Design considerations for diode-based nonlinear transmission lines

Abstract

Diode-based nonlinear transmission lines (D-NLTL) are a class of pulse shaping networks capable of increasing the discrete spectral content of a pulse at high volumetric power density. However, a systematic design procedure for D-NLTLs is lacking, limiting their prototyping, evaluation, production, and adoption. To produce a D-NLTL design approach, parameters for UHF band (0.3–1 GHz) frequency generation are presented as a function of the input excitation pulse, network topology, and sub-components’ reactive value. Excitation pulse amplitude is found to have a strong effect on center frequency ( f c), max frequency ( f Bragg), peak power ( P peak), and RF power conversion efficiency ( η RF). In general, when cell inductance is decreased, both fc and signal propagation velocity are increased. The results are then presented as an example to design, build, test, and compare a 40-cell D-NLTL whose measured f c and f Bragg are 256 and 446 MHz, respectively. Finally, we used the parameter space study results and empirical validation to present controllable waveform design rules-of-thumb.