Dual-Radiator Low-SAR Antenna for Mid-High Frequency Bands
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Solution Overview
Problem
Existing antennas face challenges in maintaining good radiation performance while minimizing Specific Absorption Rate (SAR) values, especially when positioned at the upper portion of electronic devices, as they tend to generate high radiation towards the user's head, leading to potential electromagnetic radiation damage.
Innovation Solution
A low-SAR antenna design incorporating two radiation structures, where a first radiation structure operates at low frequencies and a second radiation structure acts as a parasitic structure to excite middle/high frequencies, avoiding higher-order modes that increase SAR values, thus ensuring effective radiation performance without excessive radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is disposed at an upper portion of the electronic device, then the radiation performance is improved, but the SAR value increases
Solution Approach 1:
The antenna is divided into two separate radiation structures: a first radiation structure for low frequency bands and a second radiation structure for middle/high frequency bands. This segmentation allows each structure to be optimized for its specific frequency range, enabling the second structure to achieve good radiation performance at middle/high frequencies without generating excessive SAR values, thus resolving the contradiction between radiation performance and SAR control.
Solution Approach 2:
Different radiation structures are used for different frequency bands: the first radiation structure (with larger ground electrode area) handles low frequencies, while the second radiation structure (with smaller ground electrode area) handles middle/high frequencies. This local differentiation in structure design allows each part to perform its specific function optimally, achieving good radiation performance at middle/high frequencies while controlling SAR values through the appropriate structural configuration.
2Object-affected harmful factors
If the antenna is disposed at a lower portion of the electronic device, then the SAR value is reduced, but the radiation performance deteriorates
Solution Approach 1:
The antenna system is segmented into two independent radiation structures that can be positioned at different locations within the electronic device. The first radiation structure can be placed at the lower portion to minimize SAR impact, while the second radiation structure is positioned at the upper portion to ensure good radiation performance at middle/high frequencies. This spatial segmentation resolves the contradiction between SAR reduction and radiation performance maintenance.
3Device complexity
If a single radiation structure is used, then the device complexity is reduced, but the frequency band coverage is limited
Solution Approach 1:
The antenna system achieves multi-functionality by incorporating two radiation structures that can operate across different frequency bands. The first radiation structure covers low frequency bands, while the second radiation structure covers middle/high frequency bands. This universal design allows a single antenna system to handle multiple frequency bands effectively, providing broad frequency band coverage without requiring separate antenna systems for each band, thus balancing complexity and versatility.
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
The proposed antenna design achieves low SAR values while maintaining good radiation performance across middle/high frequencies, reducing the risk of electromagnetic radiation damage to users and improving communication efficiency.
Implementation Method 1
a second radiation structure, a parasitic structure, is configured to be electrically coupled to the first radiator through the first gap to excite a current on the second radiator
Data Source
Figure 1
Figure 2~3
Figure 4(a)~4(c)
AI summary
Embodiments of this application provide a low-SAR antenna and an electronic device, which relates to the field of electronic devices and can provide good radiation performance at middle/high frequencies and have a low SAR value. The specific solution is as follows. A first radiation structure includes a first radiator, and a second radiation structure includes a second radiator. A first end of the first radiator and a first end of the second radiator form a first gap. A second end of the first radiator is free, and a second end of the second radiator is grounded. A feed point of the antenna is coupled to the first radiator, and the first radiator is divided into a first portion and a second portion that are delimited by the feed point. In a case that the antenna is in operation, the first portion of the first radiator and the second radiator work together in a first frequency band and a second frequency band, and a frequency of the first frequency band is less than a frequency of the second frequency band.