Steerable L-Band Patch Antenna for Low-Elevation Gain
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Solution Overview
Problem
Existing L-band antennas provide limited coverage and low gain at lower elevation angles, such as near the horizon, and are not scalable for varying data rates and class operations.
Innovation Solution
A modular, scalable, and electronically steerable antenna with a crossed metallic fence and difference beam steering, featuring a patch antenna with four elements in a two-by-two grid, a ground plane, and controllers for self-acquisition and self-tracking, along with a low-profile design for improved gain at low elevations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional L-band antenna designs are used, then broad coverage is provided for lower data rates and higher elevation angles, but effectiveness is reduced at lower elevation angles near the horizon
Solution Approach 1:
The patent implements electronically steerable beams that can be dynamically adjusted to different elevation angles. The antenna system uses phase shifters and amplitude controllers to dynamically steer beams toward low elevation angles (including near-horizon angles) while maintaining appropriate gain levels, allowing the antenna to adapt its radiation pattern in real-time based on satellite position and communication requirements
Solution Approach 2:
The patent employs a feed network with independent amplitude and phase control for each antenna element. By changing the amplitude and phase parameters of individual elements through the feed network, the system can synthesize multiple beams at different elevation angles and adjust the radiation pattern to maintain effectiveness across the full elevation range from near-horizon to high angles
2Reliability
If antenna elements are spaced at half wavelength or greater, then directional gain is improved, but mutual coupling between elements increases and spatial coverage is reduced
Solution Approach 1:
The patent uses sub-half-wavelength spacing (approximately 0.25λ to 0.4λ) combined with amplitude tapering in the feed network. By reducing element spacing and compensating with amplitude control parameters, the system maintains reduced mutual coupling while achieving desired gain through constructive interference patterns created by the phase and amplitude adjustments across the array
3Length of stationary object
If a low-profile antenna design is used, then installation space is reduced, but gain at low elevation angles is typically compromised
Solution Approach 1:
The patent uses electronically steerable beams with dynamic phase and amplitude control to compensate for the low-profile design limitations. By dynamically adjusting the phase progression across elements, the system can create constructive interference in low elevation directions, achieving high gain at low angles despite the shallow antenna profile
Solution Approach 2:
The feed network implements amplitude tapering and phase shifting parameters that are optimized for low elevation angle performance. By changing the amplitude distribution across elements (e.g., using Taylor or Chebyshev distributions) and adjusting phase progression, the system achieves high gain in low elevation directions while maintaining the low-profile physical structure
Data Source
AI summary
An electronically steerable antenna for L-band satellite communication, the antenna comprising: a patch antenna including: four antenna elements spaced apart in a patch plane to form a two-by-two grid with a spacing between each antenna element of less than a half wavelength, a ground plane, and one or more controllers configured to apply difference beam steering to the four antenna elements; and a crossed metallic fence electrically connected to the ground plane and extending through the patch plane between the four antenna elements to separate the four antenna elements into respective quadrants in the two-by-two grid.