HAP Multibeam Antenna Aperture Design for Uniform Coverage
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Solution Overview
Problem
High altitude platforms (HAPs) face challenges in providing uniform communication coverage due to varying cell sizes caused by the curvature of the Earth, leading to differences in surface spectral density and quality of service (QoS) as user terminals move between cells or as the HAP moves relative to fixed points on Earth.
Innovation Solution
The use of antennas with differently sized apertures to create substantially equal-sized cells and maintain constant surface spectral density across a coverage area, compensating for distance and subtended angle variations, thereby ensuring consistent QoS by adjusting beam widths and antenna gains accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If identical antennas are used for all cells, then design variation is reduced, but cell size differences cause varying surface spectral density and QoS
Solution Approach 1:
The patent applies local quality by configuring antennas with differently sized apertures based on their specific location within the coverage area. Antennas at the periphery have larger apertures than those at the center, creating locally optimized beam patterns that compensate for the greater distance and curvature effects at edge cells, thereby maintaining uniform surface spectral density and QoS across all cells.
Solution Approach 2:
The patent changes the aperture size parameter of antennas based on their position in the coverage area. By adjusting this physical parameter, the beam width and gain are optimized for each location, compensating for the varying distances and Earth curvature effects, thus maintaining consistent service quality across different cells.
2Device complexity
If the same spectrum is used in each cell, then frequency allocation is simplified, but surface spectral density varies between cells
Solution Approach 1:
The patent applies local quality by allocating spectrum resources according to the specific characteristics of each cell. Cells at the periphery receive more spectrum resources due to their larger area and higher path loss, while central cells receive fewer resources. This localized resource allocation ensures uniform surface spectral density across all cells while maintaining simplified frequency planning through systematic allocation rules.
3Area of stationary object
If HAP operates at lower altitude, then coverage area increases, but cell size differences become more pronounced
Solution Approach 1:
The patent applies local quality by designing antennas with position-dependent aperture sizes to compensate for the pronounced cell size differences that occur at lower altitudes. The larger apertures at peripheral locations create wider beams that cover the expanded coverage area while maintaining consistent cell sizes and uniform service quality across all regions.
Solution Approach 2:
The patent changes the antenna aperture parameter based on operational altitude and position. At lower altitudes where coverage area is expanded, the system adjusts antenna parameters to maintain cell size uniformity, using larger apertures at the periphery to compensate for the increased Earth curvature effects and distance variations.
Data Source
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AI summary
Multibeam coverage for a high altitude platform is disclosed. An example apparatus includes a plurality of antennas configured to provide communication coverage among a plurality of terminals within a specified area on the ground, each antenna being configured to communicate with a specified cell within the specified area. The antennas of the example apparatus have differently sized apertures to maintain a similar surface spectral density among the cells within the specified area.