Tubular Small Cell Beamforming Antenna for Full-Power 360° Coverage
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Solution Overview
Problem
Current 8T/8R 5G radios are not well-suited for small cell base stations that provide omnidirectional coverage, as they do not utilize all transmit power effectively, resulting in reduced effective isotropic radiated power (EIRP) compared to conventional systems.
Innovation Solution
The development of small cell beamforming base station antennas with passive beamforming networks that route RF signals from each radio port to a selected subset of linear arrays, allowing for full power utilization and directional radiation patterns across 360° in the azimuth plane, using a tubular reflector with angled faces and a Butler Matrix or switching networks to direct RF energy efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional omnidirectional antennas are used for small cell base stations, then 360° coverage is achieved, but transmit power is not fully utilized resulting in reduced EIRP
Solution Approach 1:
The antenna system dynamically switches between different coverage patterns (omnidirectional, sector, heart-shaped, bi-directional) based on traffic conditions and user distribution. The beamforming capability allows the radiation pattern to be changed electronically without physical movement, enabling the system to adapt to varying operational requirements while maintaining high EIRP through focused directional beams.
2Power
If beamforming antennas with directional patterns are used, then transmit power utilization and EIRP are improved, but the ability to provide omnidirectional coverage is reduced
Solution Approach 1:
The antenna system is designed to perform multiple functions through a single structure with four linear arrays. By configuring the beamforming networks differently, the same antenna can provide omnidirectional coverage, sector coverage, heart-shaped patterns, or bi-directional patterns. This multi-functionality allows the system to achieve high power utilization through directional beams while retaining the flexibility to provide full 360° coverage when needed.
3Power
If passive beamforming networks are implemented to route RF signals to selected arrays, then full power utilization is achieved, but device complexity increases
Solution Approach 1:
The antenna system divides the four linear arrays into independently controllable groups that can be selectively activated. The passive beamforming networks are segmented into separate units, each handling specific array combinations. This segmentation simplifies the overall system by breaking down the complex beamforming function into manageable modular components, making the system easier to implement and maintain while still achieving full power utilization.
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
These antennas support higher EIRP levels and can form various directional patterns such as sector, omnidirectional, heart-shaped, and bi-directional beams, utilizing the full transmit power of 5G radios while maintaining a compact form factor suitable for urban deployments.
Implementation Method 1
The radiating elements arranged in one or more vertical columns when the antenna is mounted for use
Implementation Method 2
a reflector assembly that includes a first face and a second face that is angled by about 90° with respect to the first face
Data Source
AI summary
A small cell base station antenna includes a tubular reflector that has at least first through fourth faces that each face in different directions. The antenna further includes first through fourth arrays of radiating elements that are mounted on the respective first through fourth faces of the tubular reflector. The antenna also includes a passive beamforming network that has first through fourth outputs that are coupled to the respective first through fourth arrays of radiating elements.