1,721,032 research outputs found
Behavioural attitude towards waste prevention and recycling
No full textAvailable online 24 August 2018This paper investigates empirically the relationship between individual motivations and recycling and minimisation behaviours. Exploiting an original survey of 618 Italian households, we conducted a cluster analysis on individual motivations to identify the main motivation groups among respondents. In a second step, we used these clusters as independent variables in a simple regression framework to test their correlation with recycling and minimisation variables. Overall, the results show that recycling behaviour does not correlate with individual motivations, while waste minimisation seems to be associated with intrinsic motivation only
MEMS-based High-Q E-plane Reconfigurable Filters
No full textThis paper presents a new concept for the design of reconfigurable bandpass filters with very high unloaded Q-factor using rectangular waveguide resonators loaded with a reconfigurable E-plane circuit. Ohmic MEMS switches are placed around E-plane metal strips so as to modify the TE101 mode resonant frequency, thus the central frequency of the filters. Tuning ranges up to 7% are achieved with unloaded Q-factors over 1000. Preliminary measurements of a 3rd order bandpass hardwired filter at 10 GHz show 625 MHz frequency shift (6.25%) with unloaded Q-factors above 1000 and small variations of both the filter bandwidth and return loss. The final version using actual RF MEMS is presently under fabrication at FBK
High Performance RF-MEMS cantilever switch
No full textThis paper presents the design and fabrication of a new cantilever MEMS switch with very high performance for microwave and radiofrequency applications. The beam and the contact mechanism have been optimized in order to guarantee a repeatable and very low resistance contact. In particular the parallel of 7 gold cupped dimples has been utilized in order to obtain a total contact resistance lower than 1 Ohm. A microstrip prototype has been fabricated on a 525 %m high resistivity silicon substrate by using the micromachining process at ITC-irst in Trento, Italy. The manufacturing process has been refined in order to minimize the gradient stress among the different materials constituting the beam conductor. This prevented the beam tip from bending thus leading to a very good agreement between the theoretical and measured actuation voltage, which is around 50V. RF mmeasurements up to 15GHz have been performed showing a switch insertion loss better than 0.1 dB in the entire frequency band
High-Q Reconfigurable Waveguide Filters using Cantilever MEMS Switches
No full textThis paper presents an innovative concept for the
design of MEMS-reconfigurable bandpass filters with very high
Q-factor. MEMS switches are arranged at one or both sides of a
TE101 mode cavity so as to provide an equivalent reconfigurable
inner waveguide wall. The effective width of the cavity can be
changed by activating the MEMS switches, so as to control the
cavity resonant frequency. The proposed method yields higher Q
factors with respect to other approaches involving ridged or
conductor-loaded cavities. Preliminary measurements of a 10
GHz 4th order bandpass filter show a 400 MHz frequency shift
with a Q-factor above 900
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