MEMS For Wireless: FBAR and LiMMS

This paper describes technology of micro-electro-mechanical systems (MEMS) in the field of mobile handsets, which uses the single-mode CDMA product of 1800-1900 MHz range. In order to gain the market penetration, the HP Labs uses the FBAR project, where it reduces the size and weight of the RF resonators, filters and duplexers. Thus, the brief analysis illustrates that the FBAR, as a miniaturization technology for filters and resonators not only has functional dimension of micrometers but also the fabrication method is similar to that of the mass-market integrated-circuit fabrication. In the liquid metal micro switch (LiMMS), we employ a liquid-liquid contact to address the handset failure. The switching operation is achieved by forming a gap in the liquid metal using gas expansion. LiMMS also has good RF performance, thus the micro-machined version developed by California achieves promising parameters of 0.2 dB insertion loss at 2 GHz of below 0.3 ms switching time, switching power of 0.3 W for 2.5 microsecond duration.