Fixed-frequency and frequency-agile (Au, HTS) microstrip bandstop filters for L-band applications

In this work, we report on the performance of a highly selective, compact 1 .83x2.08 cm(2) (similar to0.72x0.82 in.(2)) microstrip line bandstop filter of YBa2Cu3O7-delta (YBCO) on LaAlO3 (LAO) substrate, The filter is designe d for a center frequency of 1.623 GHz for a bandwidth at 3 dB from referenc e baseline of less than 5.15 MHz, and a bandstop rejection of 30 dB or bett er. The design and optimization of the filter was performed using Zeland's IE3D circuit simulator. The optimized design was used to fabricate gold (Au ) and High-Temperature Superconductor (HTS) versions of the fitter. We have also studied an electronically tunable version of the same filter. Tunabil ity of the bandstop characteristics is achieved by the integration of a thi n film conductor (Au or HTS) and the non-linear dielectric ferroelectric Sr TiO3 in a conductor/ferroelectric/dielectric modified microstrip configurat ion, The performance of these filters and comparison with the simulated dat a will be presented.