Production of Lorentzian, Fano-Like, and Mixed-Type Resonance Combs at Microwave Frequencies Using Multi-Mode Transmission-Line-Based Fabry-Perot Resonators

This work examines various multiconductor transmission-line (MTL)-based Fabry-Perot resonators at microwave frequencies. It is demonstrated that an unloaded MTL supporting two modes with a particular set of properties akin to those of the canonical “dark” and “bright” modes may support a frequency “comb” response consisting of either Lorentzian or Fano-like resonances, depending on its excitation. It is then shown that promotion of modal coupling through the periodic insertion of capacitors causes the system to support both types of resonances simultaneously, or hybrid types, depending on the style of loading.