This investigation is one of the first steps towards the realization of low-cost, mass producible, miniaturized antenna solutions utilizing screen printed magnetic thick films of cobalt nanoparticle ink. The ink has a curing temperature lower than 125°C, feasible printing characteristics and metal loading higher than 85 wt.%. The properties are achieved by using an oxidatively polymerising natural fatty acid, linoleic acid, both as a surfactant and a binder. DSC-TGA-MS-analysis, TEM and SEM microscopies were utilized to investigate ink composition, nanoparticle coating and print quality. The resonant frequency of a microstrip patch antenna was tuned by screen printing of cobalt nanoparticle ink with different layer thicknesses on top of the antenna element. The influence of magnetic layers on resonance frequency, return loss, total efficiency and radiation pattern was measured and compared with a reference antenna without the magnetic films. For example, five layers of magnetic film (52 μm total thickness) tuned the resonance frequency (2.49 GHz) of the patch antenna by 68 MHz. The radiation efficiency of the patch antenna was increased from 39% to 43% by the loading of a 52 μm thick magnetic film compared to the reference antenna. The radiation patterns remained essentially unchanged, despite the presence of the magnetic thick films.
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