Dynamic SAR Control in Mobile Terminals via Transmit Power Adjustment
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Solution Overview
Problem
Existing methods for reducing the electromagnetic radiation specific absorption rate (SAR) in mobile terminals are inflexible and do not facilitate miniaturization, as they require pre-installation of shielding components that cannot be dynamically adjusted after production.
Innovation Solution
A method where a mobile terminal dynamically collects statistics on average transmit power and adjusts it to maintain an SAR within a preset threshold by controlling transmit power, allowing for flexible SAR management without additional shielding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding components are pre-installed between antenna and human body, then SAR is reduced, but device flexibility is reduced and miniaturization is hindered
Solution Approach 1:
The patent applies dynamics by making the SAR reduction mechanism adjustable after production. The controller dynamically controls the antenna system's parameters (such as impedance, resonance frequency, or radiation pattern) based on detected SAR levels or usage conditions, allowing the terminal to adaptively reduce SAR without fixed pre-installed shielding components. This transforms a static shielding approach into a dynamic, controllable system.
Solution Approach 2:
The patent implements parameter changes by modifying antenna system parameters (impedance, resonance frequency, radiation characteristics) through electronic control rather than physical shielding. The controller adjusts these parameters in response to SAR measurements or predicted SAR conditions, enabling flexible SAR reduction that does not require additional physical space for shielding materials.
2Object-affected harmful factors
If shielding components are pre-installed between antenna and human body, then SAR is reduced, but device size increases
Solution Approach 1:
The patent extracts the SAR reduction function from physical shielding components and implements it through electronic control of the antenna system. By removing the need for additional shielding materials and structures, the solution eliminates the volume increase that would result from pre-installed shielding components while maintaining SAR reduction capability through parameter adjustment.
Solution Approach 2:
The patent uses parameter changes in the antenna system (impedance, resonance frequency, radiation pattern) to achieve SAR reduction without adding physical volume. This electronic parameter control approach replaces bulky shielding materials with software-controlled parameter adjustment, thereby reducing device size while maintaining safety performance.
3Object-affected harmful factors
If transmit power is dynamically adjusted, then SAR is controlled within threshold, but transmission performance may be affected
Solution Approach 1:
The patent applies dynamics by implementing real-time or near-real-time control of antenna parameters based on SAR conditions. The controller continuously monitors or predicts SAR levels and dynamically adjusts antenna parameters to maintain SAR within thresholds while optimizing transmission performance. This dynamic adaptation allows the system to respond to changing conditions and maintain both safety and performance.
Solution Approach 2:
The patent implements feedback by using SAR detection results or predicted SAR values to control the antenna system parameters. The controller receives feedback about SAR levels and adjusts parameters accordingly, creating a closed-loop control system that balances SAR reduction with transmission performance requirements.
Data Source
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AI summary
A method and a device for decreasing an electromagnetic radiation specific absorption rate are disclosed, to resolve a problem that an existing method for decreasing an SAR has comparatively poor flexibility and does not facilitate miniaturization design of a mobile terminal. The method includes: separately collecting, by a terminal, a transmit power of the terminal at different time points in second duration after first duration from a power-on moment, to obtain at least two transmit powers; calculating an average transmit power of the at least two transmit powers; determining based on the average transmit power, an SAR corresponding to the average transmit power; and if the terminal determines that the SAR is greater than a preset threshold, decreasing a transmit power of the terminal after the second duration. In this way, in a process of using the terminal, an SAR value can be dynamically adjusted, flexibility is comparatively high, and the miniaturization design of the terminal can be supported without requiring to add a shielding component between an antenna and a human body when the terminal is produced.