Index Terms-Beam-steering, reconfigurable antenna, full-wave analysis, signal to noise ratio.

A parasitic layer-based multifunctional reconfigurable antenna (MRA) design based on multi-objective genetic algorithm optimization used in conjunction with full-wave EM analysis is presented. The MRA is capable of steering its beam into three different directions simultaneously with polarization reconfigurability having six different modes of operation. The MRA consists of a driven microstrip-fed patch element and a reconfigurable parasitic layer, and is designed to be compatible with IEEE-802.11 WLAN standards (5-6 GHz range). The parasitic layer is placed on top of the driven patch. The upper surface of the parasitic layer has a grid of 5 5 electrically small rectangular-shaped metallic pixels, i.e., reconfigurable parasitic pixel surface. The EM energy from the driven patch element couples to the reconfigurable parasitic pixel surface by mutual coupling. The adjacent pixels are connected/disconnected by means of switching, thereby changing the geometry of pixel surface, which in turn changes the current distribution over the parasitic layer, results in the desired mode of operation in beam direction and polarization. A prototype of the designed MRA has been fabricated on quartz substrate. The results from simulations and measurements agree well indicating 8 dB gain in all modes of operation.Index Terms-Beam steering, full-wave analysis, multi-objective genetic algorithm, reconfigurable antenna.

The source region of the Yellow River, China, experienced degradation during the 1980s and 1990s, but effective ecological restoration projects have restored the alpine grassland ecosystem. The local government has taken action to restore the grassland area since 1996. Remote sensing monitoring results show an initial restoration of this alpine grassland ecosystem with the structural transformation of land cover from 2000 to 2009 as low- and high-coverage grassland recovered. From 2000 to 2009, the low-coverage grassland area expanded by over 25% and the bare soil area decreased by approximately 15%. To examine the relationship between ecological structure and function, surface temperature (Ts) and evapotranspiration (ET) levels were estimated to study the dynamics of the hydro-heat pattern. The results show a turning point in approximately the year 2000 from a declining ET to a rising ET, eventually reaching the 1990 level of approximately 1.5 cm/day. We conclude that grassland coverage expansion has improved the regional hydrologic cycle as a consequence of ecological restoration. Thus, we suggest that long-term restoration and monitoring efforts would help maintain the climatic adjustment functions of this alpine grassland ecosystem.

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Full-duplex systems are expected to achieve 100% rate improvement over half-duplex systems if the self-interference signal can be significantly mitigated. In this paper, we propose the first full-duplex system utilizing Multi-Reconfigurable Antenna (MRA) with ∼90% rate improvement compared to halfduplex systems. MRA is a dynamically reconfigurable antenna structure, that is capable of changing its properties according to certain input configurations. A comprehensive experimental analysis is conducted to characterize the system performance in typical indoor environments. The experiments are performed using a fabricated MRA that has 4096 configurable radiation patterns. The achieved MRA-based passive self-interference suppression is investigated, with detailed analysis for the MRA training overhead. In addition, a heuristic-based approach is proposed to reduce the MRA training overhead. The results show that at 1% training overhead, a total of 95dB self-interference cancellation is achieved in typical indoor environments. The 95dB self-interference cancellation is experimentally shown to be sufficient for 90% full-duplex rate improvement compared to half-duplex systems.

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A new molecularly imprinted SiO2 (MISiO2) film on the surface of indium tin oxide (ITO) electrode was prepared by the sol–gel method and was then applied successfully in the electrochemical chiral recognition of tryptophan (Trp) isomers. Owing to the high chemical stability, excellent rigidity, and low cost, the resultant sol–gel SiO2 is a good matrix material for molecular imprinting. Nonionic surfactant cicosaethylene glycol hexadecyl ether (Brij58) arranged directionally on the surface of the hydrophobic ITO electrode possesses a large amount of oxygen-containing functional groups and may induce the accumulation of template molecules (L-Trp) on the surface of ITO, resulting in L-MISiO2/ITO after the removal of L-Trp templates by calcination. The characterizations of the L-MISiO2/ITO reveal that the L-Trp templates could be successfully removed from the matrix, producing complementary cavities within the L-MISiO2/ITO. The resultant L-MISiO2/ITO exhibits greatly higher affinity toward L-Trp than D-Trp due to the three-point interaction mechanism, and therefore it exhibits good chiral recognition ability for the Trp isomers. In addition, the as-prepared L-MISiO2/ITO or D-MISiO2/ITO (D-Trp as the templates) can predict the ratio of L- and D-isomers in racemic mixture. Last, the MISiO2 films exhibited quick binding kinetics and good recognition reproducibility.