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38 DESIGN007 MAGAZINE I MAY 2024 to be considered for high-speed design but is certainly worth checking. Alternatively, low-dielectric polymer mate- rials are widely used in printed circuit boards, communication materials, and other fields due to their several advantages, including process- ability, thermal stability, and electrical insula- tion. Materials such as polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP), and polyimide (PI) have already been widely used in RF circuit board substrates. Low dielectric constant and loss polymeric materials have become increasingly important key areas of electronics and communication due to the demand for high-frequency micro- electronics employing minimum signal losses. Low polymer materials are used in high-speed communication networks to improve the over- all performance of the devices due to their lower dielectric constant than traditional dielectric materials (Figure 2), which allows for faster signal transmission. ese materials are being used in cutting-edge fabrication of microelec- tronic devices like PCBs, antennas, microwave components for 5G, Internet of ings (IoT), intersatellite communications, and automotive radar applications. e sub-6 GHz range (3.5–7 GHz) is being used for the recently formed 5G, and it is already more congested than the pub- lic bands (2.5 GHz and 5 GHz) for Wi-Fi. e next generation 5G network opportunities rely on mainly mmWave (24–71 GHz) frequency range, which is expected to transfer data multi- gigabit per second. One approach to achieving low Dk and Df is to modify the polymer composite structure by incorporating fillers such as nanoparticles, nanotubes, nano-cubes, and nano-clays. ese filters can reduce the Dk and Df of the polymer matrix by increasing the interfacial polarization and facilitating the free volume of the polymer. Another approach is to develop new polymers with inherently low dielectric constant and loss properties. For example, fluorinated poly- mers such as PTFE and perfluorocyclobutane (PFCB) have low dielectric constants due to the high electronegativity of fluorine atoms. In addition, polyimides (PI), polyphenylene ethers (PPE), and polybenzoxazoles (PBO) have been developed with low dielectric con- stants and losses for high-frequency applica- tions, employing future electronics and com- munication industries' perspectives. Given the plethora of options available, selecting the right material for your specific product can be quite a task. While opting for low-cost materials might seem tempting, it oen comes with compromises in quality. Additionally, poor yields can escalate the over- all material cost. e dielectric material selection primarily hinges on the frequency and rise time of the digital signal. For high-frequency applications, materials with lower loss are preferable. ese materials typically exhibit lower dielectric con- stants, resulting in faster signal propagation. Remember, striking the right balance between performance and cost ensures an optimal choice. For instance, if we are looking for a dielec- tric material with a reasonably low dielectric constant and low loss, then we may choose Isola 370HR, which is a suitable all-arounder. is material has a Dk = 3.92 and Df = 0.025 at 5GHz specified in the datasheet. However, the manufacturers always specify the best material Figure 2: Dielectric properties of polymer. (Source: Zhendong Hu)