Multi-Antenna Grip Sensing for SAR-Compliant RF Power Control
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Solution Overview
Problem
Existing electronic devices face challenges in satisfying Specific Absorption Rate (SAR) regulations without reducing maximum output power or antenna size, which affects performance and increases production costs when using proximity sensors to detect user grip.
Innovation Solution
The electronic device employs multiple antennas with associated grip sensors to detect proximity of a dielectric body, allowing for increased recognition range without enlarging the antennas, thereby maintaining optimal transmission power and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the maximum output power of the electronic device is reduced to satisfy SAR regulations, then SAR compliance is improved, but the performance of the electronic device deteriorates
Solution Approach 1:
The system performs preliminary detection of dielectric body proximity using grip sensors before transmission occurs. When a dielectric body is detected within a predetermined distance, the system proactively adjusts transmission power to a lower level in advance, preventing SAR violations while maintaining high power when safe. This preliminary action allows the device to satisfy SAR regulations without permanently reducing performance.
2Length of stationary object
If the size of the antenna is increased to increase the recognition distance of the antenna, then the recognition distance is improved, but the space for mounting other components is reduced and production costs increase
Solution Approach 1:
The system divides the detection function into multiple grip sensors positioned at different locations on the device. Each sensor covers a specific zone, and their combined coverage achieves the required recognition distance without needing a single large antenna. This segmentation allows compact antenna design while maintaining adequate detection range for SAR compliance.
3Length of stationary object
If the maximum output power is reduced to increase the recognition distance of the antenna, then the recognition distance is improved, but the performance of the electronic device is reduced
Solution Approach 1:
The system dynamically adjusts transmission power based on real-time proximity detection. When no dielectric body is detected, the system operates at maximum output power for optimal performance. When a dielectric body approaches within the predetermined distance, the system dynamically reduces power to maintain SAR compliance. This dynamic adjustment maintains both recognition distance capability and device performance without permanent power 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 approach satisfies SAR regulations while ensuring stable communication performance and preventing frequent power adjustments, optimizing RF performance by securing a stable communication range without enlarging the antennas.
Implementation Method 1
a first grip sensor configured to detect proximity of an external dielectric body based on a capacitance change of the first antenna
Data Source
AI summary
An electronic device is provided. The electronic device includes a first antenna which transmits/receives a radio frequency (RF) signal, a second antenna which transmits/receives an RF signal, a third antenna which transmits/receives an RF signal, a first grip sensor sensing a proximity of an external dielectric body, a second grip sensor sensing a proximity of an external dielectric body, a third grip sensor sensing a proximity of an external dielectric body, and a processor operatively connected to the first grip sensor, the second grip sensor, and the third grip sensor, wherein upon sensing proximity of an external dielectric body, the first grip sensor, the second grip sensor, and the third grip sensor transmit proximity information to the processor, and upon receiving proximity information from the second grip sensor and the third grip sensor, the processor determines that an external dielectric body is in proximity to the first grip sensor.