Multi-Band Antenna Structure With FSS Parasitic Coupling Control
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Solution Overview
Problem
In multi-band array antennas, the close placement of antenna elements with different frequency bands leads to deterioration in radiation pattern indicators such as gain, beamwidth, and polarization suppression ratio, resulting in fluctuations and drops in performance.
Innovation Solution
A multi-band antenna structure is designed with a parasitic structure that includes frequency selective surface (FSS) planes, which have a stopband characteristic for one antenna element and a passband characteristic for another, optimizing the radiation pattern of the first antenna element while minimizing impact on the second element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If antenna elements with different frequency bands are placed close to each other to reduce external dimension, then miniaturization and lightweight advantages are achieved, but radiation pattern indicators such as gain, beamwidth, and polarization suppression ratio deteriorate
Solution Approach 1:
A parasitic structure is introduced as an intermediary element between the first and second antenna elements. This parasitic structure includes frequency selective surface (FSS) planes that create electromagnetic coupling to adjust the radiation patterns of adjacent antenna elements, thereby improving gain and polarization suppression ratio while maintaining the compact shared aperture configuration
Solution Approach 2:
The patent adjusts key parameters including the distance between antenna elements (less than 0.5 times the vacuum wavelength), the distance between antenna elements and parasitic structure (less than 0.5 times the vacuum wavelength), and the geometric parameters of FSS cells to optimize radiation pattern performance while maintaining compact dimensions
2Ease of operation
If antenna elements are placed close together to achieve shared aperture, then deployment ease is improved, but polarization suppression ratio deteriorates due to serious coupling
Solution Approach 1:
The parasitic structure with FSS planes serves as a mediator that controls electromagnetic coupling between closely spaced antenna elements. By adjusting the coupling strength through parasitic structure parameters, the patent maintains compact deployment while improving polarization suppression ratio
Solution Approach 2:
The FSS cells in the parasitic structure are designed with specific geometric parameters that dynamically control electromagnetic field distribution. The cell dimensions and patterns are optimized to provide frequency-selective coupling that improves polarization performance across different operating bands
3Volume of moving object
If antenna elements with different frequency bands are arranged on the same aperture to reduce external dimension, then miniaturization is achieved, but gain fluctuates greatly with frequencies
Solution Approach 1:
The parasitic structure acts as an intermediary that stabilizes gain across frequency bands. The FSS planes create controlled electromagnetic coupling that compensates for gain fluctuations, maintaining stable performance while preserving the miniaturized shared aperture configuration
Solution Approach 2:
The patent optimizes parameters including the spacing between antenna elements (less than 0.5 vacuum wavelength), the spacing to parasitic structure (less than 0.5 vacuum wavelength), and FSS cell geometric parameters to minimize gain fluctuation across different operating frequencies
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 solution effectively resolves polarization suppression ratio deterioration and gain drops in the radiation pattern of the first antenna element, maintaining performance of the second antenna element, and is applicable to near-field regions with miniaturized FSS cells.
Implementation Method 1
The first parasitic structure includes one or more frequency selective surface (FSS) planes, and the first parasitic structure has a stopband characteristic for the first antenna element
Implementation Method 2
the first parasitic structure has a passband characteristic for the second antenna element
Data Source
AI summary
A multi-band antenna structure, including a first antenna element, a second antenna element, a reflection panel, and a first parasitic structure of the first antenna element. A distance between the reflection panel and an antenna element with a higher operating frequency band is less than a distance between the reflection panel and an antenna element with a lower operating frequency band. A distance between the first antenna element and the second antenna element is less than 0.5 times a vacuum wavelength corresponding to a lower frequency bands. A distance between the first antenna element and the first parasitic structure is less than 0.5 times a vacuum wavelength corresponding to an operating frequency band of the first antenna element. A distance between the second antenna element and the first parasitic structure is less than 0.5 times a vacuum wavelength corresponding to an operating frequency band of the second antenna element.