Design of RF MEMS Piezoelectric Disk Resonator for 5G Communication

Abstract

With the growing impact of 5G communication system, Radio-Frequency Micro-Electro-Mechanical-Systems (RF MEMS) technologies are becoming increasingly important in our daily lives. Resonators have wide applications in filters for generation or selection of specific frequency signals. Bulk mode resonators have a larger rigidity than flexural mode resonators of the same size, resulting in higher frequencies that are ideal for 5G communication. Owing to this reason, bulk mode resonators are utilized for generation of frequency ranges greater than 2 GHz. As compared to electrostatic actuation, piezoelectric actuation techniques have a substantially lower motional resistance, lower operating voltages, and greater power handling capabilities. Thus, in this work, a 5 GHz piezoelectric micro-disk resonator has been designed and simulated using MEMS CAD tool. The quality factor, admittance, and scattering parameters of a radial-contour mode disk resonator are designed and tested. Along with this study, a comparative evaluation of three different piezoelectric materials based on the quality factor of the dominant resonant mode has been carried out. All three resonators are simulated for resonant frequency f0 = 5 GHz, and various analysis have been carried out. It was proposed that Lithium Niobate is preferred amongst the three piezoelectric materials for higher selectivity applications. The quality factors reported for the materials ZnO, AlN, and LiNbO3 are 1720, 1740 and 1850, respectively. Thus, this study indicates that RF piezoelectric disk resonators can achieve higher frequencies, at the cost of complicated fabrication process.