Abstract
In the structures considered in the previous chapter, a limited number of operating
attenuation poles (transmission zeros) P ≤ N + 1 is formed, which is a limiting factor for a
further increase of filter selectivity using resonators with a relatively low intrinsic Q factor.
This is due to the structural construction of these circuits and, as it seems to us, an insufficient
number of degrees of freedom in the independent control of the frequency properties of partial
two-pole impedances Za and Zb of their equivalent circuits. This chapter explores new properties
of single- and dual-resonator MSF structures, in which up to six or more operating attenuation
poles can be directly formed at finite frequencies, i.e., these structures with an extremely
minimal number of resonators sometimes demonstrate the properties of multi-resonator
microwave circuits.