(a) The schematic illustration of the gyrator-based circuit with the ideal gyrator in series configuration. In this circuit, two different LC resonators are used in a series configuration, coupled via an ideal gyrator. The sensitivity of the (b), (d), (f) real and (c), (e), (g) imaginary parts of the eigenfrequencies to (b), (c) gyration resistance, (d), (e) positive capacitance C₁ (f), (g) positive inductance L₁ perturbation. Solid lines: solution of eigenvalue problem of equation (2); green-dashed lines: Puiseux series approximation truncated to its second term. Voltage v₁ (t) under the EPD condition in the (h) time-domain, and (i) frequency-domain. The frequency-domain result is calculated by applying an FFT with 10⁶ samples in the time window of 0 μs to 100 μs. (j) Root locus of zeros of Z_total (ω) = 0 showing the real and imaginary parts of resonance frequencies of the circuit when perturbing gyration resistance. At the EPD, the system's total impedance is Z_total (ω) ∝ (ω − ω_e) ²; hence it shows a double zero at ω_e.