(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-delta/SrTiO3/LaAlO3 (YBCO/STO/LAO) and Au/SrTiO3/LaAlO3 (Au/STO/LAO) coupled microstrip line phase shifters (CMPS). These CMPS were tested at frequencies within the Ku and K bands (12-20 GHz), at temperatures from 24 to 77 K, and at de voltages (V-dc) from zero to 350 V. A relative 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 77 K, a Delta phi similar to 260 degrees was obtained for the CMPS at the same bias and frequency. Both results correspond to an effective coupling length of 0.33 cm. At both temperatures, the phase shifter exhibits 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 considerations. (C) 1997 American Institute of Physics.