Implantierbares transkutanes Energieübertragungssystem mit hohem Wirkungsgrad für Herzunterstützungsgeräte

Magnetic liquid silicone rubber composite cores to realize WPT in medical applications were designed, fabricated and precisely validated. The crucial properties of the proposed WPT design are its biocompatibility, flexibility and high magnetic conductivity. Moreover, it exhibits low electric and magnetic losses. Therefore, this design is an excellent candidate for realizing the inductive powering of medical implants at low operational frequencies. Comparing the WPT systems without and with cores, the coupling coefficient and consequently the efficiency was significantly increased. This resulted in lower currents flowing through the primary and secondary coils for a fixed transferred power. The thermal simulation results indicated that owing to the superior electric and magnetic properties of the proposed WPT design, the maximum temperature is significantly decreased. This high-efficiency WPT guarantees lower losses and consequently lower temperature rise, and therefore, can be employed for applications that require a high amount of power, such as powering of VADs. In this thesis, the integration of the WPT design into VADs was investigated. In this scenario, the part of the drive line passing through the skin layer was replaced by the designed WPT to avoid a puncture of the dermis. Moreover, using pot cores in WPT resulted in homogenizing the temperature distribution in biological layers. Finally, the relevant design issues were evaluated. For this purpose, an analytical method, namely conformal mapping, to determine the magnetic field distribution of deformed 2-D-WPT topologies is proposed. It was concluded that this method can only be applied at low operational frequencies and when the product of the permeability and electrical conductivity of the WPT medium is low. An evaluation method for the application of conformal mapping is proposed using the CST software. In our case, the electromagnetic field can be approximated as the magnetoquasistatic field, which can be presented with the Diffusion equation. Finally, It was proven that the Diffusion equation can be reduced to the Laplace equation, which ensures the application of conformal mapping to calculate the magnetic field intensity of bent WPT topologies. The accuracy of this analytical method, its ability to analyze complicated geometries as well as its easy implementation as a programming code, make this method an excellent candidate for calculating the field distribution of bendable WPT modules. Regarding the results, the self- and mutual inductances, due to the WPT geometry’s deformation, did not vary significantly

Biodegradable dual semicircular patch antenna tile for smart floors

A dual semicircular microstrip patch antenna implemented on a biodegradable substrate is presented for operation in the [863-873] MHz and [2.4-2.5] GHz frequency bands. To cover these frequency bands, two semicircular patches are compactly integrated onto a biodegradable cork tile, commonly found as support in laminate flooring, serving as a substrate. Thereby, the antenna tile may be seamlessly embedded as a sublayer of the floor structure. A higher-order mode is generated by applying via pins in the antenna topology to produce a conical radiation pattern with a null at broadside and sectoral coverage in the vertical plane. As such, the concealed floor antenna covers all azimuth angles of arrival in smart houses. The antenna performance is fully validated, also when the tile is covered by different polyvinyl chloride sheets. Owing to the supplementary design margins, the antenna impedance bandwidth remains covered. Moreover, the radiation patterns are measured in various elevation planes. Under standalone conditions, a radiation efficiency and a maximum gain of 74.3% and 5.8 dBi at 2.45 GHz and 48.1% and 2 dBi at 868 MHz are, respectively, obtained. Its omnidirectional coverage in the horizontal plane, stable performance on the inhomogeneous and biocompatible cork substrate and for various inhomogeneous superstrates, and its low-profile integration make the proposed antenna an excellent candidate for smart floors and smart houses