A Wireless Strain Sensor with Independent Bi-Directional Sensing Based on a Dual-band Antenna

With the development of Internet of Things (IoT), antenna-based sensors are increasingly replacing traditional wired sensors, offering reduced costs and improved mobility. This work presents a stretchable antenna with dimensions of 60 mm (L) × 65 mm (W) × 10 mm (H), designed as a wireless bi-directional strain sensor using a dual-band patch antenna. Ecoflex 0030 is employed as a stretchable substrate to encapsulate both the copper patch and the ground plane. The copper is patterned using a combination of cutting and folding techniques, to allow mechanical deformation in both axial and lateral directions. The proposed antenna exhibits two resonant frequencies at 3.14 GHz and 3.70 GHz, corresponding to strain along two perpendicular directions. This design is well-suited for applications where flexible, wireless, and directionally responsive sensing is required. © 2025 IEICE.