Aperiodic Array Antenna Layout With Variable Element Dimensions
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Solution Overview
Problem
Aperiodic array antennas with uniform excitation suffer from low aperture filling factor and efficiency due to large inter-element spacing, leading to poor illumination efficiency and increased complexity and cost, especially when generating pencil beams with limited scanning range.
Innovation Solution
The design optimizes both element positions and dimensions, allowing for a deterministic and analytical method to maximize aperture filling factor and directivity, using identical Power Amplifiers to reduce costs and complexity, while maintaining high radiative performances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If aperiodic arrays with uniform excitation are used to reduce complexity and cost, then the number of elements and beamforming network complexity is reduced, but the aperture filling factor and illumination efficiency deteriorate due to large inter-element spacing
Solution Approach 1:
The patent applies local quality by varying the dimensions of radiating elements according to their position in the array. Elements closer to the center have different dimensions than those at the periphery, creating a density tapering effect that improves aperture filling without requiring complex amplitude control. This local variation in element properties resolves the contradiction between simplified uniform excitation and improved aperture utilization.
2Object-generated harmful factors
If density tapering is used to achieve low sidelobes, then amplitude tapering effects are obtained without complex feeding, but large inter-element spacing results in poor aperture filling
Solution Approach 1:
The patent changes the physical parameter of element dimensions rather than excitation amplitudes to achieve density tapering. By systematically varying element sizes across the array, the patent creates an effective amplitude distribution that suppresses sidelobes while maintaining good aperture filling, thus resolving the contradiction between sidelobe control and aperture utilization.
3Area of stationary object
If element dimensions are optimized to improve aperture filling, then directivity and aperture efficiency increase, but the design complexity increases requiring stochastic optimization methods
Solution Approach 1:
The patent replaces complex stochastic optimization methods with a deterministic analytical approach. By deriving closed-form expressions for optimal element dimensions based on array geometry and desired radiation patterns, the patent eliminates the need for iterative genetic algorithms or other stochastic methods, thus achieving high aperture efficiency without excessive design complexity.
4Use of energy by moving object
If uniform excitation is used to operate power amplifiers at maximum efficiency, then power amplifier efficiency is improved, but aperture filling deteriorates due to large inter-element spacing
Solution Approach 1:
The patent maintains uniform excitation for all power amplifiers to ensure they operate at maximum efficiency, while simultaneously varying element dimensions to achieve density tapering. This combination allows uniform PA operation (improving energy efficiency) while the dimensional variation compensates for spacing issues (improving aperture filling), thus resolving the contradiction between power efficiency and aperture utilization.
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 3A~3B
AI summary
A method of manufacturing an array antenna comprising: a design phase wherein an array layout of said array antenna is synthesized and radiating elements are designed to be arranged according to said array layout; and a phase of physically making said array antenna wherein the radiating elements are arranged according to said array layout. The design phase comprises the steps of: defining a continuous reference aperture; subdividing said continuous reference aperture into a plurality of elementary cells with assigned power levels; determining, within each said elementary cell, a position for at least one maximum efficiency radiating element; determining a size and an aperture field amplitude of each said maximum efficiency radiating element, such that a variation of a cumulative field distribution of the resulting array antenna aperture over each said elementary cell is substantially equal to a variation of a cumulative field distribution of said reference aperture over the same elementary cell, subject to size constraints.