Passive-Radiator Antenna Array for Broad Beam and Fast Roll-Off
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Solution Overview
Problem
Conventional antenna arrays for cellular wireless systems face challenges in achieving a broad main beam with a fast roll-off, particularly in LTE 4G networks with frequency re-use factor of 1, where interference between adjacent sectors reduces capacity at boundaries, and existing solutions are either physically large or complex.
Innovation Solution
The antenna array assembly incorporates a linear array of patch radiator elements with strategically positioned elongate passive radiators, including first and second radiators and third and fourth radiators, which are electrically isolated and disposed symmetrically on either side of the linear array, providing a broad main beam with a fast roll-off by adjusting their width and distance from the ground plate, and additional passive radiators further enhance roll-off and cross-polar isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single linear array of patch antennas is used as a sector antenna, then the device complexity is reduced, but the beam shape performance deteriorates with limited gain flatness and slow cut-off rate
Solution Approach 1:
The antenna array is segmented into multiple functional groups: active patch antenna elements for primary radiation, first and second elongate passive radiators for beam broadening, and third and fourth elongate passive radiators for sharp cut-off. This segmentation allows each group to perform its specific function optimally, achieving both structural simplicity and precise beam shape control
Solution Approach 2:
Different regions of the antenna structure are assigned different properties: active patch elements provide omnidirectional radiation, while passive radiators at specific positions provide directional beam shaping. The passive radiators have specific width-to-length ratios and spacing that create localized electromagnetic effects to broaden the main beam and accelerate cut-off at sector boundaries
2Manufacturing precision
If a two-dimensional array of patch antennas is used to increase main beam width and cut-off rate, then the beam shape performance is improved, but the device complexity and physical size increase
Solution Approach 1:
Instead of using a two-dimensional array of active elements, the invention transitions to a one-dimensional linear array enhanced by passive radiators extending in the dimensional direction. The passive radiators create virtual extension of the array aperture without adding physical complexity of a full 2D array, achieving broad beamwidth through controlled electromagnetic interaction rather than geometric expansion
Solution Approach 2:
Passive radiators serve as intermediary elements between the active patch antennas and the surrounding environment. These passive elements mediate the electromagnetic field distribution to achieve broad main beam and sharp cut-off without requiring direct control of multiple active elements, simplifying the overall system architecture
3Ease of operation
If conventional sector antennas are used in LTE networks with frequency re-use factor of 1, then interference between adjacent sectors occurs, but the system maintains operational simplicity
Solution Approach 1:
The invention converts the harmful interference effect into a beneficial beam shaping mechanism. By strategically positioning passive radiators that interact with electromagnetic waves from adjacent sectors, the system creates constructive interference within the desired sector and destructive interference at sector boundaries, effectively using interference to enhance performance rather than merely tolerating it
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 results in a sector antenna with improved beam shape, providing a broad beamwidth and rapid cut-off outside the main beam, reducing interference and increasing capacity in cellular systems with frequency re-use factor of 1, while maintaining economical production and high performance.
Implementation Method 1
a first and second elongate passive radiator each comprising one or more substantially planar conductive parts disposed to be upstanding in relation to the first face of the ground plate and being electrically isolated from the ground plate
Implementation Method 2
the first and second elongate passive radiators being disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array
Data Source
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AI summary
An antenna array assembly comprises a ground plate (1), a linear array of patch radiator elements (2, 2a-2c) disposed in a spaced parallel relationship with a first face of the ground plate, and a first and second elongate passive radiator (3, 4), and a third and fourth elongate passive radiator (5, 6). Each passive radiator comprises one or more substantially planar conductive parts and is generally upstanding in relation to the first face of the ground plate is electrically isolated from the ground plate. The first and second elongate passive radiators are disposed symmetrically on either side of the linear array and parallel to a centre line of the linear array, on the same side of the ground plate as the linear array. The third and fourth elongate passive radiators (5, 6) are disposed further from the linear array than are the first and second elongate passive radiators (3, 4). Each of the each of the third and fourth elongate passive radiators (5, 6) is narrower than projects further from the ground plate than does each of the first and second elongate passive radiators (3, 4).