Low actuation voltage RF MEMS series switch with novel beam design

Although radio frequency micro-electro-mechanical-systems (RF MEMS) switches have experienced intensive research in last decade. Major problems like high actuation voltage and low yield due to residual stress generated during the fabrication process still exist. In order to reduce the actuation voltage, we have designed and tested several configurations with different beam designs and actuation voltage as low as 6.39 V has been achieved. This paper presents an RF MEMS metal to metal contact series switch with novel low spring constant beam design. The problem of low yield due to residual stress has been addressed by introducing a dimple under the front tip of beam. The proposed design can easily be integrated in large multi-port structures. The fabrication of the switch has been implemented using a seven mask metal based process. The numerical and experimental results illustrate the novel cantilever beam switch with excellent RF performance. The cantilever beam switch shows a calculated actuation voltage of 6.39 V with 0.37 dB insertion loss and less than 22 dB return loss. The switch also exhibits an isolation of 23.5 dB for all frequency bands of interest.