Potential of superconducting films and filters for wireless applications

Although many fundamental physics questions are still unanswered, the techn ology of high-temperature superconductors (HTSs) has become mature for use in wireless communications. In particular, superconducting filters utilizin g HTS epitaxial films can provide better interference rejection, full use o f the available frequency spectrum, decrease in the noise floor and size an d weight reduction in receiver subsystems. A comparison of the microwave pr operties between films of high-T-c superconductors YBa2Cu3O7-delta and Tl2B a2CaCu2O8 and medium-T-c superconductor Nb3Sn is reported. A first prototyp e of a superconducting bandpass filter designed to handle a high circulatin g power and spanning the frequency range from 1710 to 1785 MHz is presented . The implications of its insertion in cellular base stations are discussed .