Full-Duplex MIMO Antenna Layout for High Tx-Rx Isolation
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Solution Overview
Problem
In-band full-duplex communication systems face challenges in achieving high isolation between transmitter and receiver when using the same frequency band, leading to increased physical size or reduced isolation when using separate antennas or a single transceiver antenna, respectively.
Innovation Solution
An in-band full-duplex MIMO antenna with transmission and reception antenna elements having opposite polarization characteristics, coaxially disposed on a substrate, and a transceiver incorporating an RF switch to control signal polarization and phase, allowing for high isolation without additional isolators and facilitating modularization and array expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate transmission and reception antennas are used to increase isolation, then isolation between transmitter and receiver is improved, but physical size is increased
Solution Approach 1:
The patent combines transmission and reception antenna elements into a single integrated antenna structure. Multiple antenna elements (transmission and reception) are co-located on the same substrate, merging functions that would traditionally require separate physical antennas. This integration maintains high isolation through polarization differentiation while reducing overall physical size.
Solution Approach 2:
The patent applies different polarization characteristics to different antenna elements within the same structure. Transmission antenna elements have one polarization orientation while reception antenna elements have orthogonal polarization orientation. This local differentiation of properties enables high isolation between transmit and receive paths without requiring physical separation.
2Volume of moving object
If a single transceiver antenna is used to decrease physical size, then physical size is reduced and modularization is easier, but isolation between transmitter and receiver is decreased
Solution Approach 1:
Within the single integrated antenna structure, different antenna elements are assigned different polarization characteristics. Transmission elements use one polarization while reception elements use orthogonal polarization. This local property differentiation enables the compact single-antenna design to achieve high isolation, resolving the contradiction between size reduction and isolation maintenance.
Solution Approach 2:
The single transceiver antenna is segmented into multiple functional antenna elements with distinct polarization characteristics. By dividing the antenna into transmission elements and reception elements with orthogonal polarizations, the patent achieves both compact size and high isolation within a unified modular structure.
3Reliability
If additional circuits are used to increase isolation with a single antenna, then isolation is improved, but device complexity is increased
Solution Approach 1:
The patent changes the polarization parameter of different antenna elements to achieve isolation. Instead of adding complex isolation circuits, the solution modifies the fundamental electromagnetic parameter (polarization) of the antenna elements themselves. This parameter-based approach achieves high isolation while avoiding additional circuit complexity.
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
The solution achieves high isolation between transmission and reception signals, enabling compact modular design and easy expansion to desired array sizes while maintaining high frequency efficiency.
Implementation Method 1
transmission antenna elements and reception antenna elements having opposite polarization characteristics
Data Source
AI summary
Provided is an in-band full-duplex MIMO antenna, which includes: a substrate; and transmission antenna elements and reception antenna elements separately coaxially disposed on the same plane of the substrate, in which the transmission antenna elements have a first polarization characteristic, and the reception antenna elements have a second polarization characteristic different from the first polarization characteristic.