Comparison of conventional and minimum inductance filters

Minimum inductance filters are generally considered to have more stopband attenuation then the corresponding conventional filters for the same number of coils; however, a rigorous proof of this property has never been published. In this paper, the conventional Cauer type-B elliptic filters, designed with the coil-saving zigzag transformation, are compared with minimum inductance filters designed to meet the same requirements. It is shown that the minimum inductance filter has more stopband attenuation for the same number of inductors.