tailieunhanh - Satellite Communications Part 16

Tham khảo tài liệu 'satellite communications part 16', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Satellite coverage optimization problems with shaped reflector antennas 441 Fig. 5. Parabolic reflector antenna a . Parabolic reflector antenna A point b z p belongs to a parabola as shown in Fig. 6 when it is at the same distance from the focus a F 0 and its projection c F p onto the directrix z F which leads to the implicit equation p2 X2 y2 z 4F 4F where F is called the focal distance. The unit normal vector to the parabola can be written as 2Fz pp 2Fz xX yy y 4F2 p2 ự 4F2 X2 y2 9 10 The angle of the normal vector if to z is 9 arctan 11 The direction of a ray from the focus to a point on the parabola can be written as J z F z pp z F 12 so that J A 2zF 2F2 p2 d n -- _ z F y 4F2 p2 _ 2F 74 7 n z 2zF 2F2 4zF z F ự4F2 p2 13 cos 9 442 Satellite Communications Fig. 6. Parabola with focus a F 0 and directrix z -F defined by points b z p . Hence the angle between d and fl is the same as the angle between fl and z. If the reflection is perfect . for electromagnetic waves reflector must be a perfect electric conductor then 9 is the angle of reflection of the ray which equals the angle of incidence so that all reflected rays go towards z. A last notable feature of parabolic reflectors is that the distance traveled by two reflected rays originated from the focus up to a given z za plane are exactly the same and valued to I b a I za z b c I za z F z za z 14 F za Therefore if all rays from the feed are in phase then they will still be in phase after reflecting and reaching z za. This is highly desired considering that an aperture . a bounded region at a given z za is most directive when the field distribution on it is uniform in phase and amplitude. Unfortunately the same does not hold true for the amplitude since the dispersive behavior from the feed up to the reflector attenuates non-uniformly each ray according to the respective distance F z. Fig. 7 shows a parabolic reflector antenna with circular aperture of radius R. The reflector center was displaced H .

• Cơ khí - Chế tạo máy
• Lecture Microwave and Satellite Systems
• Bài giảng Hệ thống vệ tinh và vi sóng
• Microwave and Satellite Systems
• Characteristics of Satellite Communication System
• Fundamentals of Satellite Systems
• Digital Satellite Communication
• Synchronous satellites
• Satellite frequency allocations
• Master satellite technology
• Vietnam roadmap to master satellite technology
• Satellite technology
• Space technology
• Vietnam National Satellite Center
• Satellite cities
• Solution for development
• Development of five satellite cities
• Five satellite cities in Hanoi
• Five satellite cities
• Satellite Orbit Mechanics
• Synchronous Orbit
• Orbital Parameters
• Communication Satellite Sub systems
• Power Supply subsystems
• Antenna Sub system
• Satellite Earth Station
• Earth station design
• Earth station sub system
• Communication Satellite Link Design
• Uplink design
• Complete link design
• General link design equations
• System noise temperature
• Configuration design and modeling
• Small satellite structure
• The satellite structural mass
• The process of satellite structural design
• Aluminum honeycomb sandwich panels
• Solar energy
• Satellite based solar radiation
• Himawari 8 satellite
• Himawari 8 satellite over Viet Nam region
• Solar radiation estimated
• Remote sensing of atmosphere and underlying surface
• Radiation of global navigation satellite systems
• Global navigation satellite systems
• Daily and seasonal variability
• Global navigation satellite system
• Underlying surface
• Geostationary satellite
• Antenna system
• Geostationary satellite monitoring antenna system
• Kinematics modeling analysis
• Geostationary satellite monitoring antenna
• Satellite Communication
• system considerations
• digital video
• satellite links
• multiple access methods
• frequency bands
• Satellite communications
• Mobile computing
• Wireless and mobile computing
• Services data
• Wireless communication
• Satellite foot print
• Science and technology development
• Nonlinear analysis of thermal behavior
• Small satellite in Low Earth Orbit
• Many node model
• Low Earth Orbit
• Nonlinear thermal responses
• The satellite include six rectangular cover plates
• Areal mean precipitation
• Remote sensed precipitation product
• Satellite gauge merging
• Rainfall runoff simulations
• Satellite based precipitation product
• Radiometric calibration for earh observation satellite optical instrument
• Earh observation satellite optical instrument
• Demonstrated for VNREDSat 1 data
• Minimize the radiometric non uniformity of individual pixel
• Minimize the radiometric non uniformity
• High Throughput Satellite
• Use of the internet
• Development of information technology
• Satellite infrastructure networks
• Management of development
• Satellite precipitation estimates
• Precipitation nowcasting
• Verification of rainall
• Application of GSMaP Satellite data
• Precipitation estimation and nowcasting
• Travelling wave tube
• Traveling wave tube amplifier
• Cavity magnetron
• Multiple Access Techniques
• Multiple Access System
• TDMA Frame Structure
• Satellite networks
• MANET satellite networks
• Multicast networks
• Strictly high probability
• Computational resources
• BMC Genetics
• Satellite DNA
• Satellite DNA sequences
• Transposable elements
• General analysis
• Chromosomal analysis