Ka频段卫星通信地空链路的大气衰减

在卫星通信系统的设计中,设计人员往往更关心降雨对电波传播造成的降雨衰减,而易忽略在一般情况下晴空大气对卫星通信地空链路微波传播的影响。但是当系统的链路余度较小、天线仰角较低的情况下,应考虑晴空大气造成的衰减。论述了 Ka 频段卫星通信链路大气衰减的计算方法,给出了计算结果,可供从事类似工作的相关人员参考。     

Ka频段卫星通信的信道特性与仿真技术

分析了ka频段静止卫星通信和移动卫星通信的信道特点;研究了信号经过两类信道后的幅度和相位概率分布;给出了适合Ka频段通用的信道仿真模型。利用该模型,通过Montecarlo仿真采用BPSK调制信号对静止卫星的通信信道进行了计算机仿真,得出了仿真结果。     

Ka波段功率PHEMT的设计与研制

报道了Ｋａ 波段功率ＰＨＥＭＴ的设计和研制结果。利用双平面掺杂的ＡｌＧａＡｓ／ＩｎＧａＡｓＰＨＥＭＴ材料,采用０．２ μｍ 的Ｔ型栅及槽型通孔接地技术,研制的功率ＰＨＥＭＴ的初步测试结果为：Ｉｄｓｓ：３６５ ｍ Ａ／ｍ ｍ ;ｇｍ ０：３２０ ｍ Ｓ／ｍ ｍ ;Ｖｐ：－ １．０～－ ２．０ Ｖ。总栅宽为７５０ μｍ 的功率器件在频率为３３ ＧＨｚ时,输出功率大于２８０ ｍ Ｗ,功率密度达到３８０ ｍ Ｗ／ｍ ｍ ,增益大于６ ｄＢ。     

2.6 GHz band satellite ISDB system for mobile reception

At the World Administrative Radio Conference (WARC)-92, the 2.6 GHz frequency band was allocated to a group of East Asian countries including Japan. This band is being studied for use in mobile multimedia broadcasting. This paper describes the outline of a system for 2.6 GHz band mobile multimedia broadcasting services, together with its requirements. In particular, the effects of the broadcasting signals attenuation due to shadowing by buildings and foliage, and the signals deterioration due to multipath propagation and fading, must be taken into account in order to realize the 2.6 GHz band system. This study considers the economic and technical constraints related to the modulation schemes, transmitting power, satellite antenna reflector aperture, the gain of the receiving antennas and the scale of the satellites. The configuration of satellite hardware systems based on the channel plan, channel bandwidth, and other specifications is investigated taking into account of these constraints. For example, a bit-rate of 4.8 Mbps can be provided when a 2-ton class satellite bus is utilized. This indicates that 2.6 GHz band services are technically feasible     

Impairment of digital transmission through a Ka band satellite channel due to weather conditions

This paper describes an analytical derivation of the performance impairment of a non-coherent FSK signal and a coherent PSK signal due to fading caused by weather conditions at Ka band. Analytical results on the effect of signal phase variation on a coherent PSK signal are included. Numerical values in terms of probability of bit error are given for the two digital signals. These results should be useful to a system designer of satellite communications systems at Ka band. © 1998 John Wiley & Sons, Ltd.     

UHF to Ka band upconverter

Journal of Infrared, Millimeter, and Terahertz Waves - A balanced upconverter curcuit has been developed in planar transmission line configuration using NEC GaAs beam lead Schottky barrier diodes....     

Uhf to Ka band upconverter

A balanced upconverter circuit has been developed in planar transmission line configuration using NEC GaAs beam lead Schottky barrier diodes. RF power output of +1.6 dBm SSB is obtained at Ka-band when up converter is driven by +17 dBm IF and +20 dBm LO signal.     

Ku频段地面移动卫星多媒体传输系统分析

介绍了一种宽带Ku频段地面移动卫星多媒体传输系统。对地面移动卫星通信地球站特点进行了分析。针对3种天线口径进行了卫星链路计算，并对计算结果进行了分析。     

A hybrid tile approach for Ka band subarray modules

A “thin” array construction using tile module architecture is presented in this paper. Several transmit-only tile modules operating at 30 GHz have been fabricated. The tile module involves a layered construction that contributes to reduced array thickness, weight, and cost. In such layered construction, the radiating aperture, active devices, and signal distribution functions are placed in different layers and involve vertical interconnections. The subarray module described involves a hybrid construction in which conventional wire bonding is utilized for interconnecting devices to the signal distribution layers. As in conventional modules, the devices are mounted on the carrier plates and fully tested before insertion in the module. The radiating elements which are integral to the module housing are connected to the devices through electromagnetic coupling. This hybrid construction is a first step towards a fully batch-processed tile module architecture. The construction approach and the performance results at the module and array level are presented     

Full-band staggered-gain Gunn-effect amplification in Ka band

The feasibility of full-band low-noise instantaneous amplification in Ka band has been demonstrated using a staggered-gain amplifier technique. A simplified analysis of the overall gain variations in this two-stage amplifier is used to calculate the minimum isolation levels needed to meet a maximum allowable ripple. Using this technique, 10 ± 2.2-dB gain has been obtained from 26.6-39.4 GHz.     

Ka波段单片压控振荡器的设计

基于0.25μm GaAs pHEMT工艺设计了Ka波段单片压控振荡器,该压控振荡器采用源极正反馈结构,变容管采用源极和漏极接地的pHEMT管。通过优化输出匹配网络和谐振网络以改善输出功率和相位噪声性能,使用蒙特卡洛成品率分析对本设计的成品率进行分析和改进。版图仿真结果显示:芯片输出频率为24.6²6.3 GHz,输出功率为(10±1)dBm,谐波抑制大于19 dB,芯片尺寸为1.5 mm×1 mm。     

A flow control scheme using broadcast information for Internet services in multiple-beam satellite networks

A new flow control scheme improving performance of the future broadband satellite networks is proposed and analyzed in this paper. The proposed scheme is particularly suitable for the Internet-based services in broadband satellite networks. The complexity of the proposed scheme is comparable with the existing flow control techniques, as it does not require the additional information to be provided by either the satellite or the Earth stations. The throughput and the satellite queue size performances of the proposed scheme are mathematically analyzed and simulated. The results show the significant improvement in the proposed scheme comparing with the conventional window-based and rate-based flow control techniques. Such a scheme can be used in the future satellite networks, which are an important component in the global information infrastructure (GII).     

Ku、Ka频段龙伯透镜馈源阵列技术研究

针对卫星通信中龙伯透镜天线不同频段的馈源并排放置导致最大波束指向的偏移,无法实现多频段馈源上、下行跟踪同一颗卫星,提出了馈源阵列馈电的方法。通过辐射口面采用介质杆天线取代喇叭以改进馈源,此方法减小了馈源的阵间距,利于馈源组阵。结果表明:利用馈源组阵技术可以解决波束偏焦问题,实现多频段收发同一颗卫星的目的,同时也分析了阵列馈源馈电对天线增益和效率的影响。     

Fade countermeasures at Ka band for olympus

Fade countermeasure techniques that can be applied to K_a band satellite communication systems are reviewed. Considered in detail are diversity, adaptive forward error correction, fade spreading, up-link power control and adaptive TDMA. The techniques are compared for their effectiveness at K_a band, and recommendations are made for operating systems. The two important control techniques of fade detection and fade control are discussed in terms of their ease of implementation for each countermeasure technique. Details of a planned experiment to evaluate the application of fade countermeasures to VSAT networks via the Olympus satellite are presented.     

A review of Ka and Ku band propagation measurements on satellite paths made at the bt laboratories in the U.K.

Measurements of slant-path attenuation and crosspolar discrimination, obtained from four satellite measurement programmes carried out at the BT Laboratories, Martlesham Heath, England, are described. The measurements covered frequencies in the range 11.3 GHz to 30 GHz, path elevations ranging from 8.3° to 29.9°, and were made using both circularly and linearly polarized signals. Cumulative distributions, derived from the measured data, are extrapolated to frequencies of 12.5, 14.3, 19.8 and 29.7 GHz and then combined to give statistics for a database of more than 20 years.     

Ka/Q band GaAs IMPATT amplifier technology

GaAs IMPATT diodes are capable of generating 2 to 3 W simultaneously with 18–22% efficiency in the 33 GHz to 46 GHz frequency band. The design of the amplifier circuits which utilize these devices is discussed. The circuit design is based on a 3-step closed form algorithm. The first step is a passive circuit characterization with an automatic network analyzer. In the second step, a computer is used to generate diode device lines. The third step is load line synthesis for predictable operation. The resulting performance is described. 2 W over a 2GHz bandwidth was achieved simultaneously with a minimum gain of 12 dB.     

Ka/Ku频段多波束天线研究

文章主要介绍Ka/Ku频段复合多波束天线,采用模拟多波束体制,通过4组移相器分别控制4个独立波束,实现4个波束实时跟踪卫星。实验证明,通过混合布阵减小天线尺寸,可在较小的空间内实现双频段。     

A novel modulation for mobile satellite communications

It is a challenging problem to design a high performance modulation for mobile satellite communications due to the limited power and bandwidth resource. The paper improves Feher patented Quadrature Phase Shift Keying (FQPSK) by redefining the waveform. The novel FQPSK, with constant envelope, can be used to improve the power efficiency and frequency efficiency of mobile satellite communication. The study shows that the improved FQPSK outperforms conventional FQPSK over AWGN and is immune to the non-linearity of high power amplifier. At last, the impact of flat fading and multi-path fading of channel on the BER performance of improved modulation is analyzed.     

高增益Ka波段EBG天线阵列的设计

电磁带隙(EBG)天线是一种可以提高天线辐射口径及增益的新型天线,以FSS作为EBG反射面,角锥喇叭作为辐射源,设计了一种可以工作在29.7³0.2 GHz,最大增益为23 dB的EBG天线,并对7个喇叭阵列进行了仿真分析,证明了该种EBG天线具有良好的工作性能,可以作为小型化单口径反射面多波束天线的辐射源,用于减小通信卫星的重量。     

Parametric design and analysis of multiple-beam reflector antennas for satellite communications

This paper presents the parametric design and analysis of multiple-beam reflector-antenna systems employed for satellite communications. It is based on extending the earlier work of Rao (see IEEE Antennas and Propagation Magazine, vol.41, no.4, p.53-59,1999) by taking into account the efficiency of the horn and pointing error of the satellite in the design of the multiple-beam antennas (MBAs), and by analyzing the edge-of-coverage directivity and co-polar isolation (C/I) performance. Design and analysis equations are developed for the multiple-beam antennas using offset parabolic-reflector antennas by including various design parameters such as the number of reflectors, the number of frequency cells, the focal-length-to-diameter (F/D) ratio, the horn efficiency, and the pointing error. The analysis employs a quasi-Gaussian beam representation for the primary and secondary patterns in order to take into account the effect of the sidelobes. Results of the analysis given in this paper agree well with rigorous computations based on physical optics analysis of the antenna radiation. Design curves showing the impact of horn efficiency on the C/I performance of multiple-beam antennas are presented for various frequency-reuse schemes.