Apparatus and method for improving specific absorption rate (SAR) using metallic sheets as reflectors
Disclosed herein includes a wireless electronic device, including an outer casing, an antenna, and a metallic sheet. The outer casing may be electrically non-conductive. The antenna may be disposed within the outer casing and configured to perform wireless communication of signals at an operating wavelength of λ unit length. The metallic sheet may be disposed on a portion of the outer casing and placed at a distance of at least λ/25 unit length apart from the antenna. The metallic sheet may be configured to shield a subject exposed to energy radiated by the antenna to limit the specific absorption rate (SAR) of the subject to less than 1.6 W/kg.
1. A wireless electronic device comprising:
an outer casing that is electrically non-conductive;
an antenna disposed within the outer casing, the antenna configured to perform wireless communication of signals at an operating wavelength of λ unit length; and
a metallic sheet disposed on a portion of the outer casing and placed at a distance of at least λ/25 unit length apart from the antenna, the metallic sheet configured to shield a subject exposed to energy radiated by the antenna to limit a specific absorption rate (SAR) of the subject to less than 1.6 W/kg,
wherein the metallic sheet at least partially overlaps a radiation pattern of the antenna in an area including a radiation hotspot of the radiation pattern,
wherein the radiation hotspot is a portion of the radiation pattern where a radiation pattern intensity is highest in a certain direction, and
wherein the metallic sheet is configured to reflect a radio frequency (RF) electromagnetic field that is generated by the antenna toward the subject.
2. The wireless electronic device of claim 1 , wherein the metallic sheet is disposed on an inner surface of the outer casing.
3. The wireless electronic device of claim 1 , wherein the metallic sheet includes at least one of copper, aluminum, nickel, or platinum, silver, or gold.
4. The wireless electronic device of claim 1 , wherein the metallic sheet is a metallic tape attached to the outer casing.
5. The wireless electronic device of claim 1 , wherein the antenna is placed at a range of 3-7 millimeter (mm) apart from the outer casing.
6. The wireless electronic device of claim 1 , wherein the metallic sheet has substantially a same shape as a shape of the antenna.
7. The wireless electronic device of claim 1 , wherein the metallic sheet has an area greater than or equal to an area of the antenna.
8. The wireless electronic device of claim 1 , wherein the metallic sheet has a thickness greater than or equal to a skin depth of a material of the metallic sheet.
9. The wireless electronic device of claim 1 , wherein the metallic sheet is configured to limit the SAR of the subject to less than 1.2 W/kg.
10. The wireless electronic device of claim 1 , wherein an air gap is present between the antenna and the metallic sheet.
11. The wireless electronic device of claim 1 , wherein an air gap is present between the antenna and the outer casing.
12. The wireless electronic device of claim 1 , wherein the antenna is printed on a surface of an audio box.
13. A method for implementing a wireless electronic device, comprising:
providing an outer casing that is electrically non-conductive;
disposing an antenna within the outer casing, the antenna to perform wireless communication of signals at an operating wavelength of λ unit length; and
disposing a metallic sheet on a portion of the outer casing, at a distance of at least λ/25 unit length apart from the antenna, to shield a subject exposed to energy radiated by the antenna to limit a specific absorption rate (SAR) of the subject to less than 1.6 W/kg,
wherein the metallic sheet at least partially overlaps a radiation pattern of the antenna in an area including a radiation hotspot of the radiation pattern
wherein the radiation hotspot is a portion of the radiation pattern where a radiation pattern intensity is highest in a certain direction, and
wherein the metallic sheet is configured to reflect a radio frequency (RF) electromagnetic field that is generated by the antenna toward the subject.
14. The method of claim 13 , wherein disposing the metallic sheet comprises:
disposing the metallic sheet on an inner surface of the outer casing.
15. The method of claim 13 , wherein:
the metallic sheet is a metallic tape, and
disposing the metallic sheet comprises attaching the metallic tape to the outer casing.
16. The method of claim 13 , wherein disposing the antenna comprises:
placing the antenna at a range of 3-7 mm apart from the outer casing.
17. The method of claim 13 , further comprising:
forming an air gap between the antenna and the metallic sheet.
18. The method of claim 13 , further comprising:
forming an air gap between the antenna and the outer casing.
19. The method of claim 13 , wherein disposing the antenna comprises:
printing the antenna on a surface of an audio box.