Large Phased-Array Antenna Multi-Beam Beamformers

Wideband phased array radars are needed for accurate tracking and object classification. This will require the development of improved true time delay (TTD) technology scalable to thousands of elements and capable of multi-beam formation. CalientNetworks proposes to develop 3D micro electrical mechanical systems (MEMS) to demonstrate a true time delay (TTD) unit with 7 bit accuracy supporting 36 antenna elements within a volume of 0.06 m3 and requiring less than 100 W of power. The switch is willbe fasbricated from 2 silicon die containing all switching elements, and is a low cost VLSI technology. The nonblocking aspect of the switch allows multiple beams to be formed (up to 100 in the initial design). This TTD will operate in the L, S and Xradar bands and will support 1500 MHz at X band. Two dimensional scanning can be supported by employing two switches in series. Photonic beam-forming allows the antenna to be remotely sited from the TTD unit and processing electronics with negligibledegradation (0.4 dBe/kmCalient Networks will design a true time delay unit optimized for phased array applications in Phase I. The scalability of the design for 100,000 elements will be addressed in Phase I. This approach could enable a new generation of high resolution, low cost, highly mobile, field deployable radars scalable to 100,000 elements. True time delay has been a major problem, and optical solutions have had too high of loss to be useful for mostapplications; however, that has now changed. Calient Networks has spent over $100 Million developing low loss 256 port photonic switches for the telecommunications market. A new approach to optical switching using 3D micro electrical mechanical systems(MEMS) integrated on a silicon VLSI chip has made this possible. With a modest investment in time and money, military systems can benefit from the innovations in commercial photonic switches. The research under this program could extend beyond militaryradars to commercial radars. Further, the effort here to reduce the size and weight even further gives a competitive advantage in the commercial telecommunications marketplace.