Experimental and numerical verification of the cause of Hopf bifurcation in a microwave doubler

The appearance of Hopf bifurcation in a microwave doubler is due to the relative speed of the recombination delay of the junction diode with the input RF signal, which results in a dynamical negative resistance. This is verified here experimentally by using a back-to-back diode structure that quenches Hopf bifurcation numerically through stability analysis in the frequency domain.<>