S. Jun

UWB antenna on 3D printed flexible substrate and foot phantom

An ultra-wideband (UWB) monopole antenna on an additive manufactured (AM) flexible substrate for foot wear application is proposed. The 3D printing of foot phantoms for the testing of this type of antennas is also introduced. Inexpensive fuse filament fabrication (FFF) technology is utilized for these developments. Flexible polylactic acid plastic filament (PLA) material is used for the antenna while transparent PLA for the phantom. The antenna is intended for integration into the footwear tongue. The UWB monopole antenna achieves -10dB input impedance matching from 3.1GHz to over 10.6GHz in freespace, on the foot phantom and on the real human body. Simulation and measurement confirm the ultra-wideband operation of the antenna.

Manufacturing Considerations in the 3-D Printing of Fractal Antennas

The use of additive manufacturing (AM) techniques for the fabrication of 3-D fractal monopole antennas is presented. The 3-D printing (3-D P) of 3-D designs based on the Sierpinski fractal concept is studied, and the performance discussed. The AM allows the fabrication of the complex features of these antennas. The specific structures, on the other hand, provide a reduction of the material used in AM compared with the equivalent nonfractal designs, in which two cases can be described by over 75%. This is the first time that 3-D fractals have been studied in terms of volume reduction and their potential benefits to AM of antennas. The first investigated antenna derives from the Sierspinki tetrahedron fractal shape. From this initial design, two new structures have been developed: the dual Sierpinksi fractal and the dual inverse Sierpinski fractal. The new designs offer improved matching and radiation pattern. All the antennas operate at 2.4 GHz used in Bluetooth and wireless LAN band. Furthermore, the final inverse fractal shape is able to cover both the 2.4- and 5.5-GHz WLAN frequencies with a reflection coefficient (

Evaluation of a low-cost inkjet printed slot antenna for energy harvesting applications

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Inkjet printed GPS antenna on a 3D printed substrate using low-cost machines

) better than −10 dB, together with coverage at bands around 8 GHz. This ratio of resonant frequencies is achieved after a series of described design stages. The radiation patterns of the antennas are monopole-like at both bands. The AM technique employed is metal powder embinder printing where a binding material is jetted on a powder bed containing metal particles. Metal 3-D P is ideal for maintaining the mechanical strength of the structures. The envisaged applications are in the defense and aerospace sectors where high-value, lightweight, and mechanically robust antennas can be integrated with other 3-D printed parts. Transient simulations based on the finite integration technique compare well with measurements.

A CPW-fed antenna on 3D printed EBG substrate

This paper deals with the functionality of an inkjet printed slot antenna for radio frequency (RF) energy harvesting application. The antenna is printed on a paper substrate using an off the shelf inkjet printer with cartridges containing nano particle silver ink. The RF performance of the printed antenna is assessed, and compared with another antenna fabricated using conventional etching methods. The reflection coefficient characteristics of the two antennas are very similar. A Power Cast radio frequency (RF) power transfer and energy harvesting system is employed for the final evaluation of the antennas. The inkjet printed antenna is able to harvest a good amount of RF power, though less than the equivalent copper etched antenna on Mylar substrate. The antennas operate at the 915MHz UHF ISM band. Finite-difference-time-domain simulations compare well with test results.

3D printing technique for the development of non-planar electromagnetic bandgap structures for antenna applications

A circularly polarized patch antenna fabricated using commercially available, low-cost, printers is described. Two additive processes are combined for the fabrication: stereolithography (SLA) and inkjet printing of silver inks. A widely available SLA 3D printer is employed to fabricate the substrate of the antenna. Inkjet printing is used to deposit the metallic layers of the radiating element on the substrate. The two machines employed are very low-cost in comparison to those used in previously reported work. Good adhesion of the metallic patterns to the substrates is observed. Furthermore, the resistance of the added metallic patch is relatively low. The aim is to demonstrate the use of alternative, inexpensive machines, for the prototyping and manufacturing of antennas on 3D printed substrates. In this work, the antenna operates at the 1.575GHz GPS frequency band. Finite-difference-time-domain simulations compare well with the practical experiments.

Circular polarised antenna fabricated with low-cost 3D and inkjet printing equipment

This paper proposes a coplanar waveguide (CPW) fed antenna and electromagnetic band gap (EBG) structure on 3D printed substrates. Low-cost fuse filament fabrication (FFF) technology is employed. Two sets of experiments are described. In the first, the antenna and EBG patterns are etched on copper clad Mylar® polyester film and attached to the 3D printed substrates. In the second, the patterns of the EBG are added using silver conductive paint. Both experiments compare very well between them, and with the simulations. The EBG structure provides improved antenna performance such as gain, efficiency and directivity. The antenna and EBG are designed for the 2.4 GHz Bluetooth frequency band. The Finite-difference timedomain (FDTD) computational method was used for the study.