ABSTRACT

Besides the aforementioned principles of power scavenging from

mechanical, thermal, or solar energy source, this chapter deals

with energy harvesting fromelectromagnetic fields. Radio frequency

power transmission, or so-called wireless power transmission, is

nowadays one of the main research topics among mobile device

manufacturers since it is expected to eliminate any cables and

connectors for powering or charging devices such as cell phones

and laptops. In fact, radio frequency transmission offers the

highest energy retrieval among all energy scavenging technologies.

Since apart from the sun no natural sources of electromagnetic

fields with sufficient energy exist, sources for generating and

radiating electromagnetic waveswith enough energy to empower an

electronic device over a certain distance are necessary. The sources

are normally intended to be used for power transmission only but

can also be sources of radio frequency data transmission systems

that offer enough power. The latter is becoming more and more

attractive, as the availability of wireless data transmission systems

increases. In any case, regulatory constraints regarding the use of

frequency bands and maximum radiated radio power have to be

considered.