Thermal dissipation network of hexagonal boron nitride platelets induced by low dielectric polymeric particles for millimeter wave devices

As millimeter wave (mmWave) telecommunication (in a few tens GHz and even more) ushered in, IT devices have been under unwanted operating environment with higher heat generation but also signal distortion. In the circumference, hexagonal boron nitride (hBN) can be a good candidate to solve the issue with its high thermal conductivity and low dielectric constant and loss among ceramics. In addition, polytetrafluoroethylene (PTFE) is well known as representative polymer with low dielectric constant and loss, despite high processing temperature above 350 °C. Therefore, the combination of hBN and PTFE can be ideal for mmWave devices. In this study, hBN microplatelets and PTFE polymer microparticles are incorporated into polydimethylsiloxane (PDMS) polymer with low processing temperature, leading to thermally conductive composite film with low dielectric constant and loss. PTFE microparticles of 20 vol% induced segregated networks of hBN platelets along the PTFE surface and enhanced through-plane thermal conductivity of 1.267 W/mK and low dielectric constant and loss of 3.43 and 0.0093 at 26.5 GHz, respectively. The thermal hBN network by PTFE particles impregnated in a polymer can be a promising solution in mmWave application with additional benefits such as optimized ratio of volume fraction and size of the ceramic and polymeric particles, and matching compatibility of the particles and a matrix polymer.