True Time Delay and Constant Phase Shift Circuit Elements

This program is aimed at the development of low loss (less than 1dB), wide band, true-time-delay phase shifter circuits using thin-film BST (Barium Strontium Titanate, a tunable dielectric). Recent advances in BST deposition technology have led todramatic improvements in material quality, making BST suitable for millimeter-wave circuit components. First, we will develop physics-based equivalent-circuit models for passive structures on a variety of substrates, and optimize BST varactors for lowloss in the Ka-band. In addition, we will model distributed-circuit delay-lines using physics-based equivalent-circuit models for BST and MMIC varactors. This will quantify frequency and temperature-dependence of insertion loss and phase delay in a50-Ohm environment in terms of device and embedding circuit parameters. Modeling of IMD in distributed-circuit phase shifters to quantify IP3 in terms of fundamental parameters such as tunability, breakdown field, and loss will be performed. Additionally,proposed constant-phase shifting devices will be investigated.The drastic cost reduction of phased array antennas requires a paradigm shift in design strategy. Phase shifters are a critical component of a phased array that enables the antenna to activelysteer a beam and is also the cost driver of the array. Phase shifters have significant RF loss and therefore amplification must be provided in front of the phase shifter to compensate for this loss. Theoretically if a phase shifter could be designed withlittle or no loss up to 80% of the amplifiers could be deleted from a phased array system. This proposed SBIR program is therefore targeting a critical problem and technology barrier that will enable new paradigm shifts in phased-array development,opening up a potentially vast market.