A study on the effect of compressive strain on the resonance frequency of rectangular textile patch antenna: elastic and isotropic model

Textile antennas endure a lot of deformations like as compression during wearing that lead to change their characteristics. In the present paper, attempts have been made to investigate the effect of compressive strain on the resonance frequency of wearable rectangular patch antenna. The wearable antenna was produced using pure copper polyester taffeta fabric which is utilized in patch and ground parts. Also polyester needle-punched nonwoven fabric is used as a substrate material. Regardless the thickness of patch and ground, compression stress mainly changes the dimensions of substrate, resulting in a shift in the antenna resonance frequency. The relationship between applied strains and resonance frequency shift was derived analytically, experimentally, and numerically via finite element analysis. In addition, the mechanical properties of the substrate were also considered. In the analytical model and simulations, the substrate was assumed as an elastic and isotropic material. The results show a good agreement between analytical predictions, full wave simulations, and experimental measurements.