Vibrational energy harvesting seeks to convert ambient energy into electricity when battery replacement or line transmission is infeasible or impracticable. Electromechanical mass-spring harvesters are designed to exhibit a resonance frequency close to the principal vibrational frequency of the main or environmental system; excited near to resonance, the harvesters convert the kinetic or potent...

Recently, the need for long-term structural health monitoring has warranted the design of novel sensing transducers. In particular, nanotechnology offers new material processing techniques that allow for novel multifunctional thin film sensor designs which combine sensing, actuation, and power harvesting into one platform. In this study, single-walled carbon nanotubes (SWNT) are used as filler ...

In order to extract as much energy as possible from ambient vibrations, many vibration-based energy harvesters (VEHs) are designed to resonate at a specific base excitation frequency. Unfortunately, many vibration energy sources are low frequency (0.5 Hz-100 Hz), intermittent, and broadband. Thus, resonant VEHs would not be excited continuously and would require a large mass or size to tune to ...

In this paper, we identify the spectrum opportunities for radio frequency (RF) energy harvesting through power density measurements from 350 MHz to 3 GHz. The field trials have been performed in Covilhã by using the NARDA-SMR spectrum analyser with a measuring antenna. Based on the identification of the most promising opportunities, a dual-band band printed antenna operating at GSM bands (900/1...

This paper reports the design, micromachining and characterization of an array of electromagnetic energy harvesters (EHs) with multiple frequency peaks. The authors present the combination of three multi-modal spring-mass structures so as to realize at least nine resonant peaks within a single microelectromechanical systems (MEMS) chip. It is assembled with permanent magnet to show an electroma...

This paper presents a rectifying antenna (rectenna) for the harvesting of the microwave energy associated to UHF (UltraHigh Frequency) Radio Frequency IDentification (RFID) systems. The proposed device uses a capacitively loaded T-shaped monopole with a coplanar waveguide feeding line as receiving antenna and a five-stage voltage multiplier as rectifier. Experimental results demonstrating an RF...

A vibration-driven electret generator has been developed for energy harvesting applications. By using parylene as the spring material, a low-resonant-frequency MEMS generator is realized. Large inplane amplitude of 0.8 mm at the resonant frequency as low as 37 Hz has been achieved. With our early prototype, output power of 0.28 μW has been obtained. We also demonstrate electret-powered operatio...

We explore an analogue of optical frequency combs in driven nonlinear phononic systems, and present a mechanism for generating phononic frequency combs through nonlinear resonances. In the underlying process, a set of phonon modes is simultaneously excited by the external driving which yields frequency combs with an array of discrete and equidistant spectral lines of each nonlinearly excited ph...

the aim of this study was to determine the most suitable shaking frequency and amplitude for shake harvesting lime fruit (c. aurantifolia). a tractor mounted limb shaker with adjustable shaking frequency and amplitude, powered by the tractor power-take-off shaft was designed and developed for this study. the rotating input power was transmitted to the shaker flywheel through a multiple sheave v...

Due to the growing implications of energy costs and carbon footprints, the need to adopt inexpensive, green energy harvesting strategies are of paramount importance for the long-term conservation of the environment and the global economy. To address this, the feasibility of harvesting low power density ambient RF energy simultaneously from multiple sources is examined. A high efficiency multi-r...