SEVERAL MICROSTRIP-BASED CONDUCTOR THIN FILM FERROELECTRIC PHASE-SHIFTER DESIGNS USING (YBA2CU3O7-DELTA, AU)/SRTIO3/LAALO3 STRUCTURES/

We have designed, fabricated, and tested several novel microstrip-base d YBa2Cu3O7-delta/SrTiO3/LaAlO3 (YBCO/STO/LAO) and Au/SrTiO3/LaAlO3 (A u/ STO/LAO) phase shifters. The first design consists of eight coupled microstrip phase shifters (CMPS) in series. This design using YBCO ac hieved a relative insertion phase shift (Delta phi) of 484 degrees wit h a figure of merit of 80 degrees/dB at V-dc = 375 V, 16 GHz, and 40 K . A Delta phi of 290 degrees was observed while maintaining the insert ion loss below 4.5 dB. At 77 K, a Delta phi of 420 degrees was obtaine d for this phase shifter at the same bias and frequency. Both results correspond to an effective coupling length of 0.33 cm. A second compac t design, consisting of an An meander line and a CMPS section was also tested. Of the two samples tested, the best showed a figure of merit of 43 degrees/dB with Delta phi = 290 degrees and 6.8 dB loss, at 40 K , 10 GHz and 400 V. Experimental and modeling results on these circuit s will be discussed in the context of potential applications.