Dual Polarized Radiating Element with Parasitic Arms
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Solution Overview
Problem
Ultra broad band base station antenna systems face challenges in designing compact radiating elements that operate across multiple frequency bands (Low Band, Middle Band, and High Band) without compromising RF key performance, as resonant behavior in one band can degrade performance in others, leading to issues like unwanted peaks, phase discontinuities, and gain drops.
Innovation Solution
A radiating element design featuring a support structure with dipole arms and parasitic arms, where the parasitic arms are capacitively coupled and arranged at a specific distance to reduce the total length of the dipole arms, allowing for a dual-band configuration in a reduced spatial configuration, and are galvanically isolated from the dipole arms to maintain performance across bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the physical dimensions of radiating elements are reduced to achieve compact design, then the overall geometrical antenna dimensions are decreased, but the RF key performance deteriorates due to resonant behavior in coexisting frequency bands
Solution Approach 1:
The patent transitions from planar dipole arms to a three-dimensional structure by adding parasitic arms that extend in the vertical dimension. This allows the radiating element to maintain electrical length for resonance while reducing the horizontal footprint, enabling compact antenna design without compromising RF performance in coexisting frequency bands
Solution Approach 2:
The radiating element is segmented into dipole arms and separate parasitic arms. The parasitic arms are electrically isolated from the dipole arms but electromagnetically coupled, allowing independent optimization of each segment's function while maintaining overall broadband performance across LB, MB, and HB bands
2Reliability
If a dipole is designed to work in the MB frequency range, then it resonates properly in MB, but it generates unwanted effects and degrades performance in the LB frequency band due to resonant behavior
Solution Approach 1:
Parasitic arms serve as intermediaries between the dipole arms and the electromagnetic field. These parasitic elements are capacitively coupled to the dipole arms and provide additional resonant paths that extend the operational bandwidth while suppressing unwanted resonance in the LB band, acting as a mediator to achieve broadband performance without harmful effects
Solution Approach 2:
The patent changes the electrical parameters by introducing parasitic arms with specific lengths and positions relative to the dipole arms. By adjusting the length, position, and configuration of these parasitic elements, the resonant frequency and impedance characteristics are modified to achieve broadband operation while eliminating harmful resonance in coexisting bands
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 enables a compact, broadband radiating element that maintains RF performance across multiple bands by effectively extending the dipole arms through parasitic arms, reducing the overall dimension and minimizing interference between frequency bands.
Implementation Method 1
Each parasitic arms is capacitively coupled to at least one corresponding dipole arm
Implementation Method 2
the distance between the first and the second layer is between 0.0004 and 0.1, preferably between 0.002 and 0.02, of the minimum wavelength of the operating frequency band of the radiating element
Data Source
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AI summary
The invention refers to a radiating element for a base station antenna, the radiating element comprising: a support structure, at least a pair of dipole arms in a first layer of the support structure, and at least two parasitic arms in a second layer of the support structure, wherein the distance between the first and the second layer is between 0.0004 and 0.1, preferably between 0.002 and 0.02, of the minimum wavelength of the operating frequency band of the radiating element, wherein the area of the parasitic arms in a projection perpendicular from the second to the first layer cover at least 60% of the areas of the at least one pair of dipole arms.