Multi-Antenna Isolation via Capacitive Components
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Solution Overview
Problem
In wireless mobile communication devices with multiple antennas, strong mutual coupling between antennas due to limited space and conductive covers leads to distorted radiation patterns and degraded system performance, necessitating effective antenna isolation solutions.
Innovation Solution
The use of capacitive and inductive components between the printed wire board (PWB) and conductive cover portions, along with strategically placed slots and antenna feeds, to reduce electromagnetic coupling and adjust isolation bands, enabling efficient antenna diversity and MIMO operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple antennas are located close to each other to save space, then device compactness is improved, but mutual coupling between antennas increases causing distorted radiation patterns
Solution Approach 1:
A conductive cover portion is introduced as an intermediary element between the antennas and the device chassis. This conductive cover acts as a mediator that manages electromagnetic coupling by providing a controlled reference plane and isolation mechanism, allowing antennas to be positioned closely while maintaining proper radiation patterns through the intermediary's electromagnetic field management
Solution Approach 2:
The conductive cover is segmented into multiple portions with different ground connection configurations. Some portions are electrically connected to the chassis while others are isolated, creating distinct electromagnetic zones that allow multiple antennas to operate in close proximity without excessive mutual coupling. This segmentation enables spatial separation of electromagnetic fields while maintaining compact device form factor
2Strength
If a metal cover is used to protect the device, then device protection is improved, but electromagnetic coupling between antennas increases
Solution Approach 1:
The continuous metal cover is segmented into multiple conductive cover portions with selective electrical connections to the chassis. This segmentation creates controlled electromagnetic zones where some areas provide shielding while others maintain isolation, allowing the protective cover function to be preserved without excessive electromagnetic coupling between antennas
Solution Approach 2:
Different portions of the conductive cover have different electrical connection characteristics - some are grounded while others are isolated. This local quality variation allows the cover to provide protection where needed while maintaining antenna isolation in critical areas, resolving the conflict between device protection and electromagnetic coupling
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
This configuration effectively reduces mutual coupling between antennas, improving wireless link performance, reliability, and capacity by dynamically adjusting isolation bands and providing diverse antenna operations across various frequency bands.
Implementation Method 1
The capacitive and inductive components may be adjusted to manipulate an isolation band between the antenna feeds
Implementation Method 2
The capacitive and inductive components may be adjusted to manipulate an isolation band between the antenna feeds
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In an embodiment, isolation between antennas of a multi antenna system is disclosed. According to another embodiment, a device is disclosed comprising a conductive portion of a cover of the device; a first antenna feed configured to a first radio frequency band; a second antenna feed configured to a second radio frequency band; at least two slots of a printed wiring board, feeds being coupled to the slots and slots being coupled to the conductive portion; a first capacitive component; a second capacitive component; wherein the first and the second capacitive component are configured between the printed wiring board and the conductive portion.