Performance Evaluation of Low-Voltage Capacitive Nonlinear Transmission Lines

The potential application of low-voltage capacitive nonlinear transmission lines (NLTLs) in radar communication systems, electronic attack systems, telecommunications, and electromedical equipment has motivated studies of their performance due to the simple construction and use of low-cost commercial components. Low-voltage capacitive NLTLs consist of a nonlinear and dispersive propagation medium. The practical implementation of these lines employs radio frequency (RF) generation using commercial electronic components such as inductors and reverse-biased varactor diodes as nonlinear elements. This article presents the experimental results of capacitive NLTLs from 240 MHz to 1 GHz, showing the behavior of oscillations produced in the time and frequency domains fast Fourier transform (FFT). In the time domain, the oscillations showed a damping behavior that arises from the nonlinear behavior of the varactor diodes in response to a rectangular input pulse. Furthermore, the analysis of damping oscillations in the frequency domain demonstrated a spread-spectrum signal that negatively affects the objective of using NLTLs as generators of pulsed RF signals, for which a high spectral purity is required. Finally, we give a summary of the research performance with the practical constraints of these lines.