Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings

This article reports the design of coupled-resonator-based microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an optimization-based synthesis procedure for characteristic polynomials with a prescribed group delay profile. Thus, when compared with prior-art DDS approaches, the proposed DDS solutions allow a general group delay profile to be patterned while incorporating optimization-based coupling matrix design techniques for their synthesis. The design method is validated by full-wave simulations and measurements of three built proof-of-concept prototypes of DDS devices with different shapes of group delay response in waveguide and microstrip technologies.