Sustainable Hemp-Based Polycarbonate Substrates Enabling Low-Loss 5G and mmWave Electronic Systems

This work introduces a recyclable hemp-derived poly(cannabidiol-carbonate) (PCBDC) substrate as a sustainable low-loss material for 5G, microwave, and millimeter-wave electronics. PCBDC films were fabricated using a low-temperature process compatible with thin and flexible high-frequency packaging. Dielectric properties were extracted from microstrip ring resonator measurements up to 50 GHz, yielding εr = 1.91 and tanδ = 0.0117 at 45 GHz. Identical resonators on BOROFLOAT 33 glass demonstrated higher insertion loss under the same test conditions, while the measured PCBDC loss is also substantially lower than typical FR-4 values (tanδ ~ 0.02 in the RF range). In addition to competitive electrical performance, PCBDC offers strong mechanical properties, and a recyclable and non-halogenated composition. Life-cycle assessment further indicates reduced environmental impacts relative to FR-4. These results position PCBDC as a practical and environmentally responsible substrate candidate for high-frequency packaging and interconnects in emerging 5G and mmWave systems.