Hierarchical Beam-Forming Network for Array Antenna
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Solution Overview
Problem
Conventional beam-forming networks (BFNs) for array antennas are complex, bulky, and lossy, especially in multi-beam applications, limiting flexibility and reconfigurability, and often require a large number of high-power amplifiers, which increases cost and complexity.
Innovation Solution
A hierarchical partitioning of antenna elements into non-overlapping and overlapping sub-arrays, mirrored by a three-layer BFN architecture comprising a Multi-Beam Network, Single Mode Networks, and Multi Mode Networks, allowing for reconfigurability and lossless operation, reducing the number of control elements and amplifiers while maintaining high radiation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional beam-forming networks are used for multi-beam array antennas, then the antenna can provide multi-beam coverage, but the network becomes complex and bulky with high loss
Solution Approach 1:
The patent segments the array antenna into multiple sub-arrays, where each sub-array is fed by a separate power amplifier and beam-forming network. This segmentation allows each BFN to handle fewer elements, reducing individual network complexity while maintaining overall multi-beam capability through coordinated operation of multiple sub-arrays
Solution Approach 2:
The patent introduces a spatial dimension to the BFN architecture by distributing multiple BFNs across different physical locations, each serving specific sub-arrays. This spatial distribution reduces the complexity of any single BFN while maintaining the ability to form multiple beams through coordinated control of distributed networks
2Reliability
If the number of antenna elements is increased for better radiation performance, then the radiation pattern improves, but the number of control elements and amplifiers increases
Solution Approach 1:
The patent divides the large array into multiple sub-arrays, each with its own control elements and amplifiers. This segmentation allows the system to achieve high radiation performance through the combined effect of multiple sub-arrays while keeping the complexity of individual control networks manageable
Solution Approach 2:
The patent designs the sub-arrays and their associated BFNs to be identical or similar in structure, allowing a universal sub-array design to be replicated across the entire array. This universality reduces the variety of control elements needed while maintaining high radiation performance through coordinated operation of identical modular units
3Adaptability or versatility
If full reconfigurability is implemented for beam shape and pointing, then beam flexibility is maximized, but the number of active weight elements increases significantly
Solution Approach 1:
The patent segments the reconfigurability function across multiple identical BFNs, each handling a subset of sub-arrays. This segmentation allows full reconfigurability to be achieved through coordinated control of multiple modular networks rather than requiring a single complex network with all possible weight elements
Solution Approach 2:
The patent implements dynamic beam forming by allowing the system to selectively activate different sub-arrays and adjust their respective BFNs based on the desired beam configuration. This dynamic approach achieves full reconfigurability by combining the output of multiple dynamically controlled sub-arrays rather than requiring all weight elements to be simultaneously active
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A beam-forming network (BFN) for an emitting array antenna, having NB ≥1 beam ports (BP), each corresponding to an antenna beam, and NE ≥1 antenna ports (AP), each corresponding to an antenna element, the network comprising: a multi-beam network (MBN) having at least NB input ports connected to respective beam ports of the beam-forming network and at least N0SA>1 output ports, for associating to each said output port a linear combination of input signals from respective input ports; a set of at least NOSA lossless single-mode networks (SMN), each having an input port (OSA-IP) connected to a respective output port of said multi-beam network and at least NNOSA osa>1 output ports, for associating to each said output port a signal obtained by weighting an input signal from said input port; and a set of at least NN0SA lossless multi-mode networks (MMN), each having at least NNOSA OSA input ports (NOSA-IP), each one connected to an output port of a respective single- mode network, and at least NN0SA E>1 output ports connected to respective antenna ports of the beam-forming network, for associating to each said output port a linear combination of input signals from respective input ports. An array antenna comprising NE antenna elements and a beam-forming network as described above, whose antenna ports are connected to said antenna elements.