Reducing SAR in Wireless Terminals with Wave Absorbing Sheets
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Summary
Problems
The challenge is to reduce the Specific Absorption Rate (SAR) of wireless terminals without compromising their wireless performance or user experience, as current methods like reducing transmit power or increasing thickness are not acceptable due to performance and usability concerns.
Innovation solutions
A wireless terminal design featuring a PCB primary board with a diversity antenna, metal shielding covers, and wave absorbing sheets attached to these covers to absorb near-field electromagnetic energy without affecting far-field radiation, thereby reducing SAR values.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the transmit power of the wireless terminal is reduced, then the SAR value is decreased, but the wireless performance is degraded
Why choose this principle:
The patent segments the electromagnetic field into near-field and far-field regions, and applies different treatments to each. Wave absorbing sheets are specifically placed in the near-field region (between the radiator and metal shielding cover) to absorb harmful near-field radiation, while far-field radiation patterns and total radiation power remain unaffected, thus maintaining wireless performance while reducing SAR value.
Principle concept:
If the transmit power of the wireless terminal is reduced, then the SAR value is decreased, but the wireless performance is degraded
Why choose this principle:
The patent introduces wave absorbing sheets as an intermediary material between the radiator and the metal shielding cover. This intermediary selectively absorbs near-field electromagnetic energy without affecting far-field radiation, thereby reducing SAR exposure while preserving the terminal's wireless communication performance.
Application Domain
Data Source
AI summary:
A wireless terminal design featuring a PCB primary board with a diversity antenna, metal shielding covers, and wave absorbing sheets attached to these covers to absorb near-field electromagnetic energy without affecting far-field radiation, thereby reducing SAR values.
Abstract
An embodiment of the present invention discloses a wireless terminal. The wireless terminal according to the embodiment of the present invention includes a PCB primary board, a primary board circuit printed on both sides of the PCB primary board, and a diversity antenna, where the diversity antenna is disposed at an end of the PCB primary board, a first primary board metal shielding cover and a second primary board metal shielding cover are each disposed on the primary board circuit on the both sides of the PCB primary board, a radiator is printed on at least one side panel of the PCB primary board, the radiator and the primary board circuit are located in different areas of the PCB primary board, and a first wave absorbing sheet is attached to the first primary board metal shielding cover and/or the second primary board metal shielding cover.