天线增益频带特性确定的一种简单方法

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。     

地球站最大EIRP的测量及误差分析

介绍了地球站系统测量中等效全向辐射功率的基本概念,阐述了利用场地法对地球站系统最大等效全向辐射功率测量的原理和方法,推导并给出了场地法测量地球站系统最大等效全向辐射功率的计算公式。给出了工程测量实例(L波段16 m地球站天线最大等效全向辐射功率值的测量),并对地球站等效全向辐射功率的测量误差进行了分析。实验结果表明,其均方根误差±0.30 dB。     

卫星通信地球站系统驱动电动机的选择

卫星通信地球站天线驱动电动机的选择需从机械、电子和伺服控制等方面综合考虑,其难度较大且至关重要。具体分析各类卫星通信地球站天线选择驱动电动机的依据,对卫星通信地球站天线驱动电动机的选择有一定参考价值。     

Offset Cassegrain Earth Station Antenna for the Japanese Domestic Satellite Communication System

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.     

卫星地球站天线屏蔽方法研究

近年来,卫星地球站电磁环境日益恶化,必须加强卫星电磁干扰防护。天线作为卫星地球站最重要的设备之一,在完成正常收发任务的同时,也是电磁干扰耦合的主要途径。因此,对卫星地球站天线进行屏蔽是卫星地球站电磁干扰防护的一种行之有效的方式。根据刃峰绕射损耗模型,研究了地球站天线屏蔽体的设置方法,分析了屏蔽体设置距离与屏蔽体高度之间的关系。并根据理论分析结果,建议在地球站天线周围设置金属网。     

利用仙后座A测量16m天线G/T值及误差分析

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。     

地球站天线性能的入网要求及其发展趋势

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。     

卫星地面站天线塔不均匀沉降影响及数据分析

通过对多个全动卫星地面站天线塔不均匀沉降的长期连续测量,得出了其不均匀沉降的大小及变化趋势。分析了不均匀沉降对天线测角精度的影响,研究了不均匀沉降的补偿方法。中小型天线一般自身设置有机械调平装置,可进行一定量的调整补偿。更为普遍的补偿方法是用数学模型来修正不均匀沉降带来的测量误差,大天线和中小天线都适用。工程中这些方法都已应用,效果良好,对提高天线塔建设效费比有重要意义。     

卫星通信地球站微波干扰计算与分析

总结了微波接力通信站对卫星通信地球站的同频干扰的计算步骤和方法.首先计算地球站的工作方位和仰角,分析地球站和微波站的相对位置关系；然后,在得到卫星站和微波站相互间的干扰鉴别角的基础上,分别计算两站在干扰方向的天线增益；最后,计算卫星站接收机输入端的干扰信号允许电平和实际的干扰信号电平,通过对比两者的关系,可以判断预选站...     

圆口径地面站天线近区功率密度的计算

简述了圆口径地面站天线发射近区功率密度的计算方法。推导了圆口径均匀分布、锥削分布和高斯分布的圆口径天线近区功率密度的简化计算公式,并根据地面站天线旁瓣增益包络的要求,提出了一种快速估算地面站天线偏轴近区功率密度的简单方法。     

基于矢量网络远场测量的移动通信基站天线测试

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。     

The role of rain in satellite communications

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.     

A probabilistic model to describe the interference produced by VSAT MF‐TDMA networks

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.     

Degradation Analysis of User Terminal EIRP and G/T due to Station‐Keeping Variation of Stratospheric Platform

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.     

A cylindrical Fresnel zone antenna

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     

基于便携站的应急通信系统

首先介绍了便携式卫星通信地球站(简称便携站)系统的组成及其基本原理,然后分别对天线分系统、伺服分系统、监控分系统和跟踪接收机作了简要的描述,最后提出了一种基于便携站的应急通信方案,提高了应对突发事件的解决能力.     

力学分析、预调技术及其在工程中的应用

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。     

X-Y型天线座过顶跟踪分析

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。     

Sidelobe level reduction by improvement of strut shape

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 thetadBi (1 deg leq theta leq 48deg);G = -10dBi (theta > 48deg), whereGis the sidelobe gain relative to an isotropic antenna andthetais 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.     

梯度法——移动卫星通信天线自动跟踪的新方法

某些移动卫星通信天线自动跟踪系统采用激光陀螺进行跟踪，但激光陀螺跟踪有其不足之处。本文提出了移动卫星通信天线自动跟踪的新算法一“梯度法”，可替代激光陀螺进行天线自动跟踪，其技术有所创新。本文将介绍梯度法自动跟踪原理、计算和实现方法。