Additively manufactured perforated superstrate to improve directive radiation characteristics of electromagnetic source
21 Oct 2019-IEEE Access (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 7, pp 153445-153452
TL;DR: The AMPS has remarkably improved the radiation performance of ERA by increasing its far-field directivity from 12.67 dB to 21.12 dB and reducing side-lobe level from −7.3 dB to −17.2 dB.
Abstract: Additively manufactured perforated superstrate (AMPS) is presented to realize directive radio frequency (RF) front-end antennas. The superstrate comprises spatially distributed dielectric unit-cell elements with square perforations, which creates a pre-defined transmission phase delay pattern in the propagating electric field. The proposed square perforation has superior transmission phase characteristics compared to traditionally machined circular perforations and full-wave simulations based parametric analysis has been performed to highlight this supremacy. The AMPS is used with a classical electromagnetic-bandgap resonator antenna (ERA) to improve its directive radiation characteristics. A prototype is developed using the most common, low-cost and easily accessible Acrylonitrile Butadiene Styrene (ABS) filament. The prototype was rapidly fabricated in less than five hours and weighs 139.3 g., which corresponds to the material cost of only 2.1 USD. The AMPS has remarkably improved the radiation performance of ERA by increasing its far-field directivity from 12.67 dB to 21.12 dB and reducing side-lobe level from -7.3 dB to -17.2 dB.
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TL;DR: In this paper, the authors proposed an all-metal wideband phase correcting structure (AWPCS) with none of these limitations and is designed based on the relative phase error extracted by postprocessing the actual near-field distributions of any EM sources.
Abstract: Electromagnetic (EM) metasurfaces are essential in a wide range of EM engineering applications, from incorporated into antenna designs to separate devices like radome. Near-field manipulators are a class of metasurfaces engineered to tailor an EM source’s radiation patterns by manipulating its near-field components. They can be made of all-dielectric, hybrid, or all-metal materials; however, simultaneously delivering a set of desired specifications by an all-metal structure is more challenging due to limitations of a substrate-less configuration. The existing near-field phase manipulators have at least one of the following limitations; expensive dielectric-based prototyping, subject to ray tracing approximation and conditions, narrowband performance, costly manufacturing, and polarization dependence. In contrast, we propose an all-metal wideband phase correcting structure (AWPCS) with none of these limitations and is designed based on the relative phase error extracted by post-processing the actual near-field distributions of any EM sources. Hence, it is applicable to any antennas, including those that cannot be accurately analyzed with ray-tracing, particularly for near-field analysis. To experimentally verify the wideband performance of the AWPCS, a shortened horn antenna with a large apex angle and a non-uniform near-field phase distribution is used as an EM source for the AWPCS. The measured results verify a significant improvement in the antenna’s aperture phase distribution in a large frequency band of 25%.
54 citations
TL;DR: The main focus of this paper is to discuss primarily the antenna gain and bandwidth of wideband high-gain antennas with different functionalities required for the next generation of wireless communication.
Abstract: Resonant cavity antennas (RCAs) are suitable candidates to achieve high-directivity with a low-cost and easy fabrication process. The stable functionality of the RCAs over different frequency bands, as well as, their pattern reconfigurability make them an attractive antenna structure for the next generation wireless communication systems, i.e., fifth generation (5G). The variety of designs and analytical techniques regarding the main radiator and partially reflective surface (PRS) configurations allow dramatic progress and advances in the area of RCAs. Adding different functionalities in a single structure by using additional layers is another appealing feature of the RCA structures, which has opened the various fields of studies toward 5G applications. This paper reviews the recent advances on the RCAs along with the analytical methods, and various capabilities that make them suitable to be used in 5G communication systems. To discuss different capabilities of RCA structures, some applicable fields of studies are followed in different sections of this paper. To indicate different techniques in achieving various capabilities, some recent state-of-the-art designs are demonstrated and investigated. Since wideband high-gain antennas with different functionalities are highly required for the next generation of wireless communication, the main focus of this paper is to discuss primarily the antenna gain and bandwidth. Finally, a brief conclusion is drawn to have a quick overview of the content of this paper.
37 citations
01 Jan 2022
TL;DR: In this article , the authors reviewed the printed antennas for WSNs, explained how printed antenna sensors can be used for material characterization, gave an overview of epidermal antenna for unobtrusive human-centric wireless communications and sensing, and finally reviewed the recent AI-based approaches in designing antennas.
Abstract: Environmental sensors have come a long way over the last decade, surged in variety and capabilities. Such growth was impossible without developing wireless technologies, particularly antennas, thanks to advanced numerical computation software and artificial intelligence (AI). Sensors have numerous applications in industrial environments for purposes such as safety improvement, data acquisition, and environment and human body monitoring. For wireless sensor networks (WSNs), there may be several antennas to send the sensing data. However, further developments in the invention of planar antennas have opened up an unprecedented direction in the miniaturization of wireless sensors. Consequently, unobtrusive human-centric wireless sensing is becoming far more accessible due to the recent developments of epidermal antennas. Moreover, AI and its integration into antenna designs have resulted in more efficient WSNs. This chapter reviews the printed antennas for WSNs, explains how printed antenna sensors can be used for material characterization, gives an overview of epidermal antenna for unobtrusive human-centric wireless communications and sensing, and finally reviews the recent AI-based approaches in designing antennas.
24 citations
TL;DR: In this paper, a planar permittivity-gradient superstrate (PGS) is used to improve the directive radiation characteristics of a waveguide-fed compact resonant cavity antenna (CRCA).
Abstract: A 3-D printed planar permittivity-gradient superstrate (PGS) is used to improve the directive radiation characteristics of a waveguide-fed compact resonant cavity antenna (CRCA). Far-field directivity of classical uniform superstrate-based RCAs is limited due to nonuniform aperture phase distribution caused by even transmission through the superstrate. Transverse PGS has been used here to remarkably improve aperture phase distribution and hence directive radiation performance of RCAs. Furthermore, the PGS was rapidly prototyped in one hour and 43 min using a low-cost acrylo-butadiene styrene (ABS) filament without using traditional multistep milling and machining. Single step fabrication was performed and effective dielectric constant of the ABS was varied through controlled infill percentage in different regions of the PGS. Measurements of a prototype indicate unrivaled results, from a smaller footprint, which includes peak directivity of 16.048 dB, 3 dB directivity bandwidth of 49.65% and sidelobe levels lower than −10.4 dB throughout the operating frequency band. The 3-D printed PGS thus outperforms all previously reported superstrates, for RCAs, by demonstrating similar radiation performance with an equivalent material cost of only 0.41 USD.
20 citations
TL;DR: In this paper, a low loss beamformer with a capability of 2-D scanning in elevation and azimuth directions at 30 GHz for 5G applications is proposed, which is based on the broadband and highly efficient rectangular air-filled coaxial line.
Abstract: This article introduces a low loss beamformer with a capability of 2-D scanning in elevation and azimuth directions at 30 GHz for 5G applications. The proposed beamformer is based on the broadband and highly efficient rectangular air-filled coaxial line. The beamformer is fed by four standard waveguides (WR-28) as the input ports. Correspondingly, each of the input ports using specific transitions is connected to the coaxial beamformer network. Ultimately, the coaxial transmission lines, in the radiating part of the beamformer, feed a $2\times 2$ waveguide antenna array. The structure is aptly called a waveguide–coaxial–waveguide beamformer. The total dimensions of the fabricated prototype are 60 mm $\times60$ mm (corresponding to $6\lambda \times 6\lambda$ ). The beamformer is able to generate four fixed beams, one in each quadrant at an elevation angle of 25° from the broadside to the array axis. The results demonstrate that the proposed passive beamformer has a radiation efficiency greater than 90% over the frequency bandwidth (BW) of interest. Good stability of the radiation pattern and maximum gain over the desired BW were achieved while maintaining the sidelobe level of less than 20 dB.
18 citations
References
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11 Feb 2013
TL;DR: Fabricated as mentioned in this paper provides readers with practical and imaginative insights to the question "how will 3D printing technologies change my life?" Based on hundreds of hours of research and dozens of interviews with experts from a broad range of industries, Fabricated offers readers an informative, engaging and fast-paced introduction to 3D printers now and in the future.
Abstract: Fabricated tells the story of 3D printers, humble manufacturing machines that are bursting out of the factory and into homes, businesses, schools, kitchens, hospitals, even the fashion catwalk.The magic happens when you plug a 3D printer into today's mind-boggling digital technologies. Add to that the Internet, tiny, low cost electronic circuitry, radical advances in materials science and biotech and voila! The result is an explosion of technological and social innovation. Fabricatedprovides readers with practical and imaginative insights to the question "how will 3D printing technologies change my life?" Based on hundreds of hours of research and dozens of interviews with experts from a broad range of industries, Fabricated offers readers an informative, engaging and fast-paced introduction to 3D printing now and in the future.Chapters and contentsChapter 1: Everything is becoming sciencefiction.What would "just another regular day" look like in a future, 3D printable world?Chapter 2: A machine that can make almost anything.Information morphed from analog form to digital. Will physical objects be next? Ten key principles explain 3D printing's disruptive power.Chapter 3: Nimble manufacturing. Emerging business models lie somewhere between mass production and the local farmer's market. Small-batch manufacturing is becoming profitable, freeing entrepreneurs from the tyranny imposed by economies of scale.Chapter 4: Tomorrow's economy of printable products. 3D printing, low-cost design and manufacturing technologies create new market opportunities as consumers increasingly crave on-demand, custom "experience" products.Chapter 5: Printing in layers. For those of a technological bent, a deep dive into the inner workings of the 3D printing process.Chapter 6: Design software, the digital canvas. Without an attached computer, a 3D printer is just an elaborate paperweight. An overview of design software and "digital capture."Chapter 7: Bioprinting in "living ink." Design software and 3D printers read medical scans to fabricate living tissue and custom artificial joints. How long before all of us can tap into this Fountain of Youth?Chaper 8: Digital cuisine. Today you can 3D print "high resolution" and delicious shortbread, chocolate figurines and tortillas. In the future, Quantified Selfers and couch potatoes alike will balance their diets by streaming biometrics to a food printer.Chapter 9: A factory in the classroom. Primary and middle school teachers teach "children's engineering" using vivid, hands-on lesson plans.Chapter 10: Unleashing a new aesthetic.3D printers are the output device computer-savvy artists, designers and architects have been waiting for.Chapter 11: Green, clean manufacturing. What's cleaner to make? A 3D printed plastic toy or a mass-produced plastic toy? 3D printers may introduce greener living... or help us drown in a rising tidal wave of plastic junk.Chapter 12: Ownership, safety and legal frontiers. Technology evolves faster than the law. Consumer safety and intellectual property laws will stretch to deal with printed weapons, counterfeit products and unregulated custom-made products. Chapter 13: Designing the future. Why was Star Trek's Replicator used only to make Earl Grey tea? Because once we shape our tools, then our tools shape us. Next-generation design software will unshackle our imaginations, giving us new ways to imagine and edit the physical world. Chapter 14: The next episode of 3D printing.What lies ahead? Watercolor artists create infinite hues by blending primary colors. Regular people will design and blend standard materials -- or micro-scale electronic components -- and "print" them out in fine, meticulously patterned sprays. The result? Weird and wacky new materials. Robots that walk out of the 3D printer. Ready-made, responsive smart materials.
903 citations
"Additively manufactured perforated ..." refers background in this paper
...A technological solution, considered as a leap forward in manufacturing industry is additive manufacturing (AM), which is also known as 3D printing [20]–[22]....
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TL;DR: Wang et al. as mentioned in this paper collected and analyzed the information on how to achieve a precise and accurate food printing, and reviewed the application of 3D printing in several food areas, as well as give some proposals and provide a critical insight into the trends and challenges to 3D food printing.
Abstract: Background Three dimensional (3D) food printing is being widely investigated in food sector recent years due to its multiple advantages such as customized food designs, personalized nutrition, simplifying supply chain, and broadening of the available food material. Scope and approach Currently, 3D printing is being applied in food areas such as military and space food, elderly food, sweets food. An accurate and precise printing is critical to a successful and smooth printing. In this paper, we collect and analyze the information on how to achieve a precise and accurate food printing, and review the application of 3D printing in several food areas, as well as give some proposals and provide a critical insight into the trends and challenges to 3D food printing. Key findings and conclusions To realize an accurate and precise printing, three main aspects should be investigated considerably: material properties, process parameters, and post-processing methods. We emphasize that the factors below should be given special attention to achieve a successful printing: rheological properties, binding mechanisms, thermodynamic properties, pre-treatment and post-processing methods. In addition, there are three challenges on 3D food printing: 1) printing precision and accuracy 2) process productivity and 3) production of colorful, multi-flavor, multi-structure products. A broad application of this technique is expected once these challenges are addressed.
430 citations
"Additively manufactured perforated ..." refers background in this paper
...This advanced manufacturing technique has been tipped as a fail, fast-fail cheap technology, as quick discovery of ideas leads to swift and ideal solutions [25], [26]....
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TL;DR: Cascaded metasurfaces are two-dimensional arrangements of subwavelength scatterers that control the propagation of optical waves and provide a new optical design framework that enables new functionalities.
Abstract: Metasurfaces are two-dimensional arrangements of subwavelength scatterers that control the propagation of optical waves. Here, we show that cascaded metasurfaces, each performing a predefined mathematical transformation, provide a new optical design framework that enables new functionalities not yet demonstrated with single metasurfaces. Specifically, we demonstrate that retroreflection can be achieved with two vertically stacked planar metasurfaces, the first performing a spatial Fourier transform and its inverse, and the second imparting a spatially varying momentum to the Fourier transform of the incident light. Using this concept, we fabricate and test a planar monolithic near-infrared retroreflector composed of two layers of silicon nanoposts, which reflects light along its incident direction with a normal incidence efficiency of 78% and a large half-power field of view of 60°. The metasurface retroreflector demonstrates the potential of cascaded metasurfaces for implementing novel high-performance components, and enables low-power and low-weight passive optical transmitters.
361 citations
Additional excerpts
...INTRODUCTION The principles of refraction and reflection of electromagnetic waves, implemented through specially designed structures, have been used to develop a range of wave-manipulating artefacts [1]–[4]....
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21 Nov 2018
TL;DR: 3D printing is becoming increasingly prevalent in modern chemistry laboratories as discussed by the authors, and it provides chemists with the ability to design, prototype and print functional devices that integrate catalytic and/or analytical functionalities.
Abstract: 3D printing is becoming increasingly prevalent in modern chemistry laboratories. This technology provides chemists with the ability to design, prototype and print functional devices that integrate catalytic and/or analytical functionalities and even to print common laboratory hardware and teaching aids. Although access to 3D printers has increased considerably, some design principles and material considerations need to be weighed before employing such technology in chemistry laboratories. In addition, a certain level of expertise needs to be acquired in order to use computer-aided design, printing software and the specialist hardware associated with higher-end instrumentation. Nonetheless, the recent progress in this field is encouraging, with these printing technologies offering many advantages over traditional production methods. This Review highlights some of the notable advances in this growing area over the past decade. 3D printing is becoming a mainstream technology with considerable increase in access to affordable desktop printers. However, specific design principles and material considerations need to be weighed when printing functional devices that integrate catalytic and/or analytical functionalities, as well as when printing common laboratory hardware.
194 citations
05 Oct 2014
TL;DR: This paper proposes to print low-fidelity wireframe previews in the early stages of the design process, using 3D printers to extrude filament not layer-by-layer, but directly in 3D-space, allowing them to create the edges of the wireframe model directly one stroke at a time.
Abstract: Even though considered a rapid prototyping tool, 3D printing is so slow that a reasonably sized object requires printing overnight. This slows designers down to a single iteration per day. In this paper, we propose to instead print low-fidelity wireframe previews in the early stages of the design process. Wireframe previews are 3D prints in which surfaces have been replaced with a wireframe mesh. Since wireframe previews are to scale and represent the overall shape of the 3D object, they allow users to quickly verify key aspects of their 3D design, such as the ergonomic fit. To maximize the speed-up, we instruct 3D printers to extrude filament not layer-by-layer, but directly in 3D-space, allowing them to create the edges of the wireframe model directly one stroke at a time. This allows us to achieve speed-ups of up to a factor of 10 compared to traditional layer-based printing. We demonstrate how to achieve wireframe previews on standard FDM 3D printers, such as the PrintrBot or the Kossel mini. Users only need to install the WirePrint software, making our approach applicable to many 3D printers already in use today. Finally, wireframe previews use only a fraction of material required for a regular print, making it even more affordable to iterate.
189 citations
"Additively manufactured perforated ..." refers background in this paper
...The AM is highly sustainable, easily accessible and environment friendly technique [23], [24], as it involves very little material loss compared to traditional subtractive manufacturing (SM) methods....
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