Electromagnetic Characterization of SLG/PTFE Composites for Printed Circuit Board Fabricated Using Microwave Techniques

Abstract

The commonly used materials for printed circuit boards (PCB) in most electronics are fire retardants (FR4 and FR3). These retardants are expensive, rigid and hard to fabricate. Due to their large volumes and the presence of heavy metals with toxic substances, their environmental disposal is a concern to the environment. Consequently, there is a growing need for cost-effective, materials having low loss factors, flexible, and biodegradable in the production of electronic components. This research was focused on the characterization of silica lime glass (SLG)/Teflon (PTFE) composites and the fabrication of PCB from waste material (bottles) SLG and PTFE. The composite was prepared utilizing the Brabender poly drive machine, and hot plates were employed for the preparation and pressing of the composites into desired shapes. The microwave properties of the composites were investigated using the microstrip antenna, vector network analyzer, and open-ended coaxial probe. Surface morphology, phase composition and transmittance of the composite were studied using SEM, XRD and FTIR. Our findings showed that the average dielectric constant ranged from 1.9 to 3.36 and the loss factor was from -0.01 to -0.22 at 8 to 12 GHz. The power loss showed a trend from -0.66 to 0.65 dB. The SEM micrographs confirmed complete dispersion of the SLG particles in the PTFE and FTIR analysis showed a gradual increase in transmittance as the SLG particles 
increased in the substrates. The SLG/PTFE substrate can replace the FR4 in most electronic components based on the results obtained and it may be applicable in flexible and signal-generating devices for the future. Based on the findings, the substrates with 42.5 g SLG particles are best suited for PCB manufacture.