257 research outputs found

    Developing Novel 3D Antennas Using Advanced Additive Manufacturing Technology

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    In today’s world of wireless communication systems, antenna engineering is rapidly advancing as the wireless services continue to expand in support of emerging commercial applications. Antennas play a key role in the performance of advanced transceiver systems where they serve to convert electric power to electromagnetic waves and vice versa. Researchers have held significant interest in developing this crucial component for wireless communication systems by employing a variety of design techniques. In the past few years, demands for electrically small antennas continues to increase, particularly among portable and mobile wireless devices, medical electronics and aerospace systems. This trend toward smaller electronic devices makes the three dimensional (3D) antennas very appealing, since they can be designed in a way to use every available space inside the devise. Additive Manufacturing (AM) method could help to find great solutions for the antennas design for next generation of wireless communication systems. In this thesis, the design and fabrication of 3D printed antennas using AM technology is studied. To demonstrate this application of AM, different types of antennas structures have been designed and fabricated using various manufacturing processes. This thesis studies, for the first time, embedded conductive 3D printed antennas using PolyLactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) for substrate parts and high temperature carbon paste for conductive parts which can be a good candidate to overcome the limitations of direct printing on 3D surfaces that is the most popular method to fabricate conductive parts of the antennas. This thesis also studies, for the first time, the fabrication of antennas with 3D printed conductive parts which can contribute to the new generation of 3D printed antennas

    3D Printing of Millimetre Wave and Low-Terahertz Frequency Selective Surfaces Using Aerosol Jet Technology

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    An investigation of the use of Aerosol jet 3D Printing of frequency selective surface for millimetre and low-THz applications is presented in this article. This 3D printing technique allows the fabrication of intricate details of the designs with high resolution. Band-stop and band-pass FSS are designed and tested. The band stop FSS consisted of a Square loop array that operated in the 26-28 GHz sub-millimetre band. This design is printed on glass substrate and can be used for deployment in windows. The bandpass FSS arrays consisted of simple slot elements arranged in a square lattice and operated at 125 GHz and 280 GHz. The slot arrays were printed on Kapton. Surface profiles demonstrated the uniformity and precision of this printing technique. Simulated and measured results compared well and offered good performances at both the millimetre wave and low-THz bands. The designs find applications in 5G and imminent 6G communications. This printing technique also provides environmentally friendly, rapid, and sustainable alternative for development of highly customised FSS which can be deployed to improve communications in buildings and in future Terahertz application

    Development of 3-D RF microsystems using additive manufactruing technology

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    This work intends to explore advanced 3-D integration for state-of-the-art components in wireless systems using various 3-D printing technologies. Several packaging techniques are discussed that utilize the inherent benefits of the 3-D printing techniques. The compatible materials of the 3-D printing system are assessed for their large processing format and compatibility with the build-up process. Single layer and multilayer interconnects, transmission lines are investigated at RF and millimeter-wave (mm-wave) to explore the benefits of each in terms of convenience, reliability, cost, and performance. For the first time,the operation frequency fabricated by 3-D printing is up to D band. A novel vertical via interconnect is applied to the integration of state-of-the-art SoP. Additionally, interconnects that route the signal directly from the chip interface to matching networks are implemented on novel flexible organic material PEN are designed. This work also investigates the possible applications for cavity structures where the benefits of 3-D printing can be exploited for highly integrated receiver systems. Active and passive components are incorporated on LCP using a system-on-package approach to improve performance and enhance capability of the antenna. Wire bond interconnects are utilized as a convenient, low-cost packaging solution, ideal for prototype development.Ph.D

    Additively Manufactured Shape-changing RF Devices Enabled by Origami-inspired Structures

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    The work to be presented in this dissertation explores the possibility of implementing origami-inspired shape-changing structures into RF designs to enable continuous performance tunability as well as deployability. The research not only experimented novel structures that have unique mechanical behaviour, but also developed automated additive manufacturing (AM) fabrication process that pushes the boundary of realizable frequency from Sub-6 GHz to mm-wave. High-performance origami-inspired reconfigurable frequency selective surfaces (FSSs) and reflectarray antennas are realized for the first time at mm-wave frequencies via AM techniques. The research also investigated the idea of combining mechanical tuning and active tuning methods in a hybrid manner to realize the first truly conformal beam-forming phased array antenna that can be applied onto any arbitrary surface and can be re-calibrated with a 3D depth camera.Ph.D

    Additive Manufactured Antennas and Novel Frequency Selective Sensors

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    The research work carried out and reported in this thesis focuses on the application of additive manufacturing (AM) for the development antennas and novel frequency selective surfaces structures. Various AM techniques such as direct writing (DW), material extrusion, nanoparticle conductive inks are investigated for the fabrication of antennas and FSS based sensors. This research has two parts. The first involves the development of antennas at the microwave and millimetre wave bands using AM techniques. Inkjet printing of nanoparticle silver inks on paper substrate is employed in the fabrication of antennas for an origami robotic bird. This provides an exploration on the practicability of developing foldable antennas which can be integrated on expendable robots using low-cost household inkjet printers. This is followed using Aerosol jet printing in the fabrication of fingernail wearable antennas. The antennas are developed to operate at microwave and millimetre wave bands for potential use in 5G Internet of Things (IoT) or body-centric networks. The second part of the research work involves the development of frequency selective sensors. Trenches have been incorporated on an FSS structure to produce a new concept of liquid sensor. The sensor is fabricated using standard etching techniques and then using FDM method in conjunction with nanoparticle conductive ink. Finally, a new concept displacement sensor using an FSS coupled with a retracting substrate complement is introduced. The displacement sensor is a 3D structure which is conveniently fabricated using AM techniques

    Manufacturing, Developments, and Constraints in Full 3-D Printing of Frequency-Selective Surface Using Low-Cost Open-Source Printer

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    A comprehensive study of developing a novel printing system using a low-cost open-source printer for fully 3D printing frequency selective surface is presented in this paper. The novel printing setup employs a low-cost printer to print a plastic based filament and a conductive silver ink paste simultaneously. As there were no printers available in the market for this application, the open-source Fused Filament Fabrication (FFF) printer was modified to accommodate two extruders mounted on the same extruder carriage. Techcon TS250 air pressure dispenser was employed for the extrusion of silver ink. Extension pieces for the extruder carriage were also 3D printed using a Fused Deposition Modelling (FDM) printer to reduce the production costs. A bandstop FSS comprising of square loop elements was designed to demonstrate the full fabrication. The FSS operated at a central frequency of 2.55 GHz and provided a good angle of response with wide bandwidths. Surface profiles of the printed FSS and substrate demonstrate the reliable fabrication of the FSS design. This full 3D printing method provides an economical, eco-friendly, swift, reliable, and viable substitute for the fabrication of FSS designs that could be highly customised in terms of fabricating three-dimensional FSS designs with reliable performances. The designs can be printed and deployed to reduce the drop in signal within an enclosed environment

    Devices and structures utilizing aerosol jet printing : UV photodetectors, transmission lines and ring resonators

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    The market for printed electronics is growing continuously. Its low-cost fabrication process, large-area scalability and short processing time makes it interesting for researchers, even though the performance is lower as compared to conventional electronics. Popular printing technologies such as screen printing and inkjet printing are well established, but the upcoming maskless meso-scaled aerosol printing technique promises unique advantages. It allows the direct printing of finer 2D-3D structures, using a wide range of materials with viscosity between 1-1000 cP, while resolving the exhaustive problem of nozzle clogging. However, the implementation of printed electronics in consumer electronics remains a challenge, as device performance has to be improved. New techniques such as aerosol jet printing require additional research to fulfill their promise. This thesis investigates the implementation of fully printed structures using aerosol jet printing, focusing on devices in the fields of optoelectronics and semiconductor packaging. The system components and operation mechanism of the aerosol jet printing system are described and a methodology for process optimization is proposed. Four distinctive regions for process optimization are identified: ink selection, surface treatment, process control and postprocessing. In the preliminary work, the possibilities of the aerosol jet printing process control is explored, such as achievable line width, film thickness, material compatibility and sintering possibilities. Test structures are produced in order to test the fabrication workflow, and to observe the interaction and compatibility of multiple printed layers. The challenges associated with aerosol jet printing are identified, including wetting, alignment, overspray and satellite deposition. A fully printed ultraviolet photodetector with a nanoporous morphology is investigated. Presynthesized Zinc Oxide crystals are printed to reduce the post-annealing temperature. At a temperature of < 150 ◦C, the solvent is evaporated, resulting in a porous structure having high surface area-to-volume ratio. A fully printed photodetector that has comparable performance to the state-of-the-art is demonstrated, while the low-temperature fabrication process maintains compatibility with large area flexible plastic substrates. Next, a fully printed microstrip transmission line with SU-8 as dielectric and silver as conductor is proposed, which can provide high-bandwidth interconnections in packaged semiconductor dies. The metal and dielectric materials are characterized at microwave frequencies upto 18 GHz. It is shown that a good correspondence is reached between the simulated design parameters and the printed structure, which results in good characteristic impedance matching and low transmission losses. The transition of the printed transmission line to a microwave integrated circuit is demonstrated, thereby validating the concept of aerosol jet printed transmission lines inside the package. Lastly, the SU-8 based printed transmission lines are extended into microwave ring resonators, with applications in high frequency sensing. It is envisioned to directly print these structures inside the package, directly connected to a microwave integrated amplifier for high-Q sensing. Therefore, these ring resonator are designed for microwave center frequencies ranging from 15.5 to 21.5 GHz for reduced size which can be integrated inside a package. The material characterization of metal and dielectric materials are carried out up to 26 GHz. The simulated results showed good correspondence with the measured results in terms of center-frequency, insertion loss and Q-factor

    3D Printed Fingernail Antennas for 5G Applications

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    3D printing of antennas on removable fingernail for on-body communications at microwave and millimetre waves is proposed. Aerosol Jet technology, a fine-feature material deposition solution, has been used to directly print microstrip patch antennas on an acrylonitrile butadiene styrene (ABS) removable finger nail substrate. Two antennas have been printed and assessed, one operating at 15 GHz and the other at 28 GHz. Nanoparticle conductive silver ink has been employed to create the microstrip patch antennas and corresponding transmission line using an Optomec machine. The inks are then cured using a PulseForge machine. A further copper layer is added to the millimeter wave antenna via an electroplating process. The antennas have been simulated and measured off-the-finger and on-the-finger. Simulated and measured reflection coefficients (S 11 ) and radiation patterns are found to be in good agreement. The proposed on-body antennas can find application in the Internet of Things (IoT) where large amount of sensing data can be shared at the microwave and millimetre wave spectrum of future 5G communications. The removable finger nails could include other electronic devices such as on-body sensors, computational, storage and communication systems

    Additive Manufacturing for Antenna Applications

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    This thesis presents methods to make use of additive manufacturing (AM) or 3D printing (3DP) technology for the fabrication of antenna and electromagnetic (EM) structures. A variety of 3DP techniques based on filament, resin, powder and nano-particle inks are applied for the development and fabrication of antennas. Fully and partially metallised 3D printed EM structures are investigated for operation at mainly microwave frequency bands. First, 3D Sierpinski fractal antennas are fabricated using binder jetting printing technique, which is an AM metal powder bed process. It follows with the introduction of a new concept of sensing liquids using and non-planer electromagnetic band gap (EBG) structure is investigated. Such structure can be fabricated with inexpensive fuse filament fabrication (FFF) in combination with conductive paint. As a third method, inkjet printing technology is used for the fabrication of antennas for origami paper applications. The work investigates the feasibility of fabricating foldable antennas for disposable paper drones using low-cost inkjet printing equipment. It then explores the applicability of inkjet printing on a 3D printing substrate through the fabrication of a circularly polarised patch antenna which combines stereolithography (SLA) and inkjet printing technology, both of which use inexpensive machines. Finally, a variety of AM techniques are applied and compared for the production of a diversity WLAN antenna system for customized wrist-worn application

    Freeform terahertz structures fabricated by multi-photon lithography and metal coating

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    Direct-write multi-photon laser lithography (MPL) combines highest resolution on the nanoscale with essentially unlimited 3D design freedom. Over the previous years, the groundbreaking potential of this technique has been demonstrated in various application fields, including micromechanics, material sciences, microfluidics, life sciences as well as photonics, where in-situ printed optical coupling elements offer new perspectives for package-level system integration. However, millimeter-wave (mmW) and terahertz (THz) devices could not yet leverage the unique strengths of MPL, even though the underlying devices and structures could also greatly benefit from 3D freeform microfabrication. One of the key challenges in this context is the fact that functional mmW and THz structures require materials with high electrical conductivity and low dielectric losses, which are not amenable to structuring by multi-photon polymerization. In this work, we introduce and experimentally demonstrate a novel approach that allows to leverage MPL for fabricating high-performance mmW and THz structures with hitherto unachieved functionalities. Our concept exploits in-situ printed polymer templates that are selectively coated through highly directive metal deposition techniques in combination with precisely aligned 3D-printed shadowing structures. The resulting metal-coated freeform structures offer high surface quality in combination with low dielectric losses and conductivities comparable to bulk material values, while lending themselves to fabrication on planar mmW/THz circuits. We experimentally show the viability of our concept by demonstrating a series of functional THz structures such as THz interconnects, probe tips, and suspended antennas. We believe that our approach offers disruptive potential in the field of mmW and THz technology and may unlock an entirely new realm of laser-based 3D manufacturing
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