We demonstrate the use of a new experimental technique based on mutual indu
ctance measurements to quantitatively predict nonlinear effects in microwav
e devices fabricated from high-temperature superconductor (HTS) materials.
The mutual inductance measurements yield the current dependence of the pene
tration depth lambda(J) in unpatterned HTS thin films. This information is
used to calculate third-harmonic generation in coplanar waveguide (CPW) tra
nsmission lines and compares very well with actual measurements of CPW tran
smission lines of variable dimensions fabricated from YBa2Cu3O7-delta thin
film samples. The mutual inductance measurements should prove extremely val
uable as a screening technique for microwave applications of HTS materials
that require very low nonlinear response.