Parasitic Element Radiating Elements for Base Station Antenna Isolation
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Solution Overview
Problem
Base station antennas face challenges with increased coupling interference between closely spaced linear arrays of radiating elements, leading to degraded performance in beamforming and cross-polarization discrimination, and are limited by size, weight, and manufacturing costs.
Innovation Solution
The use of radiating elements with a parasitic element and a coupling capacitor, where the parasitic element has a meandered electrically conductive structure and operates in a lower frequency band than the radiator, reducing coupling interference and allowing for a more compact design.
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, then the antenna beam can be scanned to wide angles without significant grating lobes, but mutual coupling increases between radiating elements in adjacent linear arrays, degrading co-polarization performance
Solution Approach 1:
A parasitic element with a meandered electrically conductive structure is introduced as an intermediary component between adjacent linear arrays. This parasitic element acts as a mediator that reduces mutual coupling between radiating elements in different arrays, thereby maintaining co-polarization performance while enabling close spacing for wide azimuth scanning capability
Solution Approach 2:
The parasitic element operates at a lower frequency band than the main radiator, creating a frequency separation that reduces coupling interference. The meandered electrically conductive path of the parasitic element is designed to resonate at this lower frequency, effectively counteracting coupling effects in the desired operating band
2Productivity
If the number of arrays of radiating elements is increased to improve beamforming capability, then system capacity and signal power are improved, but the base station antenna becomes larger and heavier, increasing wind loading and manufacturing cost
Solution Approach 1:
The parasitic element with its meandered electrically conductive structure is integrated within or alongside the existing radiator structure. This nested configuration allows the parasitic element to be incorporated without significantly increasing the overall antenna footprint, enabling multiple arrays to be packed more efficiently while maintaining reduced coupling
3Device complexity
If radiating elements are reduced in size to decrease antenna weight and complexity, then manufacturing cost and wind loading are reduced, but coupling interference between elements increases
Solution Approach 1:
The parasitic element serves as a protective intermediary that mitigates coupling interference between compact radiating elements. By introducing this additional structure with specific resonant properties, the system can maintain element miniaturization while the parasitic element compensates for the increased coupling that would otherwise result from reduced spacing
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 improves isolation performance and reduces the size of the radiating elements, mitigating coupling interference and enabling more compact, high-performance base station antennas.
Implementation Method 1
a coupling capacitor is formed between the electrically conductive structure and the radiator
Implementation Method 2
the electrically conductive structure comprises a meandered electrically conductive path
Data Source
AI summary
A radiating element comprises a radiator, a feed stalk and a parasitic element. The radiator is fed by the feed stalk, and the parasitic element includes an electrically conductive structure that includes a meandered electrically conductive path. A coupling capacitor is formed between the electrically conductive structure and the radiator, and a center frequency of an operating frequency band of the radiator is higher than a center frequency of a first operating frequency band of the parasitic element.