@misc{HelbigSeliger2025, author = {Helbig, Michael and Seliger, Norbert}, title = {Combinatorics of Inductance States in Reconfigurable Air Coils}, series = {Proceedings 2nd International Conference on Recent Advances in Mathematics and Informatics (ICRAMI'25)}, journal = {Proceedings 2nd International Conference on Recent Advances in Mathematics and Informatics (ICRAMI'25)}, isbn = {978-9909-00-770-9}, pages = {8}, year = {2025}, abstract = {We propose a group theory based mathematical model for unambiguous inductance states of a reconfigurable air coil inductor utilizing elastic snapping of wire segments. Vertical (axial) and horizontal winding symmetries under group actions reveal distinguishable tuning regions and individual variation states therein. The model is applied to coils of prismatic (cylinder like) and truncated pyramidal (conical like) shape with edges forming a regular polygon as basis, and verified by numerical magnet field simulation.}, language = {en} } @inproceedings{YilmazMariAsametal.2025, author = {Yilmaz, Tugce and Mari, Jorge and Asam, Johann and Kirner, Michael and List, Andreas and Fantauzzo, Lucia and Seliger, Norbert}, title = {AC Cycling Testing of SiC MOSFET Power Module}, series = {Proccedings International exhibition and conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM 2025)}, booktitle = {Proccedings International exhibition and conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM 2025)}, publisher = {VDE VERLAG GMBH}, address = {Berlin}, isbn = {978-3-8007-6541-6}, doi = {10.30420/566541341}, pages = {2562 -- 2567}, year = {2025}, abstract = {This paper details the development of an accelerated AC cycling test bench for evaluating the aging mechanisms of SiC MOSFET power modules. Contrary to classical HTGS and DGS which only exercise gate source stresses the AC Cycler switched under high voltage and current. Operating for about 235 hours, the system maintained stable thermal conditions thanks to an integrated cooling system. Key precursors of aging, such as increases in threshold voltage and on-state resistance were identified using static characterization curve tracer before and after the test. Gate charge and Vdson were also measured on-line with specially developed gate drivers.}, language = {en} } @inproceedings{Seliger2025, author = {Seliger, Norbert}, title = {Introducing Environmental Sustainability in an RF and EMC Lab Course Utilizing Reusable, Recyclable and Biodegradable Circuits}, series = {Proceedings IEEE educon 2025}, booktitle = {Proceedings IEEE educon 2025}, publisher = {IEEE}, doi = {10.1109/EDUCON62633.2025.11016365}, pages = {9}, year = {2025}, abstract = {We propose to introduce environmental sustainability in a radio frequency (RF) and electromagnetic compatibility (EMC) laboratory course for an electrical engineering bachelor's program utilizing reusable, easily recyclable and ecologically harmless (biodegradable) circuits. Our concept is based on the replacement of state-of-the-art printed circuit boards by substrates with mechanically structured adhesive Cu and Zinc films. Furthermore, organic based circuit carriers can be substituted by biodegradable paper substrates. As an example for the RF lab, we discuss the design, simulation and experimental characterization of a microwave low-pass filter with 1.2GHz cut-off frequency. Secondly, for an EMC lab we suggest a prototype for power integrity (PI) studies based on the current imbalance method for reducing common mode radiated emission. As a novel feature during the lab course, the instructor in addition gives a lecture highlighting the electronic waste challenge, which is accompanied by group discussions on sustainability and recycling. As a final lab course task students are asked to disassemble the boards or prepare them for reuse, followed by material sorting and submission to recycling institutions.}, language = {en} } @inproceedings{SeligerLeirich2025, author = {Seliger, Norbert and Leirich, Nico}, title = {Reconfigurable single-layer air coil inductor with bistable compliant windings}, series = {Proceedings EPE 25}, booktitle = {Proceedings EPE 25}, publisher = {EPE Association}, doi = {10.34746/epe2025-0012}, pages = {10}, year = {2025}, abstract = {We present an air coil with bistable compliant single layer windings. Due to stable elastic snapping deformation of wire segments, the self-inductance of the air coil can be precisely varied in multiple steps. A numerical and analytical design methodology is proposed and successfully validated by magneto-quasi-static field simulations and experiments on prototypes.}, language = {en} } @inproceedings{PueschelSeliger2025, author = {P{\"u}schel, Maximilian and Seliger, Norbert}, title = {Multiple-Frequency Three Coil Inductive Power Transmission with Non-Linear Relay Resonator}, series = {Proceedings Southeastcon 2025}, booktitle = {Proceedings Southeastcon 2025}, publisher = {IEEE}, isbn = {979-8-3315-0484-7}, issn = {1558-058X}, doi = {10.1109/SoutheastCon56624.2025.10971670}, pages = {34 -- 39}, year = {2025}, abstract = {We propose near-field inductive power transfer with three coils in the frequency range of a few MHz. The relay coil is part of a non-linear resonator having a diode connected in parallel to the resonant capacitor. We achieve power transfer at multiple frequencies which can be tuned by the input power level and mutual coupling between the coils. Higher harmonic generation is found dominant at lower input power, whereas subharmonic generation (period doubling and period quadrupling) is observed at high levels. Power transfer at subharmonics reveals robustness against level perturbations due to pronounced amplitude hysteresis effect. A circuit simulation based on standard non-linear diode SPICE models confirms the experimental results which are obtained on a demonstration prototype.}, language = {en} } @inproceedings{SeligerLeirich2024, author = {Seliger, Norbert and Leirich, Nico}, title = {Reconfigurable Board-to-Board Interconnect Utilizing Bistable Compliant Ribbon Wires}, series = {14th International Workshop on the Electromagnetic Compatibility of Integrated Circuits (EMC Compo)}, booktitle = {14th International Workshop on the Electromagnetic Compatibility of Integrated Circuits (EMC Compo)}, publisher = {IEEE}, address = {Turin}, isbn = {979-8-3315-0462-5}, doi = {10.1109/EMCCompo61192.2024.10742066}, pages = {211 -- 215}, year = {2024}, abstract = {We propose a printed circuit board (PCB) interconnection utilizing elastically deformed ribbon wires. The wire deflection is designed as a bistable snapping mechanism, which enables post-assembly tuning of the geometry. Hence, a reconfigurable inductance is obtained, easing impedance matching and supporting signal integrity. Analytical solutions for partial and mutual inductance of buckled wires are developed, which are successfully validated by magneto-quasistatic field simulations and by experiments on a test structure for frequencies ranging from 100kHz to 100MHz. We demonstrate a tunable loop inductance from 25nH to 50nH at 10MHz.}, language = {de} } @inproceedings{SeligerLeirich2024, author = {Seliger, Norbert and Leirich, Nico}, title = {Compliant Mechanism based Planar Inductors for Reconfigurable Magneto-Inductive Wave Devices}, series = {18th International Congress on Artificial Materials for Novel Wave Phenomena - Metamaterials 2024}, booktitle = {18th International Congress on Artificial Materials for Novel Wave Phenomena - Metamaterials 2024}, publisher = {IEEE}, address = {Crete}, isbn = {979-8-3503-7349-3}, doi = {10.1109/Metamaterials62190.2024.10703322}, pages = {X-243 -- X-245}, year = {2024}, abstract = {A reconfigurable planar inductor based on bistable compliant mechanism is proposed. Flexible snapping of wire elements is used for modification of the loop area and self inductance as well as for the mutual coupling between laterally arranged multiple inductors in a magneto-inductive wave (MIW) device. A mechanical model is presented building the basis for an analytical inductance model. The bistable reconfigurability is demonstrated experimentally and confirmed by numerical simulation results.}, language = {en} } @inproceedings{Seliger2024, author = {Seliger, Norbert}, title = {A Tunable Wire Loop Inductor based on Bistable Compliant Mechanism}, series = {25th International Microwave and Radar Conference (MIKON)}, booktitle = {25th International Microwave and Radar Conference (MIKON)}, publisher = {IEEE, Warsaw University of Technology}, address = {Wroclaw, Poland}, isbn = {978-83-969726-0-6}, doi = {10.23919/MIKON60251.2024.10633977}, pages = {209 -- 214}, year = {2024}, abstract = {By axially loading of a cylindrical wire we utilize the first order buckling mode to form the shape of a segment of a wire loop inductor. The shape of the deformed wire is expressed in analytical form and provides the basis for a semi-empirical formulation of the loop inductance. Combining several buckling segments and taking advantage of the snap-through behavior of such a segment, the shape of the wire loop in air and hence the loop inductance can be varied mechanically on purpose. The analytical model for the tunable inductance enables a design methodology for bistable compliant inductors. We present two designs of mechanically tuned inductors in the range from 20nH to 50nH. Furthermore the electromagnetic properties of the proposed innovative components are confirmed by method of moments numerical modeling based on quasi-static magnetic fields and by experiment. We finally show that the design process is applicable to regular plane polygonal inductors representing multi-stable compliant stages.}, language = {en} } @inproceedings{Seliger2024, author = {Seliger, Norbert}, title = {Reconfigurable Polygonal Planar Inductor with Bistable Snapping Mechanism}, series = {2024 IEEE Open Conference of Electrical, Electronic and Information Sciences (eStream), Vilnius, Lithuania}, booktitle = {2024 IEEE Open Conference of Electrical, Electronic and Information Sciences (eStream), Vilnius, Lithuania}, isbn = {979-8-3503-5241-2}, issn = {2690-8506}, doi = {10.1109/eStream61684.2024.10542595}, pages = {1 -- 6}, year = {2024}, abstract = {A mechanically tunable planar single-turn inductor in air is proposed. The bistable flexible deflection of axially compressed wire segments is used for variation of the loop area of regular polygonal loop inductors. We present analytical expressions for the loop inductance and confirm the theoretical findings by magneto-quasi-static field simulation on exemplary polygonal circuits.}, language = {en} } @inproceedings{SeligerHelmbrecht2024, author = {Seliger, Norbert and Helmbrecht, Cordula}, title = {A high-frequency performance and degradation study of adhesive conductive EMI shielding tapes during High-Temperature Storage}, series = {Proccedings CIPS 2024 - 13th International Conference on Integrated Power Electronics Systems}, booktitle = {Proccedings CIPS 2024 - 13th International Conference on Integrated Power Electronics Systems}, publisher = {VDE VERLAG GMBH}, address = {D{\"u}sseldorf}, isbn = {978-3-8007-6288-0}, issn = {0341-3934}, pages = {297 -- 303}, year = {2024}, abstract = {The variation of the contact impedance of adhesive conductive EMI shielding tapes under high temperature storage (HTS) of 110degC is investigated. The adhesive tapes under test are implemented as signal return paths in microstrip lines. Changes in the ground plane impedance by adhesive deterioration are analyzed by S-parameter measurements from 1MHz to 3GHz. A circuit model for contact impedance degradation is proposed and applied in simulation of board level shielding. Contact resistance and contact capacitance are found to increase significantly after 2400h, causing a declined magnetic field shielding effectiveness by 30 dB below 500 MHz.}, language = {en} }