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The increasing number of biomedical applications for electronic systems have led to the need for stretchable electronics in order to significantly enhance the comfort of the user. This paper describes the design and manufacturing process of new stretchable high-frequency interconnects with meander-shaped conductors in a coplanar waveguide topology. The novel interconnects are produced based on laser-ablation of a copper foil, which is then embedded in a highly stretchable bio-compatible silicone material. Measurements on prototypes of the designed stretchable high-frequency interconnects revealed a maximal magnitude of -14 dB for the reflection coefficient and a minimal magnitude of -4 dB for the transmission coefficient in the frequency band up to 3 GHz. The influence of stretch on the performance of the high-frequency interconnects was analyzed using a stretch testing machine. The results showed that nor the magnitude, neither the phase of the transmission coefficient was influenced by elongations up to 20%. [ABSTRACT FROM AUTHOR]

Improvement of the quality and efficiency of healthcare in medicine, both at home and in hospital, is becoming more and more important for patients and society at large. As many technologies (micro technologies, telecommunication, low-power design, new textiles, and flexible sensors) are now available, new user-friendly devices can be developed to enhance the comfort and security of the patient. As clothes and textiles are in direct contact with about 90% of the skin surface, smart sensors and smart clothes with noninvasive sensors are an attractive solution for home-based and ambulatory health monitoring. Moreover, wearable devices or smart homes with exosensors are also potential solutions. All these systems can provide a safe and comfortable environment for home healthcare, illness prevention, and citizen medicine. [ABSTRACT FROM AUTHOR]

For biomedical and textile applications, the comfort of the user will be enhanced if the electronic circuits are not only flexible but also elastic. This letter reveals a simple moulded-interconnect-device technology for the construction of elastic point-to-point interconnections, based on 2-D spring-shaped metallic tracks, which are embedded in a highly elastic silicone film. Metal interconnections of 3-cm long were constructed with an initial resistance of about 3 Ω, which did not significantly increase (< 5%) when stretched. A stretchability above 100% in one direction has been demonstrated. [ABSTRACT FROM AUTHOR]

Electronic devices capable of performing in extreme mechanical conditions such as stretching, bending, or twisting will improve biomedical and wearable systems. The required capabilities cannot be achieved with conventional building geometries, because of structural rigidity and lack of mechanical stretchability. In this article, a zigzag-patterned structure representing a stretchable interconnect is presented as a promising type of building block. In situ experimental observations on the deformed interconnect are correlated with numerical analysis, providing an understanding of the deformation and failure mechanisms. The experimental results demonstrate that the zigzag-patterned interconnect enables stretchability up to 60% without rupture. This stretchability is accommodated by in-plane rotation of arms and out-of-plane deformation of crests. Numerical analysis shows that the dominating failure cause is interfacial in-plane shear stress. The plastic strain concentration at the arms close to the crests, obtained by numerical simulation, agrees well with the failure location observed in the experiment. [ABSTRACT FROM AUTHOR]

An electronic device was fabricated consisting of 2 flexible electronic circuit islands, interconnected by a 7 cm long elastic interconnection, which could be elongated for at least 50%. This interconnection was based on gold conductor tracks following a 2-D spring pattern, embedded in a biocompatible silicone elastomer. The complete device was embedded in the same silicone elastomer. An in vitro cytotoxicity extraction test, executed on small test-samples in accordance with the ISO 10 993-1 guidelines, revealed that the applied silicone encapsulation to these samples functioned as a good seal for at least 8 days.