Base Station Antenna Feeding Network for Frequency-Dependent Downtilt
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Solution Overview
Problem
Wideband base station antennas face challenges in setting a suitable electrical downtilt (EDT) due to differing antenna radiation characteristics across frequency bands, leading to signal degradation at cell borders or interference with neighboring cells.
Innovation Solution
Implement a phase delaying arrangement in the antenna feeding network that provides frequency-dependent phase delays to adjust the electrical tilt, ensuring alignment of upper 3 dB points across frequency bands to optimize signal coverage and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single feeding network is used for all frequency bands, then the number of array antennas is reduced, but the same tilt must be used for all bands which complicates setting suitable electrical downtilt
Solution Approach 1:
The patent segments the feeding network into multiple independent feeding networks, each dedicated to a specific frequency band. This allows each feeding network to have its own phase delaying arrangement that can be independently adjusted for optimal electrical downtilt settings specific to each band's propagation characteristics.
Solution Approach 2:
The patent introduces dynamically adjustable phase delaying arrangements in each feeding network that enable remote control of electrical downtilt. This dynamic adjustment capability allows the system to adapt tilt settings for different frequency bands without manual intervention, resolving the operational complexity.
2Reliability
If electrical downtilt is set to cover a certain geographical area with sufficiently high signal level, then coverage is improved, but spillover into the next cell increases causing interference
Solution Approach 1:
The patent applies different electrical downtilt settings to different frequency bands based on their specific propagation characteristics. Lower frequency bands with wider beamwidths receive different tilt adjustments compared to higher frequency bands, optimizing coverage while minimizing spillover interference in a frequency-specific manner.
Solution Approach 2:
The patent changes the electrical downtilt parameter independently for each frequency band through separate phase delaying arrangements. This allows precise control of beam direction for each band, ensuring adequate coverage while reducing interference by adjusting the tilt parameter according to each band's characteristics.
3Object-generated harmful factors
If electrical downtilt is set to minimize spillover, then interference is reduced, but signal level degradation occurs close to cell border
Solution Approach 1:
The patent segments the coverage optimization by frequency band, allowing different tilt strategies for different bands. This segmentation enables simultaneous optimization of signal level and interference reduction for each band independently, rather than compromising one for the other across all bands.
Solution Approach 2:
The patent adjusts the electrical downtilt parameter differently for lower and higher frequency bands. By changing the tilt parameter according to frequency-specific requirements, the system achieves both adequate signal level at cell borders and minimized spillover interference.
4Ease of operation
If different feeding networks are used for different frequency bands, then suitable electrical downtilt can be set for each band, but the complexity and cost of the antenna increases
Solution Approach 1:
The patent designs each feeding network with multi-functional capabilities, where the phase delaying arrangement serves both as impedance matching component and electrical downtilt control mechanism. This universality reduces overall complexity despite having multiple feeding networks for different frequency 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
Achieves consistent signal coverage across multiple frequency bands by aligning the 3 dB points within a predetermined interval, minimizing signal degradation and interference.
Implementation Method 1
a phase delaying arrangement arranged to delay the signals to one or more of the outputs to tilt the beam, wherein the phase delaying arrangement is configured to delay said signals as a function of the frequency
Data Source
AI summary
Antenna arrangement having an antenna element array including at least two antenna elements spaced apart in a vertical direction of the antenna arrangement, and an antenna feeding network configured to provide signals to said antenna element array to produce a beam. The antenna feeding network may include an input for connection to a radio base station unit, a plurality of outputs connected to a respective antenna element of the array of antenna elements, and a phase delaying arrangement arranged to delay the signals to one or more of the outputs to tilt the beam, wherein said frequency-dependent phase delaying arrangement is configured to delay said signals as a function of the frequency.