设计并制作了用于超导量子比特直流特性测试的级联低通滤波器,该滤波器由LCR滤波器和铜粉滤波器级联而成.滤波器在77K温度下的截止频率为120kHz,衰减率为-40dB/decade,10MHz以上迅速衰减至-60dB以下.频率响应优于单一的LCR滤波器或铜粉滤波器,能在低温下有效抑制高频噪声.
Cascaded low-pass filters are designed and fabricated for the measurements of dc characteristics of superconducting qubits. The filters are cascaded by LCR filter and copper powder filter. At 77 K the cutoff frequency is 120 kHz and the roll-off is -40 dB/decade. We achieved an attenuation -60 dB when the frequency is above 10 MHz. The frequency response of the cascaded filters is better than single LCR filter or copper powder filter and high frequency noise can be suppressed effectively at low temperature.