Opto-electronically controlled frequency selective surface

Details Opto-electronically controlled frequency selective surface Opto-electronically controlled frequency selective surface

1999-02-19

2001-05-15

Wang, Don (Department: 2821)

Communications: radio wave antennas

Antennas

Antenna components

C343S776000, C343S788000

Reexamination Certificate

active

06232931

ABSTRACT:

The present invention relates to frequency selective surfaces, and more particularly, to a frequency selective surface having frequency response characteristics which are opto-electronically modulated by selectively illuminating photonically controlled elements connected across frequency scattering elements integrated in the surface.
BACKGROUND OF THE INVENTION
Frequency selective surfaces (FSS) are used as filters through which electromagnetic energy within a specific frequency range and having a prescribed polarization may be selectively propagated or not propagated. FSSs generally consist of an electrically conductive layer in which patterns of frequency scattering elements, generally in the form of apertures, are formed. The electrically conductive layer is usually supported by a dielectric substrate.
Radomes are enclosures, which protect antennas from the environment and may incorporate FSSs. A typical radome is constructed of a dielectric layer or a combination of dielectric layers which include an FSS to provide frequency selective attributes. However, the FSS is in general static, yielding a fixed pass/stop band performance. A further limitation of conventional radomes is that the enclosed antenna is exposed to many different types of electromagnetic threats, i.e., jammers generating signals in the operating band of the antenna. The radome must pass signals in the antenna operational frequency band for proper functioning of the antenna and associated systems. This exposes the enclosed antenna to jamming signals and other types of interference. Therefore, it is desirable to be able to selectively filter out signals having particular wavelengths over certain intervals of time (e.g., when the enclosed antenna is non-operating or receiving only at a particular wavelength). Moreover, a further need exists for an FSS that has frequency scattering characteristics that may be selectively modulated in time.
SUMMARY OF THE INVENTION
The present invention provides an opto-electronically controlled frequency selective surfaces (FSS) comprising an array of radio frequency scattering elements which may be implemented as slots formed in an electrically conductive layer mounted to a supporting substrate. In another aspect of the invention, the radio frequency scattering elements may be formed of electrically conductive loops mounted to a dielectric substrate. One or more photonically controlled elements (PCE) connected to each of the radio frequency scattering elements may be selectively illuminated to modulate the frequency characteristics of the frequency scattering elements, and hence, of the FSS.
An important advantage of the present invention is that it provides an FSS having a pass/stop band that may be modulated by illuminating specific areas of the surface. This feature is important because it makes the system physically realizable and not excessively costly.


REFERENCES:
patent: 3919699 (1975-11-01), Hartemann
patent: 4476471 (1984-10-01), Sato et al.
patent: 4809011 (1989-02-01), Kunz
patent: 5170169 (1992-12-01), Stephan
patent: 5185613 (1993-02-01), Whatmore et al.
patent: 5208603 (1993-05-01), Yee
patent: 5262796 (1993-11-01), Cachier
patent: 5264859 (1993-11-01), Lee et al.
patent: 5278562 (1994-01-01), Martin et al.
patent: 5298909 (1994-03-01), Peters et al.
patent: 5307077 (1994-04-01), Branigan et al.
patent: 5400043 (1995-03-01), Arceneaux et al.
patent: 5402132 (1995-03-01), Hall et al.
patent: 5436453 (1995-07-01), Chang et al.
patent: 5563614 (1996-10-01), Alden et al.
patent: 5621423 (1997-04-01), Sureau
patent: 5892485 (1999-04-01), Glabe et al.
patent: 5917458 (1999-06-01), Ho et al.
patent: 5949387 (1999-09-01), Wu et al.
patent: 5959309 (1999-09-01), Tsui et al.
patent: 6028692 (2000-02-01), Rhoads et al.

Affiliated with

Also associated with

Rating

Opto-electronically controlled frequency selective surface does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Opto-electronically controlled frequency selective surface, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Opto-electronically controlled frequency selective surface will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2534452