Ultrabroadband Phased-Array Receivers Based on Optical Techniques

Military operations require the ability to locate and identify electronic emissions in the battlefield environment. However, developments in RADAR and communications technology are making it harder to effectively identify these broadband and increasingly dynamic emissions. To this end, under this effort a broadband imaging receiver for the location and identification of microwave and millimeter-wave emitters has been developed. This approach utilizes photonic techniques to realize an imaging receiver that enables us to capture and convert signals across an array using photonic modulators, routing these signals to a central location using fiber optics, and spatially and spectrally processing the incoming signals using simple free space optics. Over the course of this effort, the capability of using such an optically enabled imaging receiver array to simultaneously detect, locate, and down convert multiple high-gain beams in a non-blocking fashion using an optically enabled imaging receiver array has been demonstrated for the first time. This technology was demonstrated first by adapting an existing 35 GHz passive millimeter wave imager that predated this effort, and subsequently by building a four element broadband array, which is capable of detection over the range of 4-50 GHz.