Search

For optimal equipment procurement in Taiwan, first, the specifications and prices of a product are evaluated. Based on these evaluations, procurement decisions are made. Ensuring accurate evaluation criteria for procurement is a multicriteria decision making (MCDM) problem. Printed circuit board (PCB) manufacturers have not grasped the decision-making factors of the new equipment specification, and they continue to use the previous generation specifications as the decision-making criteria for new equipment; this results in inappropriate evaluation criteria. When new equipment with different specifications is launched, purchasers may still use the specifications of older equipment as a basis for their purchase decisions. For example, thermal power generation specifications are often used to evaluate equipment for nuclear power generation. The difference in criteria renders it difficult to make decisions for new equipment. We proposed the use of a scientific method to establish a set of criteria decision-making models for equipment procurement to help PCB factories accurately evaluate contemporary specifications. This research established criteria for new technologies to help decision makers select the most appropriate method. We used the Delphi method and the analytic hierarchy process (AHP) to provide insights into technological and commercial requirements, and a model was further developed for optimal equipment procurement.

For optimal equipment procurement in Taiwan, first, the specifications and prices of a product are evaluated. Based on these evaluations, procurement decisions are made. Ensuring accurate evaluation criteria for procurement is a multicriteria decision making (MCDM) problem. Printed circuit board (PCB) manufacturers have not grasped the decision-making factors of the new equipment specification, and they continue to use the previous generation specifications as the decision-making criteria for new equipment; this results in inappropriate evaluation criteria. When new equipment with different specifications is launched, purchasers may still use the specifications of older equipment as a basis for their purchase decisions. For example, thermal power generation specifications are often used to evaluate equipment for nuclear power generation. The difference in criteria renders it difficult to make decisions for new equipment. We proposed the use of a scientific method to establish a set of criteria decision-making models for equipment procurement to help PCB factories accurately evaluate contemporary specifications. This research established criteria for new technologies to help decision makers select the most appropriate method. We used the Delphi method and the analytic hierarchy process (AHP) to provide insights into technological and commercial requirements, and a model was further developed for optimal equipment procurement. [ABSTRACT FROM AUTHOR]

The flip chip package (FCP) based integrated circuits supports millimetre wave frequency range (30 - 300 GHz), analysing the conditions for optimal signal transmission between the integrated circuits for FCP type being the primary essence of this article. The effective signal transmission occurs through a dielectric-coated conductor structure based on the surface wave communication phenomenon, known as a surface wave communication-based wave guide (SWW). The article focuses primarily on design considerations to build SWW for FCP applications at millimetre wave frequency ranges. The efficiency of the proposed waveguide was investigated in terms of power transmission capacity, voltage standing wave ratio (VSWR) and signal attenuation. The analysis comprises examining these parameters at the frequency range of 50 GHz to 150 GHz while taking into account varied degrees of waveguide dimensions and surface reactance. The measured results show that at the signal frequency of 100 GHz with dielectric and conductor thickness of 0.2 mm and surface reactance of 100 Ω, the suggested waveguide provides efficient signal transmission with approximately 0 dB signal attenuation, ideal high-power flow of 41,000 ${{VA} \over {{m^2}}}$ VA m 2 and VSWR of 1.2. Overall, this article provides insights on the design and performance of SWW for FCP applications at millimetre wave frequency band. [ABSTRACT FROM AUTHOR]

This research review article provides a detailed examination of SMA (SubMiniature version A) connectors, which are integral components in high-frequency electronic systems. Through extensive S-parameter and time-domain reflectometry (TDR) measurements conducted on various SMA connector constructions, this study aims to evaluate the performance and impact of SMA connectors on signal integrity. Results reveal insights into the comparative performance of different SMA connector types mounted on PCB land pads, highlighting their strengths and limitations. Additionally, this paper explores the application of reference plane cut-outs for discontinuity impedance compensation, aiming to enhance the frequency response of SMA connectors. By linking measured performance parameters with relative market prices, this study offers valuable insights into the economic viability of different SMA connector types. The best and worst performing SMA connector measurements reveal an S11 < −10 dB bandwidth of more than 8 GHz and 1.5 GHz and a transition impedance of 46.5 Ω and 21 Ω, respectively. Overall, this research contributes to advancing the understanding and selection of SMA connectors for RF applications in telecommunications, aerospace, medical devices, and beyond. [ABSTRACT FROM AUTHOR]

Abstract Hepatocellular carcinoma (HCC) stands as the most prevalent form of primary liver cancer, predominantly affecting patients with chronic liver diseases such as hepatitis B or C-induced cirrhosis. Diagnosis typically involves blood tests (assessing liver functions and HCC biomarkers), imaging procedures such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), and liver biopsies requiring the removal of liver tissue for laboratory analysis. However, these diagnostic methods either entail lengthy lab processes, require expensive imaging equipment, or involve invasive techniques like liver biopsies. Hence, there exists a crucial need for rapid, cost-effective, and noninvasive techniques to characterize HCC, whether in serum or tissue samples. In this study, we developed a spiral sensor implemented on a printed circuit board (PCB) technology that utilizes impedance spectroscopy and applied it to 24 tissues and sera samples as proof of concept. This newly devised circuit has successfully characterized HCC and normal tissue and serum samples. Utilizing the distinct dielectric properties between HCC cells and serum samples versus the normal samples across a specific frequency range, the differentiation between normal and HCC samples is achieved. Moreover, the sensor effectively characterizes two HCC grades and distinguishes cirrhotic/non-cirrhotic samples from tissue specimens. In addition, the sensor distinguishes cirrhotic/non-cirrhotic samples from serum specimens. This pioneering study introduces Electrical Impedance Spectroscopy (EIS) spiral sensor for diagnosing HCC and liver cirrhosis in clinical serum—an innovative, low-cost, rapid (

Hepatocellular carcinoma (HCC) stands as the most prevalent form of primary liver cancer, predominantly affecting patients with chronic liver diseases such as hepatitis B or C-induced cirrhosis. Diagnosis typically involves blood tests (assessing liver functions and HCC biomarkers), imaging procedures such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), and liver biopsies requiring the removal of liver tissue for laboratory analysis. However, these diagnostic methods either entail lengthy lab processes, require expensive imaging equipment, or involve invasive techniques like liver biopsies. Hence, there exists a crucial need for rapid, cost-effective, and noninvasive techniques to characterize HCC, whether in serum or tissue samples. In this study, we developed a spiral sensor implemented on a printed circuit board (PCB) technology that utilizes impedance spectroscopy and applied it to 24 tissues and sera samples as proof of concept. This newly devised circuit has successfully characterized HCC and normal tissue and serum samples. Utilizing the distinct dielectric properties between HCC cells and serum samples versus the normal samples across a specific frequency range, the differentiation between normal and HCC samples is achieved. Moreover, the sensor effectively characterizes two HCC grades and distinguishes cirrhotic/non-cirrhotic samples from tissue specimens. In addition, the sensor distinguishes cirrhotic/non-cirrhotic samples from serum specimens. This pioneering study introduces Electrical Impedance Spectroscopy (EIS) spiral sensor for diagnosing HCC and liver cirrhosis in clinical serum—an innovative, low-cost, rapid (< 2 min), and precise PCB-based technology without elaborate sample preparation, offering a novel non-labeled screening approach for disease staging and liver conditions. [ABSTRACT FROM AUTHOR]

We present an innovative modular fabrication method for a green monopropellant thruster, employing printed circuit boards (PCB) as fundamental building blocks for rapid and efficient performance optimization. This PCB-based approach offers superior thermal and structural characteristics to conventional MEMS-based microthrusters. Furthermore, it streamlines mass production and facilitates the swift and reliable assembly of thrusters using well-established PCB surface mount technology. In this study, we present a conceptual demonstration of this pioneering materials and fabrication technique, exemplified by the development of a 200 mN thrust monopropellant thruster utilizing 90 wt% hydrogen peroxide. Subsequently, we conduct propulsion experiments and consistently observe identical patterns in pulse mode firing tests, demonstrating the repeatability of the system. The experimental results, including thrust and C * efficiencies, provide substantial evidence for the validity and feasibility of our proposed approach. The modular fabrication method presented in this study exhibits high potential for mass production of small satellite thrusters, effectively addressing the expanding thruster market. [Display omitted] • Novel approach to thruster fabrication using Lego-like PCB blocks. • Modular monopropellant thrusters with desired performances. • Cost-effective and simple solution compared to conventional methods. • Stable performance, high efficiency, and negligible nozzle erosion. • Potential for mass production of diverse small satellite thrusters. [ABSTRACT FROM AUTHOR]

This study introduces a groundbreaking antenna system, the directive Metasurface Half-Maxwell Fish-Eye (MHMF) lens antenna, tailored specifically for Internet-of-Things (IoT) networks. Designed to operate at 60 GHz, this antenna ingeniously integrates a dipole antenna within a parallel-plate waveguide to illuminate a Half-Maxwell Fish-Eye (HMFE) lens. The HMFE lens serves as a focal point, enabling a crucial high gain for IoT operations. The integration of metasurface structures facilitates the attainment of the gradient refractive index essential for the lens surface. By employing commercial Ansys HFSS software, extensive numerical simulations were conducted to meticulously refine the design, focusing particularly on optimizing the dimensions of unit cells, notably the modified H-shaped cells within the parallel waveguides housing the beam launchers. A functional prototype of the antenna was constructed using a standard PCB manufacturing process. Rigorous testing in an anechoic chamber confirmed the functionality of these manufactured devices, with the experimental results closely aligning with the simulated findings. Far-field measurements have further confirmed the effectiveness of the antenna, establishing it as a high-gain antenna solution suitable for IoT applications. Specifically, it operates effectively within the 60 GHz range of the electromagnetic spectrum, which is crucial for ensuring reliable communication in IoT devices. The directive HMFE lens antenna represents a significant advancement in enhancing IoT connectivity and capabilities. Leveraging innovative design concepts and metasurface technology, it heralds a new era of adaptable and efficient IoT systems. [ABSTRACT FROM AUTHOR]

The present article presents critical aspects of RF system development process and its sequential phases along with associated challenges. It also discusses importance of active and passive components thermal behavior and their impact in overall system performance. The study on performance deviation of these components with temperature change has been reported. Potential issues for gain variation and frequency selectivity have been analysed and suitable solutions are explored accordingly. Implementation of temperature stabilization method in designed RF product has been carried out during prototype development. Practical achieved results are noted down during testing and measurement to monitor effectiveness of thermal stabilization mentioned in it. Finally, wideband flat gain response has been achieved by implementation of thermal stabilization for active and passive components to avoid any performance degradation. [ABSTRACT FROM AUTHOR]

Printed circuit board (PCB) inspection is as challenging issue in electronic manufacturing. Visual inspection is broadly used to perform this task and has been instigated by many researchers. This paper focuses on review of 2D vision-based methods in PCB inspection. Traditional and modern advances methods are explored, and their advantages and disadvantages are addressed. Moreover, current research gap through literature review investigation in this domain is addressed and potential solutions are described. Finally, direction for future studies is presented for further improvement of existing methods. [ABSTRACT FROM AUTHOR]

Among hydrogen technologies, a proton exchange membrane fuel cell (PEMFC) is known as an efficient device using hydrogen as the fuel. Although different real-time fault-diagnosis methods are available (i.e., voltage-based or electrochemical-based), the problem with these methods is their dependency on being directly connected to a computer, higher costs, lower security, and the need to perform the tests in a laboratory. The focus and the solution of this study are to propose a novel design of printed circuit board (PCB) that enables the implementation of the required sensors to detect/measure the operational parameters/contamination of PEMFC. The communication of the considered PCB will be with a server without direct contact through the Internet of Things (IoT). A specified computer. exe file has also been developed to directly connect to a personalized network hotspot (to increase security) and enable the wireless communication of the sensor and the computer. The outputs of this study can be considered a novel fault diagnosis kit that measures H2S wirelessly using IoT. To verify the result 11 ppm and 12 ppm of H2S was injected into the system, the IoT kit's measured data is compared with the experiments. The results comparison validated the suitability of the system.

This paper focuses on three-dimensional measurement system of printed circuit board components. Most automated optical inspections suffer from shadows and reflections obscured by the components. We propose a new method to restore shadow and reflection regions of components for accurate shape measurements, which defines shadow and reflection regions for restoration. The region is restored with a variational auto encoder-based restoration network. It is efficient to input information about both shadow and reflection region to restore the region. Additionally, long skip connection is added to VAE for improved accuracy. We confirmed its superiority through experiments by comparing its performance with other restoration networks such as cycle generative adversarial networks and coherent semantic attention inpainting.

Ensuring the quality and functionality of printed circuit boards (PCBs) during manufacturing requires precise, automated visual inspection. Detecting integrated circuits (ICs) on PCBs poses a significant challenge due to diverse component sizes, types, and intricate board markings that complicate accurate object detection. This study addresses this challenge by proposing an enhanced EfficientNet-YOLOv4 algorithm tailored explicitly for the IC detection of PCBs. Numerous modifications are integrated into YOLOv4, with the replacement of its original backbone by a robust feature extraction network, EfficientNetv2-L, and meticulous hyperparameter tuning, including variations in loss functions, anchor size configurations, and other training techniques. The methodology further incorporates diverse data augmentation techniques to enrich the training dataset and enhance the model’s generalization ability. Extensive experiments conducted in this study showed the efficacy and robustness of the algorithm in handling complex PCB layouts and varying lighting conditions, outperforming existing PCB inspection models. The proposed method, EfficientNetv2-L-YOLOv4, achieved an impressive F1-score of 99.22 with an inference speed of 0.14 s per image. The proposed method also performed well compared to EfficientNet-B7-FasterRCNN and the original YOLOv4; it attains an F1-score of 98.96 and an inference speed of 0.10 s per image (with a batch size of 4). These results highlight the significance of effective feature extraction networks for object detection. Beyond addressing IC detection challenges, this algorithm advances the fields of computer vision and object detection. The implementation of EfficientNetv2-L-YOLOv4 in real manufacturing scenarios holds promise for automating component inspections and potentially eliminating the need for human intervention.

With the rapid increase in size and frame rate of TV products, high‐ speed data transmission has become a major issue to be solved. This paper studied the PCB impact factors of high‐speed digital signal transmission on large‐sized display panels, like channel loss, crosstalk between adjacent signals, etc. Simultaneously, improvement methods for signal amplitude attenuation in panel transmission systems was proposed. Based on 98' 4K 120Hz TV product platform, the signal attenuation of transmission system was evaluated, and the effectiveness of the improvement schemes also was verified, the result shows signal quality in system can be improved above 20%. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiaotong University (Science) is the property of Springer Nature 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 impact of four typical surface finishes on electrochemical migration in printed circuit board production was studied using a modified water drop test, and the electrochemical migration phenomena of each surface finish at different bias voltages were analyzed. Based on the analysis of the experimental results, the four surface finishes were ranked in terms of their ability to resist electrochemical migration, as follows: electroless nickel/immersion gold (ENIG) > lead-free hot air solder leveling (HASL) > HASL > Cu. For the lead-free HASL, HASL, and Cu surface finishes, the growth of dendrites was mainly related to the hydroxide solubility product of metal ions, with a smaller solubility product leading to a larger area of precipitates, which further hindered the emergence and growth of dendrites. The electrochemical migration process of ENIG differed from other surface finishes. Gold was not involved in the electrochemical migration process, and no typical cathodic dendrite growth phenomenon was observed. Only nickel hydroxide and oxide formed from the anode edge and migrated toward the cathode with low conductivity, resulting in high electrochemical migration resistance for the ENIG surface finish. [ABSTRACT FROM AUTHOR]

This exploratory study compares how young people (ages 15–16) learn circuitry concepts and layout design principles important to electrical engineering using one of two educational circuitry toolkits: paper circuits and traditional solderless breadboards. Paper-based prototyping kits are representative of a trend that incorporates new materials and approaches to integrating arts into traditional STEM disciplines. Extending prior research on how non-traditional toolkits enhance learning of electrical engineering outcomes, including basic circuitry concepts (i.e., current flow, polarity, and connections), this study examines the material affordances and design choices of the kits that contribute to youth's understanding of more advanced circuitry layout design principles, including space allocation, placement of electronic components, and routing. Results indicate that paper circuits better afford the learning of layout design principles for printed circuit boards (PCBs) with large effect sizes. This study illuminates how the materials of educational toolkits uniquely solicit body- and material-syntonic patterns of activity, and thus differentially engage learners' powerful ideas around circuitry and design principles. This investigation encourages careful consideration of the material affordances of some toolkits over others for learning purposes. [ABSTRACT FROM AUTHOR]

The technique of embedding components inside printed circuit boards (PCBs) is described, using different filling masses. To investigate the possibility of placing the components inside the printed circuit board, a residual circuit breaker with an overload protection (RCBO) system was adapted. Four types of fillings (two epoxy and two silicone) were used in the tests, which were carried out showing the full functionality of the systems embedded in the PCB, regardless of the applied sealing compound. A certain disadvantage was the shrinkage of the applied masses, which was visible in some cases in the occurrence of gaps in the flooding spaces. However, it should be emphasized that the tests were preliminary and that the adjustment of the filling shrinkage will be optimized in subsequent tests. [ABSTRACT FROM AUTHOR]

Printed circuit boards (PCBs) are extensively used to assemble electronic equipment. Currently, PCBs are an integral part of almost all electronic products. However, various surface defects can still occur during mass production. An enhanced YOLOv5s network named YOLO-MBBi is proposed to detect surface defects on PCBs to address the shortcomings of the existing PCB surface defect detection methods, such as their low accuracy and poor real-time performance. YOLO-MBBi uses MBConv (mobile inverted residual bottleneck block) modules, CBAM attention, BiFPN, and depth-wise convolutions to substitute layers in the YOLOv5s network and replace the CIoU loss function with the SIoU loss function during training. Two publicly available datasets were selected for this experiment. The experimental results showed that the mAP50 and recall values of YOLO-MBBi were 95.3% and 94.6%, which were 3.6% and 2.6% higher than those of YOLOv5s, respectively, and the FLOPs were 12.8, which was much smaller than YOLOv7's 103.2. The FPS value reached 48.9. Additionally, after using another dataset, the YOLO-MBBi metrics also achieved satisfactory accuracy and met the needs of industrial production. [ABSTRACT FROM AUTHOR]

This article presents a new technique for evaluating the consistency of the reference impedance in multiline thru–reflect–line (TRL) calibration. During the calibration process, it is assumed that all transmission line standards have the same characteristic impedance. However, these assumptions are prone to errors due to imperfections, which can affect the validity of the reference impedance after calibration. Our proposed method involves using multiple stepped impedance lines of different lengths to extract the broadband reflection coefficient of the impedance transition. This reflection coefficient can be used to validate the reference impedance experimentally without requiring fully defined standards. We demonstrate this method using multiline TRL based on microstrip structures on a printed circuit board (PCB) with an on-wafer probing setup.

In this paper, an affordable and miniaturized 140 GHz transmit/receive (TRX) array antenna-on-package (AoP) is proposed through the conventional PCB process employing a single substrate. The proposed design approach involves an in-depth analysis of the potential performance degradation of an D-band antenna operating within a coarse process and pratical design guide for the configuration of the matching network packaging with robust wedge bonding. An asymmetric matching network design technique for a $1\times 4$ array antenna packaging accounts the 1-bit digital beamforming capabilities of radio frequency integrated circuit (RFIC). In a first-of-its-kind demonstration, AoP with $1\times 2$ transmit and $1\times 4$ receive antennas are packaged with RFIC is fabricated. The measurements arrayed maximum gains of the transmit and receive antennas were noted to be 9.8 dBi and 11.8 dBi, respectively. Also, the gain bandwidths of 12.6% for the transmit antenna and 20.4% for the receive antenna are achieved. This work marks the first instance of a TRX AoP being fabricated from a single RF metal layer via a width/gap process condition of 100/ $80 \mu \text{m}$ in the D-band.

Object detection is a constantly evolving field of interest in the field of computer vision. As image-processing technologies continue to advance, detecting small objects has emerged as a critical challenge. However, currently available algorithms still struggle with this task owing to the small flaws in detection and complex backgrounds. This paper proposes a real-time detection method that specializes in recognizing small defects in images using an improved deep learning approach based on a feature pyramid network (FPN). The proposed method uses the small-object information flow (SOIF) module proposed by the backbone network to learn various features in images and quickly extract feature maps with varying gradient information. In addition, high-level feature maps are extracted from the FPN to maximize the information about small objects. These methods maximize the feature map properties of the existing layers and provide an opportunity to explore different features. The proposed deep learning model called SOIF-DN(SOIF-deep neural network) was evaluated on a public benchmark cell dataset and a private printed circuit boards (PCB) dataset. Upon reviewing the results, our method improves mAP@50 by 12.5% over YOLOv5 in terms of accuracy for small-object detection on PCBs. The speed performance (parameters/runtime) was 1.83 times better than YOLOv5 and 1.56 times better than YOLOv8. Additionally, our proposed SOIF-DN method for a different cell dataset enhances mAP@.5 by 3.8% over YOLOv5 for small object detection. The speed performance (parameters/runtime) was found to be 1.15 times better than YOLOv5 and 1.28 times better than YOLOv8.

We report a laser-micromachined electrolytic PCB micropump with an oil separation barrier. As advances in terms of miniaturization and performance from our previous mesoscale PCB electrolytic pump (Kim et al. in Sens Actuators A Phys 277:73–84, 2018), we employed a simple yet rapid tape-based laser-machining technique called tape-liner-supported plastic laser micromachining and pattern transfer to fabricate a microfluidic coverslip for a PCB electrode chip. Using our microfabrication technique, the coverslip is bonded to a PCB chip to form an enclosed microscale pump with a high machining precision and no need for alignment of intermediate adhesive tapes with structural layers as commonly done in previous tape-bonding work. The completed micropump demonstrated excellent pumping performance: flow rate up to 24.49 ml/min and backpressure up to 394 kPa. Electrochemical activation of electrodes consisting of a train of voltage pulses and sweeps improves the pumping performance. In order to prevent unwanted interspersion between the electrolyte and working fluid, various separation diaphragms were previously employed, but at the cost of limited working volume and flow rate as the diaphragms were permanently anchored to the pump body. Here we propose to use an oil plug as an untethered (mobile) separation barrier. After a systematic study of properties of common oils, we tested fluorinated oil (HFE-7500), hexadecane, and tetradecane as the candidate barrier materials. HFE-7500 was chosen because its interface was stable and did not degrade pumping performance for the flow-rate range of 8.47 μl/min–2.48 ml/min. We expect our micropump with the oil plug to be used as an excellent pressure source for integrated lab-on-a-chip devices, especially lab-on-a-PCBs. [ABSTRACT FROM AUTHOR]

With the rapid development of printed circuit board (PCB) industry, the problem of the release of tetrabromobisphenol A (TBBPA) during PCB manufacturing processes was recognized and harmful to the receiving water body. In this study, TBBPA generation paths, fates in industrial wastewater in the PCB manufacturing processes were analyzed. Gas chromatograph-mass spectrometer (GC-MS) scanning results showed that the raw materials including solder mask ink, character ink and dry film mainly contained TBBPA. The PCB fabrication procedures, mainly including development, etching, stripping of inner layer manufacturing process, and pattern plating, tin-plating of outer layer manufacturing process, and development during the forming and surface treatment process would introduce TBBPA into wastewater. Flocculation and activated sludge process (ASP) that were commonly used for industrial wastewater treatment were selected to assess their removal capability for TBBPA in the wastewater, both which could remove more than 80% TBBPA. Low pH below 7, increased PAC and PAM dosages, and proper dosing during the slow-stirring stage could enhance the TBBPA removal of flocculation-sedimentation process. The ASP removes TBBPA mainly by the path of adsorption. High activated sludge concentration, low pH, medium-temperature and limited competitive adsorbates (NH4+, Cu2+) were beneficial to remove TBBPA by the ASP. [ABSTRACT FROM AUTHOR]

This research investigates a frequency-switchable, multi-mode operation antenna contingent on ground structure slots and suitable for 4G, 5G/sub 6 GHz and other modern systems. In earlier research work, researchers used the approach of putting slots on the radiator or ground to create frequency-reconfigurable antenna designs. This antenna acquired benefits, in particular compactness, wide-bandwidth, and a consistent far-field pattern due to the amalgamation of slots on the patch and defects in the ground. The proposed antenna used various slots on the substrate's top and a π shaped DGS on the bottom layer. The pin-diodes embedded in the defects of the ground ensured the frequency agility and permitted the design to tune to various resonances. Data observed from experiment is used to demonstrate the antenna's performance. The modelling approach and analytical values manifest that this antenna could indeed reconfiguration between different operating bands, encompassing the frequency range from 2.2 to 8.9 GHz, by switching between four operating modes. The antenna can operate in a wide range of commercial bands, including WLAN, Bluetooth (2.4 to 2.5 GHz), 4G-LTE (2.3 to 2.7 GHz), S-band (2 to 4 GHz), Radio-Navigation (2.7 to 2.9 GHz), and 5G-sub6GHz (3.2 to 4.7 GHz). The antenna presented has narrowband to wideband characteristics, an omnidirectional radiation, fair gain (1.6 dB to 5.9), and an efficiency from 87 to 93%. [ABSTRACT FROM AUTHOR]

Industry 4.0 is currently the goal of many factories, promoting manufacturing factories and sustainable operation. Automated Optical Inspection (AOI) is a part of automation. Products in the production line are usually inspected visually by operators. Due to human fatigue and inconsistent standards, product inspections still have defects. In this study, the sample component assembly printed circuit board (PCB), PCB provided by the company was tested for surface components. The types of defects on the surface of the PCB include missing parts, multiple parts, and wrong parts. At present, the company is still using visual inspection by operators, the PCB surface components are more complex. In order to reduce labor costs and save the development time required for different printed circuit boards. In the proposed method, we use digital image processing, positioning correction algorithm, and deep learning YOLO for identification, and use 450 images and 10500 components of the PCB samples. The result and contribution of this paper shows the total image recognition rate is 92% and the total component recognition rate reaches 99%, and they are effective. It could use on PCB for different light, different color backplanes, and different material numbers, and the detection compatibility reaches 98%. [ABSTRACT FROM AUTHOR]

Electrical impedance spectroscopy (EIS) is widely recognized as a powerful tool in biomedical research. For example, it allows detection and monitoring of diseases, measuring of cell density in bioreactors, and characterizing the permeability of tight junctions in barrier-forming tissue models. However, with single-channel measurement systems, only integral information is obtained without spatial resolution. Here we present a low-cost multichannel impedance measurement set-up capable of mapping cell distributions in a fluidic environment by using a microelectrode array (MEA) realized in 4-level printed circuit board (PCB) technology including layers for shielding, interconnections, and microelectrodes. The array of 8 × 8 gold microelectrode pairs was connected to home-built electric circuitry consisting of commercial components such as programmable multiplexers and an analog front-end module which allows the acquisition and processing of electrical impedances. For a proof-of-concept, the MEA was wetted in a 3D printed reservoir into which yeast cells were locally injected. Impedance maps were recorded at 200 kHz which correlate well with the optical images showing the yeast cell distribution in the reservoir. Blurring from parasitic currents slightly disturbing the impedance maps could be eliminated by deconvolution using an experimentally determined point spread function. The MEA of the impedance camera can in future be further miniaturized and integrated into cell cultivation and perfusion systems such as organ on chip devices to augment or even replace light microscopic monitoring of cell monolayer confluence and integrity during the cultivation in incubation chambers. [ABSTRACT FROM AUTHOR]

In the period of high and new technology development, the application of SiC and other new semiconductors promotes the development of PCB design toward integration and high efficiency. The new ideas were provided for PCB design optimization from two aspects of high frequency and high density. Among them, the requirement of stray coefficient for PCB design was put forward by the high frequency, while high density was aimed at solving the thermal problem of PCB. On the one hand, vertical multi loop PCB layout was used to reduce parasitic parameters of power circuit and drive circuit, and compared with the vertical power loop layout, the grid circuit parasitic inductance was reduced about 50% in this method, while power circuit parasitic inductance was reduced about 30%. In this method,ringing and overshoot caused by the parasitic inductance also could be reduced, and rise and fall time of the voltage and current and switching losses were also reduced. On the other hand, the high power density thermal management method was improved. By optimizing design parameters such as PCB heat dissipation through holes and copper foil area, PCB was redesigned according to actual engineering needs to obtain an effective bottom cooling method. Through the simulation experiment and physical experiment, it is verified that the optimization scheme proposed has important guiding significance to design PCB with good performance. [ABSTRACT FROM AUTHOR]

Polymerase chain reaction (PCR) is the most common method used for nucleic acid (DNA) amplification. The development of PCR-performing microfluidic reactors (μPCRs) has been of major importance, due to their crucial role in pathogen detection applications in medical diagnostics. Closed loop (CL) is an advantageous type of μPCR, which uses a circular microchannel, thus allowing the DNA sample to pass consecutively through the different temperature zones, in order to accomplish a PCR cycle. CL μPCR offers the main advantages of the traditional continuous-flow μPCR, eliminating at the same time most of the disadvantages associated with the long serpentine microchannel. In this work, the performance of three different CL μPCRs designed for fabrication on a printed circuit board (PCB) was evaluated by a computational study in terms of the residence time in each thermal zone. A 3D heat transfer model was used to calculate the temperature distribution in the microreactor, and the residence times were extracted by this distribution. The results of the computational study suggest that for the best-performing microreactor design, a PCR of 30 cycles can be achieved in less than 3 min. Subsequently, a PCB chip was fabricated based on the design that performed best in the computational study. PCB constitutes a great substrate as it allows for integrated microheaters inside the chip, permitting at the same time low-cost, reliable, reproducible, and mass-amenable fabrication. The fabricated chip, which, at the time of this writing, is the first CL μPCR chip fabricated on a PCB, was tested by measuring the temperatures on its surface with a thermal camera. These results were then compared with the ones of the computational study, in order to evaluate the reliability of the latter. The comparison of the calculated temperatures with the measured values verifies the accuracy of the developed model of the microreactor. As a result of that, a total power consumption of 1.521   W was experimentally measured, only ~7.3% larger than the one calculated ( 1.417   W ). Full validation of the realized CL μPCR chip will be demonstrated in future work. [ABSTRACT FROM AUTHOR]

This paper presents a method for calculating the parasitic component of surface-mounted devices (SMD) on a printed circuit board (PCB) using even-odd mode analysis. The paper addresses the discrepancy between simulation results and measurements when designing high-frequency circuits using PCB and SMD. The cause of this difference is attributed to the significant impact of parasitic components between the PCB and SMD at high frequencies. Traditional simulation tuning is often time-consuming to identify these parasitic compo- nents, but this paper shows a simple even-odd mode analysis can effectively calculate them at the 3.7 GHz band. [ABSTRACT FROM AUTHOR]

The planar design of printed circuit board (PCB) fuel cells offers the advantages of simple structure, rapid prototyping and easy manufacturing. However, uneven reactants and heat distribution in each PCB cell module often result in inconsistent overall performance. Current characterisation methods mainly focus on the study of the overall performance and lack the analysis of individual cells, which provide a limited understanding of localised electrochemical and thermal effects that might play a critical part in further optimising and diagnosing the cell performance of this category. We have developed a multi-channel impedance diagnostic technique for PCB fuel cells. Combining with thermal imaging, we could simultaneously diagnose individual open cathode cell modules by measuring the heat distribution and electrochemical impedance spectra (EIS) of 11 PCB cell modules. Hence, the correlation between heat distribution, internal resistance and performance of different sections of PCB fuel cells can be established. By comparing the fuel cell's pristine and degraded, we demonstrated how this non-destructive technique could identify and locate cell modules with deteriorated performance, which would be beneficial to real-time diagnostics, quality control and optimisation. The multi-channel impedance measurement takes several seconds only through optimised multi-frequency perturbation and can be readily extended to stacks containing more cells by simply increasing the number of voltage sensors, which can be further adapted to other electrochemical devices. • Synchronisation of thermal mapping and in-house developed multi-channel EIS • The acquisition of the multi-channel impedance takes 4 seconds • Readily scale up with the need for more high-accuracy voltage sensors • Decoupled the correlation between heat profile, impedance and localised performance [ABSTRACT FROM AUTHOR]

Phantoms are used to evaluate, calibrate, and compare the performance of electrical impedance tomography (EIT) systems. This paper presents a dynamic thorax-like mesh phantom, which mimics the changes in electrical conductivity distribution within a human thorax at different time frames. Furthermore, element merging and contour smoothing, electrode placement techniques, and PCB design automation methods are proposed to simplify, optimize the mesh phantom, and reduce the hardware implementation cost. To verify the accuracy of the mesh phantom and its PCB, SPICE simulations and experimental testings are performed to obtain the conductance of the mesh phantom and reconstruct the images through the EIDORS software. These images achieve an image correlation coefficient (ICC) of 0.680 (model versus SPICE simulation) and 0.9098 (SPICE simulation versus measurement result), respectively. This demonstrates the validity of our proposed dynamic thorax-like mesh phantom.

In high-frequency electronic equipment and power electronic devices, the dynamic performance of switching devices is one of the important indicators, and a double-pulse test circuit is usually used to test the dynamic performance of switching devices. In order to reduce the stray inductance existing in the test circuit, a double-pulse test circuit structure based on PCB is firstly proposed, and then the basic principle of using the integral calculation method to extract the PCB stray inductance is analyzed. Then the 3D model of the PCB is established, and the PCB stray inductance extraction based on 3D simulation is completed. Finally, a 1200V/100A double-pulse test experimental platform is built. By comparing the three-dimensional simulation results with the numerical calculation results using the integral method under the double-pulse test experiment, the accuracy and effectiveness of the three-dimensional simulation method proposed in this paper are verified.

This paper presents the designs of a bandpass filter (BPF) and a diplexer based on the TM210 mode and the TM120 mode of the dielectric filled waveguide resonators (DFWRs). The DFWR is designed by integrating a dielectric main body and a printed circuit board (PCB) cover. The PCB cover is electrically connected with the top surface of the dielectric body. For each mode, metallized blind holes can be set at its maximum electric-field points to excite or extract it and the other mode will not be influenced. Microstrip lines on the PCB are utilized to connect different pairs of the metallized blind holes to form the internal and external coupling structures. For verification, a BPF and a diplexer are designed, fabricated and measured based on the DFWRs. In measurement, the BPF is with a frequency band of 2.515 GHz - 2.675 GHz, an insertion loss of 0.6 dB, and a return loss of 20 dB. The two frequency bands of the proposed diplexer are 3.3 GHz - 3.4 GHz and 3.7 GHz - 3.8 GHz. For the two frequency bands, the measured insertion losses are 0.9 dB/0.85 dB and the isolations are better than 40 dB/50 dB.

Due to its potential benefits in data transparency, maintenance, and optimization of operation, the Internet of Things (IoT) has recently emerged in the building automation system (BAS) domain. However, while various IoT devices have been developed, the integration into BAS remains a challenging task due to the variety of conventional interfaces used in existing BAS. From an objective point of view, integrating IoT connectivity on existing devices' printed circuit boards (PCBs) would be the most efficient option in terms of cost and resources, but requires adaptation of product lines, and vendors would often couple this with their own services and without an option for customization. By contrast, the majority of research activities focus on developing alternative or additional measurement systems, rather than connecting with legacy system components. Furthermore, most research applications cover very simple and individual use-cases with a do-it-yourself character and limited applicability in industrial applications. In this study, we present a scalable, industrial-like embedded solution to connect to common interfaces in BAS applications and share all the hardware and software design as an open-source platform for public use, customization, and further enhancement. Moreover, a thorough measurement performance analysis was conducted, suggesting an acceptable trade-off among accuracy, flexibility, and costs, e.g., achieving a performance increase by over 75% and a cost reduction by roughly 34% compared to a previous design. [ABSTRACT FROM AUTHOR]

All kinds of electronic products, such as motherboards, digital cameras, mobile phones and even chip products in manufacturing production processes, require some form of defect detection in an IoT environment. Shortcomings and improvements need to be found before a product is shipped, and various computer applications have been proposed to facilitate this, such as facial recognition, object tracking, digital picture processing and other forms of defect detection automation in an IoT environment, to reduce costs in the industrial production field. Various manufacturers have also invested in computer research aimed at replacing some labour-intensive aspects of key processes. This paper focuses on detection of printed circuit board defects, which plays a key role in the production process of general electronic products. In this study, computer theory was used as the basic architecture. This method can convert spatial domain signals into frequency domain signals, providing users with a specific frequency range. An algorithm is described here, capable of detecting defects in printed circuit boards, such as short circuits, protruding solder, solder dents and open circuits. In this study, the algorithm was used with wavelet transform technology to achieve the purpose of detecting PCB defects in an IoT environment. The results indicated that the technology in question is simple to operate and performs efficiently. It only requires an accurate picture to be inputted (after processing), containing the defect, in order to determine the location of the defect. [ABSTRACT FROM AUTHOR]

A full characterization and modeling methodology for the electrical transitions introduced by coaxial connectors serving as interfaces for accessing microstrip (MS) lines is presented and verified up to 40 GHz. The associated two-port network parameters are obtained from measurements performed on MS lines of different lengths. Subsequently, two circuit models for the transition are proposed and used to assess the performance of the connector transition as the lines vary in width. [ABSTRACT FROM AUTHOR]

Surface defect detection for the printed circuit board (PCB) is essential in PCB manufacturing. Existing defect detection networks have several problems: low detection efficiency, high memory consumption, and low sensitivity to small defects. To address these issues, we propose a new lightweight deep-learning-based defect detection network, YOLOX with a modified CSPDarknet and coordinate attention (YOLOX-MC-CA). YOLOX-MC-CA is developed on the YOLOX and uses the coordinate attention (CA) mechanism to improve the recognition capability of small PCB surface defects. The backbone network in YOLOX is also modified into a new CSPdarknet structure with some inverted residual blocks. The modified CSPDarknet (MC) backbone network helps the YOLOX decrease the number of parameters on the premise of guaranteeing the feature extraction ability. We evaluated the YOLOX-MC-CA with an augmented dataset based on a public PCB surface defect dataset. Compared to the squeeze-and-excitation (SE) module, convolutional block attention module (CBAM), and other approaches in previous research, the CA mechanism improves the network with more detection precision for the small PCB surface defects. The experimental results demonstrate that our network is superior to other state-of-the-art (SOTA) networks for PCB surface defect detection, scoring 99.13% on mean average precision (mAP) and 47.6 frames per second (FPS) on detection speed, only occupying a parameter space of 3.79 million (M). It demonstrates that the proposed network is more suitable for deployment on embedded systems. [ABSTRACT FROM AUTHOR]

Integrated circuit boards are component of most Waste Electrical and Electronic Equipment (WEEE). These are generated worldwide at an alert rhythm and their recycling is done to a small extent (about 20%). The paper presents an experimental simulation of the presence of printed circuit board waste (PCBs), from end-of-life computers, in three aquatic environments with different pH (pH 4.00, pH 5.63 and pH 8.00). After stagnation for 17 weeks, values of the concentrations of heavy metals released by the PCBs in the solutions were obtained. These indicated that the presence of these boards in aquatic media may impair water quality by inducing moderate risks for surface water and lower risks for groundwater bodies. Heavy metals such as copper and lead, especially in acidic and neutral environments, fell into the worst quality class for surface water and exceeding of the maximum allowable value for the reference groundwater body (ROSO12) were recorded for copper in the acid and neutral initial solutions.

This paper evaluates the uncertainty of S-parameter measurements on multilayer printed circuit boards (PCBs) due to the uncertainties of the dimensions and dielectric properties of the line standard in the Thru-Reflect-Line (TRL) calibration. This evaluation is performed in two ways: one is based on repeated TRL calibrations with a randomly perturbed line standard, and the other is based on equations given by Stumper. The two methods require the uncertainties of the S-parameters of the TRL line standard, which are obtained from the uncertainties of the dimensions and dielectric properties using three-dimensional electromagnetic Monte Carlo simulation. The two methods agree well with each other. This study also shows how to apply impedance renormalization in Stumper’s equations. We design the TRL standards and the devices under test (DUTs) in PCB stripline and precisely measure the cross-sectional dimensions of the fabricated striplines. Uncertainty analysis based on the measured values enables us to investigate the impact of realistic deviations in the dimensions of the TRL line standard on the S-parameter measurement uncertainty of the DUTs. Finally, as an example, we evaluated the uncertainty in the measured S-parameters of a Beatty line on the fabricated PCB.