264 MHz HTS lumped element bandpass filter

A 5-pole lumped element bandpass filter (BPF) of center frequency 264.05 MH z and fractional bandwidth (FBW) 0.76% is designed and fabricated using YBa 2Cu3O7-d (YBCO) thin films deposited on both sides of a MgO substrate(40 mm x 40 mm x 0.5 mm). The return loss, minimum insertion loss and ripple were measured to be 20.0 dB, less than 0.1 dB and less than 0.1 dB at 70 K, res pectively. These results verify both the compactness and low loss character istics in the VHF band. The simulated frequency response, where the frequen cy dependences of inductance (L) and capacitance (C) elements and housing e ffect are taken into account, is in good agreement with the measured freque ncy response.