Fig. 3: Extracting paths using active ring circuit.

A Schematics of a multi-path active ring circuit. The active part includes a voltage-tunable broadband amplifier \(G(V)\) and a voltage-tunable phase shifter \(\varPsi \left(V\right).\) The passive part is the grid, as shown in Fig. 2C. Auto-oscillation occurs in the circuit when the active and passive paths are matched in amplitude and phase. B–D Illustration of the signal re-routing depending on the position of the voltage-tunable phase shifter. There are three paths shown for the three different positions of \(\varPsi \left(V\right):0\pi ,\) \(\mathrm{0,2}\pi ,\) and \(0.4\pi ,\) respectively. The examples are shown only for one combination of the left/right switches.