Publications by authors named "Rolf Jakoby"

In addressing sensing in harsh and dynamic environments, there are no available millimeter-wave chipless and wireless sensors capable of continuous operation at extremely high temperatures. Here we present a fully dielectric wireless temperature sensor capable of operating beyond 1000 C. The sensor uses high-Q cavities embedded within a three-dimensional photonic crystal resonating at 83.

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Delivering foreign molecules and genetic material into cells is a crucial process in life sciences and biotechnology, resulting in great interest in effective cell transfection methods. Importantly, physical transfection methods allow delivery of molecules of different chemical composition and are, thus, very flexible. Here, we investigated the influence of microwave radiation on the transfection and survival of mammalian cells.

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A finite element method (FEM)-based simulation approach to predict the tunability in composite materials was developed and tested with analytical data. These tests showed good prediction capabilities of the simulation for the test data. The simulation model was then used to predict the tunability of a network-structured composite, where the dielectric phase formed clusters in a paraelectric network.

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In this paper, a broadband microwave device for cell poration is presented, that enables the analysis of the relation between frequency, electrical field strengths and temperature for a successful cell poration. Electromagnetic-thermal coupled simulations in the frequency range from 1 GHz to 10 GHz show that the device reaches electrical field strengths of 100 V/cm and temperatures lower then 40°C. Electroporation experiments with adherent C2C12 mouse myoblast cells show successful uptake of an anti-histone γ -H2A.

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Self-localization based on passive RFID-based has many potential applications. One of the main challenges it faces is the suppression of the reflected signals from unwanted objects (i.e.

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A multiobjective optimization method for a dual-mode microwave applicator is proposed. Dual-modality means that microwaves are used apart from the treatment, and also for the monitoring of the microwave ablation intervention. (1) The use of computational models to develop and improve microwave ablation applicator geometries is essential for further advances in this field.

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Since the dielectric permittivity of ferroelectric materials depends on the electric field, they allow designing switchable and continuously tunable devices for adaptive microwave front ends. Part of the ongoing research is the field of all-oxide devices, where epitaxial oxide conductors are used instead of polycrystalline metal electrodes, leading to epitaxial ferroelectric layers and resulting in high device performance. In particular, they allow engineering the acoustic properties separated from the electric ones due to the structural similarity between the dielectric and conducting oxide films.

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The purpose of the study was to validate the simulation model for a microwave thermal ablation in ex vivo liver tissue. The study aims to show that heat transfer due to the flow of tissue water during ablation in ex vivo tissue is not negligible. Ablation experiments were performed in ex vivo porcine liver with microwave powers of 60 W to 100 W.

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A microwave applicator is presented that realizes the theranostic approach by providing two operation modes to detect and treat tumor cells, exemplary in the liver. The tool is based on a planar sensor structure with Split Ring Resonators (SRR) as key elements. For the detection, changes in dielectric properties caused by tissue abnormalities are evaluated by analyzing shifts in the resonance frequency of the SRR.

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Microwave sensors in medical environments play a significant role due to the contact-less and non-invasive sensing mechanism to determine dielectric properties of tissue. In this work, a theranostic sensor based on Split Ring Resonators (SRRs) is presented that provides two operation modes to detect and treat tumor cells, exemplary in the liver. For the detection mode, resonance frequency changes due to abnormalities are evaluated, and in the treatment mode, microwave ablation is performed.

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A dual mode tool design to analyze organic tissue and locally perform thermal ablation treatment is presented. The tool is made of an array of split-ring resonators. It can operate on a sensing mode to track the relative dielectric changes from the organic tissue and on a treatment mode to perform thermal ablation at different input powers.

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