not require any new wiring installations which significantly reduces the deployment costs. Power lines are originally designed to transmit power from the suppliers to the customers at low frequency (50 Hz or 60 Hz). They are used to improve communication infrastructure, therefore making them useful as a communication channel. This paper presents an investigation of the use of the existing power grid line as a medium for Broadband communication by using orthogonal frequency division multiplexing (OFDM) technology at the transceiver. The transmitter performs coding of data signals to keep it from fading and radiation. In order to repair signals attenuated and affected by noise during transmission over the power line, the decoupling and OFDM receiver performs filtering and decoding, respectively. In the OFDM transmitter, quadrature phase-shift keying (QPSK) modulation as well as the OFDM receiver QPSK demodulation are used to create a set of data symbols and to predict the probability of errors. An error of 0.036 dB was obtained, which is in the allowable range of signals with good quality to be transmitted to the customers. The Coupling circuit is used as the heart of the system design and is used to insert the modulated signals from the transmitter to the power line. It is also used to extract the signals from the receiver, and to protect the circuit from medium and low voltage and low-frequency signals (less than or equal to 32 kV and 50 Hz). [ABSTRACT FROM AUTHOR]

Abstract In this paper, a novel phononic crystal fiber with conical input is introduced for coupling environmental acoustic waves to the fiber core. Environmental acoustic waves can be focused and coupled to the core through conical input. In the first step, a cone shape coupler has been considered for coupling the incident acoustic waves to the core region. This initial idea has a significant acoustic energy loss. This disadvantage encourages us to design a new phononic crystal fiber without it. Designed structure includes a phononic crystal fiber with conical input meaning solid rods have been shaped in conical way at the input section of fiber. By using this structure, environmental acoustic waves can be properly coupled to the core region of the fiber. Acoustic wave leakage to outside of the Phononic crystal fiber has been extremely decreased in comparison with initial coupler. Experimental results indicate that environmental acoustic waves can be focused and coupled to the core region by phononic crystal fiber with conical input.

Memory‐steel for smart steel structures – a review on recent developments and applications This study comprehensively examines recent advancements in the development and utilization of iron‐based shape memory alloy (Fe‐SMA), commonly known as memory‐steel, within the retrofitting of steel structures. The discussion is structured into several key areas. Initially, a thorough analysis of the material properties of Fe‐SMA is presented, focusing on aspects such as shape memory effect and super‐elasticity. Subsequently, the application of Fe‐SMA in prestressed strengthening of steel structures is elucidated, encompassing its role in reinforcing steel girders, connections, and addressing fatigue crack repairs. Various strengthening methodologies are explored, including the utilization of mechanically anchored or adhesively‐bonded Fe‐SMA. The study delves into an in‐depth examination of the behavior exhibited by Fe‐SMA‐to‐steel bonded joints. Notably, the research highlights the practical application of Fe‐SMA in strengthening a 113‐year‐old steel bridge. Furthermore, innovative applications of Fe‐SMA as pipe couplers are introduced, showcasing its versatility in diverse structural contexts. [ABSTRACT FROM AUTHOR]

Copyright of Micronanoelectronic Technology is the property of Micronanoelectronic Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Probe microphone measurements are an essential step in an individualized hearing aid fitting. These measurements allow audiologists to account for the individual's hearing and ear canal acoustics when programming hearing aids. An evidence-based hearing aid fitting includes matching the measured output of the hearing aids to targets for each input level and frequency. This allows the audiologist to confidently counsel the patient that the acoustic fitting is accurate, and the next step is for the individual to use the amplification during all waking hours to adapt to the newly amplified sounds. This also avoids mistakes such as overamplification or insufficient gain, which can endanger the patient and/or lead to a compromised fitting. [ABSTRACT FROM AUTHOR]

In this chapter you will be introduced to the hearing aid test box equipment and work through how to prepare the equipment so that it is ready to provide the testing you will use to evaluate, fit, and troubleshoot hearing aids and other amplifiers. At the end of this chapter, you will be familiar with terminology associated with hearing aid test box measures and the leveling required with the reference microphone and coupler microphone to ensure that your measurements are accurate and can be interpreted. [ABSTRACT FROM AUTHOR]

In this paper, a 3 dB 90-degree hybrid coupler with size reduction and harmonics rejection was designed. In the proposed coupler structure, four simple low-pass filters (LPFs) were applied. An artificial neural network (ANN) was used to determine the dimensions of the applied LPFs based on EM simulation data. The applied ANN model could also provide the desired LPF parameters, including the cut-off frequency (fc), bandwidth (BW), and insertion loss (IL). Designing an applied LPF involves complex mathematical calculations and simulations to optimize parameters. However, by utilizing neural networks, the design process can be significantly streamlined and automated. Neural networks have the ability to learn complex patterns and relationships within data, making them well suited for optimizing the performance of applied components. The proposed 90-degree hybrid coupler works correctly at 1800 MHz and has a small size of 16.6 mm × 15.15 mm, which provides a 73% size reduction compared to a normal 1800 MHz coupler. The designed coupler not only decreases the circuit size but also provides a wide rejection band from 4.8 GHz to 11.2 GHz, which suppresses the second to sixth harmonics. The insertion loss parameter of this 90-degree hybrid coupler is less than 0.1 dB at the working frequency, which shows the superior performance of the proposed coupler. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRAK IQ Mixer adalah komponen yang penting pada subsistem RF Synthtetic Aperture Radar (SAR) karena berperan untuk melakukan proses Single Side Band (SSB) modulation antara sinyal qudrature base chirp (IF) dengan sinyal carrier (LO), sehingga mampu menurunkan beban kerja Field Programmable Gate Arrays (FPGA) dan meningkatkan resolusi sistem SAR. IQ Mixer tersusun dari satu Quadrature LO Phase Shifter, dua Matched Mixer dan satu Power Combiner-Splitter. Pada penelitian ini dipaparkan mengenai perancangan Matched Mixer yang dibuat dengan menggunakan anti-phase coupler dan konfigurasi double balanced mixer. Anti-phase coupler yang digunakan merupakan modifikasi dari qudrature coupler dengan tujuan untuk menghindari interferensi karena adanya saluran transmisi yang saling menyilang. Hasil pengukuran menunjukkan bahwa anti-phase coupler memiliki nilai phase unbalance dibawah 1°, amplitude unbalance dibawah 0,6 dB dan untuk double balanced mixer memiliki nilai conversion loss (CL) sebesar 9,58 dB. Kata kunci: Coupler, Matched Mixer, IQ Mixer, Synthetic Aperture Radar ABSTRACT IQ Mixer is an important component in the RF Synthetic Aperture Radar (SAR) subsystem that plays a role in carrying out the single side band modulation process between the quadrature base chirp (IF) signal and the carrier (LO) signal, thereby reducing the workload of the Field Programmable Gate Arrays (FPGA) and increasing the resolution of SAR systems. IQ Mixer is composed of a Quadrature LO Phase Shifter, two Matched Mixers, and a Power Combiner-splitter. This research describes the process of designing a matched mixer, which is made using an anti-phase coupler and a double-balanced mixer configuration. The anti-phase coupler is a modified version of the quadrature coupler to avoid interference due to crossing transmission lines. The measurement results show that the anti-phase coupler has a phase unbalance value below 1°, an amplitude unbalance below 0.6 dB, and the double-balanced mixer has a conversion loss value of 9.58 dB. Keywords: Coupler, Matched Mixer, IQ Mixer, Synthetic Aperture Radar

Current wireless communications urgently need to provide huge data rates, high gain and high directivity radiation pattern beams. Therefore, beamforming networks (BFNs) are introduced to provide these needs. Butler matrix (BM) is a type of beamforming network, which can be realized using fixed network circuits and feeds the antenna array. BM at high frequency suffers from components loss and phase error for massive network, especially when it is implemented using common microstrip structures. Different transmission lines such as waveguide and substrate integrated waveguide (SIW) are studied and introduced to realize Butler matrix. SIW structures are good candidate for the implementation of BM due to its property of low loss transmission line which comprises of properties of microstrip and waveguide technology. However, SIW antennas and structures at millimeter waves have unwanted radiation loss coming from the vias holes. In addition, the vias separation distance is dependent on waveguide size, which leads to a more massive beamforming network at 26-GHz. Hence, this thesis is proposing a more size-friendly and optimal SIW antenna beamforming structure to reduce the vias loss and provides higher bandwidth and gain at 26 GHz. The BM components such as 3 dB coupler, 0 dB crossover, and 45-degree phase shifter are designed by implementing metallic vias determination method. Size and distance of vias are the most important factors in determining the coupling ratio and phase shifts at output ports. Hence, the coupler is designed with different vias width and distance to obtain the correct phase and coupling at output ports. Then, the designed coupler is cascaded to form a 0-dB crossover. The phase shifter is designed with alerting vias distance inside the coupling area of SIW structure. The last component in beamforming is the design of SIW slot antenna based on longitude slot distributions. All the components are integrated to form a $4\times4$ BM with four slot antennas attached to BM networks. Microtrip separation feedline used to for coupler, crossover, BM and BFN. The proposed designs are simulated using CST software and fabricated by PCB LPKF ProtoMat printer. The outcomes of wide bandwidth with more than 1-GHz and high directive gain of more than 10-dB for the beamforming network are achieved. The output power of the BM is between −6-dB to −8-dB at all four ports with phase difference error less than 5°. Four directive beams are achieved at beam scanning of −14°, −41°, 40°, and −14° at port 1 to port 4 respectively. Hence, this $4\times4$ -BM with four slot antenna theses have introduced a successful design of an antenna beamforming network based on SIW technology with significant characteristics at 26-GHz.

This paper investigates and implements a miniaturized microwave system for microstrip linear array antenna that operates in X-band (10.1 GHz), S-band (3.4 GHz) and C-band (5.6 GHz). The microwave system consists of three parts: a power divider, a directional coupler, and a matching network stub. These systems feed a linear array (16 elements) of patch antennas loaded with resonance planar omega structures array (160 elements) distributed in both patch (64 elements) and ground (96 elements) as the metamaterial structures for miniaturization purpose. The 1-to-2 divider feeds two directional couplers that act as phase shifters. The couplers fed a set of 1-to-4 dividers that in return feed a series of patch antennas. The system has been simulated and measured using microwave analyzer. The system is designed, analyzed and implemented using Roger substrate of thickness 1.27mm and 10.2 dielectric constant and simulated using HFSS. The proposed miniaturized array introduces a gain of 8, return loss of -24 dB and radiation efficiency of 90%. There is a good agreement between the simulation results and the measured values. The proposed array covers applications in mobile communication systems and Wi-MAX.

This paper presents a Ka-band beam steering transmitter exploiting a coupled varactor loaded transmission line (VLTL) phase shifter and a CMOS transmitter chip with an integrated frequency multiplier. The short-coupled line couplers placed along a single VLTL provides multi-phase outputs while minimizing the impedance mismatch and unequal power distribution along the VLTLs. The inherent phase-accumulating nature along the VLTL reduces the burden of wide phase control range required for using separate phase shifters for each channel. Additionally, the frequency multiplier with a multiplication ratio of 8 reduces the required amount of phase change at the reference frequency and therefore the tuning range of the varactor, which also minimize a change of line characteristic impedance to ensure the impedance matching of the VLTL. Hence, a 32 GHz phased array transmitter is implemented using a single VLTL phase shifter operating at a low reference frequency of about 4 GHz. The fabricated $1\times 4$ phased array transmitter achieves a continuous beam steering range of ±20° in the E-plane using a single control voltage. The sidelobe level is below -10 dB at all scan angles and the peak effective isotropic radiated power (EIRP) is 38.1 dBm at 31.6 GHz and the 3-dB bandwidth of 2.4 GHz is achieved.

Based on stub loaded meandrous coupled lines, a novel microstrip coupler is designed, fabricated and measured for wireless applications. It is very compact with high performance. The size of this coupler is only $0.0028 \; \lambda $ g2, where it operates at 875 MHz. The values of S11, S21, S31 at the operating frequency are -24.97 dB, -3.058 dB and -3.033 dB respectively. Therefore, the insertion losses are very low and the magnitudes of S21 and S31 are well balanced. The phase imbalance at the operating frequency is 0.5°. From 790 MHz up to 1.18 GHz, S11 is better than -10 dB, the maximum phase imbalance is lower than 4.5° and the maximum magnitude imbalance is lower that ±0.5 dB. Therefore, it has 40% fractional bandwidth (FBW) that covers 0.79 GHz to 1.18 GHz. Its in-band isolation factor is better than -25 dB. The important advantages of this coupler compared to most of the previous designs is having a filtering frequency response and having flat passbands with a maximum group delay of 1 ns.

The need for size and cost-efficient vector network analyzer (VNA) frequency extension modules (VNAX module) is driven by new applications in research and industry. Responding to this potential demand, we present a novel D-band VNAX module based on a single SiGe MMIC. Our work addresses the challenges associated with integrating components on a single chip compared to conventional commercial modules, which typically rely on discrete components. We provide a comprehensive discussion covering the performance of system blocks, such as multiplier chains and receivers, and their impact on the module's performance. In addition, we present extensive measurements of the entire system, including magnitude-and phase stability and dynamic ranges. At a resolution bandwidth (RBW) of 10 Hz, our module shows a system dynamic range (SDR) above 90 dB for the frequency range of 110 GHz to 151 GHz and a maximum SDR close to 100 dB at 122 GHz. The corresponding receiver dynamic range within the D-band ranges from 113 dB to 125 dB, and the Test Port power is between −27 dBm and −16 dBm. In addition, we present and evaluate several measurements of different passive components that verify the calibration capability of our module.

Pemilihan metode penyambungan tulangan untuk perkuatan struktur kolom merupakan suatu keputusan yang penting karena mempengaruhi biaya, waktu dan kualitas konstruksi. Ada beberapa macam metode yang telah berkembang dari metode konvensional diantaranya metode coupler dan welding. Metode coupler adalah penyambungan mechanical splice yang menyambungkan kedua ujung tulangan dengan pembuatan ulir atau pengepresan ujung tulangan, sedangkan welding adalah proses menyatukan dua logam atau lebih menjadi bentuk sambungan menggunakan proses panas, pencairan dengan elekroda atau filler. Penelitian ini dilakukan pada Proyek Revitalisasi Pusat Kesenian Jakarta Taman Ismail Marzuki. Proyek ini memiliki permasalahan pada metode penyambungan tulangan kolom pada basement 1 ke lantai 1 karena adanya strutting dinding penahan tanah. Jadi dibutuhkan metode tambahan untuk penyambungan tulangan kolomnya. Metode yang digunakan pada pelaksanaan proyek adalah metode coupler, pada penelitian ini akan dihitung berapa biaya dan waktu jika digunakan metode welding. Tujuan penelitian ini adalah menghitung biaya dan waktu dengan penerapan metode coupler dan welding pada Proyek Revitalisasi Pusat Kesenian Jakarta Taman Ismail Marzuki. Dari hasil penelitian, didapatkan bahwa biaya pekerjaan kolom dengan metode coupler sebesar Rp. 2.496.157.849,00 dengan waktu pelaksanaan 81 hari. Sedangkan biaya metode welding sebesar Rp. 2.529.332.648,00 dengan waktu 83 hari. Penerapan metode coupler 3,8 % lebih murah dan 2 hari lebih cepat dibandingkan dengan metode welding.

Ridge gap waveguide is one of the new technologies in the field of waveguides. Their advantages include being planar, low cost of construction, shielding by metal without the need for problems related to packaging, the formation of a narrow gap enclosed between two metal plates, realization of the texture on one of the metal plates, and lower losses. These structures have no mechanical connection. While electric currents must flow in them. In this article, two graphene-based ridge gap waveguide coupler structures are presented. The designed structures are used in the THz band. By using graphene in the THz frequency band, frequency reconfigurable can be achieved. The chemical potential of both the designed ridge gap waveguide coupler is considered to be 0.6 eV. S-parameters curves, phase difference diagrams, and e-field distributions are reported for two graphene-based ridge gap waveguide couplers. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The construction of reinforced concrete (RC) structures inevitably consumes an excessive number of rebars, leading to significant cutting waste and carbon emissions. Extensive research has been conducted to minimize this issue and its consequences; however, these methods consistently consume a substantial number of rebars. This includes a previous study that utilizes the lap splice position optimization and special-length rebar concept without considering the lapping zone regulation. Moreover, conventional lap splices pose inherent drawbacks that could jeopardize the structural integrity of RC members. In contrast, mechanical couplers eliminate the need for rebar lapping, effectively reducing rebar consumption. This research aims to evaluate the impact of an integrated mechanical coupler and special-length-priority minimization algorithm on the reduction in rebar consumption and cutting waste in RC columns, achieving near-zero cutting waste. To validate the effectiveness of the proposed algorithm, it was applied to the column rebars of an RC building. The results revealed a significant reduction in the ordered rebar consumption by 18.25%, accompanied by substantial reductions in the cutting waste (8.93%), carbon emissions (12.99%), and total costs (9.94%) compared with a previous study. The outcomes provide the industry with insights into further reducing rebar consumption and its related consequences. Applying the proposed algorithm to various construction projects will further amplify the corresponding benefits. [ABSTRACT FROM AUTHOR]

A novel design method based on a novel origami process that can create a solid structure swiftly and at a low cost is presented for rectangular waveguide-type microwave devices in this paper. A planar structure was fabricated by the lamination and laser cutting of polystyrene membranes and aluminum foils and was converted into a solid structure via origami in accordance with the selective absorption of infrared light. A rectangular waveguide, a rectangular waveguide-type coupler, and a power divider based on an origami structure with a multi-layer structure and a single-layer structure were fabricated and tested, demonstrating easy assembly and good microwave performance. The measured results of the rectangular waveguide indicated that the insertion loss was superior to −0.9 dB. Meanwhile, the results of the coupler showed that the coupling degree increased from −12.8 dB to −8.9 dB in the range of 11.0 GHz to 12.0 GHz. Correspondingly, the prepared power divider demonstrated that the return loss dwindled from −8.9 dB to −11.3 dB and that the insertion loss of one output port was approximate to that of the remaining one, varying between −3.5 dB and −5.2 dB in the range of 10.5 GHz to 11.5 GHz—verifying the effectiveness of the origami-based design method. [ABSTRACT FROM AUTHOR]

Symmetry is a key factor for Branch-Line Couplers (BLCs) in RF and microwave systems. This balanced approach evenly distributes power between two output ports, aiding impedance matching and reducing unwanted coupling and crosstalk, while increasing inputoutput isolation. Furthermore, the symmetrical design of BLCs ensures favorable return loss and phase balance, which are essential for phase-sensitive detectors and beamforming. This symmetry also guarantees consistent performance over a wide frequency range, making it suitable for broadband or multi-frequency applications. We present a compact BLC operating in two frequency bands, ideal for 5G sub-6 GHz applications. It uses Tshaped lines with folded lines and stubs in a Minkowski fractal shape, resulting in a size reduction of 90%. The design and simulation were performed using the CST Microwave Studio at 0.7 GHz and 3.5 GHz, achieving a new high frequency band ratio of 5. A prototype on Rogers RT5880 substrate (εr = 2.2, h = 0.787 mm) was tested to validate the design's effectiveness, offering potential for modern wireless applications requiring versatile frequency band operation. [ABSTRACT FROM AUTHOR]

We propose an Fiber Bragg Grating (FBG) peak detection method using edge-filtering technique with Long Period Grating (LPG)-modulated light source. A low loss-band of LPG is chosen, where the intensity varies linearly over a certain wavelength range. The broadband light source is passed through the Long Period Grating and split using a 3 dB coupler. The modulated light is separately fed to two FBG using Y-couplers. The reflected lights from FBG are measured using optical power meter. The variation in the FBG peak wavelength due to measurand will cause change in the light power detected by the power meter. The proposed method of FBG peak detection is simple, dynamic, and cost-effective. The technique has been experimentally implemented for measurement of strain and temperature and the corresponding sensitivities are obtained as 1.01 pm/με and 9.8 pm/°C. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel analytical design technique to implement a miniaturized 3-way power divider (3PD) supporting a wideband operation with a band ratio from 1-6.5. The proposed 3PD configuration comprises four distinct commensurate transmission lines and two different isolation resistors. A comprehensive theoretical analysis is conducted to arrive at a set of completely new and rigorous design equations by utilizing the text dual-band behavior of the commensurate transmission line and the recombinant approach. Additionally, corresponding text S-parameter equations are derived, which manifest the wideband capability of the proposed 3PD, as validated through several design examples. A fabricated prototype of the proposed technique exhibits excellent input return loss (>15 dB), output return loss (>15 dB) as well as insertion loss (< 5.32 dB), with remarkable isolation (>16 dB) from 0.94-2.24 GHz and even achieves a fractional bandwidth of 132% (band ratio=4.96) considering a 10 dB reference. The different features and performance provided by this simple yet compact planar structure make the design an ideal choice for applications such as microwave ICs, antenna feed networks, and Doherty power amplifiers.

This work presents the design of a compact dual-port circularly polarized antenna based on the new coupler topology. The antenna can radiate a right-hand circular polarization (RHCP) in two opposite directions depending on the input port. In the proposed structure, the radiating system has three inverted F antennas connected to a 120° hybrid coupler. The modeling and design of the 5-ports hybrid coupler are described and experimentally validated. The antenna prototype is fabricated using two 1.6mm-thick low-cost FR4 Epoxy substrates assembled with metal wires, with a dimension of 80mm $\times80$ mm $\times12$ mm (ka $ < 0.74$ ). The proposed antenna provides the realized RHCP gain of 2.4 dBic and 1.8dBic at 868 MHz for Port 1 and Port 2, respectively.

In this paper, a compact filtering coupler is presented using a new microstrip configuration. To improve the frequency response, achieve good phase balance and reduce the losses of the proposed coupler, an optimization method is used along with a mathematical analysis method. Our coupler works at 1.9 GHz, which is suitable for 5G and GSM applications. The working frequency range of our designed coupler is from 1.84 GHz to 2.11 GHz, where it has a fractional bandwidth (FBW) of 13.7%. The phase and magnitude imbalances are only $0.029^{o}$ and 0.08 dB, respectively, making it suitable for applications in microwave components, communication and radar systems. The maximum group delays at the direct and coupling ports are 1.9 ns and 2.3 ns, respectively. This is an advantage because most of the previously reported microstrip couplers have not addressed the group delay improvement. The other advantages of our coupler are its filtering frequency response and a good isolation factor of -42 dB around the operating frequency. The proposed structure is mathematically analyzed and optimized. It is fabricated and measured to verify the simulation results and the proposed mathematical analysis. The results show that all mathematical analysis, simulation and measurement results are in good agreement. The experimental results confirm its performance in terms of low losses, low group delay and low phase and magnitude imbalances. Therefore, the presented design offers a significant improvement over the traditional couplers, which generally suffer from the large size, high group delay and poor phase and magnitude balances.

Coupler parameters, such as transmitter inductance (LTx), receiver inductance (LRx), and the coupling coefficient (k) or mutual inductance (M), vary with the misalignments. Their variations must be quantified and incorporated into the design and optimization stage as they impact performance indices such as efficiency and leakage magnetic field. Most of the solutions proposed in the literature compromise the performance of the coupler in search of a misalignment-tolerant design. Therefore, this article presents a method to incorporate the misalignments into the design and optimization process of an inductive power transfer (IPT) coupler by utilizing robust optimization, where misalignments are considered as noises or disturbances or uncertainties to a perfectly aligned coupler. The optimized designs resulting from this method will not compromise the performance of the coupler in search of a misalignment-tolerant design. Effectiveness of the proposed robust optimization method is experimentally verified with a 3.7 kW hardware prototype.

This study reviews the recent works on the development and application of iron‐based shape memory alloy (Fe‐SMA), the so‐called memory‐steel, for steel structures. First, the studies on the material properties of Fe‐SMA in terms of shape memory effect and superelasticity are discussed. Next, the use of Fe‐SMA in prestressed strengthening of steel structures is explained, including the applications in strengthening of steel girders, connections, and fatigue crack repairs. Various strengthening solutions such as using mechanically anchored or adhesively‐bonded Fe‐SMA, as well as the studies on the behavior of the Fe‐SMA‐to‐steel bonded joints, are discussed. The use and application of Fe‐SMA for strengthening of a 113‐years steel bridge has been explained. In addition, studies on the innovative application of the Fe‐SMA as pipe couplers are presented. At the end, innovative ongoing research on the additive manufacturing of architected Fe‐SMA (4D‐printing) are discussed. [ABSTRACT FROM AUTHOR]

In this letter, novel spiral‐coupled transmission lines are used to obtain a high‐performance microstrip coupler. The advantages of the proposed microstrip coupler are novel structure, filtering frequency response, suppressed harmonics up to second harmonics, transmission poles, low losses, compact size, and good phase balance. The proposed structure is novel and different from the previous coupler designs such as rate‐races, rings, and branch‐lines types. It is presented for the first time in this work with a very small size and good performance. The size of this coupler is only 82.6 mm2 (0.004 λg2). The common port return loss is 33 dB and the insertion losses at port 2 and port 3 are 2.2 and 2.7 dB, respectively. To prove the accuracy of the design method and simulation results, the proposed coupler is fabricated and measured where the measurement results confirm the simulation results and the proposed design method. [ABSTRACT FROM AUTHOR]

Symmetry in designing a microstrip coupler is crucial because it ensures balanced power division and minimizes unwanted coupling between the coupled lines. In this paper, a filtering branch-line coupler (BLC) with a simple symmetrical microstrip structure was designed, analyzed and fabricated. Based on a mathematical design procedure, the operating frequency was set at 5.2 GHz for WLAN and 5G applications. Moreover, an optimization method was used to improve the performance of the proposed design. It occupied an area of 83.2 mm2. Its harmonics were suppressed up to 15.5 GHz with a maximum level of −15 dB. Meanwhile, the isolation was better than −28 dB. Another advantage of this design was its high phase balance, where the phase difference between its output ports was 270° ± 0.1°. To verify the design method and simulation results, the proposed coupler was fabricated and measured. The results show that all the simulation, design methods, and experimental results are in good agreement. Therefore, the proposed design can be easily used in designing high-performance microstrip-based communication systems. [ABSTRACT FROM AUTHOR]

In this paper, a 3 dB 90-degree hybrid coupler with size reduction and harmonics rejection was designed. In the proposed coupler structure, four simple low-pass filters (LPFs) were applied. An artificial neural network (ANN) was used to determine the dimensions of the applied LPFs based on EM simulation data. The applied ANN model could also provide the desired LPF parameters, including the cut-off frequency (fc), bandwidth (BW), and insertion loss (IL). Designing an applied LPF involves complex mathematical calculations and simulations to optimize parameters. However, by utilizing neural networks, the design process can be significantly streamlined and automated. Neural networks have the ability to learn complex patterns and relationships within data, making them well suited for optimizing the performance of applied components. The proposed 90-degree hybrid coupler works correctly at 1800 MHz and has a small size of 16.6 mm × 15.15 mm, which provides a 73% size reduction compared to a normal 1800 MHz coupler. The designed coupler not only decreases the circuit size but also provides a wide rejection band from 4.8 GHz to 11.2 GHz, which suppresses the second to sixth harmonics. The insertion loss parameter of this 90-degree hybrid coupler is less than 0.1 dB at the working frequency, which shows the superior performance of the proposed coupler.

Microvascular anastomotic coupler system is used in vascular surgical procedures. By using this device, vascular anastomosis can be performed faster and more easily. It is often used for venous anastomosis during microsurgical reconstruction. We performed distal bypass surgery on two patients with critical limb ischemia with spliced vein grafts using the microvascular anastomotic coupler system. The blood vessel diameters were 2 and 2.5 mm, respectively. Both grafts showed obstruction at 3 and 1 months, respectively, after surgery. The microvascular anastomotic coupler system may not be suitable for small-diameter spliced vein grafts.

A 4 × 4 Butler Matrix (BM) without phase shifter is proposed to provide bandwidth enhancement and size reduction by removing a conventional 0 dB/90° crossover, two 0° phase shifters and two 45° phase shifters. Two proposed 3 dB/45° patch couplers replace the combination of two conventional 3 dB/90° branch-line couplers and two 45° phase shifters, whilst a modified 0 dB/0° crossover removes two 0° phase shifters from the conventional BM. The −10 dB fractional bandwidths of reflection coefficients and isolations for the proposed BM are 18.46% in simulation and measurement. The −6 dB ± 1.5 dB average transmission coefficient and +45°, −135°, +135° and −45° of output phase differences with 1.8° average phase imbalance are accomplished at 6.5 GHz. The simulated and measured scattering parameters (S-parameters) and phase differences are in close compliance with each other. Four switched-beams pointed at +15°, −50°, +50° and −15° are developed by integrating the proposed BM with inset feeding patch antennas. The proposed BM is miniaturized by 51.56%, whilst the bandwidth performance is enhanced by 9.7% compared to the conventional BM. Hence, this compact BM is a promising candidate for the fifth generation (5G) communication system.

The 25 MeV wastewater treatment electron linear accelerator uses a 15 MW klystron as the microwave power source, which provides a microwave power no less than 13 MW at the entrance of the traveling wave tube, and accelerates the electron beam to 25 MeV/5 kW in a traveling wave tube with length of 76 cm. The operating frequency of the accelerator is 2 856 MHz in the Sband. The traveling wave tube adopts a diskloaded waveguide structure, which is simple and stable. To ensure that the beam can reach sufficient energy and power, the traveling wave tube is composed of a variable phase velocity bunching section, a constant phase velocity bunching section, and a light velocity section. The physical design of the traveling wave tube was introduced in detail. Using SUPERFISH, a two-dimensional cavity model was established, effective shunt impedance, attenuation constant, cavity wall loss, and other key parameters were calculated, and the traveling wave tube field distribution was obtained based on the power loss. Using numerical calculation methods, the phase oscillation equation and the beam envelope equation were solved, the capture efficiency of longitudinal motion is about 50% and the beam energy spread is about 72% with optimizing the length of the constant phase velocity bunching section. The solenoid magnetic field that was calculated by the SUPERFISH software was substituted, and magnetic field distribution to make the beam envelope smaller than the beam aperture of the accelerating tube was optimized. Finally, the design was verified with PARMELA. When 10 000 particles are injected, 6 106 particles can be accelerated to the exit of the acceleration tube, that is, the capture efficiency is about 61%. Good consistency is obtained. Then, the threedimensional RF structure model was established. The accelerating cavity model in the simulation software was calculated using the principle of the probe method. The coupler model was calculated by using three frequency methods, and the coupling degree was optimized by adjusting the size of the coupling port and the inner diameter of the cavity. The field distribution of traveling wave tube was analyzed by timedomain method, and cavity inner diameter was adjusted to optimize field distribution. The simulation field distribution is consistent with the beam dynamics design. Voltage standing wave ratio of operating frequency is 101, and bandwidth of accelerator tube is 2 MHz. The design of 2.5 MeV traveling wave accelerator tube is completed, providing a reference for its research and development.

This paper describes the longitudinal-vertical coupling dynamics of a high-speed train rescued by locomotives during the braking process on grades. The coupler jackknifing behaviour under compressive forces will affect the running safety of the coupling train. In this paper, the longitudinal-vertical impacts by field testing for the locomotive to train rescue scenario are firstly introduced. The quasi-static force analyses of the train and couplers are carried out to study the coupler jackknifing mechanism on graded tracks. The three-dimensional dynamic model of the train and coupler system is then developed. In this model, the coupler rotational motions, hysteresis characteristic of draft gears, braking characteristic are taken into account. The typical responses during the braking process for the high-speed train rescued by the diesel locomotive are reproduced and verified. The running safety of the longitudinal-vertical interaction for selected scenarios is further evaluated. The Influences of train speed and track gradient on the longitudinal-vertical dynamics are also studied. Two improvement measures, including the limitation of the coupler pitch angle and coupler force, are discussed to provide possible solutions. [ABSTRACT FROM AUTHOR]