Multimodal fiber antenna for proximity and stress sensing

Fiber sensors are commonly used to detect environmental,physiological,optical,chemical,and biological factors.Thermally drawn fibers offer numerous advantages over other commercial products,including enhanced sensitivity,accuracy,improved functionality,and ease of manufacturing.Multimaterial,multifunctional fibers encapsulate essential internal structures within a microscale fiber,unlike macroscale sensors requiring separate electronic components.The compact size of fiber sensors enables seamless integration into existing systems,providing the desired functionality.We present a multimodal fiber antenna monitoring,in real time,both the local deformation of the fiber and environmental changes caused by foreign objects in proximity to the fiber.Time domain reflectometry propagates an electromagnetic wave through the fiber,allowing precise determination of spatial changes along the fiber with exceptional resolution and sensitivity.Local changes in impedance reflect fiber deformation,whereas proximity is detected through alterations in the evanescent field surrounding the fiber.The fiber antenna operates as a waveguide to detect local deformation through the antisymmetric mode and environmental changes through the symmetric mode.This multifunctionality broadens its application areas from biomedical engineering to cyber-physical interfacing.In antisymmetric mode,the device can sense local changes in pressure,and,potentially,temperature,pH,and other physiological conditions.In symmetric mode,it can be used in touch screens,environmental detection for security,cyber-physical interfacing,and human-robot interactions.

3D Printing in Fiber-Device Technology

Recent advances in additive manufacturing enable redesigning material morphology on nano-,micro-,and meso-scale,for achieving an enhanced functionality on the macro-scale.From non-planar and flexible electronic circuits,through biomechanically realistic surgical models,to shoe soles individualized for the user comfort,multiple scientific and technological areas undergo material-property redesign and enhancement enabled by 3D printing.Fiber-device technology is currently entering such a transformation.In this paper,we review the recent advances in adopting 3D printing for direct digital manufacturing of fiber preforms with complex cross-sectional architectures designed for the desired thermally drawn fiber-device functionality.Subsequently,taking a recursive manufacturing approach,such fibers can serve as a raw material for 3D printing,resulting in macroscopic objects with enhanced functionalities,from optoelectronic to bio-functional,imparted by the fiber-devices properties.