共查询到20条相似文献,搜索用时 375 毫秒
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介绍了用卫星源法测量卫星通信地球站天线的特点。简述了利用3dB和10dB波束宽度确定地球站天线增益的原理和方法。提出了利用外推法确定天线增益频段特性的一种简单方法。对波束宽度法测量增益的误差进行了分析和估算,其均方根误差±0.387dB。最后给出了某工程应用的C波段15m地球站天线增益测量结果,增益测量结果与理论计算结果吻合很好。 相似文献
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简述了甚小口径天线终端(very small aperture terminal,VSAT)和超小口径天线终端(ultra small aperture terminal,USAT)站天线口径的划分及等效口径的计算方法.系统介绍了VSAT和USAT站天线性能的设计目标,即天线方向图的旁瓣特性、交叉极化特性和偏轴等效各向同性辐射功率.指出了VSAT和USAT站卫星通信天线性能设计目标的局限性,并提出了VSAT和USAT站天线方向图第一旁瓣电平要求的建议. 相似文献
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Offset reflector antennas have advantages for communication systems because they are not severely subject to blocking. Difficulties mainly arising from structual asymmetries have inhibited the realization of an offset reflector antenna with a large aperture for commercial use. This paper describes the design of an offset Cassegrain earth station antenna for the Japanese domestic satellite communication system. Antenna measurements showed 76 and 69 percent aperture efficiencies at 20 and 30 GHz, respectively, less than -20 dBi wide angle directivity and an 18 K noise temperature in operating conditions. Performances are far superior to conventional axisymmetrical earth station antennas. The antenna was reassembled on a telephone office building after the measurements. The antenna gain was reconfirmed there, using the sun as a radio frequency source. Experiments show that the earth station antenna and a terrestrial antenna can be placed on the same building without serious interference. 相似文献
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利用仙后座A测量16m天线G/T值及误差分析 总被引:1,自引:1,他引:0
阐述了利用仙后座A测量地球站天线G/T值的原理和基本公式,讨论了其修正因子的计算方法,介绍了用多项式拟合确定任意频率G/T值的方法。给出了C频段16m天线G/T值的测量结果,实测结果同理论计算结果吻合很好。对G/T值的误差进行了分析和估算,其最大均方根误差±0.384dB。 相似文献
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本文系统总结了地球站天线INTELSATM网的最新技术要求,阐述了地球站天线指标的发展趋势,指出了现代卫星通信地球站天线设计研究的方向。 相似文献
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介绍了一种基于矢量网络远场测量的移动通信基站天线测试方法,该方法具有扫频测量、有效抑制场地反射信号和场外干扰信号等特点,保证了被测天线的测量准确性和可靠性,同时大幅提高了测试效率,较好地满足了移动通信基站天线的测试需求,并进行了验证。 相似文献
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The role of rain in satellite communications 总被引:1,自引:0,他引:1
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1975,63(9):1308-1331
The most fundamental obstacle encountered in design of satellite communication systems at frequencies above 10 GHz is attenuation by rain. The microwave power radiated toward an earth station, being limited by factors such as available primary power and size of antenna on the satellite, is insufficient, with present technology, to overcome the large attenuation produced by intense rain cells on the earth-space path. The resultant loss of signal makes for unreliable transmission. In what follows, methods of measurement of this attenuation at various frequencies and a technique called path diversity that substantially improves the reliability are presented. Other degradations produced by rain, such as depolarization, interference, increase in earth-station noise, and deterioration of earth-station antenna performance, are also discussed. 相似文献
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Américo Ariel Rubin de Celis Vidal José Mauro Fortes 《International Journal of Satellite Communications and Networking》2018,36(5):427-439
This paper develops a mathematical model to describe the statistical behavior of the interference produced by VSAT/MF‐TDMA networks. The model is used to assess the interference produced by the uplinks of a VSAT/MF‐TDMA network into links of a network that uses a neighboring satellite. In the proposed model, analytical expressions were developed to account for the effects of variations in transmitting powers, antenna sizes, and transmitting antenna pointing errors. The earth station locations are modeled by a 2‐dimensional Poisson point process. The model is general enough to accommodate other types of point processes and can be applied to situations involving service areas containing multiple types of earth station geographical distribution. Numerical results obtained with the proposed model are compared with those based on the actual parameter values (eg, earth station locations, antenna sizes, and transmitting powers), which were provided by a Brazilian satellite operator. 相似文献
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Bon‐Jun Ku Do‐Seob Ahn Dong‐Cheol Baek Kwang‐Ryang Park Seong‐Pal Lee 《ETRI Journal》2000,22(1):12-19
Wireless communication systems using airship have been proposed in worldwide. The airship will be located at the stratosphere about 20 ~ 23 km above the sea level. The position of airship will vary within the station keeping range with time due to the drag of the wind in the stratosphere. When the earth station antenna has a high gain without the tracking function, the antenna performance may be degraded by a small variation of the airship. This means that variation of airship location could result in serious degradation of the system performance. In this paper, degradation in earth station's Equivalent Isotropic Radiated Power (EIRP) and Gain to noise Temperature ratio (G/T) due to the stratospheric platform movements has been derived by calculating the deviation angle of the main beam directions between the earth station and the platform antenna. In this case, the antenna of the earth station has been assumed circular and/or patch array antennas. 相似文献
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A cylindrical Fresnel zone antenna 总被引:6,自引:0,他引:6
A cylindrical Fresnel zone antenna as a candidate for a base station in wireless indoor LAN systems is described. An arbitrary angle-tilted fan beam in azimuth can be achieved by moving the position of the strip dipole feed at the cylinder center. A simple theory based on the diffraction integral is developed which predicts the antenna radiation characteristics. The antenna fabrication and measurement are carried out at 9 GHz with good agreement between calculated and measured results 相似文献
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力学分析、预调技术及其在工程中的应用 总被引:2,自引:0,他引:2
简述力学分析和预调技术原理及其在辅助大口径抛物面天线结构设计中的意义和作用;成功应用力学分析和预调技术于20m国际卫星通信地球站抛物面天线结构设计的工程实际,经济效益显著,对同类工程具有参考和借鉴作用。 相似文献
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X-Y型天线座过顶跟踪分析 总被引:2,自引:1,他引:1
为了实现地面站天线对资源卫星等特殊用途卫星的全程无盲区跟踪,需要解决过顶跟踪问题。采用数学推理方法分析研究了X-Y型天线座的过顶跟踪原理及其盲区产生机理,结合圆轨道卫星推导出X-Y型天线座的最大跟踪角速度和跟踪盲区及其之间的关系,完成了X-Y型天线座的过顶跟踪分析,提出了在工作区域内避开跟踪盲区的方法。通过工程实践验证,采用X-Y型天线座的过顶跟踪方式,可实现工作区域内的无盲区跟踪。 相似文献
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Satoh T. Shizuo Endo Matsunaka N. Betsudan S. Katagi T. Ebisui T. 《Antennas and Propagation, IEEE Transactions on》1984,32(7):698-705
From the viewpoint of effective utilization of both the geostationary orbit and the frequency spectrum in the satellite communication system, it is strongly required of an earth station antenna to have low sidelobe characteristics in order to minimize the interference from/to the adjacent satellite and the terrestrial microwave links. The reference diagram of the sidelobe gain for a large antenna recommnended by International Radio Consultative Committee (CCIR) is drawn as follows:G = 32-25 log theta dBi (1 deg leq theta leq 48deg );G = -10 dBi (theta > 48deg ), whereG is the sidelobe gain relative to an isotropic antenna andtheta is an offset angle from the main lobe axis in degrees. In the case of an axisymmetrical Cassegrain antenna operating with circular polarization, the level of the cross-polar sidelobe due to diffraction by the subreflector support struts exceeds that shown in the above reference diagram. By introduction of a new type of strut, the sidelobe gain can be suppressed below that shown in the CCIR reference diagram. In this article, a design method based on geometrical theory of diffraction (GTD) for improving the strut shape is presented. The wide-angle sidelobe gain of the standard "A " earth station antenna, installed in Yamaguchi, Japan, being equipped with the improved strut, can meet that shown in the CCIR reference diagram in all directions for both co- and cross-polar polarizations in the 6 GHz band. 相似文献