A wearable rectenna for operation in the ultra high frequency (UHF) band is presented. The proposed device consists of a compact patch antenna and a full-wave bridge rectifier, both fabricated with textile materials. The patch antenna has been realized by using an adhesive conductive fabric on a bi-layer substrate made of pile and jeans. As for the rectifier, it is on a layer of jeans on the back-face of the antenna. Experimental data referring both to the patch antenna and to the rectenna are reported and discussed. From measurements performed with an incident power density of 14 W/cm , it is demonstrated that the rectenna here presented exhibits a conversion efficiency higher than 20% over the frequency range 860-918 MHz with a maximum of about 50% at 876 MHz.

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Abstract-The dispersive behaviour of an artificial Transmission Line is investigated demonstrating the existence of a negative group velocity region. More specifically, the propagation of amplitude modulated signals in a microstrip line coupled with Split Ring Resonators is analyzed, investigating the influence of the propagating pulse shape on the possibility to observe a negative group delay.

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We investigate the thickness dependence of the amplified spontaneous emission (ASE) threshold and operational lifetime in air-poly(9,9-dioctylfluorene)(PF8)-glass asymmetric active waveguides. We show that the ASE threshold decreases with the film thickness up to about 200 nm, and increases for higher thicknesses. The ASE operational lifetime increases with the thickness up to about 300 nm, and it is almost thickness independent for higher thickness. We show that the observed results are related to the guided mode confinement in the waveguide and to the spatial overlap between the guided modes and the excited region in the film.

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Abstract-Based on the use of micro electro-mechanical system (MEMS) switches this paper presents a composite right/left-handed (CRLH) transmission line (TL) with a reconfigurable behaviour. The design strategy here adopted consists on the use of metal-insulatormetal (MIM) capacitors and short-circuited stubs resulting in a very compact and monolithic CRLH unit cell well suited for phase shifter applications.