(YBA2CU3O7-DELTA,AU) SRTIO3/LAALO3 THIN-FILM CONDUCTOR FERROELECTRIC COUPLED MICROSTRIPLINE PHASE SHIFTERS FOR PHASED-ARRAY APPLICATIONS/

We report on the design, fabrication, and testing of novel YBa2Cu3O7-d elta/SrTiO3/LaAlO3 (YBCO/STO/LAO) and Au/SrTiO3/LaAlO3 (Au/STO/LAO) co upled microstrip line phase shifters (CMPS). These CMPS were tested at frequencies within the Ku and K bands (12-20 GHz), at temperatures fr om 24 to 77 K, and at de voltages (V-dc) from zero to 350 V. A relativ e insertion phase shift (Delta phi) of 390 degrees was measured for an eight-element YBCO/STO/LAO CMPS at V-dc=350 V, 16 GHz, and 40 K. At 7 7 K, a Delta phi similar to 260 degrees was obtained for the CMPS at t he same bias and frequency. Both results correspond to an effective co upling length of 0.33 cm. At both temperatures, the phase shifter exhi bits a figure of merit of similar to 30 degrees/dB. To our knowledge, these are the best results published so far at these frequencies where miniaturization, insertion loss, and phase delay are key consideratio ns. (C) 1997 American Institute of Physics.