Electromagnetic Band-Gap Structure for Low-Profile Antennas
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Solution Overview
Problem
Existing high impedance surfaces for electromagnetic radiation in the 100MHz to 1GHz frequency range are bulky and heavy, making them impractical for low-profile antenna applications.
Innovation Solution
A lightweight electromagnetic band-gap structure featuring a periodic planar arrangement of closely-packed electrically conducting surface elements supported by flat metal support elements, which are connected to a ground plane at an angle, allowing for easier and less expensive fabrication and operation as a high impedance surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the Sievenpiper structure is scaled up for 100MHz to 1GHz operation, then the operating frequency range is extended, but the structure becomes bulky and heavy
Solution Approach 1:
The support elements are arranged in a non-planar configuration with angular offsets from the ground plane, transitioning from a flat two-dimensional array to a three-dimensional structure. This dimensional change allows the surface elements to be supported at angles rather than requiring direct vertical vias, reducing the overall footprint and weight while maintaining the electromagnetic band-gap functionality at lower frequencies
Solution Approach 2:
The structure is divided into discrete unit cells, each comprising surface elements supported by individual support elements at specific angular orientations. This segmentation allows for optimized local configurations that reduce overall material usage and weight while maintaining the periodic structure necessary for electromagnetic band-gap operation across the 100MHz to 1GHz range
2Reliability
If traditional via connections are used, then electrical connection is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The connection method transitions from vertical vias to angular support elements, changing the geometric parameters of the electrical connection path. This parameter change allows for simpler manufacturing processes such as bending and welding of metal supports rather than requiring precise via drilling and plating, while maintaining reliable electrical connection between the surface elements and ground plane
Solution Approach 2:
The electrical connection system replaces the traditional via-mechanism with a mechanical support element system that provides both structural support and electrical connection. This substitution simplifies manufacturing by using more straightforward metal fabrication techniques while ensuring reliable electrical connectivity for high-impedance surface operation
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 structure provides a high impedance surface with reduced size and weight, enabling the construction of low-profile antennas that are robust and inexpensive, while maintaining performance across the desired frequency range.
Implementation Method 1
electromagnetic band-gap structure, comprising: an electrically conducting ground plane; and a periodic planar arrangement of closely-packed electrically conducting surface elements mounted parallel to and at a predetermined distance from the electrically conducting ground plane
Implementation Method 2
each of the closely-packed electrically conducting surface elements being support the periodic planar arrangement by at least one electrically conducting flat support element extending from an edge of the closely-packed electrically conducting surface element to the electrically conducting ground plane
Data Source
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AI summary
An electromagnetic band gap structure is provided comprising a ground plane and a periodic planar arrangement of surface elements mounted parallel to and at a predetermined distance from the ground plane. Each of the surface elements is supported in the planar arrangement by at least one conducting support element extending from an edge of the surface element to the ground plane, avoiding back-to-back parallel support elements. This arrangement allows for the surface elements and their respective support elements to be folded from flat metal templates to greatly simplify manufacture. An antenna is also provided in which an antenna element is mounted in such a way as to use the electromagnetic band-gap structure as a ground plane. This allows for a low-profile antenna to be made as the antenna element may be mounted close to the plane of surface elements in the structure.