Oversized Antenna Reflector for Wide-Angle Multibeam Generation
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Solution Overview
Problem
Conventional spot beam antenna systems face inefficiencies in generating high performance contiguous spot beams over a wide angular region, with issues such as feed spillover and complex beam forming networks, and are limited by the size of their reflectors which restrict the use of larger feeds and result in suboptimal performance.
Innovation Solution
The use of an oversized antenna reflector with a diameter greater than ((100*λ)/δ) and optimized surface shape, along with a sub-reflector in configurations like Side-Fed Offset Cassegrain or Cassegrain, to generate high performance multiple spot beams without the need for complex beam forming networks, allowing for larger feeds and reduced spillover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sized antenna reflectors are used, then the antenna system is compact and easier to manufacture, but feed spillover increases and performance deteriorates
Solution Approach 1:
The antenna system is divided into multiple independent spot beam reflectors, each serving a specific angular region. This segmentation allows each reflector to be optimized for its specific function while collectively covering the desired wide angular region, reducing feed spillover loss for each individual beam.
Solution Approach 2:
The patent transitions from using a single large reflector to multiple smaller reflectors arranged in different spatial positions and orientations. This dimensional arrangement allows each reflector to capture RF energy more effectively for its specific beam direction, reducing overall feed spillover loss while maintaining system compactness.
2Reliability
If conventional sized antenna reflectors are used, then the physical size is manageable, but the reflector size restricts the use of larger feeds resulting in suboptimal performance
Solution Approach 1:
The system uses multiple smaller reflectors instead of one large reflector. Each smaller reflector can accommodate appropriately sized feeds for its specific beam, achieving optimal feed-reflector matching without requiring an excessively large overall reflector diameter.
Solution Approach 2:
Instead of using a single reflector that is exactly the minimum size needed, the patent employs multiple reflectors that collectively provide adequate coverage. This allows each individual reflector to be sized appropriately for its specific function, optimizing feed size and performance without excessive overall system size.
3Reliability
If conventional single reflector systems are used, then the design is simpler, but complex beam forming networks are required resulting in increased system complexity
Solution Approach 1:
The patent extracts and eliminates the complex beam forming network from the system by using multiple independent reflectors, each generating its own spot beam through simple RF energy reflection. This removes the need for complex electronic beam forming while maintaining high beam performance.
Solution Approach 2:
Each reflector in the array independently generates and directs its own spot beam by reflecting RF energy. This self-service approach eliminates the need for a centralized complex beam forming network, as each reflector autonomously performs beam formation for its specific direction.
4Reliability
If conventional reflector systems are used, then the structure is simpler, but scan loss increases resulting in poor edge of coverage performance
Solution Approach 1:
Each reflector in the array is positioned and oriented to provide optimal performance for its specific angular region. This local optimization ensures that each spot beam maintains high quality and low scan loss in its designated coverage area, improving overall edge of coverage performance.
Solution Approach 2:
By dividing the coverage region into multiple angular sectors, each served by a dedicated reflector, the system minimizes scan loss within each sector. The segmentation allows each reflector to be optimized for its specific angular range, preventing the high scan losses that occur in conventional single-reflector wide-angle systems.
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 approach enhances antenna directivity and reduces scan loss, achieving improved edge of coverage performance and enabling efficient operation for both transmit and receive modes with lower spillover loss and simpler designs compared to prior art systems.
Implementation Method 1
an antenna reflector having a reflector diameter greater than (100*lambda)/delta, where lambda is a wavelength in inches and delta is a beam to beam spacing in degrees. The antenna reflector surface is shaped from a nominal parabolic shape to broaden and shape reflected spot beams
Data Source
AI summary
A method and system are disclosed for wide angle multibeam antennas. The method and system involve a multibeam antenna system for generating high performance multiple spot beams. In one or more embodiments, the multibeam antenna system includes an oversized antenna reflector and a plurality of antenna feeds. The oversized antenna reflector has its surface shape optimized from a normal parabolic shape in order to broaden and shape the reflected spot beams to improve antenna performance. In addition, the diameter of the oversized antenna reflector is greater than ((100*λ)/δ), where λ is the wavelength in inches and δ is the beam to beam spacing in degrees. In some embodiments, the ratio of the focal length of the oversized antenna reflector to the diameter of the oversized antenna reflector (F/D) is greater than 0.7. In at least one embodiment, the system further includes an antenna sub-reflector.