New microwave circuits for programmable voltage standards using high-temperature Josephson junction arrays

New microwave circuits for voltage standard application containing 256 shun ted bicrystal junctions were designed and investigated. The series array fo llows a meander Line, which prevents the uniform distribution of microwave current along the array. To overcome this drawback, we are placing the mean der parallel to a coplanar waveguide line. This provides parallel feeding o f microwave power to series connected junctions. A circuit divided in 8 sub -arrays represents a seven-bit digital-to-analog converter. At a frequency f = 27332 MHz and for a constant power each of the segments of the array de monstrated the first current step at 78 K.