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Tissue-equivalent phantoms play a key role in the development of new wireless communication devices that are tested on such phantoms prior to their commercialization. However, existing phantoms cover a small number of tissues and do not reproduce them accurately within wide frequency bands. This paper aims at enlarging the number of mimicked tissues as well as their working frequency band. Thus, a variety of potential compounds are scanned according to their relative permittivity from 0.5 to 18 GHz. Next, a combination of these compounds is characterized so the relation between their dielectric properties and composition is provided. Finally, taking advantage of the previous analysis, tailor-made phantoms are developed for different human tissues up to 18 GHz and particularized for the main current body area network (BAN) operating bands. The tailor-made phantoms presented here exhibit such a high accuracy as would allow researchers and manufacturers to test microwave devices at high frequencies for large bandwidths as well as the use of heterogeneous phantoms in the near future. The key to these phantoms lies in the incorporation of acetonitrile to aqueous solutions. Such compounds have a suitable behavior to achieve the relative permittivity values of body tissues within the studied frequency band., This work was supported by the Ministerio de Economia y Competitividad, Spain (TEC2014-60258-C2-1-R) and by the European FEDER Funds.

Ultra-wideband (UWB) systems have emerged as a possible solution for future wireless in-body communications. However, in-body channel characterization is complex. Animal experimentation is usually restricted. Furthermore, software simulations can be expensive and imply a high computational cost. Synthetic chemical solutions, known as phantoms, can be used to solve this issue. However, achieving a reliable UWB phantom can be challenging since UWB systems use a large bandwidth and the relative permittivity of human tissues are frequency dependent. In this paper, a measurement campaign within 3.1-8.5 GHz using a new UWB phantom is performed. Currently, this phantom achieves the best known approximation to the permittivity of human muscle in the whole UWB band. Measurements were performed in different spatial positions, in order to also investigate the diversity of the in-body channel in the spatial domain. Two experimental in-body to in-body (IB2IB) and in-body to on-body (IB2OB) scenarios are considered. From the measurements, new path loss models are obtained. Besides, the correlation in transmission and reception is computed for both scenarios. Our results show a highly uncorrelated channel in transmission for the IB2IB scenario at all locations. Nevertheless, for the IB2OB scenario, the correlation varies depending on the position of the receiver and transmitter., This work was supported by the Ministerio de Economia y Competitividad, Spain, under Grant TEC2014-60258-C2-1-R and Grant TEC2014-56469-REDT and by the European FEDER Funds.

[EN] In December 2011, Colombia updated its national Digital Terrestrial Television (DTT) standard from DVB-T to DVBT2, the second-generation European DTT standard. DVBT2 is the current state-of-the art DTT system in the world, and it brings very significant improvements in terms of capacity, robustness and flexibility compared with any other DTT technology. The iTEAM Research Institute was very involved in the promotion and adoption of DVB-T2 in Colombia. The case of Colombia is unique because it was the first country to deploy DVB-T2 with 6 MHz channelization, and because the digital networks will co-exist with the analogue NTSC network until the analogue switch-off and with digital ISDB-Tb and DVB-T networks in the neighbor countries. Furthermore, DVB-T2 networks will be deployed from scratch without any constraint imposed by existing DVB-T infrastructure. This paper provides an overview of the frequency and network DVB-T2 planning activities performed by the iTEAM Research Institute in cooperation with the Spectrum Regulator of Colombia., This work was partially supported by the Spectrum Regulator of Colombia ANE (Agencia Nacional del Espectro). The authors thank the Spanish companies Ingenia-Telecom and Axión Infraestructuras de Telecomunicación, partners in some of the projects developed for the ANE.