Mobile Terminal Antenna SAR Reduction via Dynamic Power Control
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Solution Overview
Problem
Current mobile terminal antenna designs face issues where the specific absorption rate (SAR) of RF signals is high when the top antenna is used, potentially causing harm to the user's head during phone calls, due to the switching mechanism that reduces communication performance when the bottom antenna is held.
Innovation Solution
A method that examines and compares the signal magnitudes of the top and bottom antennas in real-time during communication, switching the communication workload to the top antenna and reducing its RF transmitting power if the top antenna has a stronger signal, utilizing a baseband chip and a double pole double throw switch to ensure communication quality and minimize SAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top antenna is used for communication, then the communication performance is improved, but the specific absorption rate (SAR) of the user's head increases causing potential harm
Solution Approach 1:
The patent dynamically adjusts the RF transmitting power parameter of the top antenna based on signal magnitude comparisons. When the top antenna has stronger signal magnitude, the system reduces its RF transmitting power to lower SAR values while maintaining communication functionality. This parameter adjustment resolves the contradiction by optimizing both communication performance and user safety.
Solution Approach 2:
The patent implements a dynamic switching mechanism that continuously monitors signal magnitudes of both antennas and adjusts communication workload distribution in real-time. The system can switch between using the bottom antenna (higher SAR) and top antenna (lower SAR when power reduced) based on current signal conditions, making the antenna selection and power level adaptive rather than fixed.
2Object-affected harmful factors
If the bottom antenna is used for communication, then the SAR value is reduced, but the communication performance deteriorates when the user holds the bottom antenna
Solution Approach 1:
The system dynamically switches between bottom and top antennas based on real-time signal magnitude measurements. When the bottom antenna is held by the user causing poor signal, the system detects this condition and switches to the top antenna, maintaining communication performance. When signal conditions are good, it can use the bottom antenna to reduce SAR exposure.
Solution Approach 2:
The patent employs a feedback mechanism where the baseband chip continuously calculates and compares signal magnitudes of both antennas. This feedback loop enables the system to make informed decisions about antenna selection and power adjustment, ensuring optimal balance between communication performance and SAR reduction.
3Object-affected harmful factors
If the RF transmitting power of the top antenna is reduced, then the SAR value decreases, but the signal strength may be insufficient for reliable communication
Solution Approach 1:
The system adjusts RF transmitting power as a variable parameter based on real-time signal magnitude comparisons. Rather than using a fixed low power level, the top antenna's power is dynamically optimized to provide sufficient signal strength for reliable communication while keeping SAR values as low as reasonably achievable. This resolves the contradiction by making power a flexible parameter rather than a fixed constraint.
Data Source
AI summary
The invention discloses a method for reducing an SAR value of a mobile terminal, a storage medium and a mobile terminal. The method comprises: detecting and comparing signal strengths of an upper antenna and a lower antenna of the mobile terminal in real time during a call; and when it is detected that the signal strength of the upper antenna of the mobile terminal is greater than that of the lower antenna, switching the communication work of the mobile terminal to the upper antenna, and reducing the radio frequency transmitting power of the upper antenna. By adoption of the scheme, the SAR value of the mobile terminal can be reduced.