1. Field of the Invention
The present invention relates to a portable electronic device, and in particular relates to a portable electronic device satisfying HAC requirements with a decreased SAR value.
2. Description of the Related Art
SAR and HAC are indices that measure the extent of radiation influence upon human health and hearing aid equipment, respectively. A high SAR value resulting from electromagnetic wave radiation may cause human health problems. Thus, mobile phones must pass SAR requirements (e.g. FCC & CE requirements). Mobile phones with excessive HAC values hinder audiphone's functions. Thus, 50% of the mobile phones sold in North America by a manufacturer must pass HAC requirements.
To pass SAR and HAC requirements, several conventional solutions are applied in mobile phone design: (a) board end power or antenna radiation efficiency is decreased to reduce radiation energy; (b) electric field distribution is modified by adding a metal element corresponding to an antenna; or (c) the antenna is disposed away from a radiation interference area thereof (e.g. away from amplifier.) However, the conventional solutions may deteriorate communications quality, reduce design flexibility, or increase hardware costs.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
An antenna is provided. The antenna includes a radiator, a feed conductor and a ground conductor. The radiator includes a body and a element. An aperture is formed on the body, and the body encloses the aperture. The element is connected to the body and extended into the aperture, wherein the element is connected to the body at a location. The feed conductor is connected to the body, wherein a signal, fed to the body by the feed conductor, travels on the body, and passes the location to the element. The ground conductor is connected to the body.
In one embodiment, a path length from the feed conductor to the location is 1/4λ, wherein λ is a wavelength of the signal.
In another embodiment, a path length from the feed conductor to the location is 1/2λ, wherein λ is a wavelength of the signal.
In one embodiment, a portable electronic device is provided, wherein the feed conductor and the ground conductor electrically connect the body (antenna) to a circuit board thereof, and the antenna modifies an electric field distribution of the circuit board.
The antenna of the embodiment of the invention modifies an electric field distribution on a ground layer of a circuit board, and reduces the electric field intensity around the amplifier to improve HAC and SAR performance. In one embodiment of the invention, the HAC performance can be improved to level M3 (68.5 V/m). Additionally, the antenna can be disposed near the amplifier of a portable electronic device, without negatively effecting HAC requirement of the portable electronic device.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
With reference to
The antenna of the embodiment of the invention modifies an electric field distribution on a ground layer of the circuit board, and reduces the electric field intensity around the amplifier to improve HAC and SAR performance. In one embodiment of the invention, the HAC performance can be improved to level M3 (68.5 V/m). Additionally, the antenna can be disposed near the amplifier of the portable electronic device, without negatively effecting HAC recruitment of the portable electronic device.
With reference to
Resistance matching and bandwidth of the antenna of the invention can be modified by changing the shapes of the body, the aperture and the element. The path length from the feed conductor to the location can be within a range from 1/2λ to 1/4λ.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
This application claims the benefit of provisional Application No. 61/235,763, filed Aug. 21, 2009.
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Entry |
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Number | Date | Country | |
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20110043421 A1 | Feb 2011 | US |
Number | Date | Country | |
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61235763 | Aug 2009 | US |