Beamforming Antenna Parasitic Elements Reduce Mutual Coupling
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Solution Overview
Problem
In beamforming base station antennas, closely spaced radiating elements lead to increased mutual coupling, distorting the radiation pattern and degrading performance parameters such as co-polarization performance and beamforming capabilities.
Innovation Solution
The antenna assembly incorporates a reflector with vertically extending arrays of radiating elements and parasitic elements placed between them, with specific spacings and configurations to reduce coupling interference and improve the symmetry of the electromagnetic environment, including staggered and stepped parasitic elements to manage coupling interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If linear arrays of radiating elements are closely spaced together to enable wide azimuth scanning without significant grating lobes, then azimuth scanning capability is improved, but mutual coupling between radiating elements increases which degrades co-polarization performance and distorts radiation pattern
Solution Approach 1:
Parasitic elements are introduced as intermediary structures positioned between adjacent radiating elements in the linear arrays. These parasitic elements act as electromagnetic mediators that reduce the direct mutual coupling between closely spaced radiating elements, thereby maintaining co-polarization performance while enabling close spacing for wide azimuth scanning capability
Solution Approach 2:
The parasitic elements are selectively positioned at specific locations between radiating elements, creating localized electromagnetic field modifications. This local quality adjustment reduces coupling in critical regions while maintaining overall array performance and scanning capability
2Power
If linear arrays of radiating elements are closely spaced together to narrow the beamwidth in the azimuth plane for increased signal power, then beamforming performance is improved, but mutual coupling increases which distorts the radiation pattern
Solution Approach 1:
Parasitic elements serve as intermediary structures that mediate the electromagnetic interaction between closely spaced radiating elements. They reduce the harmful mutual coupling that distorts radiation patterns while allowing the arrays to maintain narrow beamwidth for high signal power in the desired direction
Solution Approach 2:
The introduction of parasitic elements changes the electromagnetic parameters of the antenna system, specifically modifying the coupling coefficients between radiating elements. This parameter change allows close spacing for narrow beamwidth while maintaining radiation pattern integrity
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 configuration reduces coupling interference, enhances the shape of the radiation pattern, and improves cross-polarization performance, maintaining compactness and scanning capabilities while minimizing distortion.
Implementation Method 1
mutual coupling increases between the radiating elements in adjacent linear arrays
Implementation Method 2
A first of the parasitic elements extends farther forwardly from the reflector than a second of the parasitic elements
Data Source
AI summary
The present invention relates to an antenna assembly for a beamforming antenna, comprising a reflector and an antenna array that includes a plurality of first radiating elements that are arranged as a first vertically extending array, the first radiating elements extending forwardly from the reflector; and a plurality of second radiating elements that are arranged as a second vertically extending array, the second radiating elements extending forwardly from the reflector. Two adjacent first radiating elements are spaced apart from one another by a first distance, and a first radiating element and an adjacent second radiating element are spaced apart from one another by a second distance. The first distance is substantially equal to the second distance. The antenna assembly further comprises a plurality of parasitic elements that are placed along sides of the first and second of the vertically extending arrays.