What is this MEMS and why is it required for 4G?

The mobile technology evolving at an amazing speed going from 3G to 3.5G in around 5 years and now going from 3.5G to 4G in less than 5 years. According to Analysis, Annual Global Mobile Handset Shipments to Reach 1.5 Billion in 2011. Converged-function handsets will become a mainstream product with more than 30% share in developed markets by 2011. There is a constant pressure on the handset manufacturers to reduce the power consumption and the chipset size and at the same time driving down the cost of the device.

RF micro-electro-mechanical systems (RF-MEMS) is a semiconductor technology that allows micro-scale moving mechanical devices to be integrated with electrical transistors on silicon wafers. RF-MEMS technology can be utilized to make high-frequency components whose RF characteristics can be adjusted during operation, allowing for the first time reconfiguration of radio hardware under software control. The ability to reconfigure operating characteristics in real time results in a substantial reduction in the required number of discrete components for a given set of functions, significantly relieving pressure on the handset product developer.

While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micromechanical components are fabricated using compatible "micromachining" processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices.

An early micromotor built in the SUMMiT technology. For size comparison a microscopic dust mite is shown on top.

There are several different broad categories of MEMS technologies:

• Bulk Micromachining
• Surface Micromachining
• LIGA
• Deep Reactive Ion Etching
• Integrated MEMS Technologies

Details available here.

MEMS is not really a new technology. It has been around since 1960's but only recently it has become feasible. Samsung watch phone was the first phone to have a commercial MEMS circuit and its being used in variety of devices nowadays, not just mobiles. For those who watched the opening ceremony of 2008 Beijing olympics would have seen the different coloured torch display. That 'Waving Torch' used MEMS circuitry.

Scientists are also working on making MEMS intelligent and they are looking at microorganisms for ideas. The integration of microorganisms with MEMS, resulting in “biotic-MEMS,” is a hot topic for scientists designing micron-level machines. Recently, researcher Xiaorong Xiong of Intel, microbiologist Mary Lidstrom, and electrical engineer Babak Parviz (both of the University of Washington) have catalogued a large number of the most promising microorganisms for different areas of MEMS systems. They show that many of these microorganisms can offer capabilities beyond the limits of conventional MEMS technology.

Finally, from EE Times:

French research and strategy consulting company Yole Dveloppement (Lyon, France) provides an analysis on MEMS components for cell phone applications as it expects this market will represent $2.5 billion in 2012. In its latest report, entitled MEMS for Cell Phones, Yole stated that the cell phone industry represents a complex challenge for MEMS but also its greatest opportunity for growth in the next five years.

According to the market research firm, silicon microphones and FBAR/BAW filters have experienced "incredible growth" since their introduction in 2003 and are now entering the maturity stage. MEMS accelerometers are in "a strong development stage", and MEMS products such as gyroscope, microdisplay, micro autofocus and micro zoom are at the emerging stage.

Yole also mentioned products that are not yet in the emerging stage. Among them are pressure sensors, micromirror, RF switch/varicaps, oscillators, and micro-fuel cells.

Yole reported that, for the year 2007, cumulative sales reached $440 million for three MEMS products in cell phone applications, namely silicon microphones, FBAR/BAW filters and accelerometers.

As a conclusion, Yole said it anticipates MEMS will become a key driver for innovation in the cell phone industry, and new cell phone features will represent 60 percent of the total MEMS market by 2012.

Interested people can also read:

RF-MEMS for Wireless Communications, Jeffrey L. Hilbert, WiSpry, Inc. - IEEE Communications Magazine • August 2008