Jose M Roman

US Patent:

61374423, Oct 24, 2000

Filed:

Apr 1, 1998

Appl. No.:

9/058352

Inventors:

Jose E. Roman - Alexandria VA
Michael Frankel - Crofton MD
Ronald D. Esman - Burke VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

H01Q 322

US Classification:

342375

Abstract:

A new fiber optic based beamforming architecture for a time steered phased rray 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.