In this paper, we report on a novel sensor for the contactless monitoring of the respiration rate, made from multi-material fibers arranged in the form of spiral antenna (2.45 GHz central frequency). High flexibility of the used composite metal-glass-polymer fibers permits their integration into a cotton t-shirt without compromising comfort or restricting movement of the user. At the same time, change of the antenna geometry, due to the chest expansion and the displacement of the air volume in the lungs, is found to cause a significant shift of the antenna operational frequency, thus allowing respiration detection. In contrast with many current solutions, respiration is detected without attachment of the electrodes of any kind to the user’s body, neither direct contact of the fiber with the skin is required. Respiration patterns for two male volunteers were recorded with the help of a sensor prototype integrated into standard cotton t-shirt in sitting, standing, and lying scenarios. The typical measured frequency shift for the deep and shallow breathing was found to be in the range 120–200 MHz and 10–15 MHz, respectively. The same spiral fiber antenna is also shown to be suitable for short-range wireless communication, thus allowing respiration data transmission, for example, via the Bluetooth protocol, to mobile handheld devices.

We demonstrate the precision molecular spectroscopy of HCN using a free-running, all-fiber dual electro-optic frequency comb system. Successive interferograms, acquired at a rate of Δf=1  MHz, were phase-corrected in post-processing, averaged, and normalized to yield the complex transmission spectrum of several transitions within the 2νHCN band centered near λ=1545  nm. With spectral signal-to-noise ratios as high as 326:1 achieved in 2 ms of integration time, we report accurate measurements of HCN transition intensities which will aid in the study of extreme astrophysical environments.

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