Title :
A novel K-band tunable microstrip bandpass filter using a thin film HTS/ferroelectric/dielectric multilayer configuration
Author :
Subramanyam, G. ; Van Keuls, F. ; Miranda, F.A.
Author_Institution :
Northern Iowa Univ., Cedar Falls, IA, USA
Abstract :
We report on YBCO/strontium titanate (STO) thin film K-band tunable bandpass filters on lanthanum aluminate substrates. The 2 pole filters were designed for a center frequency of 19 GHz and 4% bandwidth. Tunability is achieved through the nonlinear DC electric field dependence of the relative dielectric constant of STO (/spl epsiv//sub rSTO/). Center frequency shifts greater than 2 GHz were obtained at a 400 V bipolar DC bias at temperatures below 77 K, with minimal degradation in the insertion loss of the filters.
Keywords :
band-pass filters; barium compounds; circuit tuning; ferroelectric thin films; high-temperature superconductors; lanthanum compounds; losses; microstrip filters; microwave filters; passive filters; permittivity; strontium compounds; superconducting microwave devices; superconducting thin films; yttrium compounds; 19 GHz; 2-pole filters; 77 K; K-band filter; LaAlO/sub 3/; SHF; YBCO/STO/LAO configuration; YBaCuO-SrTiO/sub 3/-LaAlO/sub 3/; nonlinear DC electric field dependence; relative dielectric constant; thin film HTS/ferroelectric/dielectric multilayer; tunable microstrip bandpass filter; Band pass filters; Dielectric thin films; Frequency; K-band; Lanthanum; Microstrip filters; Strontium; Titanium compounds; Transistors; Yttrium barium copper oxide;
Conference_Titel :
Microwave Symposium Digest, 1998 IEEE MTT-S International
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
0-7803-4471-5
DOI :
10.1109/MWSYM.1998.705164
