Satellite Phased Array Antenna Row Summation Complexity
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Solution Overview
Problem
Current phased array antennas for Non-GEO satellites, particularly Low Earth Orbit (LEO) satellites, are complex, inefficient, and costly due to the high number of active elements and RF chains required for high Equivalent Isotropically Radiated Power (EIRP) and Gain to Noise Temperature (G/T), with analog phase shifters causing undesirable coupling between phase and amplitude.
Innovation Solution
A phased array antenna system with a reduced number of active elements and complexity, where the RF chain is designed for summation of all radiators in a single row, allowing electronic steering in one axis and mechanical steering in the other, using digital phase shifting and polarization control to achieve high performance with low transmission loss, and supporting multi-beam generation in elevation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full phased array is used to steer beams at any angle, then beam steering capability is improved, but device complexity increases enormously (above 500 feeds and RF chains)
Solution Approach 1:
The antenna array is divided into multiple rows, with each row having a single feed element. This segmentation reduces the number of RF chains from N² (full phased array) to N (one per row), dramatically simplifying the system while maintaining beam steering capability through electronic phase control within each row
Solution Approach 2:
The patent transitions from a two-dimensional phased array requiring N² elements to a one-dimensional array of rows with N elements. Beam steering in the original array direction is achieved through phase control, while the row dimension provides additional steering capability, effectively using dimensional reduction to simplify complexity
2Ease of operation
If analog phase shifters are used in phased arrays, then phase control is achieved, but amplitude-phase coupling occurs causing performance degradation
Solution Approach 1:
The patent replaces analog phase shifters with digital signal processing. By using digital techniques to control the phase and amplitude of signals from each row, the system eliminates the inherent amplitude-phase coupling of analog phase shifters, achieving independent and precise control of both parameters without the reliability issues of analog components
3Device complexity
If the number of active elements is reduced, then hardware complexity is lowered, but transmission loss increases
Solution Approach 1:
The patent combines multiple radiating elements within each row to share a single feed and RF chain. This merging approach reduces the total number of active elements and RF components while maintaining effective radiated power through constructive interference of the combined signals, thereby reducing transmission loss despite fewer individual elements
Data Source
AI summary
A phased array antenna system that reduces the high number of active elements and complexity. In order to achieve this reduction, the RF chain is designed for summation of all radiators in a single row. This reduces the hardware complexity from N2 to N where the array size is N×N. This reduction allows the antenna to electronically steer in one axis. The other axis is mechanically steered using a rotating platform. The loss between the LNA or PA with the row summation scheme is very low resulting in very high performance. Receiving and transmitting take place from the same aperture.