Notch Radiating Element for Wideband Array Antennas
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Solution Overview
Problem
Existing notch radiating elements in antenna arrays face challenges with power reflection and mutual coupling, limiting bandwidth and frequency range due to physical constraints and grating lobe issues, particularly in electronically scanned array antennas.
Innovation Solution
The design introduces a notch element profile with reduced height, featuring a laminated substrate with a stripline sandwiched between printed circuit boards, where the elements are formed by removing conductive material to create a front and rearward rectangular region, allowing for closer spacing and increased upper frequency limits while maintaining lower frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the element length is reduced to less than half wavelength, then the upper frequency limit is extended and bandwidth is improved, but the lower frequency range may be compromised
Solution Approach 1:
The patent transitions from traditional planar slot elements to three-dimensional notch elements that protrude from the substrate surface. This dimensional change allows the elements to achieve resonant lengths corresponding to half-wavelength at center frequency while maintaining a compact footprint, thereby extending the upper frequency limit and overall bandwidth without sacrificing lower frequency operation capability
Solution Approach 2:
The patent systematically varies the notch element dimensions (width, depth, spacing) to optimize performance across the frequency band. By adjusting these geometric parameters, the elements achieve resonant frequencies that extend the operational bandwidth while maintaining adequate lower frequency response through careful dimensional optimization
2Productivity
If the spacing between adjacent elements is reduced to increase upper frequency limit, then the upper frequency is extended, but grating lobes may occur at lower frequencies
Solution Approach 1:
By transitioning to 3D notch elements with controlled spacing, the patent achieves closer element placement without creating grating lobes. The vertical dimension of the notch elements allows for reduced horizontal spacing while maintaining effective radiation patterns across the frequency band, extending the upper frequency limit without the harmful grating lobe effects that would normally occur at such close spacings
Solution Approach 2:
The patent optimizes the local geometry of each notch element and its immediate vicinity to control electromagnetic coupling and radiation patterns. By carefully designing the notch dimensions and spacing, the elements achieve enhanced upper frequency performance while local field distribution prevents grating lobe formation that would otherwise occur with closely spaced traditional elements
3Loss of energy
If power reflection is minimized through element design, then radiation efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the notch element geometric parameters (width, depth, spacing) to achieve impedance matching and minimize reflected power across the operating band. These parameter optimizations are implemented through standard PCB fabrication processes, maintaining ease of manufacture while significantly reducing power reflection through careful dimensional tuning
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 configuration achieves bandwidths comparable to longer Vivaldi elements, extending the upper frequency limit and maintaining the lower frequency range, with improved cross-polar performance and dual polarized wide band operation.
Implementation Method 1
almost all of the power that is fed into the element via the stripline is actually radiated into free space via the tapered slot
Implementation Method 2
Each element is formed by removing the coating from a substrate coated with an electrically conductive material... The elements formed are less than 1/2 the height of the comparable Vivaldi radiating element
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
This invention relates to a radiating element 20 for use in array antennas. The radiating element 20 is of simplified design and comprises a front region 26 and a rearward region 28 that are preferably substantially rectangular, which permit higher frequency limits than more conventional Vivaldi elements while maintaining the lower frequency limit. Additionally, by deployment of an array of a plurality of such elements 20 such that no gaps are formed between adjacent elements 20 along the array antenna, very wide bandwidth can be obtained using the array.