Surface-Conformal Antenna Array Layout for Omnidirectional Gain
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Solution Overview
Problem
Existing antenna array designs face challenges in achieving robustness to ambiguities, maintaining gain across a wide frequency range, and optimizing performance when integrated with a metallic platform, particularly in non-planar configurations, leading to reduced gain and elevation accuracy.
Innovation Solution
A method for designing an antenna array that includes optimizing the geometric parameters of petal-type antennas arranged on a metallic surface, considering total gain and omnidirectionality, by iteratively determining optimal orientations and positions to enhance ambiguity robustness and polarization diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a metallic surface is placed between the antenna array and the platform to minimize coupling, then the array size and weight are reduced, but the gain is significantly attenuated in certain directions and periodically across the direction of arrival
Solution Approach 1:
The patent transitions from a planar ground plane to a three-dimensional metallic surface (cylindrical or spherical). This dimensional change allows the antenna array to achieve omnidirectional coverage in both azimuth and elevation while maintaining isolation from the platform. The curved surface geometry enables uniform gain distribution across all directions of arrival, resolving the contradiction between compact size and stable gain performance.
Solution Approach 2:
The patent employs curved metallic surfaces (cylindrical or spherical) instead of flat ground planes. The curvature of the metallic surface is specifically designed to provide uniform reflection characteristics in all directions, eliminating the periodic gain attenuation that occurs with planar surfaces. This curved geometry maintains the isolating function while ensuring consistent gain across the entire 360-degree horizon and elevation ranges.
2Measurement precision
If 2D direction finding in azimuth and elevation is performed instead of 1D azimuth finding, then elevation accuracy is improved, but robustness to ambiguities is reduced
Solution Approach 1:
The patent divides the antenna array into multiple segments or elements distributed across the curved metallic surface in specific geometric configurations. This segmentation creates multiple independent signal paths with distinct phase relationships, allowing the system to resolve ambiguities in both azimuth and elevation simultaneously. The segmented structure provides redundant measurement channels that enhance robustness while maintaining 2D direction-finding capability.
3Reliability
If the number of antennas in the network is increased to improve robustness to ambiguities, then the ability to distinguish directions is improved, but the network size must increase which degrades performance for a given number of antennas
Solution Approach 1:
The patent utilizes three-dimensional spatial distribution of antenna elements on a curved surface, transitioning from two-dimensional planar arrays to three-dimensional configurations. This dimensional change increases the effective number of independent signal paths and spatial diversity without proportionally increasing the physical footprint. The 3D geometry provides better angular resolution and ambiguity resolution with fewer elements compared to planar arrangements.
Solution Approach 2:
The curved metallic surface serves multiple functions simultaneously: it acts as a reflector to enhance signal reception, provides mechanical support for the antenna elements, establishes the three-dimensional geometric configuration for omnidirectional coverage, and isolates the array from the platform. This multi-functionality reduces the need for additional components that would otherwise be required to achieve the same performance.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3a~3b
AI summary
The invention relates to a method for designing an array of N antennas arranged on a metallic surface, substantially omnidirectional in the direction of arrival and in polarization within a frequency band having a minimum frequency fmin and a maximum frequency fmax, with N greater than 1, comprising the following steps: - a step (601) of determining K antenna configurations having different geometric characteristics, satisfying a constraint of differential gain over the frequency band [fmin, fmax] and a constraint of gain variation in the main lobe of the antenna, - a step (602) of calculating, for each antenna configuration, at least one antenna array configuration, the orientations of which are chosen so as to promote omnidirectionality in polarization, and the arrangements are chosen so as to promote omnidirectionality in the direction of arrival,- a step (603) of selecting the best antenna configuration/antenna array configuration pair(s).