In this paper, we firstly propose a novel low-loss RF MEMS silicon switch which utilizes reflowed glass as a switch structure near the contact metal. A new concept of electrostatically-driven RF MEMS silicon switch was presented and realized through t...
In this paper, we firstly propose a novel low-loss RF MEMS silicon switch which utilizes reflowed glass as a switch structure near the contact metal. A new concept of electrostatically-driven RF MEMS silicon switch was presented and realized through the proposed fabrication process. By introducing reflowed glass into the silicon switch structure, the substrate loss induced by switch structure has greatly reduced. To verify the enhancement in loss characteristic, we fabricated 3 different types of RF MEMS silicon switches (silicon-, high resistance silicon-structured switch, and the proposed switch) and measured their insertion losses. In the frequency range of 5 to 30 GHz, the proposed RF MEMS switch with reflowed glass inside the switch structure showed insertion loss of 0.12 ~ 0.33 dB, while silicon- and high resistance silicon-structure switch showed 0.38 ~ 0.54 dB, 0.31 ~ 0.46 dB, respectively.
Before fabrication, theoretical analysis and simulations were carried out to predict the enhancement in insertion loss brought by the introduction of the reflowed glass. The expected improvement in the insertion loss characteristic of proposed RF MEMS switch was greater than 0.1 dB, compared to the conventional RF MEMS silicon switch.
Proposed fabrication method of the novel RF MEMS switch was based on SiOG process, assisted with the glass reflow process. The proposed fabrication process was validated with successful fabrication of the proposed switch. We believe that the proposed fabrication process could be used for a wide range of RF MEMS area where low-loss characteristic is needed.
Low insertion loss characteristic of RF MEMS switch can contribute to reduce not only the complexity and cost, but also the size of the system by eliminating additional circuitry for loss compensation in the system. Therefore, it can be said that development of low loss RF MEMS switch can widen RF application fields where RF MEMS switch can be used. Furthermore, with this enhanced loss characteristic, RF MEMS silicon switch is expected to be used in the RF applications of strict performance requirement, such as base-station antenna, defense system, satellite switching network, etc.