Biodegradable Materials for Implantable Radio-Frequency Antenna

Transient implantable medical devices require antennas that sustain wireless communication during therapy or monitoring and then safely resorb, eliminating retrieval surgery and reducing long-term foreign-body burden. This work surveys biodegradable materials for implantable radio-frequency antennas, with emphasis on material properties that directly affect wireless performance and clinical lifetime. Candidate conductors, dielectric substrates, and encapsulation layers are compared using electrical conductivity, skin depth, relative permittivity, dielectric loss tangent, corrosion or degradation rate, biocompatibility, and expected resonator quality factor. Magnesium and zinc are identified as the most practical biodegradable conductors, with conductivities of approximately 2.2 × 10⁷ and 1.7 × 10⁷ siemens per metre and skin depths near 12 and 14 micrometres at 100 megahertz. For substrates, silk fibroin offers the lowest dielectric loss tangent, about 0.005–0.01, supporting high-quality-factor resonators, while poly(lactic-co-glycolic acid) provides tuneable degradation from weeks to months and strong fabrication maturity. Polycaprolactone and poly(chloro-p-xylylene), known as Parylene-C, are evaluated as encapsulation materials for regulating water ingress to control operational lifetime. The work also highlights antenna-level compensation strategies, including wider traces, thicker biodegradable metals, lower operating frequencies, and suspended structures. These findings support the selection of biodegradable material stacks for compact, temporary biomedical telemetry implants, particularly in short-range clinical sensing applications such as ultrawideband sensing, where wireless performance, biocompatibility, and predictable resorption must be balanced.