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Cell Phone Antenna Troubles - Radio Frequency MEMS Come to the Rescue

According to the market research firm iSuppli Corp., help may be on the way for iPhone 4 users frustrated by dropped calls with the arrival of Radio Frequency Microelectromechanical Systems (RF MEMS), semiconductors that can improve the performance of antennas in cell phones

Long plagued by technological hurdles and other disappointing setbacks, RF MEMS are finally ready for the big time, with revenue projected to double in 2010 and more than triple in 2011.

From slightly less than $4 million in 2006, global RF MEMS revenue is anticipated to climb to $8.1 million this year—and then surge to $27.9 million in 2011, according to iSuppli. By 2014, revenue will reach a whopping $223.2 million—a far cry from the industry's extremely modest beginnings.

"More than 50 percent of cell phones shipped in 2014 will feature some form of front-end-module tuning using RF MEMS technology," said Jérémie Bouchaud, Director & Principal Analyst (MEMS & Sensors) at iSuppli.

"The implementation of RF MEMS switches and varactors in mobile phones could help boost the performance of smart phones like the iPhone 4, which made news headlines recently because of a problematic antenna that resulted in dropped signal strength. RF MEMS are also ideal for impedance matching of the Power Amplifier."

Although other technologies will address antenna issues, including SoS FETs and BST varactors, MEMS deliver the best performance in terms of insertion loss.

RF MEMS switches have been used in small volumes in instrumentation applications because of their small form factor and excellent RF performance. However, despite initial promise, they failed to take off on a large scale because of myriad commercialization and technological obstacles. All that is about to change as RF MEMS technology begins to realize its potential because of strong product offerings from a number of major suppliers.

Seven firms are sampling RF MEMS products.

California-based WiSpry Inc. and Japan's TDK-Epcos are offering RF MEMS for high-volume cell phone applications. On another front, U.S. firms Analog Devices Inc., Radant Technologies Inc. and XCOM Wireless Inc.—in cooperation with relay manufacturer Teledyne Technologies Inc.—as well as Japanese supplier Omron Corp. are targeting high-end applications for testing and instrumentation such as ATE and RF test. U.S. startups Radant MEMS and MEMtronics focus on defense applications.

In particular, interest is growing among mobile handset manufacturers on how RF MEMS can be used for the front-end tuning of cell phones to improve antenna performance, given the advent of new wireless standards like LTE for 4G technology. WiSpry—which has garnered several design wins for its MEMS varactors—is expected to commence volume production by the fourth quarter last year.

Outside of cell phone antennas and instrumentation, a pair of smaller—but still untapped—opportunities also exists for RF MEMS switches and varactors in the foreseeable future. One of these areas is in wireless infrastructure gear—e.g., for femto cells—and cellular base stations, where the current switches being used could be supplanted by cheaper and higher-performing RF MEMS devices. Another area is in defense and aerospace applications, including radio systems and phased array antennas, especially after 2014. This represents a high-volume opportunity for RF MEMS numbering in the millions of units.

About the Author

iSuppli's unique market research reports help deliver vital information on the status of the entire electronics value chain. iSuppli's MEMS & Sensors market research provides up-to-date, insightful coverage of the consumer, automotive, and high-value markets for MEMS, or microelectromechanical sensors. Contact us on +1.310.524.4007 for more details.

i want to connect an omron 230v realy to a 24volt circuit to switch on and off a 230volt light.?

my question is that how is the circuit wired. the relay itself is a plug in type and will be connected to a relay base. i undestand that i need a positive and negative 24v supply to the base but what do i need then for the lighting circuit. is this circuit just like a normal lighting circuit as in a common connection and a switch wire?

Hi my Friend,

Simply look at the relay's body, you will find the pin out of the relay.

For every relay, there is two contacts for the coil, beside these two terminal you will find at least three more terminals one is labeled as COM, one is labeled as NO (Normally Open) and one is labeled as NC (Normally Close)

User needs to pick the appropriate coil type either AC or DC but with different voltage range; for example 12Vdc, 24Vdc, 48Vdc, or 120Vac, 240Vac, etc...

If you want to change the state of the output terminals, you need to apply the spec. voltage onto the coil.

The contact/output side does not have any limitation on AC/DC or even the voltage, you have to make sure the voltage and current is not higher than the spec value.

For example, your application wants to connect a 230 Volt AC power to a light, first think you have to find out what is the max. current, let say its spec at 7.5A, I recommend the relay needs to be a 10A relay.

Next if it is a 24Vdc coil relay, then you need to put a 24Vdc power source in series with a switch to the relay coil. Make sure the polarity and the terminal pin numbers are correct.

Then run a 230V power to the COM of the relay contact, and from the NO output pin connect in series with the light.

Testing: If you turn on the switch which applies 24Vdc to the relay coil, the NO contact of the relay will engage and the light should turn on.

ps. if you wire the light to the NC output, the output behavior will be different. It means if you don't apply the 24Vdc to the coil, the light is ON, else the light is OFF.

I hope you understand the mechanism of a relay.

Relay Logic: Single Contact Switch Turns On/Off LED