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A strip‐typed patch antenna covered with a dielectric is studied. The antenna is excited with a differential feeding mechanism to obtain a low cross‐polarization level. When the patch antenna is totally covered with a dielectric, it can be operated at lower frequencies without tuning antenna dimensions. The simulated results show that as the relative permittivity of the dielectric is increased from 1 to 9.2, the antenna operation frequency is reduced from 4.25 to 2.38 GHz, and the cross‐polarization level is lower than −25 dB for each operation frequency. Based on such an antenna, a 1 × 8 dual‐polarized phased array is developed. The simulated results indicate that for each polarization mode, the gain variations of the array are less than 2 dB when the main beam is scanned from 60° to −60°; bedsides, a cross‐polarization level of less than −20 dB is also achieved. An array prototype is constructed, and measured data validate the simulated results. [ABSTRACT FROM AUTHOR]

Sandwich complexation involving alkali or alkaline-earth metals, multivalency, and effects associated with local environments is widely encountered in biological and synthetic systems yet the mechanic properties remain unexplored. Herein, AFM (atomic force microscopy)-based single-molecule force spectroscopy is employed to investigate a classical model of Mn+[15C5]2, a metal cation hosted jointly by two 15-crown-5 moieties immobilized on both the substrate and the AFM tip. Factors reportedly promoting the recognition performance are examined. The rupture force required to break apart Mn+[15C5]2 is found to be in the order of tens of pico-Newton, e.g., fβ=31 pN for K+[15C5]2. The presence of a second functional group, carboxylate, confers K+[15C5]2 with a longer lifetime (from 13 to 16 ms), faster association (from 0.4 to 1.3×106 M−1 s−1), and slower dissociation (from 77 to 62 s−1). The effect of local environments is significant on association yet less critical on dissociation pathways. [ABSTRACT FROM AUTHOR]

In this paper, we present a low-power high-performance WiMAX chipset fully compliant with IEEE 802.16e specification corrigendum 1, 2 for mobile broadband access and WiMAX Forum system profile Wave2. The chipset is comprised of a 632.7-mW/24.99-\ mm^2 modem/router chip and a 364-mW/11.05-\ mm^2 dual-band 2 \times 2 MIMO RF transceiver chip, both developed in 65-nm CMOS process. The proposed chipset is capable of handling a maximum peak WiMAX downlink (DL) throughput of 70 Mbps. Moreover, the chipset can reach up to -100.5-dBm sensitivity in a 10-MHz AWGN channel, which outperforms WiMAX Forum mobile radio conformance test (MRCT) by 9.5 dB. Such high sensitivity is due to the proposed low-noise high-linearity RF transceiver chip, which has 2.5-dB RX noise figure (NF) and -37-dB TX error vector magnitude (EVM), and the applied high-performance baseband signal processing algorithms. Several low-power design techniques—from SW level, firmware/DSP level, to HW module level—have been implemented to enable portable applications. The modem/router chip is highly integrated and has rich features and various interfaces for applications such as router or VoIP phone. Furthermore, this is the only published WiMAX chipset which has been in mass production. [ABSTRACT FROM PUBLISHER]

Sandwich complexation involving alkali or alkaline-earth metals, multivalency, and effects associated with local environments is widely encountered in biological and synthetic systems yet the mechanic properties remain unexplored. Herein, AFM (atomic force microscopy)-based single-molecule force spectroscopy is employed to investigate a classical model of M(n+)[15C5]2, a metal cation hosted jointly by two 15-crown-5 moieties immobilized on both the substrate and the AFM tip. Factors reportedly promoting the recognition performance are examined. The rupture force required to break apart M(n+)[15C5]2 is found to be in the order of tens of pico-Newton, e.g., f(β)=31 pN for K(+)[15C5]2. The presence of a second functional group, carboxylate, confers K(+)[15C5]2 with a longer lifetime (from 13 to 16 ms), faster association (from 0.4 to 1.3×10(6) M(-1) s(-1)), and slower dissociation (from 77 to 62 s(-1)). The effect of local environments is significant on association yet less critical on dissociation pathways., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Measurements of molecular break junction reveal quantitatively the correlation between the single-molecule conductance and the conformation of pi-conjugated molecules with 6-18 conjugated double bonds.