Green's Function Analysis of Spatially Discrete Traveling-Wave Modulated (Parametric) Loop Networks

This paper explores the analysis and design of spatially discrete traveling-wave modulated (SDTWM) loop networks, which are commonly used to achieve parametric effects and functionalities such as nonreciprocal propagation. We present an efficient method for analyzing the spatial Green's function of SDTWM loop networks using the Interpath Relation (a space-time boundary condition) and modal analysis. The method is applied to design a non-magnetic circulator, demonstrating enhanced performance, twice the fractional bandwidth, and a 2 dB improvement in insertion loss over a previous design in literature. The study highlights the versatility of SDTWM in creating compact, cost-efficient, and high-performance nonreciprocal devices and offers insights into their design.