Harmonic Generation Using Nonlinear LC Lattices

Nonlinear LC lattices have shown promise for high-power high-frequency signal generation. Here we offer the first detailed study of the frequency response of these lattices, as well as a method designed to find input excitation frequencies that result in intense harmonic generation. The crux of the method is to locate regions in frequency space where the spectral norm of the lattice response matrix is large. When the fundamental excitation frequency (or one of its multiples) is located in these regions, the lattice harmonic response is intensified. These findings are supported by extensive numerical simulations and experimental measurements. We deal chiefly with a first-order dependency of capacitance (C) on voltage (V); however, it is also shown that lattices with higher order C-V dependencies achieve proportionally higher harmonic generation. Simulations using a 0.13-μm CMOS process indicate harmonic generation at 400 GHz (three times the cutoff frequency of the fastest active device in this process), suggesting potential applications of this lattice topology in terahertz range devices.