Operating-Map Analysis of a Memristive Diode-Bridge Circuit Using Numerical Continuation

Simple memristive circuits are attractive chaos sources for secure communication, random-number generation, and chaotic sensing. Reliable operation, however, requires knowing where in parameter space the chaos persists and where periodic windows or coexisting attractors make it fragile. This paper constructs an operating map for an improved memristive diode-bridge band-pass-filter circuit in its two accessible tuning parameters, set by the filter capacitance and the feedback resistance ratio. Two-parameter bifurcation maps and Lyapunov exponent fields give the global layout of the plane; numerical continuation traces the stable and unstable periodic-orbit branches that organise it; and phase portraits, power spectra, component-level SPICE simulation, and prototype measurements characterise representative regimes. The plane separates into broad chaotic regions, higher-period windows, a period-adding window, and a multistability zone. A chaotic interval is reported as robust chaos only when the tracked periodic branches are all unstable, the Lyapunov exponent is positive throughout, and initial-condition scans detect no coexisting attractor; the continuation shows the same period-doubling mechanism bounding the chaotic regions in both parameters. Mapping the dimensionless results to component values yields design guidance for reaching candidate robust-chaos regions and avoiding fragile and multistable zones, including a hardware-confirmed limit on inductor loss beyond which the chaotic band collapses.