The Potential Impact of MEMS on Next-Generation Wireless

Louis Ross (Global Emerging Technology Institute)

Eventually, technical problems haunting the introduction of unprecedented advances in mobile wireless services and related technology will be overcome. Research and the commercialization of solutions for the reduction of the number of components used in a cell phone, the integration of these components into fewer components, and the problem with developing a reliable, long-lasting power source is picking up pace.

The use of MEMS (micro-electrical mechanical systems) is increasing in a number of key growth areas related to the wireless area. The technology has been around for some time, however, like the delays experienced in developing a solid market for integrated circuits, it has been difficult to develop a platform technology capable of building the mass necessary to move it beyond its current role as an enabling, as opposed to full-fledged disruptive, technology.

The MEMS market includes a large number of niche areas, those major sections relating to the above include information technology (data storage), telecommunications (optical devices for all optical networks) and, as mentioned, wireless applications enabling performance enhancement of existing and future wireless transceivers for example. The latter is expected to continue to grow at anywhere from about 30% to 40% per year. One of the largest markets for MEMS is for medical and biomedical applications (drug delivery systems and monitoring; micro-fluidic devices for pharmaceutical testing). These application may also incorporate a wireless component in the future. For example, a micro-fluidic device incorporating wireless communications functionality.

3G and beyond mobile wireless handsets demand a lot more functionality out of the same sized cell phones and PDAs (with cellular capability) that are currently in the market. The size of key components on the inside must be reduced and functionality and reliability must be enhanced. MEMS can significantly enhance such things as voice quality, which leads to less of a drain on battery power. Research and development into the application of micro-fabricated components and materials for generating power and unprecedented performance is critical in pushing the hardware to the point where it can effectively run on high-speed mobile networks and house the applications which generate revenue.

Cell phones are filled with filters, duplexers and resonators, passive components that sort radio frequencies in order to ensure a user that his phone works properly and does not interfere with the frequencies of other phones. These non-silicon based materials, which include ceramics, have prevented the further reduction in size of a phone's components. Some researchers and manufacturers want to replace these passive components with MEMS. MEMS components are currently being produced by an interesting array of venture companies and worked on by the R&D people of large companies across the globe, especially in the United States, Europe and Japan. Several interesting U.S. venture companies are looking to take advantage of the trend by developing technologies for wireless devices which not only include regular cell phones, but the increasingly popular converged PDA/cell phone devices that are showing up in the U.S. The more integration and convergence of technologies, the greater the need for miniaturization and stronger battery power needed. The greater the success of relatively "primitive" hardware that is on the market, the greater the support for the introduction of MEMS.

MEMS-based devices for telecommunication applications, such as switches, tunable capacitors and mechanical filters, have been intensively studied since 1998. RF (radio frequency) MEMS switches offer advantages over their solid-state counterparts (FETs and PIN diodes) because of their low drive power requirement, high isolation and good linearity. RF MEMS can deliver a substantial increase in efficiency after some of the technical challenges are overcome. It is expected that they will be in wider usage by the beginning of next year, initially being used in the antennas. The promise of RF MEMS is high due to favorable size and power consumption characteristics. RF MEMS technology will be paired with other MEMS technologies such as inducers and capacitors in the beginning. Still, costs are an issue and must come down in order to grow the market, a market that is estimated by Cahner's In-Stat Group to reach nearly $350m by 2006. RF MEMS are expensive, and hopefully the success of 3G in the consumer market will lead toward stronger demand, support, funding and commercialization of cheaper RF MEMS solutions. Large companies which are spending more on R&D in the area are looking to overcome the technical challenges, especially those associated with the high cost of production for RF MEMS, namely packaging. Some researchers are actively looking to develop innovative bonding processes that can be used for packaging of RF MEMS devices. Improvements in design software for RF MEMS also will help. Again, the success of next-generation wireless applications should help to move the development of RF MEMS forward. These devices can provide true on/off switching that will seriously improve the energy use of wireless phones, among other things. According to some industry experts, they will eventually replace the pin diodes that are currently being used to switch signals.

Profitable applications for next-generation wireless will no doubt include those associated with entertainment. In this area, the use of MEMS may come into play in the area of online, mobile wireless gaming as connect speeds reach land-based wire connections of that of cable and DSL systems. Along with applications relating to gaming, MEMS (tilt) sensors can also be used for anti-theft and security applications. As the wireless industry incorporates features such as advanced Internet access, GPS, and more to next-generation cell phones, they're running into a problem: more functionality is resulting in an increase in the number of components needed. For the answer, see above. Successful use of MEMS for wireless devices could be one of the keys toward providing the MEMS industry in general with a key, growing consumer market that it has longed for, something that would require manufacturers to expand production that would eventually lead to reduce per unit costs.