Integrated Massive MIMO Antenna Feed Board Layout for Lower PIM
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Solution Overview
Problem
The implementation of frequency division duplex (FDD) massive-MIMO antennas is challenging due to large duplexers, numerous electromechanical phase shifters, and low-efficiency radio circuitry, which result in size, weight, and passive inter-modulation (PIM) issues, as well as inefficiencies in power management and heat dissipation.
Innovation Solution
Integrating electromechanical phase shifters into radiating element feed boards, reducing duplexer size through calibration board filtering, and using separate heat sinks to improve thermal management and eliminate cabling, thereby simplifying the antenna assembly and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If large duplexers are used for FDD massive-MIMO operation, then frequency band support is improved, but antenna size and weight increase
Solution Approach 1:
The antenna system is divided into multiple independent antenna elements, each with its own integrated radio circuitry and smaller duplexer. This segmentation allows each element to handle specific frequency bands independently, reducing the size and weight of individual duplexers while maintaining overall multi-band capability through the array of elements.
2Adaptability or versatility
If numerous electromechanical phase shifters are included for beamforming, then beamforming capability is improved, but device complexity and PIM increase
Solution Approach 1:
The radio circuitry including phase shifters is integrated directly into the antenna elements themselves rather than being separate components. This merging of functions reduces the total number of discrete phase shifter components and simplifies the overall system architecture while maintaining full beamforming capability through the integrated elements.
3Loss of energy
If radio circuitry is integrated into the antenna, then insertion loss is reduced, but heat dissipation becomes more challenging
Solution Approach 1:
The antenna elements are positioned in a three-dimensional spatial arrangement that allows heat to dissipate in multiple directions. The vertical and horizontal separation between elements creates thermal pathways that enable efficient heat dissipation from the integrated radio circuitry without requiring additional cooling infrastructure.
4Adaptability or versatility
If multiple frequency bands are supported in a single antenna, then service versatility is improved, but antenna complexity increases
Solution Approach 1:
Each antenna element is designed as a universal component capable of operating across multiple frequency bands through integrated radio circuitry that supports various band configurations. This multi-functionality at the element level allows the overall antenna system to support multiple services and frequency bands without proportionally increasing complexity, as each element can be independently configured.
Data Source
AI summary
An integrated base station antenna includes a feed board having a plurality of columns of radiating elements mounted thereon and a plurality of phase shifters coupled to the plurality of columns of radiating elements mounted on a same side of the feed board as the plurality of columns of radiating elements.