Hybrid Mechanical-Lens Array Tilt for Far-Scan Gain Roll-Off
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Solution Overview
Problem
Hybrid mechanical-lens antenna phased arrays face gain degradation over elevation scan due to reduced antenna aperture area, and existing solutions like gimbaled antennas are high-profile and costly, while single-axis electrically-steered panels have limited azimuthal beamwidth and high pointing accuracy requirements.
Innovation Solution
The use of tilted elements and arrays, combined with mechanical rotation, reduces the scanning range and feed count of lens elements, maintaining low profile while enhancing gain performance at scan angles by increasing the projected array area and providing two-dimensional scanning capability within the beamwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a phased array panel is configured to electronically steer along one axis and rotated for azimuthal coverage, then the height is reduced compared to dual-gimbaled solutions, but scan losses increase at far elevation scan angles
Solution Approach 1:
The patent applies dimensional change by tilting the planar array panel at an angle (e.g., 45 degrees) relative to the horizon, transforming the originally two-dimensional electronic steering problem into a three-dimensional geometric configuration. This tilt angle optimization balances the projected aperture area across different scan angles, reducing gain degradation at far elevation angles while maintaining reduced height compared to dual-gimbaled solutions.
Solution Approach 2:
The patent changes the geometric parameter of the array orientation by introducing a specific tilt angle parameter. By optimizing this angle parameter, the system achieves improved scan performance without requiring full two-dimensional mechanical steering, thus reducing height while mitigating scan losses through parameter optimization rather than structural complexity.
2Loss of energy
If the array is tilted towards the horizon to increase scanned gain performance, then the projected area facing the scan direction increases, but the effective elevation-plane scan angle for pointing targets near the horizon decreases
Solution Approach 1:
The patent applies partial action by implementing a moderate tilt angle (e.g., 45 degrees) rather than maximizing the tilt to 90 degrees. This partial tilting provides sufficient projected area increase to improve scanned gain performance while preserving adequate elevation-plane scan angle for horizon targets, avoiding the excessive action that would completely eliminate horizon coverage.
Solution Approach 2:
The patent optimizes the tilt angle parameter to achieve a balance between scanned gain improvement and elevation scan angle preservation. By carefully selecting this geometric parameter, the system gains sufficient projected area for improved scan performance while maintaining the adaptability to point at targets near the horizon.
3Quantity of substance
If lens elements are tilted and arrays are tilted with mechanical rotation, then the feed count and cost are reduced, but the device complexity increases due to mechanical rotation requirements
Solution Approach 1:
The patent partially applies mechanics substitution by replacing full two-dimensional mechanical steering with a hybrid approach: a single-axis mechanical rotation platform combined with electronic beamforming and fixed geometric tilts of lens elements and arrays. This substitution reduces the number of mechanical feeds required while minimizing mechanical complexity compared to dual-gimbaled systems.
Solution Approach 2:
The patent segments the steering function into two independent parts: a mechanical rotation platform handling azimuthal coverage and an electronic beamforming system handling elevation scanning. This segmentation allows each subsystem to be optimized independently, reducing overall complexity while achieving the desired feed count reduction through the mechanical rotation component.
Data Source
AI summary
A hybrid mechanical-lens array antenna is described that can be configured with different orientations and arrangements of the plurality of lenses within the array to control and enhance the performance at different regions of scan. This can include the addition of a secondary array (a skirt) at a large tilt angle, tilting the primary array, tilting the individual lenses within the primary array, or any combination. These design choices, when holding the number of lens modules (and, therefore, cost and power consumption) constant, have the effect of changing the system height, reducing the boresight gain and increasing the gain at scan, with each option showing different trades of height and scan and boresight performance.