Nanostructured Low-k Dielectrics via Hybrid Phase Separation for Flexible RF Communications

The rapid expansion of portable and wearable electronics in the 5G era demands highly integrated, flexible wireless components supported by advanced low-k materials. Here, we present a nanostructured low-k dielectric fabricated via a hybrid phase separation strategy, achieving a dielectric constant of 1.86 ± 0.04 at 5 GHz. This approach combines polymerization-induced and nonsolvent-induced phase separation: the former controls micro/mesoscale pore size, while the latter generates an asymmetric structure. These nanostructured dielectrics exhibit flexibility, hydrophobicity, and good structural integrity. Furthermore, the fabrication process is environmentally friendly, avoiding toxic solvents or catalysts. A compact low-pass filter prototype was fabricated and tested based on the nanostructured dielectrics, with measured results aligning well with simulations (3-dB bandwidth range from 0 to 8.5 GHz, return loss of 16.5 dB, insertion loss of 1.2 dB, and high selectivity). This work demonstrates a promising approach for integrating functional materials into flexible electronics and RF applications.