Original Kurzfassung: We present a natural convection microfluidic loop  based on localized microwave heating of fluids  as a concept for driving flows in 3-dimensional lab-on-a-chip architectures As a proof of principle we fabricated test devices by using standard power RF-components  originally developed for mobile wireless communication applications  which are combined with Polydimethylsiloxane (PDMS) imprint technology for the realization of fluidic driving unit and channel  respectively