Improving the Voltage Modulation Depth of Radiofrequency Produced by Nonlinear Transmission Lines Using a Shock Wave Configuration

Low power nonlinear transmission lines - LPNLTL using varactor diode as a nonlinear element has been studied to produce RF signals to be used in communication systems, radars, satellites, biomedical and military applications
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. Nowadays Nonlinear Transmission Lines - NLTL has been studied to generate waves on ultrahigh-frequency in the terahertz range
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, The frequency, voltage modulation depth - VMD, power, and number of oscillations are the main parameters to be analyzed for the design of these devices. In this work, we propose a new configuration to improve the VMD using more than one LPNLTL connected to a load, named as shock wave configuration. The simulation was made by using the LT-Spice software. The results with a single line produced an RF signal with a frequency of the order of 36.4 MHz, VMD near to 9.4 V, and the number of oscillations equal to 8. In the simulation using a shock wave configuration with six lines, the VMD increased to 13.7 V, which means 45.7% higher than VMD produced with a single line. The oscillation peaks remained unchanged under the shock wave configuration and the frequency has a little increase going of the 36.4 MHz (single line) to 40 MHz, which means 9.9% higher using shock wave configuration. A MOSFET amplifier was used to increase the RF signal produced by the shock wave configuration, reaching a VMD of the order of 80 V. This technique shows that VMD is increased when RF is produced by an LPNLTL using the shock wave configuration, which can widen the cover range of the signal.