Dynamic Modulation of Flexible Molecular Multiferroic Antennas.

Abstract

Frequency modulation of microwave antennas is pivotal for advancing modern communication, radar, and electronic countermeasure technologies. Multiferroics, which couple electric and magnetic dipoles, offer unparalleled advantages such as rapid, noncontact magnetic modulation via external stimulus fields, making them highly suitable for microwave devices. Here, we present flexible and wearable multiferroic nanocomposites by combining molecular piezoelectric and magnetic materials, achieving mechanical flexibility and light-responsive multiferroic properties. The molecular piezoelectric component demonstrates a robust piezoelectric response, facilitating effective modulation of magnetic properties. Simultaneously, the molecular magnet exhibits dynamically tunable magnetic anisotropy under optical stimuli, achieving a 30% reduction in magnetization upon light irradiation. This synergistic interaction between optical and mechanical stimuli enables dynamic frequency modulation in flexible multiferroic antennas, with operational frequencies tunable from 4.3 to 4.05 GHz. Additionally, the incorporation of a poly(vinyl alcohol) matrix enhances mechanical stability and durability, as evidenced by a 36% increase in Young's modulus from 42.5 to 58 MPa under an electric field. These advancements meet the demanding requirements for flexibility, durability, and frequency tunability, positioning these materials for wearable and adaptive microwave antenna applications.