Investigation of traveling waves on some left-handed and composite lc nonlinear transmission lines

Wave propagations and interactions of waves in nonlinear left-handed transmission lines with variable capacity(C) and constant inductance(L) has been investigated. Simple left-handed and composite nonlinear transmission lines were built on breadboard and terminated by apropriate resistance, determined by minimizing reflected part of waves, at the end of the line. Sinuzoidal waves with different amplitudes of frequency sweep 200-1000 kHz were applied to the lines for 200 µs time interval. Signals at the middle of the transmission lines were observed and data were stored on digital medium for their further wavelet analysis. Analysis results imply that , for small amplitude applied waves nonlinear transmission lines behave as linear lines. however with further increase in amplitude, due to nonlinearity in lines, wave-wave interactions start and apart from applied wave new waves form. In both simple left handed and composite nonlinear lines some modes seem to transfer %20 of their energies to the modes which have double or half of their frequencies. Apart from these in nonlinear simple line a higher frequency isolated mode with large line width seems to transfer %80 of its energy to modes of lower frequencies in a very short time. This rapid transfer of energy has been taken as an existence of unstability of this mode. From the analysis of frequencies involved in this wave-wave interaction, considering line width of modes, it is concluded that 1:2 and 3:2 parametric resonance resonance has taken place. Apart from sinusoidal waves, triangular and square waves are also applied the lines and their analysis has been done.