Feed Network Metal Interlayer for PIM Reduction

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Solution Overview

Problem

The complex and excessive metal connections in feed networks of multiband antennas lead to unstable passive intermodulation (PIM) interference, reducing the reliability and quality of wireless communication systems by decreasing the carrier-to-interference ratio (C/I) and received signal strength indication (RSSI).

Innovation Solution

A feed network design where at least two radio frequency transmission channels are separated by a single metal interlayer without using screws or rivets, allowing for complete or partial closure of channels except at signal transmission ends, and incorporating a metal object or dielectric part within the interlayer to facilitate information exchange and reduce PIM interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple metal interlayers with screw connections are used to separate radio frequency transmission channels, then channel separation is achieved, but passive intermodulation interference increases and reliability decreases

Engineering Contradiction:
Improveantenna reliabilityVSAvoidpassive intermodulation interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the harmful screw connections and multiple metal interlayers from the system. Instead, it uses a single continuous metal interlayer that separates radio frequency transmission channels without requiring any mechanical fasteners, thereby eliminating the source of passive intermodulation interference while maintaining channel separation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges multiple separate metal interlayers into a single continuous metal interlayer. This unified structure achieves the same channel separation function while eliminating the need for multiple connection points and screws, thereby reducing passive intermodulation interference and improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If complex metal connections are used in feed network, then structural stability is achieved, but device complexity increases and PIM index becomes unstable

Engineering Contradiction:
Improvefeed network structure complexityVSAvoidPIM index stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent extracts and removes all screw connections and complex metal fastening structures from the feed network. The single continuous metal interlayer provides structural stability through its continuous geometry rather than through multiple discrete connections, thereby simplifying the overall structure while improving PIM index stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the structural parameter from multiple discrete connected components to a single continuous component. This parameter change transforms the feed network from a complex assembly of multiple metal interlayers and screws into a simple, stable structure with fewer potential sources of passive intermodulation interference.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If multiple metal interlayers and connection components are used, then channel separation is achieved, but antenna size increases

Engineering Contradiction:
Improveantenna sizeVSAvoidchannel separation effectiveness
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent combines multiple separate metal interlayers into a single continuous metal interlayer that performs the channel separation function. This merging reduces the overall antenna volume by eliminating redundant structures while maintaining effective separation between radio frequency transmission channels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent removes unnecessary connection components and redundant metal interlayers from the antenna structure. The single continuous metal interlayer achieves channel separation without requiring additional space for multiple connections, thereby reducing the overall antenna size while maintaining separation effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2924801B1Feed network and antenna
Publication Date: 2018.09.26 HUAWEI TECH CO LTD
  • EP2924801B1 patent drawingFigure 1~3
  • EP2924801B1 patent drawingFigure 4~7
  • EP2924801B1 patent drawingFigure 8

AI summary

Embodiments of the present invention provide a feed network and an antenna, The feed network includes at least two separate radio frequency transmission channels, characterized in that the at least two separate radio frequency transmission channels are separated by a single metal interlayer or by several metal interlayers being on the same plane, one physical surface of the single or several metal interlayer(s) faces one of the at least two separate radio frequency transmission channels, and the other physical surface of the single or several metal interlayer(s) faces another one of the at least two separate radio frequency transmission channels. In the present invention, the radio frequency transmission channels are separated by the metal interlayer without using any screw or rivet connection. Therefore, the passive intermodulation interference caused by the metal connection is reduced, which increases the reliability and stability of the antenna, and improves the mobile communication quality.