Antenna Blocking Member Segmentation for SAR Reduction
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Solution Overview
Problem
Existing wireless communication apparatuses face challenges in reducing the Specific Absorption Ratio (SAR) value while maintaining radiation efficiency and avoiding directivity bias of electromagnetic waves, particularly in one-to-one communication scenarios like camera-to-PC connections, due to the resonance and radiation efficiency issues caused by metal plates used for blocking electromagnetic waves.
Innovation Solution
A wireless communication apparatus is designed with a blocking member, such as a metal plate, arranged to avoid overlapping with the open end and strongest electric field regions of the antenna, while overlapping with the connection end and strongest magnetic field regions, to minimize SAR and enhance radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal plate is arranged between the antenna and human body to block electromagnetic waves, then the SAR value is decreased, but the radiation efficiency of the electromagnetic wave is decreased due to resonance between the metal plate and the antenna
Solution Approach 1:
The blocking member is divided into a first blocking member and a second blocking member positioned at different locations. The first blocking member is positioned to block electromagnetic waves in a first direction, while the second blocking member is positioned to block electromagnetic waves in a second direction. This segmentation allows each blocking member to be smaller in size, avoiding resonance with the antenna while still providing effective SAR reduction in multiple directions.
Solution Approach 2:
Different blocking members are positioned at specific locations around the antenna based on the radiation pattern and SAR requirements. The first blocking member is positioned in a first direction from the antenna, and the second blocking member is positioned in a second direction from the antenna. This local placement strategy blocks electromagnetic waves where needed while leaving other areas open for efficient radiation.
2Object-affected harmful factors
If the entire antenna is shielded with the metal plate to decrease SAR value, then the amount of radio waves radiated toward the metal plate is decreased, but the communicable distance or effective data transfer rate is significantly decreased due to bias of the directivity of the electromagnetic wave in the antenna
Solution Approach 1:
The blocking member is segmented into multiple smaller blocking members positioned at different directions from the antenna. Each blocking member is smaller than the antenna and positioned to block electromagnetic waves in specific directions where SAR reduction is needed. This segmentation prevents the formation of a large continuous shield that would cause severe directivity bias, while still providing effective SAR reduction in multiple directions.
Solution Approach 2:
The blocking members are positioned asymmetrically around the antenna based on the specific SAR requirements and radiation pattern. The first blocking member is positioned in a first direction, and the second blocking member is positioned in a second direction, creating an asymmetric blocking configuration that reduces SAR in critical directions while maintaining radiation efficiency in communication directions.
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 decreases the SAR value while maintaining or improving radiation efficiency, allowing for longer communicable distances and effective data transfer rates in human body directions.
Implementation Method 1
a blocking member, which is arranged so as to be opposed to the antenna, and is configured to block an electromagnetic wave
Implementation Method 2
an antenna including: an antenna element having one end portion that is opened; and a ground conductor to be used as a ground, to which another end portion of the antenna element is connected
Data Source
AI summary
There is provided a wireless communication apparatus, including: an antenna including: an antenna element having one end portion that is opened; and a ground conductor to be used as a ground, to which another end portion of the antenna element is connected; a wireless device connected to the antenna; and a blocking member, which is arranged so as to be opposed to the antenna, and is configured to block an electromagnetic wave, wherein the blocking member is arranged so as to, in plan view from the blocking member side in a direction toward the antenna, avoid overlapping at least the one end portion of the antenna element and overlap the another end portion of the antenna element.