This paper investigates the surge reliability of commercial 1200V SiC MOSFETs through a combined approach of experimental testing and multiphysics simulation, elucidating the failure mechanisms under both step and repetitive surge current stress. The innovative integration of package-level electro-thermal coupling simulation with transient junction temperature estimation overcomes the limitations of conventional methodologies that rely solely on decapsulation analysis and Technology Computer Aided Design (TCAD) simulation. Experimental evaluations on six Devices Under Test (DUTs) with distinct structural configurations, employing surge testing and failure analysis techniques including C-mode Scanning Acoustic Microscopy (C-SAM), optical microscopy, and Scanning Electron Microscope (SEM), confirm that device failure primarily originates from gate-source short circuits caused by aluminum bonding wire melting. COMSOL multiphysics simulations further replicate the transient thermal characteristics of bonding wire regions, demonstrating rapid temperature escalation to the Aluminum melting point within 5-6 ms during surge events. A transient thermal resistance-based junction temperature characterization method is proposed, revealing an inverse proportionality between thermal resistance and chip area. ... Read more

In this paper, the full calibration chain of FMCW radar with simultaneous transmission of two orthogonally polarized orthogonal waveforms is considered. Specifically for this type of polarimetric radar, compensation of signals’ biases and equalization of the amplification gains of the parallel polarimetric channels in the receiver are jointly performed using the noise measurements. The calibrations of the absolute complex gains of the transmitter’s polarimetric channels together with complex antenna gains are done using the model-based fit of the measurements of the rotating dihedral reflector. Phase relations between polarimetric channels are treated in the Doppler domain using the unfolded velocity of the target. The performed calibration results in high-accurate measurements of the radar targets’ polarimetric scattering matrix (PSM) in the Doppler domain. All the proposed calibration steps are illustrated using real radar data. ... Read more

We typically search for images by keywords, e.g., when looking for images of apples, we would enter the word “apple” as query. However, there are limitations. For example, if users input keywords in a specific language, then they may miss results labeled in other languages. Moreover, users may have an image of the object they want to obtain more information about, e.g., a landmark, but they may not know the name of it. In such scenario, word-based search is not adequate, while imagebased search would be ideally suited. These needs drive us to develop a purely content-based image search engine, meaning that users can search images with an image as query. Motivated by this use case with numerous applications, in this paper we propose and validate an image query based search engine... ... Read more