Hemispherical Array Antenna Horizon Interference Nulling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-beam hemispherical arrays used in fleet command and control communications are susceptible to interference from horizontal signals, leading to signal degradation and erroneous location determination of mobile objects due to the lack of interference mitigation from the horizon.
Innovation Solution
A multibeam hemispherical array is designed with three annular rows of antenna elements, each spaced half a wavelength apart, featuring varying elevation angles and parasitic directors to insert nulls at horizontal and near-horizontal angles, suppressing interfering signals without degrading authentic signals from other angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the array uses elements at the bottom row with smallest elevation angle to transmit and receive signals, then signal coverage at azimuth is improved, but interference from horizon is not mitigated
Solution Approach 1:
The patent applies local quality by configuring different rows of antenna elements with different elevation angles specifically tailored to their functional requirements. The bottom row elements are oriented at smallest elevation angles for azimuth coverage, while upper rows use progressively larger elevation angles to achieve nulls at horizontal angles, allowing each local region of the array to perform its specialized function
Solution Approach 2:
The patent segments the hemispherical array into three distinct rows of antenna elements, each row serving a specific functional purpose. This segmentation allows the array to simultaneously achieve azimuth coverage from the bottom row while using upper rows to suppress horizon interference, resolving the contradiction between coverage and interference mitigation
2Reliability
If the array receives signals reflected off ground-based objects, then signal reception capability is maintained, but location determination becomes erroneous due to multipath
Solution Approach 1:
The patent applies preliminary anti-action by proactively suppressing signals from horizontal and near-horizontal angles before they can cause multipath interference. The upper rows of antenna elements are configured with larger elevation angles to create nulls at these angles, preventing reflected signals from ground-based objects from being received in the first place, thus maintaining both reception reliability and location determination precision
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
The array effectively suppresses interfering signals from the horizon while maintaining the integrity of authentic signals, improving the accuracy of signal transmission and reception in fleet command and control communications.
Implementation Method 1
The single driven circular patch of each antenna element of the second row is spaced apart from each adjacent single driven circular patch of each adjacent antenna element of the second row by a distance of about one half a wavelength of a wave radiated from the single driven circular patch
Implementation Method 2
The multibeam hemispherical array inserts nulls at horizontal and near horizontal angles to suppress interfering signals
Data Source
AI summary
A multibeam hemispherical X-band array inserts nulls at horizontal and near horizontal angles to suppress interfering signals, without degrading authentic signals arriving at other angles. The multibeam hemispherical array includes three annular (360) rows of antenna elements, each row having 64 elements. Elements of the first row, which have the smallest elevation angle, have pairs of circular patches coupled with a phase delay line. Each pair of circular patches is spaced apart from and aligned with two pairs of similarly shaped (circular) and sized parasitic directors. The spacing between driven patches of adjacent elements in a row is about equal to one half of the wavelength of the radiated wave. The array fits within a conventional 24-inch diameter marine radome.