Cantilever-based RF- mems switches for 5G applications

Official URL: https://risc01.sabanciuniv.edu/record=b2767128_(Table of contents)

Fifth-generation (5G) mobile communications are developed for Internet of Things (IoT) applications such as industrial automation, cloud robots, and safety-critical vehicle communications. The emerging 5G requires fast data rates, minimal latency, and wide coverage. In order to fulfill these demands improved slot-based architecture, mm-wave bands, and beamforming are being designed. These technologies require RF front-end switches with high isolation, frequency filtering, low insertion loss, high linearity, and fast switching. This thesis studies cantilever-based RF-MEMS switch performance at high frequencies for 5G applications. The RF-MEMS switch is first designed in a series configuration and exploits intrinsic stresses within a thin film to build a self-assembled cantilever beam based on bi-directional control of intrinsic stresses to reconstruct straight cantilever beams into out-of-plane wavy structures. The novel switch design displays a low insertion loss of -0.5 dB in the on-state and high RF isolation of -22 dB in the off-state at 30 GHz due to the large air gap between the distal end of the cantilever switch (RFin) and underlying contact pad (RFout), while maintaining a low operation voltage of 10.5 V. In addition, to reduce the inherent high actuation voltage needs of conventional electrostatic fixed–fixed shunt switches, a cantilever-based RF-MEMS switch with a shunt configuration has also been designed and, systematically optimized both from electromechanical and RF performance aspects achieving a pull-in voltage of 9 V, low insertion loss of -0.14 dB, and high isolation of -44.7 dB at 30 GHz. The novel cantilever-based series and shunt RF-MEMS switches designed in this thesis exhibit low insertion losses, high isolation and low pull-in voltages, making them ideal for 5G mobile applications.