约瑟夫森结的电感效应及新型可调谐滤波器

通过WINS软件模拟，我们研究了处于直流零电压状态的约瑟夫森结的电感效应。对于Ic=0．1mA的约瑟夫森结，当把它偏置在0．08mA时，相当于一个5．46pH的电感。同时我们模拟出约瑟夫森结等效电感值随偏置电流变化的关系曲线。利用这一效应，设计并模拟了一种新型的5阶超导可调谐滤波器，其中心频率从600MHz到750MHz连续可调，带宽为50MHz，插入损耗小于0．3dB，带外抑制大于40dB，矩形系数优于0．5。这种滤波器适于集成化，在通信系统中具有重要的应用价值。

Inductance Effect of Josephson Junctions and a New Type of Tunable Filter

By theoretical analysis and simulation,we investigated the inductance effect of Josephson junctions in zero voltage state. For a junction with a critical current of 0.1 mA , when its bias current is 0.08mA, its effective inductance is 5.46pH. The bias current dependence of the inductance was presented. Taking advantage of this effect, we designed and sinulated a new, type of tunable filter. For a 5 - order filter we designed, its bandwidth is 50MHz. Its center frequency can be tuned from 600MHz to 750MHz. The insertion loss is less than 0.3dB and the square ratio is better than 0.5. This kind o f filter is suitable for integration and will play an important role in the communication system .