Solidly Mounted Overtone Magnetoelectric Antennas for Miniaturized Implantable RF Links

Magnetoelectric antennas that exploit acoustic resonance can shrink RF radiators to subwavelength footprints for implantable and body-adjacent links, but deployment is constrained by impedance matching, bandwidth, and the lack of standardized cytocompatibility data for thin-film stacks. Here we demonstrate a solidly mounted resonator magnetoelectric antenna fabricated as a Pt/AlN/FeGa heterostructure, with a laminated FeGa/AlN multilayer top stack designed to mitigate eddy-current losses. One-port reflection measurements show broadband power coupling with a superimposed, closely spaced high-overtone ripple attributed to longitudinal wave propagation and echoes in the silicon substrate, while the phase response remains predominantly capacitive over 3-4 GHz. To establish a baseline for biomedical translation, diced devices were screened using ISO-aligned L929 assays, showing >90% metabolic activity at 24 and 72 h and predominantly live-cell staining.