Mario Francisco Velez

Cross-sectional dilation mode resonator with very high electromechanical coupling up to 10% using AlN

For the first time in the development of piezoelectric micromechanical resonators, this paper presents a new class of cross-sectional dilation mode resonators (XDMR) that achieve unprecedentedly high electromechanical coupling constant: kt2 up to 10% for aluminum nitride (AlN) based resonators and 19% for zinc oxide (ZnO) based resonators. Detailed discussions on the geometry design, FEM simulation, and process challenge are provided in this paper to give insight on this novel high-kt2 piezoelectric resonator technology and, more importantly, guide the future development of mechanical resonators with coherent 2D/3D mode shapes.

Modeling, design and demonstration of ultra-miniaturized glass PA modules with efficient thermal dissipation

This paper addresses the thermal dissipation of power amplifier (PA) chips, which is one of the biggest challenges in the development of ultra-miniaturized glass-based RF modules. Glass packages with 3D or double-side active and passive integration offer the best miniaturization and performance enhancement for RF modules because glass has ultra-low loss, dimensional stability for precision thinfilm components, ability to process through-vias in large panels to reduce cost. However, glass is a poor thermal conductor. Cooling of the high-power PA die with integrated miniaturized RF modules is, therefore, a key challenge. This paper provides extensive modeling studies of RF power amplifier modules with copper thermal vias in ultra-miniaturized glass, without additional process steps. It considers various power amplifier design options such as: Si vs. Silicon-on-Insulator (SOI); location of die hotspot; via geometry; and conformal vs. fully-filled vias, and provides optimal design recommendations with modeling and analysis.