Florian Boes, Research Associate, Karlsruhe Institute of Technology
Florian Boes received his master’s degree in electrical engineering from the Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany, in 2013. His master thesis on the topic of high-speed millimeter-wave photonic wireless communication results in a record data rate of 100 GBit/s at 240 GHz carrier frequency. He is currently working as a research and teaching assistant at the Institute of Radio Frequency Engineering and Electronics at the Karlsruhe Institute of Technology (KIT), where he is working toward his Ph.D. degree on ultra-broadband on-wafer measurement techniques.
Investigation of Parasitic Modes by 3D Full-Wave Electromagnetic Simulations Including RF Probe Tips
In the millimeter-wave frequency range on-wafer measurements of passive and active circuits are prone to severe deviations between measurement and simulation. One way to achieve a better match is to perform full 3D electromagnetic field simulations (EMFS) of the devices under test (DUT). These simulations cover effects like coupling between structures or complex electromagnetic behavior e.g. in coplanar waveguide (CPW) corners and T-junctions, which are enhanced with air bridges. While these simulations are sufficient at lower frequencies, at frequencies above 200 GHz part of the deviation between measurement and simulation arise from the excitation of parasitic modes which are unobserved using classical EMFS techniques. An extensive study resulted in the conclusion, that these modes depend on the RF probe tip, which used in the measurement setup, and therefore has to be included into the EMFS simulation. Therefore, part of an Infinity probe tip was remodeled and used to excite various circuits. Furthermore, in order to be able to de-embed the probe tip out of the simulation results, the ISS calibration standards were also remodeled and a thru-reflect-line (TRL) error set based on EMFS simulations was calculated. Finally, a very good agreement between measurement and simulation was achieved with this method.