The research provided in this thesis focuses on the development of the novel additively manufactured antennas using the additive 3-D and material inkjet printing fabrication as well as the conventional subtractive manufacturing by using milling machine for the compact Internet of Things (IoT) and wearable applications. The initial part of the work focuses on the different ways of fabrication of the additively manufactured antenna that includes Finite Deposition Method (FDM) and PolyJet 3-D printing technique for the substrate material fabrication. And the material inkjet printing for the conductive radiating antenna element fabrication. The document discusses the unconventional issue of the surface roughness in the 3-D printed substrates materials. The later part focuses on the designing and testing techniques for the compact electrically small antennas (ESA) for the compact IoT applications.

Heritage iron objects are ubiquitous in the archaeological assemblage, frequently covered in thick, chloride-containing corrosion layers. Accurate monitoring of their corrosion rates is crucial for continued preventative conservation. Measurement of storage environment corrosivity is commonplace for a variety of metals, but use un-corroded metal as a proxy. Corrosion rates measured will be different with respect to chloride infused and corroded artefacts and data recovered difficult to reconcile with actual artefact degradation. Electrical resistance corrosion monitors have been applied to create proxy corrosion rates for various metals in industry, academia and heritage contexts. Pre-corrosion of such has previously been shown to be effective in providing altered corrosion rates in atmospheric environments. This research sets out to develop and refine the manufacture of such probes, to create sensors which will corrode similarly to chloride infested heritage iron and can be used in heritage environments to inform conservation strategy. Photochemical milling was used to create ERCM. Salt loading on the surface was achieved through a piezoelectric inkjet printer, shown to be adept at printing a variety of salt concentrations (down to 4μg/cm) and patterns, with consistency, regularity and reliability. The results of the methodology show the potential of the technique for future salt loading and corrosion testing applications. Corrosion products were grown on the treated ERCM by controlled atmospheric corrosion, shown to create a constant corrosion layer, no significant localised corrosion and good reproducibility. The products formed were shown to be compositionally similar to those found on archaeological iron. The sensors have been tested in both stable and dynamic relative humidity environments, within a test chamber and in ersatz heritage type, desiccated boxes. The corrosion rates and reactions were compared to those of heritage iron. Pre-corroded ERCM are shown to give similar corrosion rates to heritage iron; though direct calibration was not possible, further research is likely to remedy this. The final outcomes of the project are discussed with respect to the closeness of fit between proxy and archaeological iron corrosion rate data, benefits and shortcomings of the system and how the corrosion data affects current conservation understanding. It is concluded that the technique can detect corrosion rates down to storage relative humidity levels, provides more accurate representation of corrosion rate for chloride infested iron objects than bare metal ERCM, can be calibrated to suite specific objects and could represent excellent cost-effectiveness for environmental monitoring in heritage institutions.

This thesis presents a comparative study between two silver nanoparticle inks that were deposited using a Drop-on-Demand (DoD) inkjet printer, aiming at finding a functional ink that can be used to print electrodes in Light-emitting Electrochemical Cells (LECs). To achieve this, a DoD inkjet printer was installed and an acquaintance with the printer was attained. Among the two inks, one was employed as received while the other was reformulated, and successful deposition of both the inks was observed. During the reformulation process, it was seen that the highly volatile tetrahydrofuran (THF) solvent can be used to improve the ink properties, in contrast to what is recommended. After that, the inks were deposited on UV-ozone treated glass substrates, sintered at an elevated temperature under ambient conditions, and their specific resistances and thicknesses were measured. Finally, the inks were used to print the anode in a structured sandwich-cell LEC. The performance comparison was conducted by observing the emitted light of the LECs. The results indicate that the reformulated ink performs better, probably due to the lower silver concentration that results in flatter surface, which in turn effectively alleviates shorts.

This thesis represents a major contribution to wideband and high gain inkjet-printed antennas on paper. This work includes the complete characterization of the inkjet printing process for passive microwave devices on paper substrate as well as several ultra-wideband and high gain antenna designs. The characterization work includes the electrical characterization of the permittivity and loss tangent for paper substrate through 10 GHz, ink conductivity data for variable sintering conditions, and minimum feature sizes obtainable by today’s current inkjet processes for metallic nanoparticles. For the first time ever, inkjet-printed antennas are demonstrated that operate over the entire UWB band and demonstrate gains up to 8dB. This work also presents the first fractal-based inkjet-printed antennas with enhanced bandwidth and reduced production costs, and a novel slow wave log periodic dipole array which shows minimizations of 20% in width over conventional log periodic antennas.