A Lattice-Hinge-Design-Based Stretchable Textile Microstrip Patch Antenna for Wireless Strain Sensing at 2.45 GHz

The manuscript presents a novel approach to designing and fabricating a stretchable patch antenna designed for strain sensing and the wireless communication of sensing data at the same time. The challenge lies in combining flexible and stretchable textile materials with different physical morphologies, which can hinder the adhesion among multiple layers when stacked up, resisting the overall stretchability of the antenna. The proposed antenna design overcomes this challenge by incorporating a lattice hinge pattern into the non-stretchable conductive e-textile, transforming it into a stretchable structure. The innovative design includes longitudinal cuts inserted in both the patch and the ground plane of the antenna, allowing it to stretch along in the perpendicular direction. Implementing the lattice hinge pattern over the conductive layers of the proposed patch antenna, in combination with a 2 mm thick Polydimethylsiloxane (PDMS) substrate, achieves a maximum of 25% stretchability compared to its counterpart antenna without a lattice hinge design. The stretchable textile antenna resonates around a frequency of 2.45 GHz and exhibits a linear resonant frequency shift when strained up to 25%. This characteristic makes it suitable for use as a strain sensor. Additionally, the lattice hinge design enhances the conformability and flexibility of the antenna compared to that of a solid patch antenna. The realized antenna gains in the E and H-plane are measured as 2.21 dBi and 2.34 dBi, respectively. Overall, the presented design offers a simple and effective solution for fabricating a stretchable textile patch antenna for normal use or as a sensing element, opening up possibilities for applications in the communication and sensing fields.