Antenna Device with Slit Ground Electrode for SAR Reduction
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Solution Overview
Problem
Existing antenna designs face challenges in reducing Specific Absorption Rate (SAR) while maintaining thin housing for portable wireless devices, as increasing the distance between the antenna and the human body is difficult due to space constraints.
Innovation Solution
The antenna device incorporates a ground electrode with a slit and a bent grounding portion, along with a feed plate and radiation electrode, to create a distance between the antenna and the human body, reducing radiowave absorption by using a dielectric layer configuration that allows for efficient radiowave transmission and reception across multiple frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distance between the antenna and the human body is increased to reduce SAR, then SAR is reduced, but the housing thickness increases
Solution Approach 1:
The ground electrode is bent in a direction away from the radiation electrode, creating a three-dimensional configuration that increases the distance between the antenna and the human body without increasing the planar footprint of the device. This dimensional change allows SAR reduction while maintaining thin housing.
Solution Approach 2:
The ground electrode is divided into multiple portions with a slit formed between them, creating separate functional zones. The bent grounding portion is electrically connected to the ground, allowing the antenna to radiate or receive radiowaves while maintaining a configuration that increases distance from the human body.
2Adaptability or versatility
If a slit is formed in the ground electrode to enable multi-frequency operation, then frequency versatility is improved, but the structural integrity and grounding effectiveness may be compromised
Solution Approach 1:
The ground electrode is segmented into multiple portions with a slit formed between them, enabling the antenna to operate at multiple frequencies including the resonant frequency of the slit. The segmentation creates different resonant modes while maintaining overall grounding through the bent grounding portion.
Solution Approach 2:
The bent grounding portion acts as an intermediary that maintains electrical connection to ground while being positioned away from the radiation electrode. This intermediary structure preserves grounding effectiveness despite the slit in the ground electrode, ensuring reliable operation across multiple frequencies.
3Object-affected harmful factors
If the ground electrode is bent away from the radiation electrode to increase distance, then SAR is reduced, but the electrical connection and grounding may be affected
Solution Approach 1:
The ground electrode is bent in a direction away from the radiation electrode, utilizing three-dimensional space to increase the physical distance between the antenna and the human body. The electrical connection is maintained through the bent structure's continuity, preserving grounding effectiveness while reducing SAR.
Solution Approach 2:
The bent grounding portion serves as an intermediary structure that maintains electrical connection to ground while positioned away from the radiation electrode. This intermediary configuration ensures reliable electrical connection while achieving the desired distance for SAR reduction.
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 SAR by blocking radiowaves with the feed plate and ground electrode, while the slit's design increases the distance from the human body, achieving compliance with regulatory SAR limits without compromising radiating characteristics.
Implementation Method 1
a radiation electrode which is provided on a surface of the second dielectric layer opposite from the feed plate, and which is fed by being electrically connected to the feed plate at a feed point to radiate or receive a radiowave with a first frequency
Implementation Method 2
a first dielectric layer which is provided on one surface of the ground electrode; a second dielectric layer which is provided in such a manner as to sandwich the feed plate with the first dielectric layer
Implementation Method 3
the slit radiates or receives a radiowave with a second frequency
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3~4
AI summary
An antenna device includes: a ground electrode; a first dielectric layer which is provided on one surface of the ground electrode; a feed plate which is provided on a surface of the first dielectric layer opposite from the ground electrode, and which is shorted to the ground electrode; a feed line which feeds to the feed plate; a second dielectric layer which is provided in such a manner as to sandwich the feed plate in combination with the first dielectric layer; and a radiation electrode which is provided on a surface of the second dielectric layer opposite from the feed plate, and which is fed by being electrically connected to the feed plate at a feed point and thereby radiates or receives a radiowave with a first frequency.