Interleaved Antenna Array Layout for RF Isolation and ACLR
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Solution Overview
Problem
Existing antenna array configurations in 5G-NR radio nodes face challenges in reducing nonlinearity distortion and signal leakage, which are exacerbated by the use of power amplifiers and antenna paths, making it difficult to meet stringent RF performance requirements such as ACLR mandated by 3GPP, while also incurring increased cost and size due to the need for numerous antenna isolators.
Innovation Solution
The interleaved antenna array configuration combines isolated and non-isolated antenna elements, where isolated elements are protected by antenna isolators and non-isolated elements are coupled with simplified digital pre-distortion circuits, reducing the number of isolators and using a combination of isolators and DPD circuits to satisfy RF performance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antenna isolators are used to protect each antenna element from signal leakage, then RF performance requirements are satisfied, but cost and device size increase
Solution Approach 1:
The patent applies local quality by differentiating between isolated and non-isolated antenna elements within the same array. Only certain antenna elements (those more susceptible to interference or causing interference) are equipped with isolators, while others use simplified DPD circuits. This selective approach maintains RF performance where needed while reducing overall complexity and cost.
Solution Approach 2:
The antenna array is segmented into distinct groups: isolated antenna elements with full isolator protection, non-isolated elements with simplified DPD, and hybrid configurations. This segmentation allows the system to apply different protection strategies to different parts of the array based on their specific requirements, optimizing the balance between performance and complexity.
2Power
If power amplifiers are used to amplify RF signals, then transmission power is increased, but nonlinearity distortion occurs
Solution Approach 1:
The patent implements preliminary action through digital pre-distortion (DPD) circuits that pre-compensate for the nonlinear distortion introduced by power amplifiers. By applying the inverse of the expected distortion before amplification, the system maintains high transmission power while canceling out the harmful nonlinear effects that would otherwise occur during amplification.
3Ease of operation
If antenna paths are used to connect power amplifiers to antennas, then signal transmission is enabled, but signal leakage between paths occurs
Solution Approach 1:
The patent applies local quality by implementing different isolation strategies for different antenna paths. Some paths use full isolator protection, while others rely on simplified DPD circuits to mitigate leakage. This selective approach addresses signal leakage in critical paths while maintaining overall system functionality and reducing complexity in less critical paths.
Data Source
AI summary
An interleaved antenna array configuration in a radio node is disclosed. The antenna array includes a mixture of isolated and non-isolated antenna elements interleaved in each row and each column of the antenna array. Each isolated antenna element is only adjacent to one or two non-isolated antenna elements in each row and each column. Each non-isolated antenna element is only adjacent to one or two isolated antenna elements in each row and each column. By interleaving the isolated and non-isolated antenna elements in each row and column of the antenna array, it is possible to reduce a number of antenna isolators, thus helping to reduce cost and footprint of the radio node. Further, by using a combination of antenna isolators and simplified digital pre-distortion (DPD) actuators in association with the interleaved antenna array, the radio node is able to satisfy stringent radio frequency (RF) performance requirements.