Multiband Antenna Fences With Frequency-Selective Coupling Isolation
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Solution Overview
Problem
Existing multiband antennas face issues with parasitic coupling between radiating element arrays of different frequency bands, leading to distortion of radiation patterns and increased HPBW, while also requiring compactness and integration within acceptable dimensions.
Innovation Solution
The multiband antenna incorporates frequency selective surfaces on fences to filter electromagnetic waves, allowing for reduced undesired parasitic coupling between radiating element arrays by configuring fences with passbands and stopbands that match the operating frequency bands, maintaining positive effects on one frequency band while minimizing interference on others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple arrays of radiating elements are used to support service in different frequency bands, then the antenna can provide multi-band service, but parasitic coupling occurs between the radiating element arrays causing distortion of the radiation pattern
Solution Approach 1:
The antenna structure is segmented into different functional zones using fences with frequency selective surfaces. Each fence is positioned between specific radiating element arrays (e.g., low-band and mid-band arrays) to segment the electromagnetic space and reduce parasitic coupling between bands while maintaining multi-band service capability.
Solution Approach 2:
Fences with frequency selective surfaces act as intermediary structures between radiating element arrays of different frequency bands. These fences selectively pass desired frequency bands while blocking parasitic coupling, serving as mediators that maintain radiation pattern quality without compromising multi-band functionality.
2Adaptability or versatility
If the number of base station antennas is increased to accommodate more frequency bands, then more frequency bands can be served, but the antenna tower reaches weight and wind loading limits
Solution Approach 1:
Multiple radiating element arrays for different frequency bands (low-band, mid-band, high-band) are merged into a single integrated antenna structure. This consolidation reduces the total number of separate antenna units and their supporting infrastructure, thereby reducing overall weight and wind loading on the tower while maintaining service in multiple frequency bands.
Solution Approach 2:
The antenna structure is designed as a universal multi-functional system that can serve multiple frequency bands simultaneously through a single integrated platform. The fences with frequency selective surfaces enable one structure to perform multiple functions (supporting low-band, mid-band, and high-band services) without requiring separate dedicated antennas for each band.
3Reliability
If fences are added to improve front-to-back ratio, then radiation pattern performance improves, but the antenna width increases
Solution Approach 1:
Fences with frequency selective surfaces are strategically positioned only in specific locations where they are most effective (between radiating element arrays of different frequency bands). This localized placement improves front-to-back ratio without requiring fences throughout the entire antenna structure, thereby minimizing the increase in overall antenna width.
Solution Approach 2:
Instead of increasing antenna width in the horizontal plane to improve front-to-back ratio, the solution uses vertical fences extending in the vertical dimension. This dimensional transition allows the antenna to achieve improved radiation pattern performance without proportionally increasing the horizontal footprint or overall width of the 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
This design enhances the front-to-back ratio performance of the radiation pattern and maintains compactness by reducing parasitic coupling, thus improving antenna efficiency and reducing interference across frequency bands.
Implementation Method 1
the first fence and the second fence respectively comprise a frequency selective surface with a passband and a stopband, the passband covers at least the first operating frequency band, and the stopband covers at least the second operating frequency band
Data Source
AI summary
A multi-band antenna includes a first column of radiating elements that are configured to operate in a first operating frequency band mounted on a reflecting plate; a second column of radiating elements that are configured to operate in a second operating frequency band mounted on the reflecting plate; a first fence and a second fence located on both sides of the reflecting plate that extend forward from the reflecting plate, where the first and second columns of radiating elements are arranged in between the first and second fences, the first fence and the second fence respectively comprise a frequency selective surface with a passband and a stopband, the passband covers at least the first operating frequency band, and the stopband covers at least the second operating frequency band.