Precise High Frequency Modelling of SMD Components

Vratislav Sokol received M.Sc. and Ph.D. degrees in radioelectronics from the Czech Technical University in Prague in 2000 and 2004, respectively. He was a Post-Doctoral Research Associate with Cork Institute of Technology in Ireland where he dealt with an ultra-wideband transceiver. His activities are focused on microwave circuit design and modeling using electromagnetic field simulators and precise microwave measurement and calibration. Since 2006 he has been with CST as an application engineer.

Surface-mount devices (SMDs) have gained an attraction over the last decades. Surface-mount technology has been successfully used in many communication and RF sensing/control systems. For instance the low-noise block for the satellite broadcasting is widely used in households in a frequency band of 10-12 GHz. However the higher operating frequency is used the higher accuracy of the SMD models is required. 

Simple models based on the equivalent circuits may fail because of interaction between the SMD body and the layout where the SMD is placed to. In principle such an interaction can’t be omitted and therefore the SMD models usually provided by vendors are valid just in the layout where the model was extracted from. Any change of the footprint, substrate thickness or permittivity might cause that the model become to be invalid. Electromagnetic field simulation can be successfully used for correction of such effects with a reasonable effort providing enhanced accuracy of the SMD models. 

This webinar will present a technique for an extraction of the SMD models from measured S-parameters in a given test-fixture using CST STUDIO SUITE. The concept will be demonstrated on the example of SMD low-pass filter.