Cost-Effective Conductive Paste for Radiofrequency Devices Using Carbon-Based Materials

With the increasing demand for compact, lightweight, cost-effective, and high-performance radiofrequency (RF) devices, the development of low-profile antennas becomes crucial. This article presents a study of a novel carbon–cellulose-based paste intended for screen printing RF devices. The investigation specifically explores the application of high-reactivity carbon mixture (HRCM) particles as conductive fillers. The results demonstrate that optimal electrical conductivity values and discrete electromagnetic dipole performances can be achieved at lower concentrations of solid conductive material compared to conventional pastes, for similar applications. This offers benefits in terms of total cost, material consumption, and environmental impact. The paste formulation showcases a complex non-Newtonian behavior, where yielding flow and thixotropicity are found to be independent and dependent on preshear conditions, respectively. This behavior can be attributed to the network orientation and rearrangement of filler structures within the paste system, which in turn are responsible for filler pattern uniformity and overall printing quality. Compared to traditional conductive materials, HRCM pastes are proven to be a viable alternative for RF devices fabrication, including printed Wi-Fi antennas.