Time-Modulated Circuits and Metasurfaces for Emulating Arbitrary Transfer Functions

Temporal modulation unlocks possibilities to dynamically control and modify the response of electromagnetic systems. Employing explicit dependencies circuit or surface parameters on time enables engineering systems with conventionally unachievable functionalities. Here, we propose an alternative approach that emulation can have arbitrary frequency dispersion nonlinear properties, including non-Foster response. In particular, show a proper time-varying capacitor allows one mimic static inductance, capacitance, resistance having values, both positive negative. We discuss necessary modifications determined ideal functions ensure stability system. To demonstrate applicability proposed method, introduce simulate invisible sensor, i.e., device does not produce any scattering is capable sensing. Three different geometries are validated using full-wave simulations. addition that, modulated externally. believe this study introduces paradigm modulations engineer system responses be applied only (in electronics, microwaves, optics) but also in other branches physics.