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The reduction of parasitic currents induced on the outer conductor of electrically long coaxial cables feeding the dipoles of a collinear array is addressed. Firstly, an experimental model is presented, and its appropriateness has been verified through validation with simulations data. The above model has been used to show the effectiveness of a low-cost technique to suppress the RF currents induced on the coaxial cables running inside the metallic mast of a collinear dipole array. The proposed solution consists of a dielectric-loaded coaxial choke, realized as a shorted quarter-wavelength coaxial cylinder mounted on the external conductor of the coaxial cable, and filled with Polytetrafluoroethylene (PTFE) to reduce its physical length. The PTFE-loaded choke performance is shown through both numerical simulations and measurements on prototypes, in the 200–400 MHz frequency range. Finally, a numerical parametric analysis is performed to get some design criteria for more complex multiple-choke arrangements. [ABSTRACT FROM AUTHOR]

A feasibility study, where small wireless transceivers are used to classify some typical limb movements used in physical therapy processes is presented. Wearable wireless low-cost commercial transceivers operating at 2.4 GHz are supposed to be widely deployed in indoor settings and on people's bodies in tomorrow's pervasive computing environments. The key idea of this work is to exploit their presence by collecting the received signal strength measured between those worn by a person. The measurements are used to classify a set of kinesiotherapy activities. The collected data are classified by using both support vector machine and K-nearest neighbor methods, in order to recognise the different activities. [ABSTRACT FROM AUTHOR]