Switched Splitter-Combiner for Wideband Local Array Excitation
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Solution Overview
Problem
The design of a wideband switch-beam GRIN lens antenna system faces challenges in achieving an extremely wide impedance bandwidth due to strong coupling between adjacent elements, which leads to impedance mismatch, reduced efficiency, and altered radiation patterns, especially when only one or a few elements are actively excited.
Innovation Solution
A switched splitter-combiner circuit is employed to dynamically route power to multiple feed antennas, allowing for local excitation and mitigating efficiency degradation by using splitter circuits and switches that divide the incident excitation among elements, with optional tunable impedance terminations to manage mutual coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If local excitation of tightly coupled antenna arrays is used to enable beam steering in GRIN lens antenna systems, then device complexity and power consumption are reduced, but impedance bandwidth is limited due to strong coupling between adjacent elements
Solution Approach 1:
The patent divides the antenna array into multiple groups where adjacent elements are excited simultaneously. This segmentation approach allows the system to maintain the simplicity of local excitation while mitigating the bandwidth limitation caused by strong coupling between tightly spaced elements, thereby resolving the contradiction between device complexity and adaptability.
2Adaptability or versatility
If adjacent antenna elements are excited simultaneously to mitigate coupling effects, then impedance bandwidth increases, but power distribution complexity increases
Solution Approach 1:
The patent combines multiple excitation sources and merges their outputs through a unified power distribution network. By simultaneously exciting adjacent elements through a coordinated power distribution system, the patent achieves wide impedance bandwidth while managing power distribution complexity through integrated circuit design.
3Area of stationary object
If element spacing is reduced to achieve compact array design, then array size is reduced, but mutual coupling between elements increases causing impedance mismatch
Solution Approach 1:
The patent applies partial excitation by simultaneously activating only the necessary adjacent elements rather than all elements in the array. This partial action approach maintains compact array sizing while reducing the overall coupling effects that would occur if all tightly spaced elements were excited, thereby preserving impedance matching performance.
Data Source
AI summary
Tightly coupled array antennas exhibit wideband behavior when all elements are excited simultaneously. A switched splitter-combiner allows a scalable number of adjacent feed elements of the array to be excited depending on the frequency of excitation and degree of coupling. This allows the tightly coupled array to be locally excited while retaining wideband performance. The performance may be further improved by complex per-element control of excited elements or tunable reactive termination of non-excited elements.