A wideband dual-polarized antenna is proposed. With chamfers in cross loop dipoles, the two resonating modes can be controlled, the first resonating mode can move lower and the second resonating mode can move higher by changing the size of the chamfer. Therefore, the radiator size is reduced to 48 mm 3 48 mm (0.35 k 3 0.35 k, k is the wavelength at 2.2 GHz) and a wider bandwidth is achieved. Measured results show that the proposed antenna has a bandwidth of 48.8% from 1.7 to 2.8 GHz for VSWR < 1.5. Stable radiation pattern and stable gain are also obtained over the operating band.
Paper-based electrochemical sensors provide the opportunity for low-cost, portable and environmentally friendly single-use chemical analysis and there are various reports of surface-functionalized paper electrodes. Here we report a composite paper electrode that is fabricated through designed papermaking using cellulose, carbon fibers (CF), and graphene oxide (GO). The composite paper has well-controlled structure, stable, and repeatable properties, and offers the electrocatalytic activities for sensitive and selective chemical detection. We demonstrate that this CF/GO/cellulose composite paper can be reduced electrochemically using relatively mild conditions and this GO reduction confers electrocatalytic properties to the composite paper. Finally, we demonstrate that this composite paper offers sensing performance (sensitivity and selectivity) comparable to, or better than, paper-based sensors prepared by small-batch surface-modification (e.g., printing) methods. We envision this coupling of industrialized papermaking technologies with interfacial engineering and electrochemical reduction can provide a platform for single-use and portable chemical detection for a wide range of applications.
A broadband dual-polarised antenna for 2G/3G/LTE/5G wireless communication is proposed. A new resonant mode is induced with parasitic resonator loaded inside the loop radiator. Wide impedance bandwidth of 72.2% for VSWR<2 (1.69-3.6 GHz) is achieved with three controllable resonant modes. Stable gain and radiation patterns are obtained over the whole band.
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