Antenna Ground Isolation for Mobile Device Interference

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Solution Overview

Problem

Existing mobile communication devices face interference issues between antennas and other metal components, particularly when a data transmission interface is present, affecting performance and Bio-Compatibility requirements such as SAR and HAC.

Innovation Solution

The mobile communication device incorporates a system circuit board with a system ground plane and an antenna substrate, featuring first and second radiation elements, an antenna ground plane, and a transmission line with branches connected to a feed point, where the antenna substrate is spaced apart from the system circuit board, and a data transmission component is positioned between additional and antenna ground planes to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the antenna is disposed on the bottom of the mobile communication device to improve Bio-Compatibility (lower SAR and HAC), then the antenna performance deteriorates due to interference from data transmission interface components

Engineering Contradiction:
ImproveSAR and HAC valuesVSAvoidantenna performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A ground isolation structure comprising a first ground plane and a second ground plane is introduced as an intermediary between the antenna and the data transmission interface. The first ground plane is disposed below the antenna radiation element, and the second ground plane is disposed below the first ground plane. This intermediary ground isolation structure effectively isolates the antenna from interference caused by data transmission interface components, allowing the antenna to be disposed on the bottom of the device for improved Bio-Compatibility while maintaining reliable antenna performance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ground system is segmented into multiple separate ground planes (first ground plane and second ground plane) rather than using a single continuous ground. This segmentation creates distinct electromagnetic zones that isolate the antenna from interfering components, enabling the antenna to operate reliably on the bottom of the device while maintaining low SAR and HAC values

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the antenna substrate is spaced apart from the system circuit board to reduce interference, then the device complexity increases due to additional structural requirements

Engineering Contradiction:
Improvesignal interferenceVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The ground isolation structure is merged with the existing antenna assembly by integrating the first and second ground planes directly into the antenna's ground system. This merging approach reduces interference by creating electromagnetic isolation zones without requiring separate structural components, thereby reducing device complexity while maintaining the spacing between the antenna substrate and system circuit board

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2546922B1Mobile communication device and antenna device
Publication Date: 2018.09.12 MEDIATEK SINGAPORE PTE LTD
  • EP2546922B1 patent drawingFigure 1A
  • EP2546922B1 patent drawingFigure 1B
  • EP2546922B1 patent drawingFigure 1C

AI summary

A mobile communication device for operating in LTE and WWAN bands is provided in the invention. The mobile communication device includes a system circuit board and an antenna. The system circuit board includes a system ground plane. The antenna includes: an antenna substrate, substantially parallel to the system ground plane; a first radiation element, disposed on the antenna substrate; a second radiation element, disposed on the antenna substrate; an antenna ground plane, disposed on the antenna substrate, and coupled to the system ground plane; and a transmission line, disposed on the antenna substrate, coupled to the first and second radiation elements, and having a feed point. The mobile communication device is further configured to accommodate a data transmission component.