Stepped Mobile Antenna Design for SAR Reduction
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Solution Overview
Problem
Existing mobile device antennas face challenges in reducing Specific Absorption Rate (SAR) while maintaining Over the Air RF Performance (OTA) characteristics, as improvements in SAR often result in degradation of OTA characteristics.
Innovation Solution
The design incorporates an antenna carrier with first and second antenna radiators disposed on one surface, maintaining their effective volumes and having a height difference to reduce SAR while preventing degradation of OTA characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna radiator size, grounded surface area, and height between emitter and grounded surface are increased to improve radiating performance, then OTA characteristic is improved, but SAR increases
Solution Approach 1:
The patent introduces a stepped configuration where the first and second antenna radiators are positioned at different heights on the antenna carrier, creating a three-dimensional spatial arrangement. This dimensional change allows the radiators to maintain effective radiation volume while reducing the near field electromagnetic energy concentration that causes high SAR values.
Solution Approach 2:
The patent applies different spatial positions and orientations to different parts of the antenna system. The first antenna radiator is positioned at a first height while the second antenna radiator is positioned at a second height, creating local variations in the electromagnetic field distribution that reduce overall SAR while maintaining OTA performance.
2Object-affected harmful factors
If conduction power or emission power is reduced to improve SAR performance, then SAR is reduced, but OTA characteristic degrades
Solution Approach 1:
The patent changes the spatial parameters of the antenna radiators by positioning them at different heights (first height and second height) on the antenna carrier. This parameter change optimizes the electromagnetic field distribution, allowing the antenna to maintain effective radiation power for good OTA performance while reducing the concentration of near field energy that causes high SAR.
Solution Approach 2:
By transitioning from a two-dimensional planar arrangement to a three-dimensional stepped configuration, the patent increases the effective radiation volume without increasing power consumption. This dimensional change allows the antenna to maintain OTA performance while distributing electromagnetic energy more favorably to reduce SAR.
3Reliability
If the antenna radiator is fixed to an antenna carrier installed in the main board to improve radiating performance, then OTA characteristic is improved, but SAR increases due to increased near field strength
Solution Approach 1:
The patent employs a stepped configuration on the antenna carrier where radiators are positioned at different heights, creating a three-dimensional radiation pattern. This dimensional approach increases the effective radiation volume and improves OTA performance while distributing the electromagnetic field to reduce near field concentration and SAR values.
Solution Approach 2:
The antenna system is segmented into multiple radiators (first and second antenna radiators) positioned at different heights on the carrier. This segmentation allows each radiator to contribute to the overall radiation pattern, improving OTA performance while the distributed configuration reduces the concentration of electromagnetic energy in the near field, thereby reducing SAR.
Data Source
AI summary
An antenna of a mobile device is provided. The antenna includes two antennas that are disposed to be stepped from each other, thereby preventing degradation of an OTA characteristic and reducing an SAR. The antenna includes first and second surfaces stepped from each other on the top surface of an antenna carrier, and a low-band antenna emitter disposed on the first surface and a high-band antenna emitter disposed on the recessed second surface.