Split Sector Antenna Reflector Layout for Multiband Gain Control
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Solution Overview
Problem
Designing multiband cellular antennas that operate effectively across various frequency bands (low band, mid band, C-Band, and CBRS) is challenging due to constraints such as minimal profile requirements, inter-band interference, and stringent gain performance needs.
Innovation Solution
The design incorporates a split sector reflector with inclined sector panels and a center flat section, featuring columns of dipoles with mechanical and electrical tilt angles to optimize gain performance across multiple frequency bands, while minimizing interference and profile depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If antenna dipoles of different frequencies are packed in close proximity to each other, then the antenna can operate in multiple frequency bands, but inter-band interference such as cross polarization occurs
Solution Approach 1:
The antenna array is divided into multiple independent dipole elements operating at different frequency bands. Each dipole is independently positioned and tilted, allowing separate optimization of each band's radiation pattern while minimizing interference between bands. The segmentation of the reflector surface into discrete elements enables independent control of each frequency band's beamforming.
Solution Approach 2:
Different portions of the antenna array are assigned different local properties - specifically, dipoles for different frequency bands are positioned at different locations and oriented at different angles. Low band dipoles have different tilt angles compared to mid band dipoles, creating local variations in radiation patterns that reduce cross-band interference while maintaining optimal performance for each band.
2Weight of stationary object
If the multiband antenna is designed with a minimal profile to meet wind loading constraints, then wind loading is reduced, but gain performance in certain frequency bands deteriorates
Solution Approach 1:
The antenna employs electrical tilt adjustment capability that allows dynamic reconfiguration of the radiation pattern without mechanical movement of the entire structure. By electrically tilting the beam direction, the antenna can optimize gain performance for different frequency bands while maintaining a fixed, wind-loading-minimized physical profile. The feed circuits can independently adjust tilt angles for low band and mid band operations.
Solution Approach 2:
The antenna changes operational parameters (electrical tilt angle, phase distribution, amplitude weighting) to optimize performance for different frequency bands without changing the physical structure. By adjusting electrical parameters, the same minimal-profile structure can achieve optimal gain patterns for both low band and mid band operations, resolving the contradiction between profile depth and gain performance.
3Shape
If the antenna uses a flat reflector surface, then the profile depth is minimized, but gain performance in specific frequency bands is reduced
Solution Approach 1:
The antenna introduces electrical tilt as an additional degree of freedom to compensate for the limitations of a flat reflector surface. While the physical reflector remains flat to minimize profile depth, the electrical tilt capability allows the radiation pattern to be steered and shaped to achieve optimal gain performance. This adds a dimensional control parameter that decouples physical shape from radiation pattern optimization.
Solution Approach 2:
The patent replaces mechanical tilting of the entire antenna structure with electrical phase and amplitude control of individual dipole elements. Instead of mechanically inclining the reflector surface to improve gain, the system uses electronic beamforming to achieve the same effect, maintaining a flat mechanical structure while obtaining the radiation pattern benefits of an inclined surface through electrical means.
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 enhances gain performance in specific frequency bands without degrading other bands, improves beam quality, and reduces wind loading, effectively addressing the challenges of multiband antenna design.
Implementation Method 1
a first plurality of columns of first dipoles disposed on the first inclined sector panel; and a second plurality of columns of first dipoles disposed on the second inclined sector panel
Implementation Method 2
the first plurality of columns of first dipoles are coupled to a first feed circuit that is configured to impart a first electrical tilt at a first electrical tilt angle in the azimuth plane
Data Source
AI summary
A multiband antenna comprises a split sector reflector having a first inclined sector panel having a first mechanical tilt angle in an azimuth plane, and a second inclined sector panel having a second mechanical tilt angle in the azimuth plane; a first plurality of columns of first dipoles disposed on the first inclined sector panel; and a second plurality of columns of first dipoles disposed on the second inclined sector panel, wherein the first plurality of columns of first dipoles are coupled to a first feed circuit that is configured to impart a first electrical tilt at a first electrical tilt angle in the azimuth plane, and wherein the second plurality of columns of first dipoles are coupled to a second feed circuit that is configured to impart a second electrical tilt at a second electrical tilt angle in the azimuth plane.