Multi-band MIMO Antenna Isolation via Switched Feed Networks
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Solution Overview
Problem
Current MIMO antenna systems face challenges in maintaining high isolation and de-correlated radiation patterns across multiple frequency bands, requiring optimization for efficient operation.
Innovation Solution
A multi-band antenna system utilizing a transmission line network with filters, switches, and active/passive components to provide optimized isolation and beam steering, incorporating filters and switches in transmission lines to dynamically tune the antenna system for improved performance across frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-feed antenna structure is used to simplify the system, then device complexity is reduced, but isolation between multiple antennas deteriorates
Solution Approach 1:
The patent divides the antenna system into multiple independently fed antenna elements, each with its own feed structure. This segmentation allows each antenna to be independently controlled and fed, thereby maintaining high isolation between elements while enabling MIMO operations across multiple frequency bands.
Solution Approach 2:
The patent introduces feed networks and impedance matching structures as intermediary components between the transmission line and antenna elements. These intermediaries enable proper signal distribution and isolation between multiple antennas, resolving the contradiction between simplified feeding and maintained isolation.
2Area of stationary object
If antennas are closely spaced to reduce device area, then area is reduced, but isolation between antennas deteriorates
Solution Approach 1:
The patent employs local quality enhancement through strategic placement of ground structures, parasitic elements, and impedance matching components in specific locations between and around antenna elements. These localized structures improve isolation between closely spaced antennas without requiring increased separation distance, thereby maintaining compact form factor while achieving high isolation.
3Adaptability or versatility
If de-correlated radiation patterns are maintained across multiple frequency bands, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent designs antenna elements with universal characteristics that enable them to operate effectively across multiple frequency bands while maintaining de-correlated radiation patterns. The antenna structures are configured to support multiple resonant modes and frequency operations, providing multi-band adaptability without requiring separate antenna systems for each band, thus controlling complexity while achieving versatility.
Data Source
AI summary
A multi-band antenna system for MIMO applications is adapted to provide high isolation between antennas across a wide range of frequencies. Multiple Isolated Magnetic Dipole (IMD) antennas are co-located and connected with a feed network that can include switches that adjust phase length for transmission lines connecting the antennas. Filtering is integrated into the feed network to improve rejection of unwanted frequencies. Filtering can also be implemented on the antenna structure. Either one or multi-port antennas can be used.