Multi-resonant AgNW/PDMS patch antenna for biaxial strain sensing

A silver nanowire (AgNW) conductor embedded in a polydimethylsiloxane (PDMS) elastomeric substrate forms a microstrip patch antenna that can sense an applied biaxial strain. The flexible conductor and substrate allow the antenna to be repeatedly deformed by applied force. The two resonant modes of the antenna respond differently to strain applied in orthogonal directions and can be used to uniquely identify the biaxial strain state. The trends expected from the cavity model enable mapping of the change in the resonant frequencies to an applied strain state. Measured S₁₁ data under biaxial strain verify the simulations.