Microwave impedance miceroscopy (MIM) is a scanning microscopy techique where the reflection of microwave signals is used to determine materical properties at nanometer scales. MIM is performed in the linear case, where the reflection is measured at the same frequency as the original signal. We extend this to the nonlinear case where higher harmonics of the orginal signal are measured. We derive an equation relating the reflected signal to MIM circuit properties in order to optimize the nonlinear MIM setup.
You can read more about this in Waghmare, Bromley, Shan & Ma 2025