Frequency-Selective Surface With Tripole Segments For Multi-Band Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing frequency-selective surfaces are limited by their dependence on the angle of incidence and polarization of electromagnetic waves, and they can only filter a single frequency band, requiring multiple surfaces to cover different frequency bands.
Innovation Solution
A frequency-selective surface design featuring a set of identical elementary conductive patterns with specific geometric configurations, including tripole segments and additional fins, repeated on a dielectric support, which allows for independent filtering of multiple frequency bands regardless of wave orientation and polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional frequency-selective surface with a single elementary pattern is used, then the manufacturing cost is low and the structure is simple, but the surface can only filter a single frequency band and requires stacking multiple surfaces for different bands
Solution Approach 1:
The patent applies multi-functionality by designing a single elementary conductive pattern that can filter multiple frequency bands simultaneously. The pattern includes a tripole structure with three segments extending from a center point, where each segment has a specific length Ls. Additionally, each segment has two branches extending from an intermediate point at a distance ds from the center, with the branches forming an angle of approximately 120°. The combination of the tripole segments and branches creates multiple resonance frequencies, enabling the surface to filter GSM frequencies (0.9, 1.8, and 2.1 GHz) and Wi-Fi frequencies (2.4 and 5.4 GHz) with a single surface layer, eliminating the need to stack multiple single-band surfaces.
2Reliability
If the conductive pattern coverage rate is increased to improve filtering efficiency, then the filtering performance improves, but the manufacturing cost increases and the ease of manufacture decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the conductive pattern to achieve high filtering efficiency with low coverage. Key parameters include: the length Ls of the tripole segments, the distance ds from the center to the intermediate point where branches extend, and the angle of approximately 120° between branches. By carefully tuning these parameters, the surface achieves effective filtering of multiple frequency bands with a coverage rate of only 5% to 15%, significantly reducing the amount of conductive material needed compared to conventional designs while maintaining or improving filtering performance.
3Adaptability or versatility
If a frequency-selective surface is designed to filter multiple frequency bands, then the versatility improves, but the conductive pattern coverage rate increases
Solution Approach 1:
The patent applies segmentation by dividing the conductive pattern into distinct functional segments: a central tripole structure with three segments of length Ls extending from the center, and additional branches extending from intermediate points at distance ds. Each segment and branch is optimized to contribute to specific resonance frequencies. This segmented design allows the pattern to create multiple resonance frequencies (corresponding to different frequency bands) without requiring a high coverage rate, as each segment is precisely sized and positioned to maximize filtering efficiency with minimal material.
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 surface effectively filters multiple frequency bands, including GSM and Wi-Fi frequencies, with reduced conductive pattern coverage, maintaining performance across varying angles and polarizations, and is cost-effective due to the use of paper- or cardboard-type supports and conductive ink.
Implementation Method 1
The surface thus formed has a resonance frequency essentially depending on the parameters relative to length Ls of the tripole segments and to distance Dm between neighboring patterns. Such a surface has the property of filtering the electromagnetic waves belonging to a frequency band centered on its resonance frequency.
Data Source
AI summary
The invention relates to a surface suitable for filtering a plurality of frequency bands, said surface including a set of separate identical basic conductive units (31) that are reproduced in a periodic arrangement on a dielectric substrate (10). The basic unit includes: a tripole consisting of three identical segments (12) that extend radially from a center (14); and two arms (32) that extend symmetrically from an intermediate point of each segment, said intermediate point being located at a common distance (Db) from the center (14) for each of the segments (12). The general directions of both arms form an angle of approximately 120° and define an arrowhead pointed toward the outside, wherein the arms (32) corresponding to two separate segments (12) do not intersect.