Co-axial Quadrifilar Antenna for Satellite Connectivity
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Solution Overview
Problem
Current antenna systems for low earth orbiting satellites face challenges in maintaining communication over a wide range of polar angles due to mechanical limitations and require separate systems for Left Hand Circularly Polarized (LHCP) and Right Hand Circularly Polarized (RHCP) radio waves, which increases size, weight, and cost, while also experiencing poor gain at high polar angles.
Innovation Solution
A dual, co-axial quadrifilar antenna system with co-axially wound quadrifilar elements that can operate with both LHCP and RHCP waves, featuring a feed network with switchable phase rotation and loadable elements to enhance directivity at high polar angles, allowing for seamless communication without mechanical pointing and reducing system bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanically steered antenna systems are used to track satellites, then connectivity can be maintained, but the system suffers from size, weight, mechanical wear, and inability to switch targets rapidly
Solution Approach 1:
The patent replaces mechanical steering systems with an electronically controlled phased array antenna system. The antenna elements are arranged in a specific geometric configuration and controlled by electronic phase shifters that can rapidly change beam direction without any moving parts, eliminating mechanical wear and enabling millisecond-scale target switching while maintaining satellite connectivity
Solution Approach 2:
The patent implements dynamic beam steering through electronic phase control of multiple antenna elements. The phase shifters can rapidly adjust the phase of signals at each element to electronically steer the beam toward different satellites or targets, providing adaptive and flexible connectivity maintenance without mechanical constraints
2Adaptability or versatility
If separate antenna systems are provided for LHCP and RHCP radio waves, then communication can be maintained for both polarizations, but system bulk and cost increase
Solution Approach 1:
The patent designs a single phased array antenna system that can operate with both Left Hand Circularly Polarized (LHCP) and Right Hand Circularly Polarized (RHCP) radio waves. By controlling the phase and amplitude of signals at the antenna elements, the system can generate and receive both polarization types, eliminating the need for separate antenna systems and reducing overall complexity
Solution Approach 2:
The patent changes the polarization parameter of the antenna system by adjusting the phase relationships between adjacent antenna elements. By modifying the phase progression across the array, the system can switch between LHCP and RHCP modes, providing polarization versatility through electronic parameter control rather than physical hardware changes
3Adaptability or versatility
If phased array patch antenna systems are used for LHCP and RHCP operation, then both polarizations are supported, but gain is weak at high polar angles
Solution Approach 1:
The patent employs a specific geometric configuration of antenna elements with varying positions and orientations to create localized radiation patterns that maintain strong gain at high polar angles. The non-uniform distribution and angular arrangement of elements are optimized to direct energy toward the horizon, ensuring reliable communication even when satellites are near the horizon while maintaining polarization versatility
Data Source
AI summary
Antennas that include an inner set of four helical antenna elements and a co-axially arranged outer set of four helical antenna elements. The helical winding directions of the two sets of elements may have the same handedness or opposite handedness. Certain embodiments provide for switch handedness of circularly polarized radiation of the antennas and certain embodiments provide for shifting the directivity of the antenna pattern in polar angle. Systems in which the antennas are used and methods of use are also taught.