Array Antenna Design with Iterative Optimization
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Solution Overview
Problem
Existing array antenna designs often result in high radar cross sections due to mirror reflection, edge scattering, and grating lobes, particularly when integrated into composite material hulls, where frequency selective surfaces are inefficient and difficult to manufacture, especially when curved.
Innovation Solution
An iterative optimizing method is employed to design array antennas that simultaneously meet antenna and signature performance requirements, using genetic algorithms and frequency selective surfaces to match the antenna's reflection factor with the surrounding material, reducing the need for space-demanding absorbents and addressing grating lobes by integrating structures with higher periodicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency selective surfaces are used to reduce signature, then radar cross section is reduced, but manufacturing difficulty increases especially when curved
Solution Approach 1:
The frequency selective surface is divided into unit cells that are periodically repeated across the surface. Each unit cell can be independently designed and manufactured, then assembled into the complete surface structure. This segmentation makes manufacturing more manageable, especially for curved surfaces where the surface can be segmented into manageable patches.
Solution Approach 2:
The electromagnetic properties of the frequency selective surface are controlled by varying geometric parameters of the unit cells (such as shape, size, orientation, and arrangement). By changing these parameters, the surface can be tuned to achieve desired radar cross section reduction at specific frequencies and polarizations without changing the fundamental structure or material composition.
2Reliability
If array antenna is designed to meet antenna performance requirements, then antenna performance is improved, but radar cross section increases
Solution Approach 1:
The antenna design and signature reduction design are merged into a single integrated optimization process. Instead of designing the antenna elements and their positions separately from the signature reduction requirements, both objectives are combined into one unified design framework that simultaneously optimizes for both antenna performance and low radar cross section.
Solution Approach 2:
Multiple design parameters of the array antenna (element positions, orientations, types, and spacing) are varied and optimized to achieve the desired balance between antenna performance and signature reduction. The optimization process explores different parameter combinations to find designs that satisfy both sets of requirements.
3Object-affected harmful factors
If absorbents are added to reduce signature, then radar cross section is reduced, but device complexity and space requirements increase
Solution Approach 1:
The signature reduction function is extracted from the traditional approach of adding separate absorbent materials and integrated directly into the frequency selective surface structure. The frequency selective surface itself performs the signature reduction function through its geometric design, eliminating the need for additional absorbent layers and reducing overall device complexity.
Solution Approach 2:
The frequency selective surface serves multiple functions simultaneously: it acts as the radiating or receiving element of the antenna, provides impedance matching, and reduces radar cross section. This multi-functionality eliminates the need for separate components for each function, thereby reducing device complexity and space requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves simultaneous optimization of antenna and signature performance, allowing for the use of arbitrary hull materials and minimizing radar cross sections, while reducing the need for additional absorbents and effectively managing grating lobes at high frequencies.
Implementation Method 1
The most important subcontributions are mirror reflection, edge scattering, scattering, reflections in the feed network
Implementation Method 2
The most important subcontributions are mirror reflection, edge scattering, scattering, reflections in the feed network
Implementation Method 3
One way of obtaining signature reduction in this connection is to introduce frequency selective surfaces and space demanding absorbents located around the edges of the array antenna
Data Source
AI summary
A method for designing low signature array antennas using a calculation method. The method proposes a way of improving antenna and signature performance of array antennas. According to the method electromagnetic antenna and signature characteristics are specified, an iterative optimizing method is performed to design the antenna to fulfil the specified characteristics, the iterative method is interrupted when a design fulfils the specified characteristics, and the specified characteristics are readjusted in an iterative optimizing method to follow if the specified characteristics not are fulfilled.