High frequency direction-finding system based on high-Tc Ion-Damaged Josephson Junction SQUID arrays

ABSTRACT: In this STTR phase II, HYPRES and University of California San Diego team will demonstrate a small size, weight and power Direction Finding (DF) system prototype based on SQUID array technology. High sensitivity, linearity, and wide bandwidth of SQUID arrays antenna sensors will be enable close spacing of smaller antennas even for high frequency (HF) range. Our SQUID array designs are based on highly linear bi-SQUID cells arranged into a 2-dimensional (2D) array using our patented coupling-junction synthesis technique. The 2D arrays are fabricated using high-temperature superconductor Ion Damaged Josephson junction fabrication process suitable for integration of large number of SQUID devices on a single chip. This affords the use of small size robust 70K cryocoolers and will make overall system suitable for airborne deployment. The HF DF system comprises of three antenna channels, each consisting of the bi-SQUID 2D array chip, a cold low noise amplifier, pre-amplifier and digital processing module. The entire system fits into a 12 x 5 x 4 cubic inch cryogenic package with an rf-transparent radome. It draws about 85 W power. BENEFIT: The SQUID array technology will be leveraged into several application areas: compact and energy-efficient direction finding and geolocation systems for wide frequency ranges, compact and extremely low noise receivers for satellite and deep space communications, low noise, high sensitivity biomedical imaging systems, secure point-to-point microwave links, biomagnetic sensors, and geomagnetic prospecting. The small footprint, low noise, high sensitivity, high linearity, high directivity and angular accuracy, wide bandwidth SQUID array systems can be installed on moving platforms as it allows maintaining practical pointing alignment of directional antennas while vehicles and aircraft platforms are in motion. It will fit into platform space limitations to allow the installation of the multiple systems enabling low profiles to maintain a small visual and radar target silhouette; fitting into limited electronics rack space; energy-efficient to meet power production limitations on a moving vehicle (motor driven generators).