PCB Board Research Articles

Steam gasification for waste valorization with energy recovery

Steam gasification seems a promising technology of waste transformation since the steam is the only oxidizing reagent in the process and gaseous carrier of volatiles. Gasses are equilibrated at high temperature for conversion to the H2-rich syngas. After this step, the excess of steam condenses during cooling, together with non-converted tars, oils and fine particles. Condensing steam efficiently absorbs hydrogen bromide and hydrogen chloride. The use of steam eliminates carbonaceous residue from the solid mineral/metal product, which is convenient for further processing (for example extraction of metals). The syngas and the solid residue are generally the only products of gasification, because aqueous condensate may be returned to the process together with non-volatile hydrocarbons and sediments. The process was illustrated by laboratory scale gasification experiments with a) carton packaging, b) abrasive disc, c) pork bones, d) Cu multiwire cable e) PC/AT card and f) inverter (PCB board). The mineral/metal products of gasification may be considered as a raw materials for further processing, including typical routes of metals recovery. There is no direct emission to the atmosphere from the process. However, providing the energy from the syngas back to the reactor as well as the energy balance of steam condensation and recirculation of condensate to the reactor need careful analysis.

A <inline-formula> <tex-math notation="LaTeX">$1\times8$ </tex-math> </inline-formula> Linear Ultra-Wideband Phased Array With Connected Dipoles and Hyperbolic Microstrip Baluns

A $1\times 8$ linear single polarized ultra-wideband connected dipole phased array with wide angle scan range is proposed. The dipoles in the array are connected with each other in E-plane to improve the impedance matching on the low end of the frequency band. The frequency band and the scan range in E-plane is 2~9 GHz for broadside radiation, 2~8 GHz for 30° scan, 2~7 GHz for 45° scan, and 2~6.5 GHz for 60° scan. The VSWR is better than 2.0 across the frequency band from 2 to 9 GHz for broadside radiation and the cross-polarization level is below −10 dB. A hyperbolic microstrip balun is used as an impedance transformer to connect the 50 $\Omega $ SMA connector to a $150~\Omega $ broadband dipole in an array. The structure of this antenna is totally planar and low profile, thus it is made easy to integrate with the PCB boards. To eliminate the surface wave blindness, no other dielectric layer is used in the array. The proposed balun supports common mode (CM) current and the radiation of this CM current cancels the radiation of the dipole in some frequency for a certain scan angle, this results in feed blindness. Adding H-plane PEC walls decreases the feed blindness frequency in the design.

Pembelajaran Microcontroller MCS-51 Dengan Metodologi Interaktif

Evaluation Board Microcontroller 89S51 / 89S82 / 89S53 (PEM-51) is a tool used to support microcontroller subject learning with an interactive methodology. PEM-51 consists of input / output modules that are integrated in one PCB board. The modules consist of a switch input, keypad module, LED module, seven segment display module, LCD display module, ADC (Analog to Digital Converter) module, DAC (Digital to Analog Conver) module, Stepper motor module. The software used in this tool is C using the Keil µVision4 compiler. The interactive learning process can be done by making a simulation circuit using Proteus software before implementing it to a microcontroller. With PEM-51, it is expected to increase student competency in studying Microcontroller courses.

Pembelajaran Microcontroller MCS-51 Dengan Metodologi Interaktif

Evaluation Board Microcontroller 89S51 / 89S82 / 89S53 (PEM-51) is a tool used to support microcontroller subject learning with an interactive methodology. PEM-51 consists of input / output modules that are integrated in one PCB board. The modules consist of a switch input, keypad module, LED module, seven segment display module, LCD display module, ADC (Analog to Digital Converter) module, DAC (Digital to Analog Conver) module, Stepper motor module. The software used in this tool is C using the Keil µVision4 compiler. The interactive learning process can be done by making a simulation circuit using Proteus software before implementing it to a microcontroller. With PEM-51, it is expected to increase student competency in studying Microcontroller courses.

Design and fabrication of a small‐form transmitter optical subassembly for 100 Gbps short reach optical interconnect

AbstractA high‐coupling‐efficiency and convenient‐integration transmitter optical subassembly for 25 Gbps small‐form transceiver is developed in this paper. In the structure, the VCSEL is vertically mounted on the silicon substrate by the flip‐chip method to enable direct and passive alignment with the fibers plugging in the fiber guide holes on the silicon substrate. By the optical simulation, the maximum coupling efficiency of VCSEL is −0.38 dB. The vertical electrical pads of the VCSEL are connected to the horizontal wire‐bonding pads on silicon substrate by the 90°‐bend GS micro strip lines. Thus, the interconnection between the transmitter optical subassembly and the electrical PCB board is conveniently realized by the low‐cost wire‐bonding method. The electrical performance of the 90°‐bend GS micro strip lines on the optical subassembly is also evaluated by the 3D electromagnetic simulation. In order to verify the transmission performance of the transmitter optical subassembly, it is integrated with an electrical board using bonding wires, and then the optical performance of the transmitter is measured. By the measurement, the optical subassembly can operate up to 25 Gbps per channel.

The P̄ANDA Barrel-TOF Detector at FAIR

The barrel-Time-of-Flight subdetector is one of the outer layers of the multi-layer design of the \\panda target spectrometer. It is designed with a minimal material budget in mind mainly consisting of 90×30×5 mm3 thin plastic scintillator tiles read out on each end by a serial connection of 4 SiPMs. 120 such tiles are placed on 16 2460 × 180 mm2 PCB boards forming a barrel covering an azimuthal angle from 22.5̂ to 150̂. The detector is designed to achieve a time resolution below σ< 100 ps which allows to distinguish events in the constant stream of hits, as well as particle identification below the Cherenkov threshold via the time-of-flight; simultaneously providing the interaction times of events. The current prototype achieved a time resolution of ∼54 ps, well below the design goal.

Construction and quality assurance of large area resistive strip Micromegas for the upgrade of the ATLAS Muon Spectrometer at LHC/CERN

Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. To cope with increasing background rates, associated with the steadily increasing luminosity of LHC to 10 times design luminosity, the present detector technology in the current innermost stations of the muon endcap system of the ATLAS experiment (the Small Wheel), will be replaced in 2019/2020 by resistive strip Micromegas and small strip TGC detectors. Both technologies will provide tracking and trigger information. In the "New Small Wheel" the Micromegas will be arranged in eight detection layers built of trapezoidally shaped quadruplets of four different sizes covering in total about 1200 m2 of detection plane. In order to achieve 15 % transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction of each active plane, with an alignment of the readout strips at the level of 30 μm RMS along the precision coordinate and 80 μm RMS perpendicular to the plane. Each individual Micromegas plane must achieve a spatial resolution better than 100 μm at background rates up to 15 kHz/cm2 while being operated in an inhomogeneous magnetic field (B ⩽ 0.3 T). The required mechanical precision for the production of the components and their assembly, on such large area detectors, is a key point and must be controlled during construction and integration. Particularly the alignment of the readout strips within a quadruplet appears to be demanding. The readout strips are etched on PCB boards using photolithographic processes. Depending on the type of the module, 3 or 5 PCB boards need to be joined and precisely aligned to form a full readout plane. The precision in the alignment is reached either by use of precision mechanical holes or by optical masks, both referenced to the strip patterns. Assembly procedures have been developed to build the single panels with the required mechanical precision and to assemble them in a module including the four metallic micro-meshes. Methods to confirm the precision of components and assembly are based on precise optical devices and X-ray or cosmic muon investigations. We will report on the construction procedures for the Micromegas quadruplets, on the quality control procedures and results, and on the assembly and calibration methods.

Synthesis of silicon-containing cycloaliphatic diepoxide from biomass-based α-terpineol and the decrosslinking behavior of cured network

The intractable after-treatment problem of thermosetting epoxy resins due to the insolubility and infusibility brings about an ever-increasing pressure on environment. In this work, new degradable silicon-containing cycloaliphatic diepoxide (Epo-Si) was designed and synthesized using biomass-based 2-(4-methylcyclohex-3-enyl)propan-2-ol (α-terpineol) as a major material. After curing with anhydride, large amounts of heat-labile tertiary carbon ester and tertiary C-O ether linkages in the network made the crosslinked Epo-Si degrade at a lower temperature of 269 °C. Moreover, its degradation temperatures could be readily tuned through co-curing with the commercial diepoxide ERL-4221. At room temperature, the shearing strength of the cured Epo-Si is 6.74 MPa, superior to that of ERL-4221 (5.24 MPa), exhibiting excellent adhesion property. More importantly, the cured Epo-Si maintains the high shearing strength up to 240 °C, but when further increasing temperature, the strength rapidly dropped and almost completely lost at around 285 °C. Therefore, if integrated circuits have been encapsulated with Epo-Si, their dismantlement or repair at a suitably lower temperature could be realized without damaging the PCB board. The thermal decrosslinking mechanism of the cured products were investigated by means of isothermal and temperature-programmed thermogravimetric and FTIR spectra in detail.

Design of picosecond pulse source based on MOSFET and step recovery diode

As the existing pulse source can not balance pulse width and amplitude, a scheme of based on field effect transistor (MOSFET) and step recovery diode (SRD) combined with picosecond pulse source was put forward. Analyzing traditional designs of several pulse sources, we designed a high repetition rate picosecond pulse generator of 100 volt level and made a design simulation with PSPICE and developed the pulse source PCB board. Measurement shows 2 MHz repetition rate, half amplitude width 400 ps around, range above 110 V and stable waveform. The scheme providedes a new selection for high resolution UWB detection radar transmitter.

Evaluation of PCB Shielding Characteristic in Near Field

Wireless electronic devices nowadays always operate in high frequency while having small and compact form factor which led to electromagnetic interference among traces and components. PCB shielding is the common solution applied in electronic industry to mitigate electromagnetic interference. In this paper, PCB shielding characteristics such as shield’s thickness, height, and ground via spacing in PCB boards were evaluated in near field. Test boards with various ground via spacing were fabricated and evaluated by using 3D Electromagnetic scanner. On the other hand, shields with various thickness and height were modeled and evaluated through simulation. Results suggested that shielding effectiveness could be improved by having greater shield’s height with smaller ground via spacing in shielding ground tracks. Shielding effectiveness can be improved by 1 dB with every step of 0.5 mm increase in shield’s height. Besides that, approximately 0.5 dB improvement in shielding effectiveness with every step of 1 mm decrease in ground via spacing. Furthermore, greater shield’s thickness can contribute better shielding effectiveness for operating frequency below 300 MHz.

An artifact detection scheme with CUDA-based image operations

Many image filtering techniques can be accelerated with compute unified device architecture (CUDA)-based massively parallel implementations. In this paper, we show the major issues on our acceleration techniques, and also its implementation details. We implemented various image filtering operations in our own CUDA kernel programs, and they are combined to build an artifact-detection scheme in PCB board soldering process. We designed our own computational logics on the artifact detection, and finally, the whole system figure out the potential artifact regions. Comparing with the central processing unit-based reference implementation, we show its correctness and feasibility, with much execution speed-ups.

Robotized semiautomatic motorcycle transmission development. Electronic and software design

In this paper, we propose an electrical design (implemented on a PCB board) and an accompanying software design for controlling the automatic gear change. The designs complement the mechanical solutions developed in Part 1. The paper also analyses the issues encountered during the intermediate steps of the development of the electronic module, which is expected to be small and adaptable enough to be installed on a motorcycle without changing its ergonomics. The control software runs on the Arduino Nano board and is built as a state machine with one idle state, five active states that cover different stages of the gear change and one error state for preventing malfunctions in case of an unexpected event. The sketch uses 5,760 bytes (or 18%) of program storage space and 706 bytes (or 34%) of the dynamic memory.

휴대폰 충전기 내 트래킹 발생 원인 분석 및 대책

핸드폰 충전기 내 커패시터의 전해액이 전원 입력단자로 누출되고 PCB 기판에 트래킹이 발생하여 탄화도전로가 형성되는 것을 확인하였다. 트래킹이 발생하는 원인을 구조적으로 분석한 결과, 전원 입력단자와 PCB 기판이 커넥터를 이용하여 직결되는 경우에 발생하였다. 커패시터에서 누출된 전해액이 전원입력단자로 흘러 들어가는 양이 많을수록, 전원입력단자의 플러그 핀 사이에 설치된 격벽의 높이가 낮을수록 트래킹 발생율이 높았다. 이에 따라 충전기 내 트래킹 발생율을 낮추기 위해서는 누출된 전해액이 전원입력단자로 흘러 들어가지 않도록 커패시터에 격벽을 설치하거나, 전원입력단자에 설치된 격벽의 높이를 높일 필요가 있다. 또한, 전원 연결단자와 맞닿아 있는 PCB기판의 형태를 <TEX>${\Pi}$</TEX>로 변경한다면 트래킹 발생율이 더욱 줄어들 것으로 판단된다. The electrolyte of the capacitor in mobile phone chargers leaks to the power input terminal resulting in tracking on the PCB board to form a carbonized conductive path. As a result of structural analysis of the cause of the tracking, It occurred when the power input terminal and the PCB board were connected directly using the connector. The larger the amount of electrolyte leaked from the capacitor into the power input terminal, or the lower the height of the partition provided between the plug pins of the power input terminal, the higher the tracking occurrence rate. Accordingly, to lower the occurrence rate of tracking in the charger, it is necessary to provide a partition on the capacitor or increase the height of the partition provided on the power input terminal so that the leaked electrolyte does not flow to the power input terminal. In addition, the tracking occurrence rate will be reduced further if the shape of the PCB board touching ther power connection terminal is changed to <TEX>${\Pi}$</TEX>.

Adaptive Data Mining Approach for PCB Defect Detection and Classification

Objective: To develop a model for PCB defect detection and classification with the help of soft computing technique. Methodology: To improve the performance of the prediction and classification we propose a hybrid approach for feature reduction and classification. The proposed approach is divided into three main stages: (i) data pre-processing (ii) feature selection and reduction and (iii) Classification. In this approach, pre-processing, feature selection and reduction is carried out by measuring of confidence with the adaptive genetic algorithm. Prediction and classification is carried out by using neural network classifier. A genetic algorithm is used for data preprocessing to achieve the feature reduction and confidence measurement. Findings: The system is implemented using MatLab 2013b. The resulting analysis shows that the proposed approach is capable of detecting and classifying defects in PCB board.

Polarization Control by Using Anisotropic 3-D Chiral Structures

Due to the mirror symmetry breaking, chiral structures show fantastic electromagnetic (EM) properties involving negative refraction, giant optical activity, and asymmetric transmission. Aligned electric and magnetic dipoles excited in chiral structures contribute to extraordinary properties. However, the chiral structures that exhibit n-fold rotational symmetry show limited tuning capability. In this paper, we proposed a compact, light, and highly tunable anisotropic chiral structure to overcome this limitation and realize a linear-to-circular polarization conversion. The anisotropy is due to simultaneous excitations of two different pairs of aligned electric and magnetic dipoles. The 3D omega-like structure, etched on two sides of one PCB board and connected by metallic vias, achieves 60% of linearto- circular conversion (transmission) efficiency at the operating frequency of 9.2 GHz. The desired 90-degree phase shift between the two orthogonal linear polarization components is not only from the finite-thickness dielectric substrate but also from the anisotropic chiral response slightly off the resonance. The work enables elegant and practical polarization control of EM waves.

(Invited) Reliability Study of RF Power Amplifiers with GaN-on-SiC HEMTs

In total 50 RF amplifier demonstrators consisting each of a PCB board containing one GaN-on-SiC, HEMT, CHZ015A-QEG, from UMS in SMD quad-flat no-leads package (QFN) were assembled for the study. Two types of solders, one of which is lead-free, (Sn63Pb36Ag2 and SAC305) and two types of TIM materials (NanoTIM and TgonTM805) for PCB attachment to liquid cold plate were tested for thermo-mechanical reliability. Out of the total number of the demonstrators 24 were subjected to thermal stress by 2300 thermal cycles (TC) between -20°C and 80°C and remaining 26 were subjected to the electrical stress by power cycling (PC) with drain current of 100 mA at drain voltage of 45 V and cycle time of 2 min. HF characterization of all the boards was done before subjecting them to the thermal and electrical stresses. All the devices were also subjected to static electrical characterization by measuring threshold voltage and output and voltage blocking characteristics. The static electrical and HF characterization was performed again after 2300 cycles of TC stress and after 1100, 4700 and 14500 cycles of PC stress. In addition failure analysis was performed on the TC and PC stressed demonstrators by using optical microscopy and 2D X-ray microscopy. The results of electrical and HF characterization show clearly changes and degradation in device performance as a function of the number of the PC cycles and accumulated current stress time. No significant differences between the boards equipped with different solder or TIM materials are observed which means that the observed changes in performance are due to the degradation of the HEMT devices. A reduction in value of saturation current (VDS=10 V, VGS=0.8 V) of about 5, 12 and 16 % is observed after 1100, 4700 and 14500 cycles of PC stress, respectively. There is a clear tendency of the threshold voltage shift (measured at 10 mA) towards more negative values showed by devices from different groups. The shift is by -0.1 to -0.15 V from typical value of about -2.25 V. The leakage current is less well behaved. There are devices with no significant change in leakage current but also devices which show an increase in leakage current by a factor larger than 2, as a result of the PC stress. Results of HF measurements show a decrease in S11 and S21 parameters from -10.91±0.23 to -10.0±0.21 and from 16.04±0.24 to 15.51±0.28 after PC stress (measurement conditions VDS=45 V, IDS=100 mA, power level 5 dBm, 1.3 GHz). The support of Sweden´s innovation agency, Vinnova, and Sweden Energy Authority is acknowledged. Figure 1

Investigating the Effect of Chlorides on the Reaction Kinetics of a Copper Electrodeposition Process

Over the past two decades, the replacement of aluminum interconnects with copper is one of the biggest advances in semi-conductor industry. As the wiring density continues to increase, so does the demand for tighter control on the electrolytic copper deposition process for these industries. Apart from organic additives and other trace metals, one of the crucial component in plating baths mixtures for manufacturing PCB boards and photovolotaic cells is the intermediate cuprous ion composition, which is formed during the copper dispropornation reaction: 2 Cu + (aq) ⇌ Cu(s) + Cu2+ (aq) The cuprous ion is typically unstable in normal acidic solution and it disproportionates into metallic copper and cupric ions. In the presence of chlorides however, the disproportionation reaction equilibrium is shifted and the cuprous ions are stabilized. Cuprous ions are also required in order for the other additives (brightener, suppressor, leveler) used in the process to operate at maximum efficiencies. It is therefore important to know if the Cu2+ intermediate is truly formed and present during the a copper electrodeposition process. In this work, we used Autolab RRDE system to identify mechanisms governing copper electrodeposition process and study the influence of chloride concentration on the generation of intermediates.

Robot-Server Architecture for Optimizing Solar Panel Power Output

Solar panel facilities for generating electricity have increased exponentially in the recent years. Dust and bird droppings on the solar panels inhibit the energy production. Having people to inspect them and, if needed, clean them is expensive and increases the energy cost. In this research paper we introduce a robot-server architecture for the purpose of inspecting the panels and cleaning them if there is a need for it. The general architecture of the robot consists of a mechanical part, an electromechanical part, an electronic part, and a software part. The mechanical and electromechanical parts consist of an all-terrain vehicle, two electric brushless motors, a telescopic vision system, and telescopic cleaning system with a brush, stepper motors controlling the telescopic vision system, and the telescopic vacuum system with a brushless electric motor. The electronic system consists of three electronic speed controllers, navigation sensors, a computer board, a hard disk, a transceiver, and an antenna for wireless communication. The software consists of a scalable operating system, an intelligent vision system with pattern recognition, a communication software system, an intelligent navigation system, and a file server with a database, TLS security, network communication software based on UDP, and internet communication based on websockets and TCP-IP. In addition to that for street solar lights we designed a PCB board with a sensor that activates a mechanism similar to windshield wipers that cleans the glass of the solar panels powering the lights automatically when needed.

77-GHz Four-Element Phased-Array Radar Receiver Front End

A phased-array receiver module operating at 77 GHz is designed and manufactured to obtain beam-steering capability. The module has four patch antennas integrated with three active phase shifter (APS) chips on a single-layer Rogers 3003 printed circuit board PCB board. The W-band 1.65-mm2 novel APS chip is fabricated using 0.13- $\mu \text{m}$ SiGe Heterojunction Bipolar Transistor (HBT) technology. The APS consumes 100-mW dc power and achieves a peak gain of 9 dB at W-band and covers 360°. The phase shifter chips and PCB are packaged using low-cost wire-bond interconnections with insertion loss less than 7.5 dB. A novel method that exploits Klopfenstein tapering is also designed to connect coplanar waveguide to microstrip line with minimum insertion loss around 77 GHz. The measured gains of the phased-array receiver and passive four-element antenna array are compared. The module and passive array achieve the maximum gains of 9.7 and 10.4 dBi at 77 GHz. The simulated and measured results present well agreement at the W-band frequency. The beam can be steered to ±30°.

A Smart Automated Embedded Based PCB–Bare Board Testing Machine Design and Development using Flexible Flying Probe

Background/Objectives: To design an automated embedded based flexible flying probe for testing PCB bare board more accurately which is one of the toughest challenge in manual testing. Methods/Statistical Analysis: Embedded based flexible flying probe can precisely position a probe on test points with high accurateness achieved by means of microstepping motors and linear laser encoders. The probe is moved horizontally and vertically based on the command passed by stepper motor which in-turn get the information from the prototype in format of Gerber file. First the flying probe checks the connectivity between two points then if the connectivity is good it will check the next track. Findings: This novel invention of flying probes are developed from new-fangled and novel thought intended to produce fasten testing speed, improved access, and enhanced error coverage. During the testing process if the machine determines some problem in the connectivity, it read the problem and send the error report on the PC display. From the error report, we can identify the fault placed in the PCB. A log file with test results is generated & stored on the PC. Fault details are sent to display unit of PC. The PC displays the matching accuracy and fault detection. The experimental result was conducted on 3 different PCB Bare board and the testing result shows the 92% accuracy and 18% false detection rate. It is compared with the jig board tester which produces less result compared to the proposed technique. The chief confront of this proposal is low down equipment and dispensation cost, absolute testing accurateness and capability to position close to faults and faults that may source irregular breakdowns. Applications/Improvements: This machine can be used for testing any type of PCB board. This proposed work develops a smart flying probe to test PCB which will significantly decrease test times therefore increasing productivity.