共查询到20条相似文献,搜索用时 15 毫秒
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Theoretical investigations of a U-slot loaded half disk patch antenna are presented using equivalent circuit concept. It is
found that the antenna shows dual band characteristics with resonant frequency at 4.76 and 6.79 GHz. The dual nature of the
antenna is realized by loading shorting pin with U-slot loaded patch. The lower and upper frequency bands are achieved as
443 and 287 MHz respectively. It is noted that the antenna shows frequency ratio of 1.4. 相似文献
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天线选择技术(AS)和虚拟MIMO(Virtual MIMO,VMIMO)技术都被广泛应用于只有一个无线射频(RF)模块的上行通信传输中。为了使两者的优势都得以发挥,该文提出将天线选择技术应用在虚拟MIMO系统中,该文中称作VMIMO-AS系统。然而,仅从被调度用户设备(User Equipment,UE)中选择最好的天线组成虚拟MIMO并不能确保系统获得最佳的性能。该文提出了VMIMO-AS系统中几种不同用户设备配对算法,并对这些算法就吞吐量性能和用户间公平度进行了比较。仿真结果表明第1个用户的选择需要应用AS原则,而考虑到复杂度和性能的折中,配对用户的选择则不需要应用AS原则。 相似文献
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本文讨论了阵列天线的基本技术指标及在无线移动通信系统中的应用,分析了应用阵列天线时可以获得的系统各方面的性能改善. 相似文献
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移动通信中的天线标准及测试 总被引:1,自引:0,他引:1
安少赓 《电信工程技术与标准化》2006,19(10):17-20
文章简单介绍了移动通信系统中天线的标准和测试方法,测试项目包括天线方向图,天线增益,驻波比等指标,并对天线方向图进行了详细的说明. 相似文献
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Ung Hee Park Haeng Sook Noh Seong Ho Son Kyong Hee Lee Soon Ik Jeon 《ETRI Journal》2005,27(3):243-249
A mobile antenna for multimedia communications with Ku‐band geostationary satellite KOREASAT‐3 and JSAT‐2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non‐periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance. 相似文献
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《Antennas and Propagation, IEEE Transactions on》2009,57(5):1367-1372
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Neelaveni Ammal Murugan Ramachandran Balasubramanian Hanumantha Rao Patnam 《Radioelectronics and Communications Systems》2018,61(6):267-273
This paper presents an ultra wideband (UWB) planar printed monopole antenna fed by microstrip line. The antenna configuration contains a beveled ground plane. The beveled partial ground plane improves the impedance bandwidth. The measured frequency response demonstrates that the fabricated antenna exhibits an impedance bandwidth of 7.9 GHz over 3.1 to 11 GHz for VSWR < 2. The proposed antenna has ultra-wideband characteristics with omnidirectional radiation pattern and stable gain. Ultra-wideband performance of the proposed antenna is examined through the simulated surface current distributions. Measured results confirm that the antenna is suitable for UWB applications due to its compact size and high performance characteristics. 相似文献
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在阐述了小型移动终端天线传统设计思想的基础上,考虑到人体影响及比吸收率(SAR)问题等因素,讨论了天线设计改进的途径如采用平衡结构等;并针对现代移动通信系统的要求讨论了自补偿天线、一体化以及软件天线等新的天线设计思想,为小型移动终端天线的近一步研究提供参考。 相似文献
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Kah-Seng Chung 《Selected Areas in Communications, IEEE Journal on》1984,2(4):487-497
Continued investigation of tamed FM (TFM) has led to an extension called generalized tamed FM (GTFM). The very narrow spectral property of a GTFM signal meets the stringent requirements on bandwidth utilization in modern mobile radio applications. The principle of GTFM is first described. It is then shown that the generation of GTFM signals can be made very simple by the use of an ROM table-lookup technique. By an appropriate choice of parameters in GTFM signal generation at the transmitter, a joint optimization for coherent and noncoherent detection with regard to BER performance in the presence of additive white Gaussian noise can be achieved. For mobile radio applications, the robustness of the detection scheme to fast fading is important. A low-complexity noncoherent receiver is presented, Comprising a frequency discriminator and a simple maximum-likelihood sequence estimator. This receiver performs well in a fast fading environment. Computer simulated results of BER performance of this scheme are given. These results are confirmed by experimental measurements. 相似文献
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Wireless Personal Communications - Underwater communication is a mode of transmitting or receiving the signals below water. Many applications such as shipments, autonomous vehicle, climate... 相似文献
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提出了一款应用于超高频段(Ultra High Frequency,UHF)(912 ~935 MHz)的射频识别(RFID)读写器圆极化单层结构微带天线,基板采用FR4 板材达到价格低廉、辐射贴片采用开槽的结构实现小型化、接地板采用开槽结构提高天线的增益,该天线实现了小型化设计,满足了天线的设计要求。利用三维电磁仿真软件对天线模型进行了分析,仿真与测试结果吻合良好。天线测试结果表明:回波损耗小于-10 dB 的阻抗带宽为25 Hz(910 ~ 935 MHz),轴比(AR)小于3 dB的带宽为21 MHz(914 ~935 MHz);在UHF 频段内,读写器天线的最大增益为-1.2 dB,所以本天线能满足我国射频识别读写器的应用要求,具有良好的应用前景。 相似文献
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分析了适用于手机和数据卡等各种移动终端的小型天线,该类天线主要工作在GSM、CDMA、WCDMA、GPS、DCS、UMTS以及WLAN等小型终端设备的无线通信频段。对小型终端天线的工作原理作了详细分析,并设计了一种典型的三频段平面倒F天线,仿真结果验证了设计方法的有效性。最后对该类小尺寸天线的LC匹配方法进行了研究,可供同类设计进行参考。 相似文献
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设计了一款适用于手机的小型化WLAN天线,尺寸为10 mm×35 mm,天线的主要结构为一个折叠型倒L-L结构.设计过程中采用了共面波导馈电(CPW)技术,有效地增加了天线的带宽.仿真结果表明,天线在2.45 GHz时覆盖了2.38 GHz ~ 2.688 GHz,5.2 GHz时覆盖了4.77 GHz~6 GHz,同时达到了IEEE 802.1 1a和IEEE 802.11 b/g标准.整体来说,天线尺寸小、频带宽,方向图性能良好.对天线进行了实物加工并进行了测试,结果显示仿真与实验结果吻合,均能覆盖所需频段. 相似文献