Board Design Research Articles

Equation-Based Solutions to Coupled, Asymmetrical, Lossy, and Nonuniform Microstrip Lines for Tab-Routing Applications

In this paper, analytical equation-based solutions are derived to allow quick and accurate calculations directly from the physical parameters of coupled, asymmetrical, lossy, and nonuniform microstrip lines with interdigital trapezoidal tabs incorporated, resulting in their corresponding scattering parameters. Capacitance and inductance matrices under a quasi-static condition are derived from the cross-sectional dimensions of asymmetrical coupled microstrip lines with unequal widths. They are converted into a frequency-dependent resistance–inductance–conductance–capacitance model, allowing complete equation-based solutions to their four-port Z-matrix, S-matrix, and ABCD-matrix. As an application example of tackling the complexity of transmission lines, the derived analytical method is applied to a transitional structure with linearly varying trace width in tabbed microstrip lines by the method of segmentation. In addition, a new concept of tab-coupling fringing capacitance is specifically introduced to compensate for underestimated mutual capacitance at tab positions, which will improve the accuracy of the proposed approach. Numerical modeling results from commercial simulation tools are compared for validation purposes. As a conclusion, the proposed method and its versatility are demonstrated with applications to practical high-speed and high-density printed circuit board designs, which renders itself effective and efficient in an optimization process.

The Design of UDOO Boards: Contributing to the Appropriation of Digital Technology

The domain of Human-Computer Interaction does not concern just the design of technology that is easy to use, useful, and fancy – it has to do with our role in shaping our environment, our ecological niche that today involves the whole earth. A key concept in the interaction between humans and computing resources is that of appropriation originally proposed by Aleksei Nikolaevich Leontiev. In the present paper we will first review the concept of appropriation and will present bricolage as a key activity for fostering appropriation. Then we will present the Makers Movement as a socio-cultural movement relevant for the process of appropriation of digital technology. Finally, we will describe our approach and vision in the design of the UDOO, a single board computer, and of a specific developing environment, UAPPI, for enabling the appropriation through meaningful activities of digital technologies.

Layer Assignment of Buses and Nets With Via-Count Constraint in High-Speed PCB Designs

It is necessary for cost consideration to minimize the number of the used layers in a high-speed printed circuit board (PCB) design. In this paper, any independent net cannot be treated as a bus-oriented net in a high-speed PCB design because of no timing-matching constraint on an independent net. Any independent net in a high-speed PCB design can be modeled to obey the via-count constraint as the maximum number of the permitted vias for signal integrity. Clearly, the introduction of the permitted vias onto the independent nets can lead to the reduction on the number of the used layers in a high-speed PCB design. Given a set of bus-oriented nets and a set of independent nets with a via-count constraint in a high-speed PCB design, by introducing virtual vias onto independent nets and eliminating redundant vias on any used layer, a generalized algorithm can be proposed to minimize the number of the used layers with satisfying the via-count constraint on any independent net and assign the given bus-oriented nets and the separated segments inside the given independent nets onto the used layers. Compared with Yan’s algorithm with no via introduction on independent nets, the experimental results show that our proposed algorithm with ${c_{\max } = 1}$ , ${c_{\max } = 2}$ , ${c_{\max } = 3}$ , ${c_{\max } = 4}$ , and ${c_{\max } = 5}$ use reasonable CPU time to insert permitted vias to reduce 2.1, 2.8, 3.8, 4.4, and 4.6 used layers on the average for ten tested examples, respectively. Compared with a two-phase algorithm with via introduction on independent nets, the experimental results show that our proposed algorithm with ${c_{\max } = 1}$ , ${c_{\max } = 2}$ , ${c_{\max } = 3}$ , ${c_{\max } = 4}$ , and ${c_{\max } = 5}$ use less CPU time to reduce 1.6, 1.7, 1.7, 1.6, and 1.5 used layers on the average with increasing 13.3%, 16.3%, 10.6%, 4.2%, and 2.6% of the total used vias on the independent nets for ten tested examples, respectively.

Effect of Aspect Ratio and The Maximum Relative Camber on Hydrodynamic Performance of A Vertical Double-Curved Otter Board

As an important accessory of Antarctic krill fishing gear, otter board has the effect of providing net horizontal expansion. To study the effects of aspect ratio and maximum relative camber on the hydrodynamic performance of Antarctic krill otter board, provide theoretical basis for the design and optimization of the otter board, the hydrodynamic performance parameters were analysed by flume model experiments. The results show: with the increase of aspect ratio, Clmax and Kmax show an upward trend; when the maximum relative camber is less than or equal to 10%, the value of ∝0 fluctuates around 20°. When the maximum relative camber is greater than 10%, ∝0 decreases gradually in the range of 32.5° to 22.5°; K∝0 increases firstly and then decreases. With the increase of maximum relative camber, Clmax shows an upward trend; Kmax shows a downward trend; when the aspect ratio is less than or equal to 2.0, ∝0 shows an upward trend in the range of 20° to 32.5°, and when the aspect ratio is greater than 2.0, the value shows a fluctuating trend around 20°. K∝0 fluctuates and there is no obvious principle.

SCEMA: a high channel density electronics module for fast waveform capture

The development of fast, highly pixelated photodetectors with single-photon sensitivity has the potential to enable a variety of new radiation detection concepts. Systems that desire to employ these detectors without loss of information demand waveform digitization with high sampling rates. Switched capacitor arrays provide a low-cost, low-power, compact solution to fast readout with high channel density. The Sandia Laboratories Compact Electronics for Modular Acquisition (SCEMA) was developed to meet these demands. A single module employs two domino ring sampling switched capacitor arrays (DRS4) [1] to provide 16 channels of up to 5 GS/s waveform digitization. This paper presents an overview of the board design and function. Calibration procedures for the module are discussed. Finally, temporal resolution tests are presented demonstrating the module's viability as readout for high fidelity temporal measurements of single photons in suitable photodetectors.

A Paper-Based Inkjet-Printed Graphene Sensor for Breathing-Flow Monitoring

Continuous monitoring of breathing flow is an essential but often poorly utilized predictor that is causing poor patient outcome. A low-cost, light-weight, easy-to-use, reliable, and disposable breathing sensor is required to bypass the limitations of existing conventional sensors, which are bulky, expensive, and often require experts to handle. In this article, a low-cost, inkjet-printed graphene sensor on a disposable glossy photo-paper substrate is presented for breathing-rate monitoring. The sensor architecture consists of a graphene nanoparticle based thin functional layer on top of a silver nanoparticle based interdigitated conductive pattern. A standard office inkjet-printer was configured with nanoparticle inks and a printed circuit board design software was utilized for the layouts. The sensor was tested in a laboratory environment, and its data were analyzed for different breathing patterns. An empirical model of the sensor was developed using the Cole-Cole impedance model. Test results showed successful detection of breathing rates for different breathing patterns. The prototype sensor provides a low-cost, disposable, and practical solution for frequent breathing pattern recognition.

Printed Circuit Board Design Methodology for Embedded Systems Targeting Space Applications

This paper presents an overview of the theory and main aspects involved in designing reliable printed circuit boards (PCB) for embedded systems to be used in space applications. To that end, the design and layout process of a satellite-oriented hardware architecture is described, along with an introductory text on PCB design theory, including high-speed signals, impedance control, and general good practices. As a case study, we present a board layout which follows the European Space Agency (ESA) design rules for printed circuit boards (ECSS-Q-ST-70-12C) with signal integrity analysis and a layered structure that mitigates electromagnetic interference effects. In this context, all components were selected to withstand wide temperature variation, the vacuum, and some even can tolerate radiation – as a microcontroller with ferroelectric program memory and a novel European radiation-hardened Field Programmable Gate Array (FPGA). Simulations results are presented in order to demonstrate the PCB signal integrity performance.

A Boosting-Based Intelligent Model for Stencil Cleaning Prediction in Surface Mount Technology

This research proposes a stencil cleaning decision-making model in surface mount technology. Stencil cleaning is a critical process that influences the quality and efficiency of printing circuit boards. Stencil cleaning operation depends on various process variables, such as printing speed, printing pressure, and aperture shape. The objective of this research is to develop an intelligent model to guide stencil cleaning decision-making to reduce process defects. The stencil cleaning process is considered as a sequential detection problem in this study. Based on quality measures of printed historical boards, such as solder paste volume and the number of defects, a novel feature space is proposed by considering both short-term and long-term process trend. A gradient boosting model is applied to make the stencil cleaning decision. To validate the effectiveness of the proposed model, different scenarios are designed in the experimental test. State-of-art data mining models are also compared to the proposed cleaning decision-making model. Experimental results show that the proposed boosting-based intelligent model outperforms other models and can effectively provide the cleaning suggestion even the board design is changed in the future.

Whose Game is it Anyway ? Board and Dice Games as an Example of Cultural Transfer and Hybridity

Board games in antiquity are characterized by their continuity in both shape and playing practice when crossing socio-political borders and centuries of time. But as much as these games appear similar throughout the archaeological record, traces of integration and appropriation are found in aspects not necessarily affecting rules of play or configurations of boards. Recently uncovered examples of the game of Duodecim scripta in Egypt and Sudan point to changes in board design or, at least, in design preference when compared to those found elsewhere in the Roman Empire. The presence of game boards in grave contexts further illustrates the extent of the appropriation that may have taken place. Egypt and Sudan in Greco-Roman times are on and across the border of the Roman world and provide ideal contexts for the understanding of the cultural appropriation process of board games in antiquity.

Traces of Appropriation: Roman Board Games in Egypt and Sudan

races of appropriation: Roman board games in Egypt and Sudan Board games in antiquity are characterized by their continuity in both shape and playing practice when crossing socio-political borders and centuries of time. But as much as these games appear similar throughout the archaeological record, traces of integration and appropriation are found in aspects not necessarily affecting rules of play or configurations of boards. Recently uncovered examples of the game of Duodecim scripta in Egypt and Sudan point to changes in board design or, at least, in design preference when compared to those found elsewhere in the Roman Empire. The presence of game boards in grave contexts further illustrates the extent of the appropriation that may have taken place. Egypt and Sudan in Greco-Roman times are on and across the border of the Roman world and provide ideal contexts for the understanding of the cultural appropriation process of board games in antiquity.

Alleviating concentration polarization: a micro three-electrode interdigitated glucose sensor based on nanoporous gold from a mild process.

Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or diagnose diabetes. Compared with the traditional enzyme-based electrochemical glucose sensors, the non-enzymatic ones have gradually come to people's attention recently. By integrating three electrodes into one device, glucose sensors can achieve superior performance and are convenient to carry. Herein, a non-enzymatic three-electrode interdigitated glucose sensor (TEIDGS) based on nanoporous gold is designed and fabricated. To our best knowledge, it is the first time that interdigitated electrodes are combined in a single non-enzymatic glucose sensor device. Due to the advantage of the interdigitated structure and the smart design of the three-electrode circuit board, the TEIDGS can effectively reduce concentration polarization and achieve a high detective sensitivity for glucose of 1217 μA mM−1 cm−2 and 343 μA mM−1 cm−2 in the ranges of 0.001–0.590 mM and 0.59–7.00 mM, respectively. Moreover, a low detection limit of 390 nM can be reached. In addition, this TEIDGS possesses excellent selectivity for glucose among other interferents. Strikingly, after three weeks of operation, it can still retain a high detection performance. This work will certainly provide an efficient structure and proper catalytic material choice for future non-enzymatic glucose sensors.

The driver design for N2O gas detection system based on tunable interband cascade laser

In this paper, the driver circuit for N2O gas detection system based on tunable interband cascade laser (ICL) is developed. Considering the influence of power supply stability on the digital-analog hybrid drive circuit of tunable diode laser absorption spectroscopy (TDALS), the high-efficiency TPS5430 is used to design the positive and negative power supply circuit. The large electrolytic capacitor + post-stage LC filter combination filter is used to effectively filter out high and low frequency ripple and switching noise. The use of thick high current trace + via + multilayer printed circuit board (PCB) design makes the line temperature rise smaller, more stable and durable, and uses high frequency shielding inductance to effectively reduce radiation interference to ensure the stability of the drive. The STM32F407, a highperformance microcontroller based on the ARM Cortex-M4 core, is used as the master control chip and generates a sawtooth scanning signal. The direct digital synthesizer (DDS) chip ICL8038 is used to generate a sinusoidal modulated signal of a specific frequency. The two signals are superimposed by a reverse addition circuit, and the laser drive signal is generated by a developed positive feedback balanced voltagecurrent conversion circuit. Experimental results show that the driver circuit can well meet the drive development requirements of N2O gas detection systems based on tunable interband cascade laser.

Say on Pay and the 'Quiet Life' of Boards

The rapid rise in CEO pay over the past decades has fueled an intensive debate on corporate governance. Fiduciary duty rules are supposed to safeguard shareholders' interests when boards design compensation packages for managers. However the so-called power view holds that boards may be colluding with CEOs to transfer wealth from shareholders. In response, recent regulatory initiatives such as Say on Pay and the Dodd-Frank Act aim to reinvigorate fiduciary duty rules and to put shareholders back in control. I develop a model in which a self-interested board contracts with a CEO in a setting that combines agency frictions and strategic communication. The board can learn about the firm's environment through monitoring and/or communication. In equilibrium, the board has an excessive preference for communication. As a result, the board grants the CEO a greater equity stake than as preferred by the shareholders. While this may seem consistent with the managerial power view, it is in fact more a manifestation of the board pursuing a quiet life, because the greater CEO equity stake promotes CEO-board communication, and thereby reduces the pressure for the board to engage in costly monitoring. By adjusting the board's equity stake, the shareholders can actively preempt such behavior, though they may not always choose to do so. Ironically, I find that precisely for those cases where the board successfully subverts the shareholders' intent, the board is ultimately worse off from having discretion. This illustrates the importance of taking boards as strategic, self-interested players, rather than assuming they align themselves fully with either shareholders or management.

A investigation and analysis of characteristics of solid furniture boards made of post-consumer wood

It is substantiated that post-consumer wood (PCW) is an additional timber resource for the woodworking industry. It is established that the physical and mechanical parameters of all furniture boards, regardless of their design, satisfy the requirements of regulatory documents. It has been found that the ratio of thickness to the width of the strips is most influenced by the physical and mechanical properties of the furniture boards. The highest physical and mechanical parameters are characterized by a solid furniture boards with a strips cross section of 22×20 mm. The average static bending strength across the strips of such a solid furniture boards is 27.03MPa. The lowest physical and mechanical indicators are characterized by a solid furniture boards with a strips section of 22×80 mm. The average static flexural strength across the strips of such a solid furniture boards is 16.10MPa. The physical-mechanical parameters of a traditional solid furniture boards made of primary wood are slightly higher than the physical-mechanical parameters of a similar solid furniture boards design made of PCW. Thus, the static flexural strength across the strips of a traditional solid furniture boards is 22.05MPa, and the strength of a solid furniture boards made of PCW is 19.88MPa. According to the results of experimental researches it is established that in order to achieve the shape resistance and sufficient strength of the solid furniture boards on a static bend across the strips, it is recommended that the width of the rail for gluing the furniture board should be no more than triple its thickness.
 It is recommended to use radial cross-section wooden strips when making solid furniture boards to ensure high resistance. Remodeling the iron on the furniture boards will bring financial and environmental benefits. The financial advantage of the manufacturer is to reduce the material costs of making solid furniture boards made of PCW of iron from the traditional furniture boards. Yes, our calculations show that the cost of solid furniture boards made of PCW is 43.57% depending on the design of the furniture boards. The social and ecological and economic benefit is that by using used wood we reduce by 3 4% the landfill area, reduce deforestation by 0.29 hectares each year, thereby improving the environment.

The Main Control System of UUV for Maricultre

The water quality environment is the key to marine aquaculture, which directly affects the quality and output of seafood. Therefore, an Unmanned Underwater Vehicle (UUV) that can detect seawater environment is designed. The thesis firstly outlines the overall working principle of UUV system, and then focuses on the design and development of the main control board of the STM32-based UUV. Based on the modular design concept, the hardware part mainly includes the main control chip circuit, the timer interface circuit, the attitude detection circuit, the solenoid valve control circuit and the sensor interface circuit. The software part designs the corresponding program flow for different hardware circuit modules. Finally, the main control board model was produced. The development program was written based on the HAL library. Test results show that the performance of the main control board is stable and reliable, and can meet the basic needs of seawater detection.

245 GHz subharmonic receiver with on-chip antenna for gas spectroscopy application * * Project supported by the Zhejiang National Natural Science Foundation of China (No. LQ17F040001) and the Key Laboratory Open Project Fund of Southeast University, China (No. K201817).

A 2nd transconductance subharmonic receiver for 245 GHz spectroscopy sensor applications has been proposed. The receiver consists of a 245 GHz on-chip folded dipole antenna, a CB (common base) LNA, a 2nd transconductance SHM (subharmonic mixer), and a 120 GHz push-push VCO with 1/64 divider. The receiver is fabricated in fT/fmax = 300/500 GHz SiGe:C BiCMOS technology. The receiver dissipates a low power of 288 mW. Integrated with the on-chip antenna, the receiver is measured on-chip with a conversion gain of 15 dB, a bandwidth of 15 GHz, and the chip will be utilized in PCB board design for gas spectroscopy sensor application.

General-compensation-purpose Static var Compensator prototype

Abstract Static var Compensator (SVC) has a general topology and its operational principle allows its application with distinct compensation purposes, such as voltage regulation or load balancing. Thus, this paper presents the development of a SVC prototype that could be used to test and validate a variety of control strategies proposed for the SVC applications. These strategies may include distributed/cooperative approaches, since the designed prototype has two control units with independent metering hardware. The design of the analog signal conditioning boards developed for voltage and current measurement is also presented. Design and control methods for reactive compensation under unbalanced and/or distorted voltages or loads are described and validated using the presented prototype.

Reactive material jetting of polyimide insulators for complex circuit board design

Polyimides are a group of high performance thermal stable dielectric materials used in diverse applications. In this article, we synthesized and developed a high-performance polyimide precursor ink for a Material Jetting (MJ) process. The proposed ink formulation was shown to form a uniform and dense polyimide film through reactive MJ utilising real-time thermo-imidisation process. The printed polyimide film showed a permittivity of 3.41 and degradation temperature around 500 °C, both of which are comparable to commercially available polyimide films. Benefiting from the capability of being able to selectively deposit material through MJ, we propose the use of such a formulation to produce complex circuit board structures by the co-printing of conductive silver tracks and polyimide dielectric layers. By means of selectively depositing 4 μm thick patches at the cross-over points of two circuit patterns, a traditional double-sided printed circuit board (PCB) can be printed on one side, providing the user with higher design freedom to achieve a more compact high performance PCB structure.

EMC Board Design Utilizing High-Frequency Transmission Line Characteristics of Wiring Patterns

EMC Board Design Utilizing High-Frequency Transmission Line Characteristics of Wiring Patterns

Convolutional neural network‐based multi‐label classification of PCB defects

Due to the rapid development of printed circuit board (PCB) design technology, inspection of PCB surface defects has become an increasingly critical issue. The classification of PCB defects facilitates the root causes of detects’ identification. As PCB defects may be intensive, the actual PCB classification should not be considered as a binary or multi-category problem. This type of problem is called multi-label classification problem. Recently, as one of the deep learning frameworks, a convolutional neural network (CNN) has a major breakthrough in many areas of image processing, especially in the image classification. This study proposes a multi-task CNN model to handle the multi-label learning problem by defining each label learning as a binary classification task. In this study, the multi-label learning is transformed into multiple binary classification tasks by customising the loss function. Extensive experiments demonstrate that the proposed method achieves great performance on the dataset of defects.