Intermodulation measurements in superconducting meander lines

The intermodulation measurements are used to study the nonlinear effects in high-T/sub c/ microstrip meander lines at microwave frequencies. The superconducting YBa/sub 2/Cu/sub 3/O/sub 7/ (YBaCuO) thin films were grown by laser ablation on both sides of lanthanum alumite substrates and the microstrip pattern was defined using photolithography. The meander line is elicited by two microwave signals from two sweep oscillators at both frequencies of 4.70052 GHz and 4.69952 GHz over temperature range of 19 to 86 K. The measured harmonic signals show a gradual decrease in transmission and disappear as the critical temperature is reached. As for the dependence on the input power the transmission (A) of the third-order harmonic signals at 19 K shows a linear dependence on the input power (P), A(P)=1.30P-61 in the range of 12.5-17.0 dBm.