Wideband Bisector Antenna Array With Shared Rows for Beam Isolation
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Solution Overview
Problem
Wideband bisector array antennas face challenges in achieving high co-polar isolation due to non-ideal isolation and coupling between beam ports, especially in compact designs where vertical space is limited, leading to issues like low co-polar isolation and return loss.
Innovation Solution
The solution involves sharing at least one horizontal row of elements between the left and right beam bi-sector array segments, using a shared row of elements connected to a joint asymmetric beamforming network, which improves co-polar isolation while maintaining reasonable physical height and signal gain characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two independent vertically stacked arrays are used to provide left and right beams, then co-polar isolation is improved (>30 dB), but the vertical height and device complexity increase
Solution Approach 1:
The patent combines left and right beam arrays into a single planar structure with shared elements, merging previously separate arrays to reduce vertical height while maintaining isolation through careful phase and amplitude control in the beamforming network
Solution Approach 2:
Certain antenna elements are designed to serve dual purposes, functioning as part of both the left beam array and right beam array simultaneously, allowing a single element to contribute to multiple beam formations and reducing the total number of elements needed
2Length of stationary object
If a single array with azimuth beamformer is used for left and right beams, then the vertical height is reduced, but co-polar isolation deteriorates (11-12 dB) due to coupling between array columns
Solution Approach 1:
The beamforming network is designed with location-specific phase and amplitude characteristics for each element, allowing precise control of signal contribution from each position in the array to achieve both compact size and proper isolation
Solution Approach 2:
The patent employs dynamic phase and amplitude parameter adjustments across different frequency bands and beam directions to maintain isolation performance in the compact single-array configuration, adapting parameters to compensate for coupling effects
3Reliability
If traditional narrowband approaches are used to improve co-polar isolation, then isolation is improved at specific frequencies, but the solution cannot be applied to wideband arrays with more than 40% beamwidth
Solution Approach 1:
The beamforming network incorporates frequency-dependent phase and amplitude characteristics that dynamically adapt across the wide bandwidth, allowing the system to maintain isolation performance from 2.5 GHz to 3.5 GHz despite the compact single-array configuration
Solution Approach 2:
The antenna design pre-compensates for coupling effects and isolation challenges through carefully designed feed network parameters and element positioning, establishing isolation performance across the entire wideband range before operation rather than requiring post-deployment adjustment
Data Source
AI summary
A wideband bisector antenna has a plurality of antenna elements disposed in horizontal rows, a left beam bi-sector array segment at one section of the antenna comprising a plurality of the horizontal rows of elements, and a right beam bi-sector array segment at one section of the antenna comprising a plurality of the horizontal rows of elements. At least one horizontal row on the antenna is shared in both the left beam bi-sector array segment and the right beam bi-sector array segment.