Parametric Energy Conversion by Nonlinear Admittances

The combination of nonlinear resistance (NR) and nonlinear capacitance (NC) elements for parametric frequency conversion shows promise for obtaining nonreciprocal features not present in pure NR or pure NC networks. This paper treats the simplest NR-NC combinations consisting of a single NR element connected either in series or in parallel with a single NC element. When the NR and NC elements are "pumped" in time quadrature, such circuits are capable of yielding unconditionally stable up-conversion gains, for both the inverting and noninverting case, considerably in excess of the output-to-input frequency ratios. Simultaneously, the down-conversion loss can be made infinite at one frequency and considerably in excess of the up-conversion gain over a band of frequencies. With ideal NR and NC elements, the maximum available up-conversion gain to either an inverted or noninverted sideband with unconditional stability (|down-conversion loss|≥|up-conversion gain|) approaches the square of the output-to-input frequency ratio.