Adaptive Transmit Power Control for Multi-Mode Antenna SAR Compliance
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Solution Overview
Problem
Existing wireless communication devices face challenges in designing antennas that balance strong far-field radiation for communication with minimized Specific Absorption Rate (SAR) to human users, as these requirements often conflict with each other.
Innovation Solution
A radio control system within a communication device that includes a sensor to detect usage modes, a power controller to determine optimal power configurations based on these modes, and a power regulator to apply the appropriate power settings to the transmitted signal, dynamically adjusting transmit power and other radio configurations to optimize SAR, battery life, communication range, and spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is designed to generate strong far field radiation for wireless communication, then communication performance is improved, but Specific Absorption Rate (SAR) increases exceeding regulatory limits
Solution Approach 1:
The patent applies dynamics by making the antenna configuration changeable between at least two different positions or states. The antenna can be dynamically reconfigured based on operational conditions to optimize the balance between far-field radiation performance and near-field SAR exposure, allowing the system to adapt rather than being fixed in a single configuration
Solution Approach 2:
The patent changes physical parameters of the antenna system by utilizing multiple operating positions with different electrical characteristics. Each position alters the antenna's radiation pattern, impedance, and field distribution, thereby changing the relationship between far-field gain and near-field SAR to satisfy both communication requirements and regulatory limits
2Object-affected harmful factors
If multiple operating antenna positions are used to balance SAR and antenna gain, then SAR requirements are satisfied, but communication performance deteriorates due to compromised antenna gain
Solution Approach 1:
The system dynamically selects the appropriate antenna position based on real-time operational conditions. Rather than being stuck in a compromised fixed position, the antenna can switch between positions to optimize performance for each specific scenario, maintaining both SAR compliance and communication effectiveness
Solution Approach 2:
By utilizing multiple operating positions with different electrical parameters, the system can change the antenna's radiation characteristics to achieve the desired balance. Each position offers a different trade-off between SAR and gain, allowing optimization for specific operational requirements
3Object-affected harmful factors
If maximum transmit power is set to limit SAR, then SAR compliance is achieved, but communication range and battery life are compromised
Solution Approach 1:
The system dynamically adjusts transmit power based on the selected antenna position and operational conditions. Rather than using a fixed conservative power level that limits battery life, the system can increase power when the antenna position provides favorable radiation characteristics, thereby extending battery life while maintaining SAR compliance
Solution Approach 2:
The patent changes the transmit power parameter based on antenna position selection. Different positions allow for different maximum power levels that still comply with SAR limits, enabling the system to use higher power (and thus conserve battery) when the antenna configuration supports it
Data Source
AI summary
A radio control system in a wireless communication device includes a sensor operable to detect a change in a use mode of the wireless communication device during a communication session according to a pre-determined list of conditions, the use mode being one of a plurality of use modes that the communication device can operate in. The radio control system also includes a power controller connected to the sensor, that is operable to determine a power configuration according to the user mode detected. The power configuration is adjusted to balance the radio frequency coverage of a signal to be transmitted and the SAR. Of the radiation absorption. Each use mode is a different scenario in which the wireless communication device can be used.