title: A microwave resonator integrated on a polymer microfluidic chip.
abstract: We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10mm by 10mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7·10(11)spins·Hz(-1/2)G(-1) for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.
authors: Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. Electronic address: sebastian.kiss@kit.edu.
authors: S Z
authors: SZ
authors: Kiss
authors: Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
authors: A M
authors: AM
authors: Rostas
authors: Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
authors: L
authors: L
authors: Heidinger
authors: Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors: N
authors: N
authors: Spengler
authors: Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors: M V
authors: MV
authors: Meissner
authors: Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors: N
authors: N
authors: MacKinnon
authors: Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
authors: E
authors: E
authors: Schleicher
authors: Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
authors: S
authors: S
authors: Weber
authors: Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors: J G
authors: JG
authors: Korvink
keywords: EPR; ESR; Fluidic chip; Microfluidic; Resonator; Resonator modes; Small-volume EPR; Spin nutation; Stacked resonator; Transient EPR