In this paper, a novel compact printed monopole antenna with multiband operation for wireless local area networks (WLAN) is presented. A simple C‐shaped strip and a straight strip of this antenna provide two resonant paths to achieve 2.4‐, 5.2‐, and 5.8‐GHz multiband operation. Good similar omnidirectional radiation patterns in the azimuth plane of the proposed antenna with compact radiator size of 11.5 × 8.5 mm2 in the desired frequency bands have been achieved. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 365–367, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23078

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Abstract-A compact band-notched ultra-wideband (UWB) spatial diversity antenna is presented in this paper. The antenna is fabricated on an FR4 substrate and consists of two tapered microstrip feeding lines and two radiating elements. The wireless local area network (WLAN) for IEEE 802.11a operating in 5.15-5.825 GHz band-notched function is achieved by introducing two slits in the radiators as λ/4 resonators. The simulated and measured results show that the presented antenna has a broadband impedance bandwidth which covers UWB band and also has a band-notched characteristic. Additionally, the antenna has a good transmission coefficient better than −15 dB across the UWB. The radiation patterns, peak gain, and envelope correlation coefficient are measured and discussed.

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Adaptive streaming over Hypertext Transport Protocol (HTTP) has been widely used for the transmission of video content. Most of the existing studies about HTTP adaptive streaming (HAS) concentrate on improving resource efficiency, fairness among users, and quality of service for single-source videos. However, there is a growing number of live streaming applications, such as video-casts of courses, where service providers want to transmit video streams of different scenes simultaneously over the bandwidth-constrained network. Since concurrent streams further deteriorate the insufficient bandwidth situation, a systematic solution is highly needed to utilize the resources efficiently and guarantee the quality of multi-view video services. In this paper, we propose a priority-based adaptive scheme for multi-view live streaming based on HTTP streaming. Firstly, we adopt an integrated bandwidth prediction approach to calculate the available bandwidth, solving the low bandwidth utilization problem existing in the benchmark method. Secondly, we design a unified segment request strategy to restrict the interval between each request, and guarantee the synchronization of different live video streams. Finally, an adaptive scheduling algorithm is proposed with respect to priorities, to dynamically adjust the quality level of multiple video streams and improve the quality of multi-view video service. Simulations show that the proposed scheme makes considerable improvements compared to the benchmarks.

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A compact printed ultrawideband (UWB) diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

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