Antenna-in-package (AiP) technology, in which there is an antenna (or antennas) with a transceiver die (or dies) in a standard surface-mounted device, represents an important antenna and packaging ...technology achievement in recent years. AiP technology has been widely adopted by chipmakers for 60-GHz radios and gesture radars. It has also found applications in 77-GHz automotive radars, 94-GHz phased arrays, 122-GHz imaging sensors, and 300-GHz wireless links. It is believed that AiP technology will also provide elegant antenna and packaging solutions to the fifth generation and beyond operating in the lower millimeter-wave (mmWave) bands. Thus, one can conclude that AiP technology has emerged as the mainstream antenna and packaging technology for various mmWave applications. This article will provide an overview of the development of AiP technology. It will consider antennas, packages, and interconnects for AiP technology. It will show that the antenna choice is usually based on those popular antennas that can be easily designed for the application, that the package choice is governed for automatic assembly, and that the materials and processes choices involve tradeoffs among constraints, such as electrical performance, thermal-mechanical reliability, compactness, manufacturability, and cost. This article also shows a probe-based setup to measure mmWave AiP impedance and radiation characteristics. It goes on to give AiP examples implemented, respectively, in a low-temperature co-fired ceramic, an embedded wafer level ball grid array process, and a high-density interconnect processes. Finally, this article will summarize and present some recommendations on research topics to further the state of the art of AiP technology.
Phased-array modules at frequencies >20 GHz are expected to play an important role for 5G applications. Antenna-in-package (AiP) is a reliable and cost-effective method to realize these phased ...arrays. This paper introduces a practical Ka-band AiP structure and discusses the antenna element design and implementation tradeoffs. The AiP design is based on multilayer organic buildup substrates that are suitable for phased-array module integration needs and supports both horizontal and vertical polarizations. Measurement results from the fabricated antenna prototypes show 0.8 GHz return loss bandwidth and 3.8-dBi peak gain at 30.5 GHz. Simulation results agree with the measured ones.
Predictor effect displays, introduced in this article, visualize the response surface of complex regression models by averaging and conditioning, producing a sequence of 2D line graphs, one graph or ...set of graphs for each predictor in the regression problem. Partial residual plots visualize lack of fit, traditionally in relatively simple additive regression models. We combine partial residuals with effect displays to visualize both fit and lack of fit simultaneously in complex regression models, plotting residuals from a model around 2D slices of the fitted response surface. Employing fundamental results on partial residual plots along with examples for both real and contrived data, we discuss and illustrate both the strengths and limitations of the resulting graphs. The methods described in this paper are implemented in the effects package for R.
Bibliometrics has become an essential tool for assessing and analyzing the output of scientists, cooperation between universities, the effect of state-owned science funding on national research and ...development performance and educational efficiency, among other applications. Therefore, professionals and scientists need a range of theoretical and practical tools to measure experimental data. This review aims to provide an up-to-date review of the various tools available for conducting bibliometric and scientometric analyses, including the sources of data acquisition, performance analysis and visualization tools. The included tools were divided into three categories: general bibliometric and performance analysis, science mapping analysis, and libraries; a description of all of them is provided. A comparative analysis of the database sources support, pre-processing capabilities, analysis and visualization options were also provided in order to facilitate its understanding. Although there are numerous bibliometric databases to obtain data for bibliometric and scientometric analysis, they have been developed for a different purpose. The number of exportable records is between 500 and 50,000 and the coverage of the different science fields is unequal in each database. Concerning the analyzed tools, Bibliometrix contains the more extensive set of techniques and suitable for practitioners through Biblioshiny. VOSviewer has a fantastic visualization and is capable of loading and exporting information from many sources. SciMAT is the tool with a powerful pre-processing and export capability. In views of the variability of features, the users need to decide the desired analysis output and chose the option that better fits into their aims.
This paper contributes to the package design research by proposing and verifying process-based framework that explain how various package features affect customers visual attention. An exploratory ...study was carried out in virtual settings, deploying eye-tracking methodology in combination with package collages in order to assure a reasonably realistic product category context, yet better control over non-package factors that affect attention. Findings suggest that physical and semantic package features affect attention during the ‘orientation’ phase and reveal how efficiently attention is transferred to the brand in the ‘discovery’ phase. Results in addition reveal that packages that attract the most attention are not necessarily likeable or suitable, but also that recall is a questionable measure of attention. The study provides important implications by informing management on how to break the visual clutter and stand out from competitors, while staying in line with the product category ‘code’.
•Sequential phases of visual attention are affected by different package features.•Visual attention does not necessarily correspond with package preferences.•Package design factors depend upon visual competitive context and category ‘code’.•Eye-tracking measures needs to be complemented with survey methods.
Although vast technological advances have been made and genetic software packages are growing in number, it is not a trivial task to analyse SNP data. We announce a new r package, dartr, enabling the ...analysis of single nucleotide polymorphism data for population genomic and phylogenomic applications. dartr provides user‐friendly functions for data quality control and marker selection, and permits rigorous evaluations of conformation to Hardy–Weinberg equilibrium, gametic‐phase disequilibrium and neutrality. The package reports standard descriptive statistics, permits exploration of patterns in the data through principal components analysis and conducts standard F‐statistics, as well as basic phylogenetic analyses, population assignment, isolation by distance and exports data to a variety of commonly used downstream applications (e.g., newhybrids, faststructure and phylogeny applications) outside of the r environment. The package serves two main purposes: first, a user‐friendly approach to lower the hurdle to analyse such data—therefore, the package comes with a detailed tutorial targeted to the r beginner to allow data analysis without requiring deep knowledge of r. Second, we use a single, well‐established format—genlight from the adegenet package—as input for all our functions to avoid data reformatting. By strictly using the genlight format, we hope to facilitate this format as the de facto standard of future software developments and hence reduce the format jungle of genetic data sets. The dartr package is available via the r CRAN network and GitHub.
Summary
The Nutrition Transition model is presented with the nature and pace of change in key stages varying by location and subpopulations. At present, all high‐income and many low‐ and ...middle‐income countries are in a stage of the transition where nutrition‐related noncommunicable diseases including obesity, type 2 diabetes, and hypertension are dominating adult morbidity and mortality and are very high or growing rapidly in prevalence. Some countries still have key subpopulations facing hunger and undernutrition defined by stunting or extreme thinness among adults. We call these double burden of malnutrition countries. All low‐ and middle‐income countries face rapid growth in consumption of ultra‐processed food and beverages, but it is not inevitable that these countries will reach the same high levels of consumption seen in high‐income countries, with all the negative impacts of this diet on health. With great political and civil society commitment to adoption of policies shown in other countries to have improved dietary choices and social norms around foods, we can arrest and even reverse the rapid shift to diets dominated by a stage of high ultra‐processed food intake and increasing prevalence of nutrition‐related noncommunicable diseases.
Package-on-Package (PoP) is a popular technology for fabricating chipsets of accelerated processing units. However, the coefficient of thermal expansion mismatch between Si chips and polymer ...substrates induces thermal warpage during the reflow process. As such, the reflow temperature and reliability of solder joints are critical aspects of PoP. Although Sn58Bi is a good candidate for low-temperature processes, its brittleness causes other reliability issues. In this study, an in-situ observation was performed on composite solders (CSs) made of an Sn-3.0Ag-0.5Cu (SAC305) solder and an Sn58Bi solder that were mixed during reflow at temperatures of 170 °C (CS-170), 180 °C (CS-180), and 190 °C (CS-190). The volumes of the mixed-solder regions were in the order of CS-190 > CS-180 > CS-170. A calculated Sn58Bi-SAC305 isoplethal section of the Sn-Ag-Cu-Bi quaternary system was employed to elucidate the melting behavior of CS-190. CS-190 with Sn cyclic twin boundary and Bi phase preferred orientation of 0001 was demonstrated by electron backscatter diffraction. Moreover, Cu/CS-190/Cu joints with a shear strength of 46 MPa were formed. CS-190 can reduce the brittleness of SnBi solder owing to the reduced solid-solution hardening with the decrease in the Bi content. These factors can improve the reliability of PoP technology.
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•An in-situ observation was performed on a composite solder made of SAC305/Sn58Bi.•SAC305/Sn58Bi were completely mixed by 190 °C reflow to form Sn-31.1Bi-1.4Ag-0.2Cu with a melting-like point of 176°C.•Cu/SAC305-Sn58Bi/Cu solder joints were assembled with a shear strength of 44.6 MPa.
The source code of a Java-based software system is often structured into packages. When packages are large, they often carry maintainability quality issues. In the literature, there is a lack of ...empirical evidence on the specific maintainability issues that occur when packages become too large. Our study fills this gap by performing relationship analysis of package size with respect to internal maintainability characteristics (coupling, cohesion, and complexity) using package-level metrics collected from 111 open-source Java projects provided in Qualitas Corpus. Our results show significantly higher maintainability issues in large packages as indicated by the maintainability metrics. We also report strong relationships of package size with cohesion (represented by the number of connected components in a package) and complexity (measured by the number of internal relationships in a package). Based on these strong associations with package size, we show that these cohesion and complexity metrics can be used to identify large package refactoring opportunities. Furthermore, we also discuss why some maintainability metrics (e.g., coupling metrics) may not be useful for refactoring large packages.
Editor’s note: Open Science material was validated by the Journal of Systems and Software Open Science Board.
•Large packages have significantly higher coupling, cohesion, and complexity issues.•A package cohesion metric could be used for refactoring large packages.•A package complexity metric could be used for refactoring large packages.•Package coupling metrics may not be useful for refactoring large packages.
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