A five-slot hexagonal shape chipless RFID tag is designed, simulated, and manufactured on FR4 substrate. The designed tag's copper geometry was replicated on a wide range of dielectric substrate to quantify the impact on resonance quality factor (RQF) and resonating frequencies. The tag's performance was assessed in three configurations. First, a hexagonal shape tag's radar cross section (RCS) was studied over different dielectric substrates. The various dielectric substrate effects were investigated over the maximum read range, resonant frequencies and RQF. In the second evaluation, the physical geometry of the tag was adjusted to achieve the spectral signatures in 2–7 GHz frequency band with high RQF. In step three, the optimized tag geometry was manufactured on FR4, Roger Duroid 5880, and polyethylene naphthalate (PEN) substrates. Denford milling machine for PCB engraving and inkjet printing for silver nanoparticles deposition were used for tags manufacturing. During tag manufacturing, copper and silver were used as conducting materials for RCS backscattering. The tag RCS response was measured by vector network analyzer with bi-static antenna setup. The analysis of different dielectric substrate provides a pathway of designing a novel substrate by using various nanomaterials.

Shape-changing mechanical metamaterials have drawn the attention of researchers toward the development of continuous-range tunable frequency selective surfaces (FSSs). In this paper, a novel tunable FSS utilizing an origami-inspired “eggbox” structure is presented featuring four-degrees of freedom that can change the frequency response of two orthogonal linear polarizations. The centrosymmetric “eggbox” structure can be folded or rotated along two axes that lead to unprecedented reconfigurability compared to traditional Miura-Ori-based structures which have fewer degrees of control. The utilized cross-shaped dipole FSS element shows enhanced bandwidth, support for orthogonal linear polarization, and ease of fabrication. The prototype is fabricated using a low-cost fully additive inkjet printing process with silver nanoparticle conductive ink. The outcome of this study shows a 25% frequency tunable range over two polarization directions. The design can be an ideal spatial filtering candidate for advanced ultra-wideband terrestrial and space applications.

An ultra-wideband (UWB) log-periodic dipole array (LPDA) antenna inkjet-printed on a 0.5 mm thick photo paper substrate is presented. The overall size of the LPDA antenna is 130 × 60 mm2. The LPDA antenna exhibits stable input-impedance characteristics and a consistent end-fire radiation pattern over the whole operating band of 2.2–11 GHz. Fulfilling the need of high-gain flexible antennas for UWB, a highly directive measured gain of 9.5 dBi on a paper substrate makes it an excellent candidate for flexible wireless devices.

Fabrication of nanoperforated TiO2 thin films (NP-TiO2) on various substrates utilizing evaporation-induced self-assembly has been widely reported during recent years. For many applications, such as solar cells and gas sensors, it would be beneficial if the active material could be deposited onto a desired area or in the form of a pattern or array. In this study, inkjet printing was successfully used to produce NP-TiO2 at both ambient temperature and 60 °C. Especially for intermediate drop spacings (40 and 50 µm), millimeter-sized homogeneous NP-TiO2 patches were obtained with similar NP structure as those being processed by dip coating and drop casting. Compared to ambient temperature, inkjet printing at 60 °C provides a narrower height distribution of the NP structures of about 5 nm. Compared to dip coating and drop casting, inkjet printing enables the deposition of the ink onto target areas, thus enabling the fabrication of microscale arrays and other patterned structures.

Organ shortage is a severe challenge worldwide. Three-dimensional (3D) printing, a rapidly developing engineering and materials science tool, holds considerable promise in generating implantable organ scaffolds that may reduce or eliminate organ shortage. However, translation of 3D printing into clinical therapies has been astonishingly slow and certainly has not matched the pace of technology development. This review outlines challenges and opportunities for the application of 3D printing in tissue and organ regeneration, with emphasis on in vivo applications of 3D-printed scaffolds. Three-dimensional-printed scaffolds for the regeneration of complex tissues and organs, including bone, cartilage, tooth, and skin, serve as prototypes for 3D printing of other tissues and organs such as the liver, kidney, or heart. The aspiration to reduce or eliminate organ shortage appears to hinge on the translation of 3D bioprinting technologies into preclinical studies and clinical trials. The remaining challenges of cell survival, directed differentiation, angiogenesis, and metabolic exchange are far from trial and need to be addressed. Three-dimensional-printed materials will remain a biomaterials and engineering showcase unless applications in preclinical and clinical models are realized. In balance, 3D printing holds considerable promise in regenerative medicine as a unique approach to address organ shortage.

Three-dimensional (3D) printing represents the direct fabrication of parts layer-by-layer, guided by digital information from a computer-aided design file without any part-specific tooling. Over the past three decades, a variety of 3D printing technologies have evolved that have transformed the idea of direct printing of parts for numerous applications. Three-dimensional printing technology offers significant advantages for biomedical devices and tissue engineering due to its ability to manufacture low-volume or one-of-a-kind parts on-demand based on patient-specific needs, at no additional cost for different designs that can vary from patient to patient, while also offering flexibility in the starting materials. However, many concerns remain for widespread applications of 3D-printed biomaterials, including regulatory issues, a sterile environment for part fabrication, and the achievement of target material properties with the desired architecture. This article offers a broad overview of the field of 3D-printed biomaterials along with a few specific applications to assist the reader in obtaining an understanding of the current state of the art and to encourage future scientific and technical contributions toward expanding the frontiers of 3D-printed biomaterials.

Within the last decade, inkjet printing technology has developed from only a text and graphic industry to a major topic of scientific research and development. Inkjet printing can be used as a highly reproducible noncontact patterning technique to print at high speeds either small or large areas with high quality features; it requires only small amounts of functional materials, which immediately lower production costs. Furthermore, inkjet printing reduces the amount of processing steps due to its additive technique of materials deposition, which further decreases productions costs. This contribution provides a literature survey covering the latest results in low temperature sintering inkjet-printed metal precursor materials in a fast and efficient manner, aiming for roll-to-roll processing. The prepared features can be used as interconnects and contacts for microelectronic applications, including organic light-emitting diodes, organic photovoltaics, and radio frequency identification tags.

In this paper, double-walled carbon nanotubes (DWNTs) network layers were patterned using inkjet transfer printing. The remarkable conductive characteristics of carbon nanotubes (CNTs) are considered as promising candidates for transmission line as well as microelectronic interconnects of an arbitrary pattern. In this work, the DWNTs were prepared by the catalytic chemical vapor deposition process, oxidized and dispersed in ethylene-glycol solution. The DWNTs networks were deposited between electrodes contact and then characterized at DC through current–voltage measurements, low frequency, and high frequency by scattering parameters measurements from 40 MHz up to 40 GHz through a vector network analyzer. By varying the number of inkjet overwrites, the results confirm that the DC resistance of DWNTs networks can be varied according to their number and that furthermore the networks preserve ohmic characteristics up to 100 MHz. The microwave transmission parameters were obtained from the measured S-parameter data. An algorithm is developed to calculate the propagation constant “γ”, attenuation constant “α” in order to show the frequency dependence of the equivalent resistance of DWNTs networks, which decreases with increasing frequency.

We present a process for manufacturing printable thin-film transistors (TFTs) that is based on solution processing and direct inkjet printing of polymer semiconductors, dielectrics, and conductors, as well as inorganic nanoparticle conductors. We show that the high device yield, uniformity, and resolution required for thin-film electronic applications can be achieved by using a substrate that contains a surface energy pattern to control the flow and spreading of inkjet droplets. This technique overcomes many of the limitations of current inkjet printing technology related to its limited droplet placement accuracy. We demonstrate the potential of this printing-based TFT manufacturing process with the fabrication of 50 dpi active-matrix, polymer dispersed liquid-crystal and Gyricon Smartpaper electronic paper displays.

Inkjet print heads have become the dominant printing element for home and office printers; they have been a key driver forthe digitization of wide-format graphic arts printing and other printing areas as diverse as addressing and carton coding. In the past few years, inkjet print heads have begun to have an impact in areas outside the graphics arts. In these applications, the inkjet print head may be considered a manufacturing tool; this implies that it will differ in design depending on the application. Also, standards forreliability, consistency, and dependability will differ from those in graphic arts areas. Even though non-graphic-arts applications differ widely in their details, there are general considerations in terms of the systems that are required. Each nontraditional application has specific goals for manufacturing, and a unique inkjet print head designed to meet these goals may be required. This article focuses on a specific piezo-based inkjet print head that has been engineered to meet the manufacturing requirements for flat-panel displays basedon light-emitting polymeric materials.

Protein biochips have recently gained a lot of attention as bioanalytical tools in the life sciences. The creation of such biochips has been made possible by the integration of scientific approaches and methodologies in microfabrication, organic interface chemistry, protein engineering, detection physics, and—last but not least—advances in microarrays and microfluidic dispensing technologies. This article reviews some of the current drop-on-demand technologies developed for printing biomolecular arrays, with an emphasis on proteins and the technical challenges associated with them.

This article introduces the November 2003 issue of MRS Bulletin on Inkjet Printing of Functional Materials. The issue is devoted to the emerging non-graphic-arts uses of inkjet printing as a technique for depositing and patterning functional materials in the liquid phase onto a substrate. The articles provide an overview of a selected range of representative applications in the field of structural ceramics, polymer electronics, and protein chips, and address some of the key challenges that face the broad scientific and industrial community as it attempts to apply a mature and well-developed graphic arts printing technique to the deposition of functional materials.

Based on the concept of a microliquid process, we have developed an organic electroluminescent display using conductive polymers, including light-emitting polymers. The technology of inkjet printing has progressed enough to be used for the microliquid process. First, we describe the process used to form a patterned thin film. This involves inkjet-related technologies, the self-patterning behavior of a microliquid on the substrate, and the drying process that defines the thickness profile and film properties. Some microliquid behaviors and related phenomena, along with properties of the resulting film, were identified as distinct from those coming from a macroscopic liquid, as a result of size effects. By fully utilizing these unique properties of microliquids, we have succeeded in fabricating color-pixel arrays by direct patterning of polymer solutions. As a result, an organic electroluminescent display with a vivid full-color image has been developed.

Inkjet printing is an attractive method for patterning and fabricating objects directly from design or image files without the need for masks, patterns, or dies. In order to achieve this with metals or ceramics, it is often necessary to print them as highly concentrated suspensions of powders in liquids. Such liquid suspensions must have physical properties appropriate to the inkjet delivery mechanism. These properties are presented using a nondimensional formalism to illustrate the requirements for both drop formation and spreading on impact. Further critical issues relevant to inkjet printing of particulate suspensions are discussed and illustrated with experiments on a model alumina-containing colloidal suspension.