RF stretchable sensor using flexible substrate and eutectic gallium-indium

In this paper, we proposed a radio frequency (RF) stretchable sensor using 3D printing, Ecoflex elastomer and eutectic gallium-indium (EGaIn). The proposed stretchable sensor is composed of two complementary split ring resonators (CSRRs). We can detect amount of stretching length from variation of resonant frequencies. Initially, two resonators are designed to resonate 2.03 GHz and 3.63 GHz. When we stretched the sensor, the resonant frequencies are shifted because the electrical length of resonators is changed.