Synthesizing Arbitrary Tunable Nonreciprocal Devices via a Programmable Chaotic Cavity

Microwave nonreciprocal devices, such as isolators and circulators, are indispensable in radar and communication systems. Here, we demonstrate a programmable chaotic cavity platform capable of realizing arbitrary frequency-agile nonreciprocal functionalities. Fixed magnetically self-biased ferrites inside the cavity provide intrinsic time-reversal symmetry breaking, while tunable reciprocal port terminations enable boundary programmability. As an example, a two-port isolator functionality is realized by optimizing the load reflection phases. Near-unity forward transmission and isolation exceeding 110 dB are achieved, with the possibility for continuous shift of the operating frequency in the relative spectral range of 15%. The proposed platform is capable of realizing reconfigurable, arbitrary passive nonreciprocal multiport devices.