Recent advancements in conductive yarns and fabrication technologies offer exciting opportunities to design and knit seamless garments equipped with sensors for biomedical applications. In this paper, we discuss the design and application of a wearable strain sensor, which can be used for biomedical monitoring such as contraction, respiration, or limb movements. The system takes advantage of the intensity variations of the backscattered power (RSSI) from an inductively-coupled RFID tag under physical stretching. First, we describe the antenna design along with the modeling of the sheet impedance, which characterizes the conductive textile. Experimental results with custom fabricated prototypes showed good agreement with the numerical simulation of input impedance and radiation pattern. Finally, the wearable sensor has been applied for infant breathing monitoring using a medical programmable mannequin. A machine learning technique has been developed and applied to post-process the RSSI data, and the results show that breathing and non-breathing patterns can be successfully classified.

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In this paper we propose a pattern reconfigurable planar antenna with integrated control circuitry, for flexible applications with Software Defined Radio (SDR) platforms. The antenna's layout is made by four folded microstrip elements placed symmetrically on a low cost FR-4 substrate. By using PIN diodes, the metallic elements can be switched to generate a single omnidirectional beam or six directional beams around the azimuth plane. The design includes MOSFET based control circuitry for switching the PIN diodes. The RF performance has been experimentally evaluated under different levels of control voltage. The radiation of omnidirectional and directional beams along with an integrated control board, allows for convenient utilization of the antenna in numerous SDR MIMO platforms.Index Terms-Adaptive and reconfigurable antennas, MIMO, Multiband and wideband antennas.