3d System Integration Simulation Dr. Thomas Fischer Siemens Audiology Solutions fischerthomas@siemens.com CST Usergroup Conference, May 2012 T. Fischer, CST User Conference 2012, Page 1 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Modeling of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 2 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Modeling of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 3 Copyright Siemens AG 2012. All rights reserved.
Introduction (I) Modern hearing aids in a world of communication (1) Ear to ear communication with magnetic link @ 3 MHz (2) Ear to RCU communication with magnetic link @ 3 MHz (3) RCU to mobile phone or audio transmitter communication with Bluetooth technology @ 2.4 GHz T. Fischer, CST User Conference 2012, Page 4 Copyright Siemens AG 2012. All rights reserved.
Introduction (II) Components of a hearing aid Microphones Battery External speaker connector PCB with ASICs Wireless antenna T. Fischer, CST User Conference 2012, Page 5 Copyright Siemens AG 2012. All rights reserved.
Motivation Sources of interferences and influences at 3 MHz Microphones (2) Battery (1, 2) External speaker connector (3) PCB with ASICs (1, 2, 3) (1) Changes in inductance L (2) Changes in ESR (3) Interference sources T. Fischer, CST User Conference 2012, Page 6 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Modeling of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 7 Copyright Siemens AG 2012. All rights reserved.
Antenna Simulation (I) Antenna data Operating frequency 3 MHz, λ = 100 m Coil with ferrite core 2 winding layers, 90 turns Wire diameter 34 um Flexible PCB connector 1.65 mm 6.4 mm PCB Inductance (L) Geometry and core Losses (ESR) Wire diameter Skin effect Proximity effect Core losses T. Fischer, CST User Conference 2012, Page 8 Copyright Siemens AG 2012. All rights reserved.
Antenna Simulation (II) Simulation in CST Microwave Studio (MWS) Frequency domain (electrically small, narrow band) Tetrahedral meshing (for round core, wires, complexity) Thin wire model for L calculation only due to PEC wire Name Measurement L [uh] 74,4 ESR Duration [Ω] [min] 18,6 - Model thin wire (PEC) 74,6 1,6 1,5 T. Fischer, CST User Conference 2012, Page 9 Copyright Siemens AG 2012. All rights reserved.
Antenna Simulation (III) Volume wire model for L and ESR calculation Wire as lossy material for skin depth δ< material thickness Wire as normal material with 3rd order tetrahedral mesh Proximity Effect Eddy currents with current density at 0 phase T. Fischer, CST User Conference 2012, Page 10 Name Measurement L [uh] ESR Duration [Ω] [min] 74,4 18,6 - Model volume wire (lossy metal) 74,5 13,3 3,0 Model volume wire (normal material), 1st order tet mesh Model volume wire (normal material), 3d order tet mesh 74,5 28,2 3,0 75,5 17,6 14,0 Copyright Siemens AG 2012. All rights reserved.
Antenna Simulation (IV) Influence of an adjacent thin metal plane as part of PCB Decreased inductance (L) and increased losses (ESR) Good agreement between measurement and simulation T. Fischer, CST User Conference 2012, Page 11 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Modeling of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 12 Copyright Siemens AG 2012. All rights reserved.
Bending Process (I) How could the PCB be imported into MWS? PCB from ECAD tool 2d layout All traces and VIAs Components as lumped elements PCB from MCAD tool 3d bended design Missing traces and VIAs Components as bricks T. Fischer, CST User Conference 2012, Page 13 Copyright Siemens AG 2012. All rights reserved.
Bending Process (II) Usage of additional tool Mecadtron Nextra + Combines ECAD/MCAD world + Back annotation for redesign + Components as lumped elements since CST Studio Suite 2013 - Rework of materials - Meshing difficult for tetrahedral mesh - Handling of ECAD tools and Nextra requires workflow T. Fischer, CST User Conference 2012, Page 14 Copyright Siemens AG 2012. All rights reserved.
Bending Process (III) Import via CST EDA filter using bend sheet command Cut PCB 2 times Rotate upper part Define Cylinder for each multiple layer Bend faces of connectors + Usage of full EDA import functionality - Complex bend process - Handling of redesign T. Fischer, CST User Conference 2012, Page 15 Copyright Siemens AG 2012. All rights reserved.
Bending Process (IV) Import via CST EDA filter using analytical face and thicken sheet commands (VBA macro) Cut PCB 2 times Rotate upper part Pick point and face of connector Create analytical face Thicken sheet command + Usage of full EDA import functionality + Easy bend process - Handling of redesign T. Fischer, CST User Conference 2012, Page 16 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Modeling of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 17 Copyright Siemens AG 2012. All rights reserved.
PCB Simulation (I) Modeling of interference, PCB and antenna in MWS ASIC Load (discrete port) ASIC Noise source (discrete port) Antenna as sink Capacitors (discret ports) T. Fischer, CST User Conference 2012, Page 18 Copyright Siemens AG 2012. All rights reserved.
PCB Simulation (II) Source and load impedances in CST Design Studio (DS) Influence of different coupling capacitors Different signal shaping Observation of antenna voltage T. Fischer, CST User Conference 2012, Page 19 Copyright Siemens AG 2012. All rights reserved.
PCB Simulation (III) Magnetic field distribution with MWS and DS as combined result (qualitative observation) Analysis of induced coil voltage in DS (quantitative observation) T. Fischer, CST User Conference 2012, Page 20 Copyright Siemens AG 2012. All rights reserved.
Content Introduction Magnetic link - antenna simulation Simulation of bended multilayer PCBs Magnetic link system integration simulation Conclusion T. Fischer, CST User Conference 2012, Page 21 Copyright Siemens AG 2012. All rights reserved.
Conclusion Antenna simulation works pretty well Inductance and losses Influence of metal planes Import and handling of bended multilayer PCBs Additional tool Mecadtron Nextra combines MCAD/ECAD world Usage of MWS commands to bend multilayer PCBS System integration simulation Simulation of PCB, components, noise sources and antenna Prediction of induced interference voltage Magnetic field distribution to analyze interference problem T. Fischer, CST User Conference 2012, Page 22 Copyright Siemens AG 2012. All rights reserved.