The radiating cable (or leaky feeder) is the leading solution for distributed broadband wireless access in underground mines and tunnels. The traditional radiating cable has equally spaced slots along its axis radiati...The radiating cable (or leaky feeder) is the leading solution for distributed broadband wireless access in underground mines and tunnels. The traditional radiating cable has equally spaced slots along its axis radiating evenly. However, with the new requirement for tracking and localization of miners, this paper shows how to modify the leaky feeder to function as a beam forming antenna array by appropriately optimizing the slot spacing. Optimizing the leaky feeder slot distances using Genetic algorithm has a good impact on the channel parameters, making it an excellent choice for leaky feeder antennas. Linear, as well as bent practical leaky feeder shapes, were considered, and we tested five different optimization algorithms and compared side lobe energies, varying the slot distance which had an impact on side lobe level. Also, we derived the expression for the BER, spectral efficiency and throughput considering a time-varying wireless channel. We observed that as the radius of curvature of the feeder increased (approaching a straight line), the spectral efficiency decreased as expected. Interestingly different optimization algorithms perform differently at different carrier frequencies. An optimization method should be chosen according to the required goal to be achieved (maintaining uniform equal power along the cable, or a more directed beam, or using a certain frequency of operation).展开更多
提出了一种新型频率可重构的手机天线,尺寸为43mm×9mm×3mm.该天线由曲折馈电枝节、耦合枝节,以及多路射频开关(RF-Switch)组成.通过RF-Switch接入不同的电感改变天线的感抗值和带线的有效电长度,在低频段得到了四种不同的工...提出了一种新型频率可重构的手机天线,尺寸为43mm×9mm×3mm.该天线由曲折馈电枝节、耦合枝节,以及多路射频开关(RF-Switch)组成.通过RF-Switch接入不同的电感改变天线的感抗值和带线的有效电长度,在低频段得到了四种不同的工作状态,天线的低频带宽显著增加.研究结果表明:所设计天线能够很好地覆盖长期演进(Long Term Evolution,LTE)、无线广域网(Wireless Wide Area Network,WWAN)八个频带且频段内回波损耗小于-6dB.实测表明天线具有良好的辐射效率和辐射增益,能够实现全向覆盖,具有很好的应用前景.展开更多
文摘The radiating cable (or leaky feeder) is the leading solution for distributed broadband wireless access in underground mines and tunnels. The traditional radiating cable has equally spaced slots along its axis radiating evenly. However, with the new requirement for tracking and localization of miners, this paper shows how to modify the leaky feeder to function as a beam forming antenna array by appropriately optimizing the slot spacing. Optimizing the leaky feeder slot distances using Genetic algorithm has a good impact on the channel parameters, making it an excellent choice for leaky feeder antennas. Linear, as well as bent practical leaky feeder shapes, were considered, and we tested five different optimization algorithms and compared side lobe energies, varying the slot distance which had an impact on side lobe level. Also, we derived the expression for the BER, spectral efficiency and throughput considering a time-varying wireless channel. We observed that as the radius of curvature of the feeder increased (approaching a straight line), the spectral efficiency decreased as expected. Interestingly different optimization algorithms perform differently at different carrier frequencies. An optimization method should be chosen according to the required goal to be achieved (maintaining uniform equal power along the cable, or a more directed beam, or using a certain frequency of operation).
文摘提出了一种新型频率可重构的手机天线,尺寸为43mm×9mm×3mm.该天线由曲折馈电枝节、耦合枝节,以及多路射频开关(RF-Switch)组成.通过RF-Switch接入不同的电感改变天线的感抗值和带线的有效电长度,在低频段得到了四种不同的工作状态,天线的低频带宽显著增加.研究结果表明:所设计天线能够很好地覆盖长期演进(Long Term Evolution,LTE)、无线广域网(Wireless Wide Area Network,WWAN)八个频带且频段内回波损耗小于-6dB.实测表明天线具有良好的辐射效率和辐射增益,能够实现全向覆盖,具有很好的应用前景.
