Wireless Terminal Stub Structure for Lower SAR and Radiation Loss
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Solution Overview
Problem
The absorption of electromagnetic waves by the human body, leading to reduced radiation efficiency and increased specific absorption rate (SAR), which affects user experience and health, due to the proximity of wireless terminals to the body.
Innovation Solution
Incorporation of a loss reduction structure with symmetrically arranged metal stubs on the housing of wireless terminals to counteract induced currents on the body surface, thereby reducing electromagnetic wave absorption and enhancing radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the wireless terminal is placed close to the body for portability and convenience, then ease of operation is improved, but the human body absorbs electromagnetic waves leading to reduced radiation efficiency and increased SAR
Solution Approach 1:
The patent introduces a loss reduction structure as an intermediary component between the antenna and the human body. This structure includes a first stub and a second stub that are symmetrically arranged and electrically connected to the circuit board. The stubs generate induced currents that are equal in magnitude but opposite in direction, which cancel out the electromagnetic fields that would otherwise be absorbed by the human body, thereby reducing energy loss while allowing the terminal to remain close to the body
Solution Approach 2:
The loss reduction structure performs preliminary anti-action by preemptively generating counteracting electromagnetic fields before the human body can absorb the antenna's radiation. The first stub and second stub are designed to produce induced currents that oppose the original electromagnetic field, effectively neutralizing the harmful absorption effect before it occurs. This allows the terminal to maintain close proximity to the body without suffering from reduced radiation efficiency
2Ease of operation
If the wireless terminal is placed close to the body for convenience, then ease of operation is improved, but specific absorption rate increases affecting health safety
Solution Approach 1:
The loss reduction structure serves as a protective intermediary between the antenna and the human body. The symmetrically arranged first stub and second stub generate counteracting electromagnetic fields that reduce the net electromagnetic energy absorbed by the human body, thereby lowering the specific absorption rate while allowing convenient close placement of the terminal
Solution Approach 2:
The patent converts the potentially harmful electromagnetic interaction with the human body into a beneficial effect. By introducing the loss reduction structure with symmetrically arranged stubs, the induced currents in the stubs create electromagnetic fields that cancel out the harmful absorption, transforming the harmful close-proximity effect into a beneficial reduction of SAR while maintaining convenience
3Loss of energy
If a loss reduction structure with metal stubs is added to reduce electromagnetic wave absorption, then radiation efficiency is improved, but device complexity increases
Solution Approach 1:
The loss reduction structure is segmented into distinct functional components: a first stub and a second stub that are symmetrically arranged and electrically connected to the circuit board. This segmentation allows each stub to be independently optimized for generating counteracting electromagnetic fields, improving radiation efficiency while maintaining a relatively simple overall structure that can be integrated into the existing terminal design
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
Significantly reduces induced currents on the body surface, improving radiation efficiency and decreasing SAR, thus enhancing user experience and health safety.
Implementation Method 1
When the first side plate of the housing is close to or attached to a human body, because the current direction on the first stub is opposite to that on the second stub, induced currents on a body surface of the human body may also have opposite directions correspondingly. In this case, currents in a region that is of the body surface and that is close to the connection stub substantially cancel each other out.
Data Source
AI summary
A wireless terminal includes a housing, an antenna, a circuit board, and a loss reduction structure. The housing has a first side plate. The circuit board is arranged proximate to and facing the first side plate, and the circuit board is a ground end of the antenna. The loss reduction structure is made with a metal material. The loss reduction structure includes a connection stub, a first stub, and a second stub. The connection stub is electrically coupled to the circuit board. The first stub and the second stub are located on two sides of the connection stub, and both are coupled to the connection stub. The first stub and the second stub are proximate to the first side plate and are arranged in a direction parallel to the first side plate.