Antenna Hopping Across Multiple Antennas for SAR Reduction
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Solution Overview
Problem
Wireless communication devices face challenges in meeting regulatory SAR requirements without reducing TX power and using expensive SAR sensors, which affect system performance and link reliability.
Innovation Solution
Implementing multiple antenna configurations and antenna switching mechanisms to hop the transmit signal at regular intervals, reducing hot spots and eliminating the need for SAR sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If SAR sensors are used to detect human proximity and reduce TX power, then SAR regulatory requirements are met, but system performance and link reliability deteriorate due to power back-off
Solution Approach 1:
The patent segments the transmission function across multiple antennas, switching between them in different time intervals. This allows the system to meet SAR requirements by distributing exposure across multiple antenna elements while maintaining full TX power on the active antenna, thereby avoiding the performance degradation associated with power back-off.
Solution Approach 2:
The patent implements periodic switching between multiple antennas at defined time intervals. This periodic action ensures that no single antenna continuously exposes a specific body region to high RF energy, meeting SAR requirements while maintaining full transmit power during each interval, thus preserving link reliability.
2Object-affected harmful factors
If SAR sensors are used to detect human proximity, then SAR regulatory requirements are met, but device cost and design complexity increase
Solution Approach 1:
The patent extracts and eliminates the SAR sensor component from the system by replacing it with a software-based antenna switching mechanism. This approach removes the need for expensive, area-consuming hardware sensors while achieving SAR compliance through intelligent transmission management across multiple antennas.
Solution Approach 2:
The patent substitutes the mechanical/hardware-based SAR sensing system with a software-controlled antenna switching system. Instead of using physical sensors to detect proximity and trigger power reduction, the system uses baseband processing to manage antenna selection, replacing complex hardware with simpler software control logic.
3Object-affected harmful factors
If SAR sensors are used to detect human proximity, then SAR regulatory requirements are met, but device area and cost increase
Solution Approach 1:
The patent removes the physical SAR sensor components from the device architecture, eliminating the area they would occupy on the PCB and within the device form factor. The solution achieves SAR compliance through antenna switching controlled by existing baseband processing resources, requiring no additional hardware space.
Solution Approach 2:
The patent leverages the existing multi-antenna infrastructure already present in modern wireless devices for other purposes (such as MIMO and diversity) and repurposes it for SAR compliance. This multi-functional use of existing components eliminates the need for dedicated SAR sensor hardware, saving device area.
Data Source
AI summary
A method comprising: retrieving a predefined power threshold; determining a transmission power of a transmitting antenna, wherein the transmitting antenna is actively transmitting a signal; retrieving a predefined transmission time interval; determining that the transmission power exceeds the predefined power threshold; determining a duration of transmitting the signal; comparing the duration with the predefined transmission time interval; and switching transmitting the signal from the transmitting antenna to a further antenna when the duration equals the predefined transmission time interval.