In many scenarios where vibration energy harvesting can be utilized – particularly those involving bio-motions or environmental disturbances – energy sources are broadband and non-stationary. On the other hand, design procedures have been predominantly developed for harmonic or white noise excitation, specifically for single degree of freedom approximations of the transducer. In this paper, a g...

We investigate the dynamics of coherent optical phonons in tellurium after high-density excitation with femtosecond laser pulses. The data show a continuous redshift of the phonon frequency with increasing excitation density. Experiments with double-pulse excitation prove that the observed frequency shift is of purely electronic origin. We demonstrate that coherent phonons allow monitoring the ...

This paper presents a simple test bench providing RF vector measurements of typical wireless communication system building blocks under realistic signal conditions. The instruments are synchronized by use of an experimental method based on an estimate of the signal path’s time delay. As an example, a complex digitally modulated signal with a carrier frequency of 2.45 GHz was used. The ultimate ...

A control law for an electromagnetic vibration energy harvester is derived using the maximum power transfer theorem. Using regenerative electronics, the controller cancels the reactive portion of the harvester’s impedance by eliminating the effect of mechanical inertia and stiffness elements, and the coil’s electrical inductive element. The result is an energy harvester approach that captures m...

Within the adiabatic approximation, time-dependent density functional theory yields only single excitations. Near states of double excitation character, the exact exchange-correlation kernel has a strong dependence on frequency. We derive the exact frequency-dependent kernel when a double excitation mixes with a single excitation, well separated from the other excitations, in the limit that the...

Vibration energy harvesters are designed to gather parasitic energy from the motion of their host structures. In many germane scenarios, this motion is broadband; however, the preponderance of design criteria appearing in the literature for vibration energy harvesters considers sinusoidal base excitation at a single frequency. While this analysis often leads to analytical formulas for estimatin...

A measurement technique [1] is presented that allows measurement of MOSFET low frequency (LF) noise under large signal RF (Radio Frequency) excitation. Measurements indicate that MOSFETS exhibit a reduction in LF noise when they are cycled from inversion to accummulation and that this reduction does not depend on the frequency of excitation for excitation frequencies of up to 3 GHz. The measure...