https://www.avient.com/products/engineered-polymer-formulations/conductive-signal-radiation-shielding-formulations/preperm-low-loss-dielectric-thermoplastics
With a dielectric constant (Dk) range spanning 2.55 to 23, these materials are optimized to boost antenna efficiency and deliver lightweight solutions for 5G infrastructure and devices.
They provide very high permittivity up to 23.