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Aerosol Jet Printing of Conductive Patterns on Paper Substrate
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Abstract
Aerosol jet printing (AJP) is a promising method for microscale digital additive manufacturing for printed electronics. However, it requires a high sintering temperature (280 ° C) and a long sintering time (e.g. 12 hours on a glass substrate) to guarantee a highly conductive metallic structure, which confined AJP to limited types of substrates and applicati ons. In this paper, a fabrication method to use cellulose fiber paper as substrates for AJP printing is proposed. With the proposed approach, the sintering temperature is reduced to 80 ° C and the sintering time is shortened to 220 minutes for the printing on printing papers. The printed structure can have a sheet resistance of 0.0203 Ω/ with good adhesion to the substrate. The effect of folding on the conductivity is examined, and an application to wireless power transfer serving as a resonator is demonstrated. The proposed paper-based AJP printed electronics can be folded, bent, and pasted to any surface. This combination of AJP with paper substrates opens a window for low-cost flexible, high resolution printed electronics.
... The AJP technology has been applied to fabricate various types of functioning components, such as sensors [5], antennas [6], solar cells [7], etc. It can be applied to provide compact components to wireless power transfer [8][9][10], metamaterials [8,11,12], portable magnetic resonance imaging [13], etc. ...
... The AJP technology has been applied to fabricate various types of functioning components, such as sensors [5], antennas [6], solar cells [7], etc. It can be applied to provide compact components to wireless power transfer [8][9][10], metamaterials [8,11,12], portable magnetic resonance imaging [13], etc. ...
... The effect of the sintering sequence is examined. Besides the proposed sintering sequence as shown in Fig. 3(b), the proposed hot-air sintering can be done after all the layers are printed [8]. Fig. 11(a) shows such an alternative sintering sequence, named SQ 2, for AJP printing on cellulose fiber paper when a high conductivity can be obtained. ...
Aerosol jet printing (AJP) is a promising method for micro-scaled digital additive manufacturing for printed electronics. It usually requires a high sintering temperature (280 °C) and a long sintering time (e.g., 12 h on a glass substrate) to guarantee a high conductivity of the printed structures, which has limited AJP to only a few types of substrates. Moreover, the printed metallic structure peels off from the substrate easily. In this paper, a procedure of AJP printing on cellulose fiber paper is proposed, which includes the use of cellulose fiber paper as the substrate, and a new sintering method, i.e., hot-air sintering with an optimized sequence. With the proposed approach, the sintering temperature is significantly lowered (80 °C), and the sintering time is considerably shortened (40 min). The printed structure has a measured sheet resistance of 1.13 × 10⁻² Ω/m² which is equivalent to a conductivity of greater than 10⁶ S/m and close to that of the bulk silver (6.30 × 10⁷ S/m), and it has good adhesion to the substrate. The determinant factors underlying the diffusion and curing processes of AJP, i.e., the properties of the substrate (cellulose fiber paper), the printing parameters, the sintering parameters, and the sequence were systematically investigated. The investigation is carried out through evaluation of the morphologies of the printed structures based on scanning electron microscope (SEM) images and through the study of the correlation between the morphology and the conductivity of the structures. Moreover, the proposed paper-based AJP electronics offer tremendous flexibility. They can be folded, bent, and pasted to any surface. This proposed cellulose-fiber-paper-based AJP opens a window for low-cost, eco-friendly, flexible, and high-resolution printed electronics. It will be an essential alternative fabrication approach for flexible electronic circuits, antennas, and electromagnetic-functioning surfaces, such as reconfigurable meta-surfaces.
Aerosol-based direct-write refers to the additive process of printing CAD/CAM features from an apparatus which creates a liquid or solid aerosol beam. Direct-write technologies are poised to become useful tools in the microelectronics industry for rapid prototyping of components such as interconnects, sensors, and thin film transistors (TFTs), with new applications for aerosol direct-write being rapidly conceived. This paper aims to review direct-write technologies, with an emphasis on aerosol-based systems. The different currently available state-of-the-art systems such as Aerosol Jet CAB-DW, MCS, and aerodynamic lenses are described. A review and analysis of the physics behind the fluid-particle interactions including Stokes and Saffman force, experimental observations, and how a full understanding of theory and experiments can lead to new technology are presented. Finally, the applications of aerosol direct-write for microelectronics are discussed.
A fast and accurate calculation of the resonant frequency of a solenoid coil is needed in many applications, e.g., wireless power transfer and magnetic resonance imaging. It helps to accelerate the design and optimization of a coil. However, the existing calculation models for the key equivalent parameters, the inductance (L) and the capacitance (C), of the solenoid coils can only provide estimations for standard tightly wound cylindrical coils, and the accuracy is not high. There are no accurate models available for calculating L, C, and the resonant frequency when a solenoid becomes irregular, e.g., when it is sparse (with a large pitch), when it has nonuniform pitches, or when it is noncylindrical. In this paper, we propose a fast and accurate model for such an irregular solenoid coil to calculate its inductance, capacitance, and, thus, the resonant frequency. The accuracy of the proposed model is tested on the solenoid coils (with large pitches, nonuniform pitches, or noncylindrical shape) by comparing the calculated results to those using commercial simulation software and the measurement results. For a sparsely wound solenoid, the proposed model provides an accurate calculation of the inductance with a maximal pitch-to-wire-diameter ratio of 40 (an error rate of 8.33% at this ratio). For a varied-pitch solenoid and a noncylindrical one, an error rate of less than 5% can be achieved for a calculation of the inductance.
Conventional strongly coupled magnetic resonance (SCMR) wireless power transfer (WPT) systems have high quality factor (
Q
), leading to limited system bandwidths. In practical applications, especially in human-involved environments, the resonant frequency of SCMR resonators will shift due to the effect of highly dielectric human body. In this letter, a wideband four-coil SCMR WPT system is proposed by improving the coupling between the tx/rx coil and their corresponding resonators. The bandwidth is increased by over 100% compared to a conventional system without sacrificing the efficiency much. The wideband feature is demonstrated by both simulation and measurement. It is analyzed physically and by using an equivalent circuit analysis.
Optimization of radio-frequency identification (RFID) tags often requires several iterations of antenna design/fabrication/testing to meet cost and performance targets. The use of a rapid prototyping approach for antenna development would allow the designer an inexpensive and fast route to the refinement process. In this study, the performance of a commercial-off-the-shelf ultrahigh frequency (UHF) etched copper antenna was compared to printed silver antennas prepared by the following three direct-write techniques: maskless mesoscale materials deposition; matrix-assisted pulsed laser evaporation direct-write; and, collimated aerosol beam direct-write. The morphologies of the antennas were analyzed using contact and optical profilers with sheet resistance also being measured. Operational characteristics were determined by mounting silicon integrated circuits (IC) to the four different types of antennas. The performance of tags that utilized direct-write silver antennas was comparable to the copper-based commercial tag. To our knowledge, this is the first demonstration where some of the direct-write rapid prototyping attributes (e.g., slight overspray, overlap of written lines, overall thickness less than 500 nm) are shown to not seriously impede RFID tag performance. These results demonstrate the utility of direct-write for rapid prototyping studies for UHF RFID antennas.
Using self-resonant coils in a strongly coupled regime, we experimentally demonstrated efficient nonradiative power transfer
over distances up to 8 times the radius of the coils. We were able to transfer 60 watts with ∼40% efficiency over distances
in excess of 2 meters. We present a quantitative model describing the power transfer, which matches the experimental results
to within 5%. We discuss the practical applicability of this system and suggest directions for further study.
Direct writetm system
- M J Renn
M. J. Renn, "Direct writetm system," 18 2007, uS Patent 7,270,844 B2.