Accession Number:

ADD018891

Title:

Chirped Fiber Grating Beamformer for Phased Array Antennas Field of the Invention

Descriptive Note:

Patent Application, Filed 10 Apr 98,

Corporate Author:

DEPARTMENT OF THE NAVY WASHINGTON DC

Report Date:

1998-04-10

Pagination or Media Count:

23.0

Abstract:

A new fiber optic based beamforming architecture for a time steered phased array antenna based on chirped fiber gratings. All of the gratings are identical in length and period chirp so that they all have the same dispersion, thus at a given optical wavelength they have the same time delay. In a preferred embodiment an optical signal is modulated with an RF signal. The RF modulated optical is split and a portion propagates through a length of fiber to a photodetector feeding an antenna array. The second portion of the optical signal is routed through a circulator, which feeds the optical signal to a chirped fiber grating. The grating reflects and delays the optical signal back to the circulator which routes the reflected optical signal to a second coupler. The amount of delay incurred is determined by the grating dispersion and the wavelength of the optical source. The second splits the time delayed optical signal, passing a portion of the time delayed optical signal to the second antenna element and the other portion to other circulators and ultimately to other antenna elements comprising the antenna array. The time delay imposed on the optical signal through the use of chirped fiber gratings controls the relative timing between the antenna elements, thus allowing one to steer the antenna by changing the wavelength of the optical signal.

Subject Categories:

  • Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE