Miniaturized 10-pole superconducting filter on MgO substrate for mobile communication

Abstract

Size of narrow band superconducting filters depends on the permittivity of the substrate used and the filter frequency. Size of good quality high temperature superconducting thin film wafers at a reasonable price is limited to two inches, as cost of bigger wafers makes the filters not economical. In this paper we present a design of a 10-pole filter for a centre frequency of 1.88 GHz and bandwidth of 20 MHz using ideas of the modified hairpin, the Chebyshev approximation without the influence of cross coupling between the non-adjacent resonators. The design fits onto a half of a two inch YBa2Cu3O7 on MgO wafer. The simulated passband insertion loss of the filter is 0.1 dB and the out-of-band rejection is 50 dB at 4 MHz from the passband on both sides.