High-gain backup antenna design for Pioneer Venus Orbiter spacecraft

The development and performance is described of a high-gain antenna designed to serve on the Pioneer Venus Orbiter spacecraft as a backup to the principal high-gain antenna unit in the unlikely event the mechanically despun antenna mechanism malfunctioned. The final design, a center-fed standing wave array of six sleeve dipoles enclosed in a fiber glass radome, performed successfully, as did all the antennas, on the Pioneer Orbiter spacecraft which was launched on May 20, 1978, as part of the Pioneer Venus mission. Photographs of experimental models giving details of design and construction are included, as well as graphs showing measured pattern and impedance matching characteristics of the subject antenna.     

A satellite-tracking K- and Ka-band mobile vehicleantenna system

This paper describes the development of the K- and K_a-band, satellite-tracking mobile-vehicular antenna system for NASA's ACTS Mobile Terminal (AMT) project. ACTS is NASA's Advanced Communications Technology Satellite, which will be launched into its geostationary orbit in September 1993. The AMT task will make the first experimental use of the satellite soon after the satellite is operational, to demonstrate mobile communications via the satellite from a van on the road. The AMT antenna system consists of a mechanically steered small reflector antenna that uses a shared aperture for both frequency bands and fits under a radome of 23 cm diameter and 10 cm height, and an antenna controller that tracks the satellite as the vehicle moves about. The RF and mechanical characteristics of the antenna and the antenna tracking control system are discussed. Laboratory measurements of the antenna performance are presented     

Millimeter wave personal radio using an advanced communication satellite

THIS PAPER describes a millimeter-wave personal radio system using a communications satellite. It focuses on the development of a 50/40-GHz-band earth station. First, the trends of future satellite services are discussed. Satellite communications will be ready for personal utilization, namely the personalization of satellite communications, in the near future. The idea of a personal radio using a satellite and an example of an advanced communications satellite are introduced. The communications system and access method are also discussed and an FDMA system is recommended. Second, a small earth station for the millimeter-wave personal radio is proposed which has a 30-cm-diameter antenna, a transmission rate of 64 kb/s for wide applications, direct FSK modulation in the RF stage, the local signal fed from the transmit system, and link availability of 99%.     

Satellite communications relay system using a retrodirective space antenna

A system has been developed for relaying messages via a satellite between earth points. In this system, messages transmitted to a satellite modulate a retrodirective antenna. Earth stations receive messages by irradiating the satellite antenna. Methods of modulating the retrodirective array are discussed with emphasis on methods to facilitate communications among several ground stations. There are advantages in spectrum usage and sharing with surface facilities. System design parameters are presented. Minimal power is required in the satellite as compared to the active communications satellites. Extremely high reliability is inherent in the design of the satellite electronic system, which can be made entirely from solid-state components.     

VHF antenna systems for spin-stabilized satellites

Lincoln Laboratory has developed two circularly polarized VHF antenna systems for use on spin-stabilized satellites, Both are described, and test results are discussed. One is a low-gain (3-dB) antenna with omnidirectional coverage in the equatorial plane. The second is a high-gain (10-dB) antenna with a despun beam electronically scanned to always be Earth directed. Development of the component dipole and slot array elements is explained, and performance data are given for the final flight configuration.     

一种新型实用的天线控制器的设计

随着卫星通讯技术的不断发展,卫星的数量不断增加,对卫星天线伺服设备的要求也越来越高,为了保证系统的不间断通讯,同时避免对空间微波环境产生不必要的干扰,高可靠的天线控制器起到了重要的作用。特别是大口径的卫星天线,由于其波束宽度窄,对天线的角度控制要求更高。介绍了一种基于系统级单片机的实用型大口径卫星通讯地面站天线控制器的基本设计,阐述了该系统的设计特点,并对主要部分的软硬件实现方式进行了说明。     

Satellite system measurements

This paper describes the measurement techniques employed to test the elements of a communications satellite system. Techniques for measuring the gain-to-noise-temperature ratio (G/T) of an earth station antenna are presented. The measurement of earth station polarization characteristics is discussed extensively in terms of the new requirement for frequency reuse on orthogonal polarizations. Methods for in-orbit measurement of spacecraft performance including antenna characteristics are included, as well as some typical experimental results.     

30/20 GHz Band SCPC Satellite Communication Using Small Earth Stations

This paper presents a domestic satellite communication system accommodating numerous 30/20 GHz band small earth stations emphasizing the system outline, the use of multiple-access (MA) techniques. It also describes associated earth station configurations, equipment performance, and experimental results using the Japanese CS (medium capacity communications satellite for experimental purposes). Two kinds of earth stations are employed in this system, a small earth terminal (SET) and a master earth station (MES). The SET, which has an antenna about 2 m in diameter, is placed near a subscriber. The MES, which has an 11.5 m diameter antenna, is connected to the terrestrial telephone network through a satellite telephone switching center (STC). There are about 50 two-way channels with bit rates of 32 kbits/s which are achieved through the use of a 30/20 GHz band transponder whose EIRP is about 71.5 dBm, aG/Tof about 2.7 dB/K and an SET's antenna diameter of 1.8 m. This results in a system availability of 99.5 percent under typical Japanese statistical rain attenuation data. To enable a demand-assigned MA technique to be employed in this system, a single channel per carrier (SCPC) is selected, taking into consideration power efficiency of the SET, flexibility of system configurations, and the adaptability of the adaptive power control during rainy periods.     

Antenna technology for frequency reuse satellite communications

In the past few years, the capacity of communications satellite systems has become limited by the available bandwidth. One method of overcoming this limitation is to reuse the bandwidth by employing spatially isolated antenna beams and/or orthogonal polarizations. This paper surveys the required antenna technology. The multiple-beam spacecraft antenna problem is addressed, and the curreent design status is summarized. The earth terminal antenna for a dual-polarized system is discussed along with polarization measurement techniques. Finally, circuits for compensating the depolarization resulting from precipitation on the propagation path are presented.     

Computer control of the Haystack antenna

The 120-foot diameter Haystack antenna operates at X-band and is used for satellite communications, radio astronomy, and radar astronomy. Haystack is used to study stars, planets, the sun, the moon, and earth satellites. In order to point the antenna to within 1/10 beamwidth (22 seconds of arc) and to provide flexible control and data processing for diverse users, a digital computer is tightly integrated into the control system. The parameters of an experiment and computer control are arranged via simple operator discourse through a keyboard/printer. The computer system can simultaneously direct the antenna, process receiver signal data, drive convenient operator displays, and permit operator discourse. Thus, processed signal data can be observed in real time, and experiment modifications rapidly implemented. The computer control system is in full operation.     

可重构全息超表面辅助卫星通信关键技术

超密集低地球轨道卫星通信网络能弥补传统地面网络频谱资源稀缺、覆盖范围有限的不足,有潜力提供全球大规模接入的高速率服务。由于卫星的高速移动性,卫星通信对天线性能,如波束控制能力和天线增益等,也提出了更为严苛的要求。因此,对一种新型的超材料天线——可重构全息超表面（reconfigurable holographic surface,RHS）辅助卫星通信展开了研究。RHS采用全息原理对超材料单元进行电控,从而实现波束成形。基于 RHS 的硬件结构和全息工作原理,提出了一种 RHS 辅助多卫星通信方案,该方案同时考虑卫星跟踪和数据传输。同时,设计了全息波束成形优化算法以最大化和速率。仿真结果验证了所提方案的有效性并表明了相较于传统相控阵天线,RHS提供了一种成本效益更高的卫星通信支持方式。     

Development of a 45 GHz multiple-beam antenna for militarysatellite communications

Design and experimental results of a wide-angle coverage 45 GHz multiple-beam antenna for military satellite communications are presented in this paper. The high-gain spot beams with low sidelobe levels and efficient adjacent beam overlap are generated by employing an offset parabolic reflector with overlapping feed clusters. The beam shape can be adapted to cancel either single- or multiple-jammers by varying excitations within the feed cluster corresponding to the beam. Development of antenna components including Potter horn, polarizer, phase-amplitude controller, and beamforming network is discussed. Measured results of the demonstration antenna have shown that sidelobe and crosspolar levels of better than -25 dB are achieved for beams scanned over an eight-degree diameter circular coverage region. The adapted patterns of the antenna agree well with the computations, and null depths of better than 30 dB have been realized over a 4.5% bandwidth     

Earth-satellite propagation research

Slant-path propagation research is contributing to technical developments and business growth in new satellite-communications applications. Because of a radio spectrum shortage below about 17 GHz, frequencies in the Ka- and higher spectral bands are seen as good candidates for Earth-space communications in the future. New challenges in propagation research include the characterization of mobile/personal links and the investigation of higher bands for satellite communications. An example of the radiowave propagation scenarios is illustrated where the mobile terminal, with a low-gain antenna, operates in frequencies below 10 GHz and is faced with propagation anomalies caused by shadowing, Doppler, and multipath effects. The fixed terminal, with a high-gain antenna, operates at frequencies above 10 GHz and suffers from atmospheric effects     

Ku-band satellite digital transmission systems

A nation-wide data communications service is being placed in service by a major telecommunications carrier. This service will rely on a satellite network being provided and installed by Harris Satellite Communications Corporation. The network supports information data rates from 56 kb/s to 2·048 Mb/s. This data communications network has been architectured to include a number of innovative monitor and control functions, up-link power control, modular equipment shelter design and a modular antenna/feed subsystem. This paper will detail this application.     

Icosahedrons microstrip antenna network architecture proposal for new USS telecommunication subsystem

The paper presents a new antenna network subsystem architecture developed for application on board wireless communication subsystem. Founded research work results demonstrate the success of mathematical modeling and simulation of the proposed Icosahedrons Microstrip Antenna Network Architecture. Antenna elements are simulated, prototyped and tested. The Icosahedrons Microstrip Antenna Network is developed to meet the visibility requirements during inter small USS satellite radio communications.     

Beamforming experiment with a DBF multibeam antenna in a mobilesatellite environment

This paper describes a digital beamforming (DBF) multibeam antenna that incorporates a compact digital signal processor (DSP) engine, and the results of using it in a beamforming experiment receiving a satellite signal in a land-mobile environment. A considerable reduction in the scale of the DSP engine has been achieved by using field programmable gate arrays (FPGAs). To capture a satellite signal arriving from an unknown direction, a two-dimensional (2-D) spatial FFT signal processing provides orthogonal multibeam patterns on the broad side of a planar array antenna. The experimental results demonstrated the features of coarse acquisition and tracking of a signal arrival by selecting the strongest of the beams without assistance from direction finding sensors or microwave phase shifters. The DBF multibeam antenna will provide high-quality communications and increase traffic capacity if it is applied to high-gain mobile antennas or multispot-beam base station antennas in cellular or satellite mobile communications     

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。     

Satellite communications for manned spacecraft

Future manned spaceflight programs may require continuous real-time communications between the spacecraft and the mission control center. This paper examines the feasibility of relay satellite (RS) systems to meet these requirements. Anticipated requirements range from voice and low-speed data for the Skylab and Space Shuttle to television for the Space Station. Frequencies in S, C, X, and K bands (2, 5, 8, and GHz bands, respectively) are considered. Terrestrial radio-relay links may cause interference in the mission spacecraft (MS) and RS and vice versa. Possible remedies include better control of antenna sidelobes and judicious choice of channel frequencies. It is found that INTELSAT IV offers a technically feasible means of providing voice and data communications but not TV. A new dedicated satellite system can meet the requirements with two geostationary satellites both of which are visible to a single earth station (ES) in the United States. A shared satellite system, catering to other potential users as well as to manned spacecraft, offers the possibility of reduced cost to individual users. Satellite configurations for both dedicated and shared systems are presented. The satellites can be launched by boosters of the Thor-Delta class if the links between satellite and spacecraft operate in K band.     

Active phased arrays for multi-beam earth coverage

The anticipated density of satellite communications traffic with mobiles will require multi-beam earth coverage. Multiple beams can be generated from reflector antennas with multiple feeds or from a phased array aperture. The constraints on each system are discussed, and it is concluded that for more than about seven beams the best system involves a phased array antenna, particularly if reconfigurability of the beams may be required. Active phased arrays, with a power amplifier at each radiating element offer advantages in reliability and may indeed be the only way of handling the large total radiated power of future systems at acceptable levels of intermodulation.     

Maximum Power Transmission in Mass-Limited Radio Systems

A simple fundamental relationship is derived between antenna gain and transmitter power which maximizes the effective radiated power in mass-limited satellite systems. In the most common case, maximum effective radiated power is achieved when the payload mass is divided equally between the antenna system and the power system. Although this may have been known intuitively to satellite designers, to the author's knowledge this relationship has never been published. Example calculations show that considerable increases in performance can be expected for satellites which employ high-gain multibeam antennas.