The United States Federal Communications Commission (FCC) is set to enact new regulations in 2005 to improve hearing aid compatibility (HAC) for hearing impaired users of mobile phones. As part of mobile phone HAC assessment, near field components of electro-magnetic fields are measured. The components are comprised of electric and magnetic fields.
What is needed is a method, means, or apparatus for reducing the undesirable effects of electro-magnetic scattering at metallic discontinuities that exist within mobile phone designs.
The present invention uses metallization termination techniques to reduce the electro-magnetic field scattering at the edges of metallized areas including the PCB and metallized housing assemblies. The metallization termination techniques present a gradual transition from high conductivity areas to high impedance areas. The mobile phone antenna illuminates the PCB allowing currents to flow on the PCB. When the currents reach edges of the PCB they flow through a region of increasingly high impedance without reflecting back or scattering.
In a related patent application, a high impedance translucent coating was used to attenuate RF surface waves (electro-magnetic scattering) over a desired region. Such a configuration is effective for attenuating the electric field in the near field region. It also attenuates the generation of surface currents in that region. For improved antenna performance, it may be desirable to allow surface currents to flow on a region of the mobile phone such as the top portion of a flip phone. However, these currents generate scattered electro-magnetic fields at abrupt discontinuities of the PCB and other metallized areas.
As part of hearing aid compatibility (HAC) assessment, near-field components of electromagnetic fields are measured. These components comprise electric and magnetic fields.
A sample electric field distribution for the mobile phone 100 of
The present invention uses metallization termination techniques to attenuate electro-magnetic field scattering at the edges of metallized areas. The metallization termination techniques provide a gradual transition from high conductivity areas to high impedance areas. The mobile phone antenna illuminates the PCB allowing currents to flow on the PCB. When the currents reach edges of the PCB they flow through a region of increasingly high impedance without reflecting back or scattering.
Embodiments of the present invention include a method of attenuating scattering electro-magnetic waves present on metallized areas within a mobile phone that are caused by components within the mobile phone, the method comprising varying the metallization pattern near an edge of the metallized area such that electric current due to scattering electro-magnetic waves present on the metallized area encounters higher impedances as it approaches the edge of the metallized area.
Embodiments of the present invention include a method of attenuating scattering electro-magnetic waves present on metallized areas within a mobile phone that are caused by components within the mobile phone, the method comprising placing capacitive gaps and inductive lines near an edge of the metallized area such that electric current due to scattering electro-magnetic waves present on the metallized area encounters higher impedances due to the capacitive gaps and inductive lines near the edge of the metallized area.
Embodiments of the present invention include a mobile phone that attenuates scattering electro-magnetic waves present on metallized areas within the mobile phone that are caused by components within the mobile phone, the mobile phone comprising: a varied metallization pattern near an edge of metallized areas such that electric current due to scattering electro-magnetic waves present on the metallized areas encounters higher impedances as it approaches the edge of the metallized areas.
Embodiments of the present invention include a mobile phone that attenuates scattering electro-magnetic waves present on metallized areas within the mobile phone that are caused by components within the mobile phone, the mobile phone comprising: capacitive gaps and inductive lines placed near an edge of metallized areas such that electric current due to scattering electro-magnetic waves present on the metallized areas encounters higher impedances due to the capacitive gaps and inductive lines near the edge of the metallized areas.
This application is a divisional application of U.S. patent application Ser. No. 10/710,876, for “Reduction of Near Field Electro-Magnetic Scattering Using High Impedance Metallization Terminations,” filed on Aug. 10, 2004, and that will issue as U.S. Pat. No. 7,376,408, on May 20, 2008, which is incorporated by reference herein in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
5926377 | Nakao et al. | Jul 1999 | A |
5966294 | Harada et al. | Oct 1999 | A |
6150895 | Steigerwald et al. | Nov 2000 | A |
6215373 | Novak et al. | Apr 2001 | B1 |
6557154 | Harada et al. | Apr 2003 | B1 |
6668025 | Sumi et al. | Dec 2003 | B1 |
6775122 | Dishonigh et al. | Aug 2004 | B1 |
6791434 | Tsujiguchi | Sep 2004 | B2 |
6870436 | Grebenkemper | Mar 2005 | B2 |
7180718 | Anthony et al. | Feb 2007 | B2 |
7366554 | Hayes | Apr 2008 | B2 |
20050104678 | Shahparnia et al. | May 2005 | A1 |
20050227665 | Murray et al. | Oct 2005 | A1 |
20060009156 | Hayes et al. | Jan 2006 | A1 |
Number | Date | Country |
---|---|---|
6214799 | Jan 1987 | JP |
63305597 | Dec 1988 | JP |
4189695 | Jul 1992 | JP |
2008509633 | Mar 2008 | JP |
Number | Date | Country | |
---|---|---|---|
20080214136 A1 | Sep 2008 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 10710876 | Aug 2004 | US |
Child | 12121828 | US |