Emerging multifrequency atomic force microscopy (MF-AFM) methods rely on coherent demodulation of the cantilever deflection signal at multiple frequencies. These measurements are needed in order to close the z-axis feedback loop and to acquire complementary information on the tip-sample interaction. While the common method is to use a lock-in amplifier capable of recovering low-level signals fr...

Nonlinear bistable systems have been shown to provide improved efficiency for harvesting energy from random and broadband vibration sources. This article explores the distinct frequency response in the broadened spectrum of a particular nonlinear energy harvester, a piezoelectric cantilever with magnetic coupling. The cantilever response evolves dynamically with frequency around the main cantil...

The capability of multifrequency polarimetric synthetic aperture radar (SAR) to discriminate among nine vegetation classes is shown using both experimental data and model simulations. The experimental data were collected by the multifrequency polarimetric AIRSAR at the Dutch Flevoland site and the Italian Montespertoli site. Simulations are carried out using an electromagnetic model, developed ...

The distortion and limited resolution of the image are serious problems of single-frequency diffraction tomography. Multlfrequency methods, such as the multifrequency backscattering tomography, can improve the resolution and image quality significantly. In this work, we extend the multifrequency backacattering tomography to the case of vertically varying background. The image reconstruction for...