We were honored to have Stefan Castravete from Caelynx Europe present at the SIMULIA Americas Users Conference, May 1-2, 2024 in Novi, Michigan.

Abstract

The study was performed by Caelynx Europe and National Institute of R&D in Microtechnologies (IMT).

5G devices operating up to the millimeter wave band (> 30 GHz) are already widely deployed, offering up to 20 Gbps transfer rated. The smaller wavelengths have already led to higher integration features and on-chip antenna deployment. The next generation of communication devices (6G) will go even further and with operating frequencies up to the THz being taken into consideration. As always, one bottleneck is the wavelength and substrate dependent antenna. One approach to direct integration of high-performance antennas in mainstream CMOS/BiCMOS technologies is the use of thin dielectric membranes processed through back end of line (BEOL) deep etching of the lossy silicon substrate. With this motivation, we designed a fully parametric model of a Folded Slot Antenna Array (FSAA) using CST Microwave Studio. The layout was optimized for operation above 100 GHz. The antenna is supported by a 2.1 µm thick SiO2/Si3N4 dielectric membrane released through deep reactive ion etching (DRIE) of low-resistivity (ρ = 10 Ω·cm) silicon. Input matching and radiation performance as a function of frequency are the main tradeoff parameters. Over 20 % fractional bandwidth and peak gain of 5 dBi are obtained by 3D full-wave simulations using the Time Domain Solver (Finite Difference Time Domain method). The results are validated using on-wafer measurements of a fabricated test device. Since the membrane-supported antenna has a symmetrical, bi-directional radiation characteristic, one application scenario will place the antenna over a metalized reflector, which will lead to the recovery of the backside radiation. The result will be a single lobe broadside radiation characteristic with a peak gain around 7-8 dBi. In the case of vacuum applications, it’s important to assess the effects of the pressure on the membrane.

The 3D model exported by CST MWS is thus imported in Abaqus, where pressure/force/deformation analysis are performed. The breaking point and deformation of the membrane are assessed and a worst-case scenario of the deformation (right before failure) is exported as a 3D model back to CST MWS. A new 3D EM simulation is performed and the input matching and radiation characteristic changes are presented.

Presenter Bio

Stefan Castravete is a seasoned expert in Computational Aided Engineering (CAE) with over two decades of experience across diverse industries including medical engineering, automotive, aerospace, marine, and renewable energy. Holding a Ph.D. in Mechanical Engineering from Wayne State University, his expertise lies in computational and numerical methods, structural mechanics, fluid dynamics, and optimization. Stefan is a certified instructor and technical support specialist for Dassault Systems Simulia, showcasing his proficiency in industry-leading CAE software.

Throughout his career, Stefan has managed and coordinated complex projects, conducting in-depth analyses such as CFD, finite element analysis, and analytical calculations. He has made significant contributions to research, developing algorithms for fluid-structure interaction, stochastic finite element methods, and wing flutter simulation. As a former research assistant and teaching assistant, Stefan has mentored students and contributed to academic advancements in dynamics and vibrations.

His dedication to advancing engineering knowledge is reflected in his numerous publications, presentations, and involvement in research grants. As a certified trainer and judiciary technical expert, Stefan remains committed to driving excellence in engineering practices and fostering industry growth.

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