Patent ID: 7609971
Filing Date: 2009-10-27
Classification: H01Q

Abstract:
1. An electro optical scanning antenna comprising: a first variable wavelength tunable laser having an output wavelength variable within a first range, a first microwave source which amplitude modulates an optical output from said first laser via a first optical modulator and produces a modulated first output, a second variable wavelength tunable laser having an output wavelength variable within a second range, said second range being mutually exclusive of said first range, a second microwave source which amplitude modulates an optical output from said second laser via a second optical modulator and produces a modulated second output, an optical combiner which combines said first and second modulated laser outputs into a combined output signal, a control circuit which controls the wavelength of said lasers, an antenna array having a plurality of radiators aligned adjacent each other, a photodetector associated with each said radiator to convert the combined optical output from said lasers to microwave signals, each said microwave signals being connected to its associated radiator, a plurality of optical beam splitters, each beam splitter having an input and a first and a second output so that a portion of light entering said input is directed to said first output and the remainder of the light entering said input is directed to said second output, said first output of each beam splitter being optically coupled to one of said optical detectors, a plurality of first optical wavelength-dependent time delay elements operable within said first range and a plurality of second optical wavelength-dependent time delay elements operable within said second range, one of said first optical wavelength-dependent time delay elements and one of said second optical wavelength-dependent time delay elements being optically connected in series between the second output of each beam splitter and said input of the beam splitter associated with the adjacent radiator, said combined output signal being optically coupled to said input of the first beam splitter.