Printed Wiring Boards Research Articles

Design of elastic and dissipation joints in bearing structures of electronic packages

Mathematical modeling and experimental research represented in this paper is aimed at dynamic force analysis of circuit cards in order to eliminate or reduce dynamic stress and deflection to an acceptable level and to provide strength and reliability in design of circuit card assemblies subjected to vibration. In conditions when viscous friction forces are negligible and viscous friction dampers, such as liquid dampers, cannot be used reduction of oscillation amplitude in critical frequencies was proposed by creating dry friction damper. On the base of mathematical model, the method for reducing dynamic stress and deflection in critical section of circuit cards in resonance conditions has been developed by inserting additional elastic and dissipation joint introduced by dry friction damper. The dry friction damper device is introduced in three variants of design. The effectiveness of dry friction damper is characterized by its elastic and damping characteristics and especially by the stiffness.

Trends in Wireless Power Transfer: WPT Technology for Energy Harvesting, Mllimeter-Wave/THz Rectennas, MIMO-WPT, and Advances in Near-Field WPT Applications

Wireless power transfer (WPT) technology gained wide recognition over a decade ago following a resonance coupling WPT study conducted by a group at the Massachusetts Institute of Technology (MIT) [1]. WPT was originally proposed by Nicola Tesla at the end of the 19th century [2] based on a study of near-field inductive-coupling WPT and far-field WPT via radio waves. The first patent involving inductive WPT as a wireless charging system was granted in 1894 for the earliest electric vehicle (EV) [3]. Inductive WPT technology is based on a transformer and was commercialized as a wireless charger for an electric toothbrush in 1981 by Panasonic Corporation and as a power source for an integrated circuit (IC) card in 1995 by Sony Corporation. Daifuku Corporation produces many systems for material handling in stockroom and clean room applications [4]. From the 1970s through the 1990s, several research projects on wireless chargers for EVs were undertaken in New Zealand, the United States, and Europe. Advances in microwave technology led to improvements in WPT via radio waves, with many field experiments on microwave power transfer (MPT) conducted from the 1960s through the 1970s by William C. Brown in the United States [4]. The commercialization of RFID at the 920-MHz band started recently, and the proliferation of mobile rechargeable batteries since 2010 accentuates the need for a wireless charger in, e.g., mobile phones, EVs, and sensors for the Internet of Things (IoT).

An Energy Saving Road Sweeper Using Deep Vision for Garbage Detection

Road sweepers are ubiquitous machines that help preserve our cities cleanliness and health by collecting road garbage and sweeping out dirt from our streets and sidewalks. They are often very mechanical instruments, needing to operate in harsh conditions dealing with all sorts of abandoned trash and natural garbage. They are usually composed of rotating brushes, collector belts and bins, and sometimes water or air streams. All of these mechanical tools are usually high in power demand and strongly subject to wear and tear. Moreover, due to the simple working logic often implied by these cleaning machines, these tools work in an “always on”/“max power” state, and any further regulation is left to the pilot. Therefore, adding artificial intelligence able to correctly operate these tools in a semi-automatic way would be greatly beneficial. In this paper, we propose an automatic road garbage detection system, able to locate with great precision most types of road waste, and to correctly instruct a road sweeper in order to handle them. With this simple addition to an existing sweeper, we will be able to save more than 80% electrical power currently absorbed by the cleaning systems and reduce by the same amount brush weariness (prolonging their lifetime). This is done by choosing when to use the brushes and when not to, with how much strength, and where. The only hardware components needed by the system will be a camera and a PC board able to read the camera output (and communicate via CanBus). The software of the system will be mainly composed of a deep neural network for semantic segmentation of images, and a real-time software program to control the sweeper actuators with the appropriate timings. To prove the claimed results, we run extensive tests onboard of such a truck, as well as benchmark tests for accuracy, sensitivity, specificity and inference speed of the system.

Surface resistivity and bonding strength of atmosphere plasma sprayed copper‐coated alumina substrate

AbstractCeramic substrate metallization is widely used in electronic device packaging and ceramic circuit board. Currently used methods of ceramic metallization are thick film technology (TFC), activity metal blazing (AMB), direct bonded copper (DBC), and direct plated copper (DPC) etc Here we report a facile approach for the metallization of alumina substrate using an atmosphere plasma spray (APS) process. The APS‐coated copper layer is dense, high purity, and attached very firmly with alumina substrate. The maximum bonding strength is 9.02 MPa, which is higher than that obtained by conventional methods. With EDS mapping, it is found that element interdiffusion occurred at the interface region during coating, which may be one of the reason of high bonding strength. The high dense and purity Cu layer demonstrates quite lower surface resistivity as 8.7 × 10−5Ω⋅mm. The influence of APS current on the quality of Cu coating has been systematically investigated, and the results proved that the method is efficient and economical.

Real Time PC-Based Flow Measurement Technique Using Optical Channel as a Signal Transmitting Media

A PC based cost effective electro-optic type flow measurement technique is designed and developed. The anemometric principle i.e. the effect of heat loss on a heating element due to flowing fluid is utilized for the measurement of flow rate of liquid in the process industry. A constant voltage p-n junction diode is used as a basic sensing element and the output of the sensing element is amplified and conditioned with the help of the instrumentation amplifier and signal conditioning circuit. Transmission of electrical signals in remote locations suffers from measurement errors due to electromagnetic induction effect, stray capacitance effect etc. The transmission of electrical signal is also not safe for the industries where an inflammable area is present between fields to remote locations and optical transmission is preferred in such areas. To overcome these, an electro-optical system has been developed. The process variable is first sensed electrically. This electrical signal of the transducer is converted into an optical signal using an electro-optic amplitude modulator and then it is transmitted in the form of an optical signal from field to control room through inflammable areas. The modulated signals are demodulated in the control room or remote location and then send to the PC through an optoisolator circuit and DAS card. The experiment has been performed and the theory as well as the mathematical equation has been derived to explain the operation of the proposed system. The overall PC based flow indicator system is also found to have linear characteristics with very good repeatability within tolerable percentage error.The experimental result is reported in the paper.

Power-Saving Design of Radio Frequency Identification Sensor Networks in Bus Seatbelt Monitoring Systems.

Seatbelt state monitoring is important in intercity buses for passenger safety. This paper discusses the issues and challenges in power-saving design of radio frequency identification (RFID) sensor networks in bus seatbelt monitoring. A new design approach is proposed in this work for low-power layout and parameter setting in RFID sensor nodes in hardware and software design. A one-to-many pairing registration method is suggested between the concentrator and the seat nodes. Unlike using extra computer software to write seat identification (ID) into an integrated circuit (IC) card, the node ID in this project can be stored into the concentrator directly, which can reduce intermediate operations and reduce development costs. The effectiveness of the proposed low-power design approach is verified by some experimental tests.

무인체계 신뢰성 물리학 기반 PBA 신뢰성 설계방안 연구

Purpose: This study was aimed at developing a method to enhance the reliability of the main circuit acrd assembly of an unmanned surface vehicle by examining the design methods based on the reliability physics analysis (RPA).BRMethods: The physics of failure (PoF)-based software Sherlock was used to perform the failure physics analysis and design optimization.BRResults: The optimal design method was derived to improve the reliability of the considered circuit card assembly.BRConclusion: Using the PoF theory, the optimal design method of printed board assembly (PBA) can be established by performing an PRA, considering physics failure factors such as the PBA material, placement of the electronic devices, interconnection of the electronic components, thermal cycling, and solder material characteristics. This theory can be extended to improve the reliability of the system.

Patterned anodes with sub-millimeter spatial resolution for large-area MCP-based photodetector systems

Micro-channel-plate-based photo-detectors are unique in being capable of covering very large areas such as those required in elementary particle and nuclear physics, while providing sub-millimeter space resolution, time resolutions of less than 10 picoseconds for charged particles, and time resolutions of 30psec–50psec for single photons. In such systems the electronic channel count is a major cost driver. Incorporating a capacitively-coupled anode allows the use of external pickup electrodes with patterns of individual channels optimized for occupancy, rate, and time/space resolution. The signal pickup antenna can be economically implemented as a printed circuit card with a 2-dimensional array of pads for high-occupancy/high-rate applications such as in particle colliders and medical imaging, or a 1-dimensional array of strips for a lower channel count in low-occupancy/low-rate applications such as large neutrino detectors. Here we present pad patterns that enhance signal-sharing between pads to lower the channel count per unit area in large-area systems by factors up to 4, while maintaining spatial resolutions of approximately 100 to 200μm for charged particles and 400 to 1000μm for single photons. Patterns that use multiple signal layers in the signal-pickup board can lower the channel count even further, moving the scaling behavior in the number of pads versus total area from quadratic to linear.

Magnetic solder to reduce porosity of solder joints formed in microgravity

Solder joints formed in microgravity are inferior to joints formed in Earth gravity. They are mechanically weaker and less electrically conductive due to voids forming in the joints when soldering in microgravity. Surface tension and lack of gravitational buoyancy combine to prevent flux and water vapors from escaping the molten solder in absence of gravity, resulting in more porous solder joints. Additionally, corrosive flux vapor products remain trapped in the voids causing further deterioration.Parabolic aircraft flight microgravity soldering data are presented, to compare the joint porosities of conventional nonmagnetic solders and new magnetic solders, to determine if the magnetic solder, when soldered in the presence of a magnetic field, would reduce porosity of solder joints formed in microgravity. Soldering irons were used to hand-solder resistor leads into PC board though-holes, for nonmagnetic and magnetic solders. Addition of 4 wt% and 6 wt% of iron microparticles to the solder pastes resulted in 24% and 28% reductions in the solder joint average cross-sectional porosity, respectively, relative to average nonmagnetic solder joint porosity. Joint porosity distributions were log-normal, so the Wilcoxon Rank Sum test for statistical significance was used to show these porosity reductions are statistically significant at α = 0.05. A fully-developed wire magnetic solder could enable in-space repair of electronics at the component level, giving space mission planners additional flexibility to eliminate some or all spare board-level electronics, and plan instead to perform electronics repairs at the component level. This could then reduce or eliminate required mass of these spare electronics boards.

Trend of Wiring Densification of Printed Wiring Board and Jisso

Trend of Wiring Densification of Printed Wiring Board and Jisso

Optimal Dummy Pattern Design Method for PWB Warpage Control Using the Human-Based Genetic Algorithm.

In this work, a method that minimizes printed wiring board (PWB) warpage by dummy pattern design is proposed. This work suggests that dummy patterns are placed on a preset discretized location in the PWB to reduce the warpage. On each discretized candidate area, the dummy pattern can be set or unset. The warpage is numerically simulated based on direct modeling of the as-is PWB patterns to evaluate the warpage alongside the dummy pattern design set. The optimal pattern that minimizes warpage is determined using the human-based genetic algorithm where the objective function is evaluated by the structural simulation. The optimization method is realized in a spreadsheet that allows scripting language with which the input and output files of the simulation tool can be modified and read. Two different cases have been tested and the results show that the method can determine the optimal dummy patterns. The measured and simulated deflections agree well with each other. Moreover, it has been shown that certain dummy pattern designs that should reduce the warpage can be sought by the optimization.

Transparency of SIM profiles for the consumer remote SIM provisioning protocol

In mobile communication, User Equipment (UE) authenticates a subscriber to a Mobile Network Operator (MNO) using credentials from the MNO specified SIM profile that is securely stored inside the SIM card. Traditionally, a change in a subscriber’s SIM profile, such as a change in a subscription, requires replacement of the physical SIM card. To address this shortcoming, the GSM Association (GSMA) has specified the consumer Remote SIM Provisioning (RSP) protocol. The protocol enables remote provisioning of SIM profiles from a server to SIM cards, also known as the embedded Universal Integrated Circuit Card (eUICC). In RSP, any GSMA-certified server is trusted by all eUICCs, and consequently any server can provision SIM profiles to all eUICCs, even those not originating from the MNO associated with the GSMA-certified RSP server. Consequently, an attacker, by compromising a server, can clone a genuine SIM profile and provision it to other eUICCs. To address this security problem, we present SIM Profile Transparency Protocol (SPTP) to detect malicious provisioning of SIM profiles. SPTP assures to the eUICC and the MNO that all SIM provisioning actions—both approved and unapproved—leave a permanent, non-repudiatable trail. We evaluate security guarantees provided by SPTP using a formal model, implement a prototype for SPTP, and evaluate the prototype against a set of practical requirements.

Double-Sided Polishing Simulation Based on the Gap Theory - Theory of Pressure Distribution Analysis and Conditions for High Flatness

The double sided polishing technique is often applied to achieve high total thickness variance (TTV) of large silicon wafers that are employed to manufacture integrated circuit (IC) cards and smartphones. However, the theoretical analysis of high TTV is not sufficiently studied for the double sided polishing. Whereas, a polishing simulation for single sided polishing based on the gap theory was already developed. This simulation results were compared to the experimental results and indicate good behavior characteristics. This study presents a description of the theory for analyzing pressure distribution for double sided polishing and the simulation results of the surface generation process. It was demonstrated that the average of total running distance is nearly equal for the upper and the lower plates. Improved flatness is obtained when the rotation speed differences of the upper and lower plate rotations for the carrier revolution are equal. Furthermore, it was shown that TTV of less than 0.04 μm with a flatness of less than 0.05 μm may be attained when the cone upper plate with the optimum slope and the flat lower plate are employed with lower carrier rotation.

Verdet constant determination of dielectric media using a new versatile, portable and low-cost magneto-optical rotator

The full details of a newly developed versatile, portable and low-cost magneto-optical device for the accurate determination of Verdet constant over the wavelength range of 400–480 nm in undergraduate physics and chemistry labs are presented. The elevated sensitivity of the device is achieved by using a semiconducting photodiode detector coupled with an electronic circuit board, which is configured to autonomously record the finest rotation angle in the polarization direction of the transmitted light relative to a reference polarizer. Two different mechanisms to generate a strong coaxial magnetic field of ∼1.34 T are presented, using either a ring neodymium permanent magnet or a solenoid fed by a lithium-ion battery cell. Due to its versatility, portability and low-cost, the presented device is expected to replace most currently existing bulky and expensive setups.

Design and Interfacing of I2C Master with Register and LCD Slaves

One of the foremost, well-liked, less sophisticated Serial communication standards, I2C; a bus protocol familiarly meant for the exchange of information among the peripherals residing on the constant circuit card, houses two-wires i.e., data and clock for supporting duplex communication between multiple masters and slaves do considered as prominent and efficient in Data transmission. The present work emphasizes on the I2C controller designed for interfacing with slaves, a simple control register of I2C switches/card where the data is written or scan from, subsequently, I2C core implementation on Spartan 3E FPGA, where one of its on-chip peripheral, in this case LCD treated as a slave for performing data transactions. The entire module is designed in Verilog HDL, functional checking is accomplished with the ISIM 10.0b simulator, followed by the design synthesis using Xilinx ISE14.4 tool

Efforts to Reduce the Impact of Coronavirus Disease 2019 Outbreak on Radiation Oncology in Taiwan

Efforts to Reduce the Impact of Coronavirus Disease 2019 Outbreak on Radiation Oncology in Taiwan

Study of LTCC-GEM gain properties

Low Temperature Co-fired Ceramic (LTCC) is an insulator and has been used for electronic circuit boards. The features of LTCC are good electric discharge resistance and high rigidity. A GEM foil using LTCC is expected not to be broken by an electric discharge. The manufactured LTCC-GEM has a hole area of 100 × 100 mm2, the hole diameter is 100 µm, and the hole pitch is 200 µm. We have measured the performance with respect to the gain properties of 200 µm thick LTCC-GEM with 55Fe X-ray. In the measurement, the gain achieved was about 2000 for three gases, ArCO2 (Ar:CO2 = 70:30), P10 (Ar:CH4 = 90:10) and T2K (Ar:CF4:iC4H10 = 95:3:2), and the long-term (100 hours) fluctuation was within 6%. And when the 100 × 100 mm2 LTCC-GEM hole area was divided into 10× 10 mm2, the gain uniformity of the entire region was estimated to be 12%.

Methylsiloxanes and Their Brominated Products in One e-Waste Recycling Area in China: Emission, Environmental Distribution, and Elimination.

The present study investigated the sources and fates of methylsiloxanes and their brominated products in one e-waste recycling area of China. During thermal (30-1000 °C) recycling experiments for printed wiring boards (PWBs), besides volatile methylsiloxanes (D4, D5, and D6), their monobrominated products, that is, D3D(CH2Br), D4D(CH2Br), and D5D(CH2Br), were also found by quadrupole time-of-flight gas chromatography-mass spectrometry to have 2-3 orders of magnitude lower emissions (0.31-1.3 μg/g) than those (18.1-866 μg/g) of parent methylsiloxanes. Overall, the fastest emissions of methylsiloxanes and bromo-methylsiloxanes occurred at 300-400 and 400-500 °C, respectively, accounting for 35.3-51.0 and 39.4-82.1% of their total emission. In the e-waste recycling area, concentrations of D4-D6 were 1.1-75.0 μg/g dw [detection frequency (df) = 100%] in 31 dusts from PWB treatment workshops, while limits of detection (LOD) < 683 ng/g dw (df = 69-100%) in 48 surrounding soils were up to 3 orders of magnitudes higher than those in reference areas. Meanwhile, D3D(CH2Br)-D5D(CH2Br) were detected in both dusts (<LOD-1.2 μg/g dw, df = 48-52%) and soils (<LOD-70.3 ng/g dw, df = 23-77%) from the e-waste recycling area, but they were not present in reference samples. Simulating experiments showed that hydrolysis (9.07-378 d) and volatilization (8.55-1007 d) half-lives of monobrominated D4-D6 in soils were 1.6-5.0 times longer than those of their parent methylsiloxanes.

Predicting the Effects of HPEM Radiation on a Transmission Line Terminated With Linear/Nonlinear Load in Perforated Metallic Enclosure Using FDDM/VF

High-power electromagnetic (HPEM) pulse affects electronic devices that have linear/nonlinear characteristics. To protect the electronic circuit board, the use of metallic enclosure as an electromagnetic shield is one of the best methods. Apertures and slots in the body of metallic enclosure is the path of coupling HPEM fields to electronic board and equipment. In this article, we are following to evaluate the effect of HPEM fields on the microstrip line with nonlinear load that is enclosed by perforated metallic enclosure. For this purpose, a method has been proposed that uses the benefits of the time domain analysis and frequency domain analysis. The whole electromagnetic system of the problem is decomposed into linear and nonlinear subsystems. Thevenin’s equivalent circuit of the linear subsystem from the connection point to nonlinear load has been evaluated by using finite difference delay modeling (FDDM) in the frequency domain. By vector fitting method and by using rational functions, Thevenin’s equivalent circuit is converted to circuits with RLC elements and the time domain voltage source. This circuit can be analyzed in Spice. Results obtained from this model are well adopted with those that are calculated by CST-Microwave studio for linear and nonlinear load and have better time efficiency.

Electro-vibration modeling and response of 3D skeletal frame configuration for energy harvesters

3D skeletal frame configuration is introduced as a means for overcoming deficiencies encountered by conventional 1D beam energy harvesters (EHs). A composite finite element model based on 3D beam kinematics is further developed and tailor-made for this purpose. A comprehensive electro-vibration analysis is conducted using a MATLAB code for the 3D skeletal frame EH as an enhanced application of the theory and compared to the corresponding 1D beam harvester. The results obtained by the theory is then validated against numerical responses based on active solid elements. It is shown that the novel 3D skeletal frame configuration offers substantial benefits over the conventional 1D beam including higher strain areas, multi-directionality, and effectively higher extracted power levels. These are actually among the most significant deficiencies by 1D beam topologies. The internal volume of the novel EH along with the surfaces of the tip mass can be utilized for electronic components and circuit boards.