Multibeam Antenna Compact Sources Beamformer
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Solution Overview
Problem
Existing multibeam antennas in satellite telecommunications face challenges in producing a large number of contiguous fine beams with small angular apertures due to physical constraints and increased complexity, leading to inefficiencies in radiation and increased losses when trying to achieve high directivity and reduce spillover losses.
Innovation Solution
A multibeam antenna configuration with compact sources, where sources are grouped and connected in specific patterns to form beams without the need for orthogonal Beam Forming Networks (BFNs), allowing for independent distribution circuits for each beam and reducing the complexity and size of the beamformer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of elementary radiating elements is increased to produce a large number of contiguous fine beams, then the number of beams increases, but the volume allocated for each RF radiofrequency chain decreases, making it impossible to achieve sufficient directivity and avoid spillover losses
Solution Approach 1:
The patent combines multiple functions (transmission and reception for multiple frequencies and polarizations) into a single integrated RF chain per beam. The RF chain includes a circulator that routes signals between the radiating element, transmission port, and reception port, allowing one physical chain to handle multiple operational modes that would traditionally require separate chains for each function.
Solution Approach 2:
Each RF radiofrequency chain is designed to be multi-functional, handling both transmission and reception, and supporting multiple frequencies and polarizations through the circulator architecture. This universal design allows a single chain to perform what would traditionally require multiple dedicated chains, reducing the overall volume required.
2Productivity
If the space between two sources is reduced to accommodate more beams in limited space, then the number of beams increases, but the horns cannot be sufficiently directive to illuminate the edge of the reflectors with sufficiently low levels, increasing losses by overflow
Solution Approach 1:
The patent changes the operational parameters of the radiating elements by implementing amplitude tapering across the array. Elements at the edges of the antenna aperture are assigned lower amplitudes compared to central elements, which controls the radiation pattern to reduce sidelobes and spillover losses. This parameter adjustment allows tighter spacing while maintaining energy efficiency.
3Loss of energy
If three or four different antennas are used to solve the space constraint problem, then spillover losses are reduced, but the complexity of the system increases and the geometric constraints still prevent sufficient space for each horn
Solution Approach 1:
The patent merges the functions of multiple antennas into a single antenna system. By using amplitude tapering and a shared RF chain architecture with circulators, the system achieves the performance benefits of multiple dedicated antennas (reduced spillover, proper illumination) while maintaining a single integrated structure, thereby reducing system complexity.
4Productivity
If the angular aperture of spots is reduced to increase the number of beams, then the number of beams increases, but the subtended angle of the reflector becomes too small for sources to produce sufficient directivity
Solution Approach 1:
The patent adjusts the amplitude parameters of individual radiating elements to compensate for the reduced subtended angle. By applying amplitude tapering where edge elements have reduced amplitudes, the radiation pattern is shaped to maintain sufficient directivity even when the reflector subtends a small angle, allowing fine spots with small angular apertures to be formed effectively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the production of a large number of contiguous fine beams with improved radiation efficiency and reduced losses, allowing for efficient coverage of ground spots with smaller angular apertures without the drawbacks of existing systems.
Implementation Method 1
The considered multibeam antennas are composed of at least one reflector, for example an asymmetrical paraboloid with feed offset with respect to the radiated beams called offset paraboloid
Implementation Method 2
Geometric laws make it possible to project the desired terrestrial coverages in the focal plane of the antenna and to correctly position the phase center of each primary source corresponding to each spot
Implementation Method 3
each source consists of a radiating element, for example of the horn type or of any other known type, and of an RF radiofrequency chain supplying the radiating element
Implementation Method 4
each source comprises a polarizer connected to a radiating element and two diplexers respectively integrated in two output channels of the polarizer
Data Source
Figure 1~2a
Figure 2b~4a
Figure 4b
AI summary
The multibeam antenna comprises an array of sources illuminating a reflector (26), the sources (10, 10a, 10b, 10c, 10d, 10'a, 10'c) being associated in several groups (G1 to GN). Each source (10, 10a, 10b, 10c, 10d, 10'a, 10'c) includes a polarizer (12), two diplexers (15, 18) and four ports operating in four different colors. All sources belonging to the same group (G1 to GN) have first ports (16) having the same first color (P1, F1), or second ports (17) having the same second color (P1, F2), linked together to form a first beam and third ports (19) having the same third color (P2, F1), or fourth ports (20) having the same fourth color (P2, F2), linked together to form a second beam.