Broadband Wire Antenna Resistive Grid for Surface Wave Suppression
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Solution Overview
Problem
Existing wire antennas are bulky, inefficient, and suffer from degradation in radiation performance due to surface waves and structural edge effects, particularly in wide frequency bands and goniometric networks.
Innovation Solution
A wire antenna design incorporating a resistive grid with empty patterns to trap and attenuate surface waves, enhancing gain and maintaining consistent radiation performance across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an absorbing cavity is used to eliminate backward waves, then the antenna can operate in a wide frequency band, but the antenna becomes bulky and efficiency decreases due to power absorption
Solution Approach 1:
The invention extracts and removes the absorbing cavity from the antenna structure, replacing it with a thin resistive sheet that performs the same function of absorbing backward waves without requiring a large volume. This resolves the contradiction by eliminating the bulky cavity while maintaining wide frequency band operation.
Solution Approach 2:
The invention changes the parameter of the absorbing structure from a three-dimensional cavity with significant volume to a two-dimensional thin resistive sheet with negligible thickness. This parameter change maintains the electromagnetic wave absorption function while dramatically reducing the antenna volume.
2Volume of moving object
If a resistive sheet is used to absorb backward waves, then the antenna becomes thin and compact, but surface waves are generated that degrade radiation pattern quality
Solution Approach 1:
The invention uses a composite structure combining a dielectric substrate with a resistive sheet deposited on it. This composite material approach allows the resistive sheet to absorb backward waves while the dielectric substrate controls and suppresses surface wave generation, thereby maintaining thin antenna volume while eliminating harmful surface waves.
Solution Approach 2:
The dielectric substrate acts as an intermediary between the resistive sheet and the surrounding environment. It mediates the interaction between the resistive sheet and electromagnetic waves, preventing surface wave propagation while allowing the resistive sheet to perform its wave absorption function.
3Reliability
If high-impedance surfaces are used to improve radiation performance, then the antenna operates in narrow bands, but it cannot cover multi-octave frequency bands
Solution Approach 1:
The invention converts the typically harmful backward waves into a beneficial function by using the resistive sheet to absorb them. This absorbed energy would otherwise create interference, but instead is dissipated as heat. This allows the antenna to maintain stable radiation performance while operating across wide frequency bands, transforming a potential problem into a solution.
4Device complexity
If the radiating element is etched onto a flat surface, then the antenna structure is simple, but radiation pattern consistency deteriorates due to edge effects and surface waves
Solution Approach 1:
The invention applies local quality by placing the resistive sheet specifically in the region where backward waves are generated, without modifying the entire antenna structure. The resistive sheet is positioned at the back of the radiating element, providing localized control over wave propagation while maintaining the simplicity of the overall flat surface structure.
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 antenna achieves improved gain and stable radiation patterns over a broad frequency range, minimizing surface wave interference and maintaining accuracy in angle determination and reducing mutual coupling.
Implementation Method 1
one or more layers with sets of periodic resistive patterns... The resistive patterns are placed in the near field of the antenna's radiating element... trap and attenuate surface waves
Data Source
Figure 1~4
Figure 3~5
Figure 6~8
AI summary
The invention relates to a wire antenna (2) suitable for operating in at least one frequency band, including a plurality of stacked layers, including at least one radiating element (4) placed on a support layer (6), said support layer (6) being placed on a spacing substrate (8) placed on a reflective plane (10), characterised in that it includes at least one resistive grille (12) having a resistive surface (14) with predetermined resistance, including at least one set of repetitive, non-contiguous empty patterns (18), said grille (12) being placed between the spacing substrate (8) and the reflective plane (10).