| PhD Viva

Name of the Speaker: Ms. Kanaka Joy (EE17D407)
Guide: Prof. Deleep R Nair
Online meeting link: meet.google.com/xfz-drbs-ktj
Date/Time: 7th December 2023 (Thursday), 3:00 PM
Title: Development and Wafer-Level Packaging of RF MEMS SPDT Switches

Abstract

With the current developments in 5G and modern telecommunication systems, there is a compelling need for highly efficient passive devices for switching and tuning applications. RF MEMS (Radio Frequency Micro-electromechanical System) switches possess exceptional characteristics such as low insertion loss, high isolation, high linearity, and low power consumption, making them a preferred alternative for high-frequency applications in place of PIN diodes and FETs.

This study explores the different aspects of RF MEMS switches, such as the design, fabrication, characterization and wafer-level packaging. A capacitive shunt SPST RF MEMS switch and an ohmic SPDT RF MEMS switch are reported in this study. A capacitive shunt switch is designed to overcome the limitations associated with conventional designs, such as self-actuation at high power operations and insertion loss dependence on the air gap. RF MEMS SPDT switch presented here is an attempt to develop a completely dielectric-less SPDT switch for space applications, specifically 12- 18 GHz (Ku-Band). Both the capacitive shunt switch and SPDT switch are fabricated and characterized.

Two approaches are studied for the wafer-level packaging of the RF MEMS switches: wafer bonding and thin film encapsulation. For the thin film encapsulation, a bi-layer SiN and SU-8 are used as the structural layer, and the encapsulation is successfully demonstrated on a CPW structure. This encapsulation offered only nominal insertion loss to the structure, particularly less than 0.2 dB till 30 GHz. The same encapsulation method is attempted on switches.