Apparatus for controlling indoor electromagnetic signal propagation

• US 5,276,277 A
• Filed: 12/16/1992
• Issued: 01/04/1994
• Est. Priority Date: 06/12/1991
• Status: Expired due to Term

• Current Assignee: Bellsouth Intellectual Property Corporation (AT&T, Inc.)
• Original Assignee: BellSouth Corporation (AT&T, Inc.)
• Inventors: Hightower, Neale C., O'Neil, Douglas R.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Ledynh, Bot L.
• Application Number:
  US07/991,437
• Time in Patent Office: 384 Days
• Field of Search: 174/35 R, 174/35 MS, 361/424, 219/10.55 R, 219/10.55 D, 333/236, 333/243
• US Class Current: 174/376
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
• CPC Class Codes: H05K 9/0003 Shielded walls, floors, ceilings, e.g. wallpaper, wall panel, electro-conductive plaster, concrete, cement, mortar

Abstract

A system for the establishment and control of an electromagnetic signal propagation environment containing a particular set of desirable radio frequency characteristics within a bounded area. The bounded area is typically either a business office environment or a residential environment. The electromagnetic signal propagation control system provides interference rejection by preventing electromagnetic interference signals from entering an enclosure to interfere with an enclosed communications system or by preventing signals generated by the enclosed communications system from exiting the enclosure and interfering with another nearby communications system. The system also customizes the electromagnetic signal environment to improve communications within interior areas otherwise blocked from signal propagation and to absorb signal reflections from interior surfaces that may cause interference for the enclosed communications system. In addition, the system selectively rejects or accepts electromagnetic signals passing into and exiting from the enclosure to permit desired radio frequency communications between a communications system inside the enclosure and a second system outside the enclosure. The system is installed by utilizing aesthetically appealing building materials comprising conductive, absorptive, reflective, or frequency selective electromagnetic characteristics.

Claims

1. Apparatus for selective control of propagation of electromagnetic signals including the signals of at least one wireless communications system operating within a certain frequency range throughout a bounded region, the apparatus comprising:

shielding means for attenuating said electromagnetic signals within said certain frequency range that enter or leave said bounded region; and

filtering means permitting the relatively unattenuated passage across the boundary of signals in at least one second frequency range outside said certain frequency range,

so that users of each wireless communications system within said bounded region can communicate therein without interfering with or interference from another wireless communications system using the same frequency range and located outside said bounded region, and also can communicate through said boundary and outside said bounded region with an exterior wireless communications system operating in said one of said second frequency range.

2. Apparatus as in claim 1, wherein:

said shielding means comprises a band-reject filter spatially substantially coextensive with said boundary of said region.

3. Apparatus as in claim 1, wherein:

said filtering means comprises a filter spatially substantially coextensive with the boundary of the region.

4. Apparatus as in claim 1, wherein:

said bounded region comprises a space defined by structural means; and

said shielding means comprises a band-reject filter spatially substantially coextensive with said structural means.

5. Apparatus as in claim 1, wherein:

said bounded region comprises a space defined by structural means; and

said filtering means comprises a filter spatially substantially coextensive with said structural means.

6. Apparatus for selective control of propagation of electromagnetic signals including the signals of at least one communications system operating within a certain frequency range throughout a bounded region, the apparatus comprising:

shielding means for attenuating said signals within said certain frequency range that enter or leave said bounded region;

filtering means permitting the relatively unattenuated passage across the boundary of signals in at least one second frequency range outside said certain frequency range; and

signal leveling means within said bounded region for selectively customizing the propagation of selected electromagnetic signals within said certain frequency range such that said propagation of said selected signals is relatively uniform throughout said bounded region, so as provide effective communications operations by said communications system operating within said certain frequency range,

so that users of each communications system within said bounded region can communicate therein without interfering with or interference from another communications system using the same frequency range and located outside said bounded region, and also can communicate through said boundary and outside said bounded region with an exterior communications system operating in said second frequency range.

7. Apparatus as in claim 6, wherein:

said shielding means comprises a band-reject filter spatially substantially coextensive with said boundary of said region.

8. Apparatus as in claim 6, wherein:

said filtering means comprises a filter spatially substantially coextensive with said boundary of said region.

9. Apparatus as in claim 6, wherein:

said signal leveling means is spatially substantially coextensive with said boundary of said region and is selected from the group consisting of a signal reflective means, and a signal absorptive means, and a signal cancellation means.

10. Apparatus as in claim 6, wherein:

said bounded region comprises a space defined by a structural means; and

said shielding means comprises a band-reject filter spatially substantially coextensive with said structural means.

11. Apparatus as in claim 6, wherein:

said bounded region comprises a space defined by a structural means; and

said filtering means comprises a filter spatially substantially coextensive with said structural means.

12. Apparatus as in claim 6, wherein:

said bounded region comprises a space defined by a structural means; and

said signal leveling means is spatially substantially coextensive with said structural means and is selected from the group consisting of a signal reflective means, a signal absorptive means, and a signal cancellation means.

13. Apparatus as defined in claim 6, wherein:

said bounded region comprises a space defined by a structural means.

14. Apparatus as defined in claim 13, wherein:

said structural means comprise building materials that display selected electromagnetic spectrum characteristics.

15. Apparatus as defined in claim 14, wherein:

said shielding means is spatially substantially coextensive with said structural means;

said filtering means is spatially substantially coextensive with said structural means; and

said signal leveling means is spatially substantially coextensive with said structural means.

16. Apparatus as defined in claim 15, wherein:

said shielding means is a band-reject filter.

17. Apparatus as defined in claim 15, wherein:

said filtering means is selected from the group consisting of a band-pass filter, a high-pass filter, and a low-pass filter.

18. Apparatus as defined in claim 15, wherein:

said signal leveling means is selected from the group consisting of a signal absorptive means, a signal reflective means, and a signal cancellation means.

19. Apparatus as defined in claim 15, wherein:

said shielding means comprises said building materials displaying frequency selective electromagnetic characteristics that attenuate said signals within said certain frequency range.

20. Apparatus as defined in claim 15, wherein:

said filtering means comprises said building materials displaying frequency selective electromagnetic characteristics that allow said signals of said second frequency range to pass through said building materials.

21. Apparatus as defined in claim 15, wherein:

said signal leveling means comprises building materials displaying a selected absorptive electromagnetic characteristic to absorb said selected signals within said first frequency range, reflective electromagnetic characteristics to reflect said selected signals within said certain frequency range, or a combination of said characteristics.

22. Apparatus as defined in claim 13, wherein:

said communications system operating within each certain frequency range is a wireless communications system.

23. Apparatus for selective control of propagation of electromagnetic signals including the signals of at least one communications system operating within a certain frequency range through a bounded region, the apparatus comprising:

shielding means for attenuating said electromagnetic signals within said certain frequency range that enter or leave said bounded region; and

filtering means permitting the relatively unattenuated passage across the boundary of signals in at least one second frequency range outside said certain frequency range, said filtering means spatially substantially coextensive with said boundary of said region,

so that users of each communications system within said bounded region can communicate therein without interfering with or interference from another communications system using the same frequency range and located outside said bounded region, and also can communicate through said boundary and outside said bounded region with an exterior communications system operating in said one of said second frequency range.

24. Apparatus as in claim 23, wherein:

said shielding means comprises a band-reject filter spatially substantially coextensive with said boundary of said region.

25. Apparatus as in claim 23, wherein:

said bounded region comprises a space defined by structural means;

said shielding means comprises a band-reject filter spatially substantially coextensive with said structural means; and

said filtering means comprises a filter spatially substantially coextensive with said structural means.