Single- and Dual-resonator Structures with the Properties of Multi-Resonator Microwave Networks

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.

Keywords: Attenuation pole, Coupled microstrip line, Equivalent circuit, Frequency selectivity, Impedance, Lattice section, Microwave filter, Positive electric length, Passband, S-parameters.