In the world of test and measurement, precision, efficiency, and adaptability are essential to success. MEMS, which stands for Microelectromechanical Systems, is a microscopic switching technology that is revolutionizing the field, especially in RF & microwave switching. MEMS devices incorporate both electronic and mechanical moving parts and consist of components ranging from 1 to 100 micrometers.
First presented to DARPA (Defense Advanced Research Projects Agency) by the University of Utah in 1968, MEMS devices have found their way into a variety of applications, including inkjet printers, accelerometers in modern cars for airbag deployment, electronic stability control gyroscopes for drones and optical switches but until now could only carry small signals, making them unsuitable for electrical test.
In terms of electro-mechanical switches, MEMS switches are fabricated on silicon substrates where a three-dimensional structure is micro-machined (using semiconductor processing techniques) to create relay switch contacts. The contacts can then be energized using either a magnetic or electrostatic field. Like Reed Relays, MEMS can be fabricated so the switch contacts are hermetically sealed (either in a ceramic package or at a silicon level), and this generally leads to consistent switching characteristics at low signal levels.
Much has been written over the years about the promise of MEMS technology for RF switching as an alternative to the commonly used Electromechanical Relay (EMR) and Solid-State (SS) switching solutions. However, technical challenges tempered the potential it could practically deliver. Many of these hurdles have now been cleared, and commercially viable RF switching solutions are now gaining traction for Test & Measurement (T&M) applications where fast switching speed and a very long operational life are necessary, alongside consistent, low-loss RF performance.
While MEMS technology offers numerous advantages, it's important to be aware of its limitations:
|
MEMS |
EMR |
Solid State |
Frequency Range |
DC to 4 GHz (usable to 5 GHz) |
DC to 3 GHz |
10 MHz to 8 GHz |
Insertion Loss |
<1.4 dB to 4 GHz |
<1.0 dB to 3 GHz |
<6.0 dB to 8 GHz |
VSWR |
<1.5:1 to 4 GHz |
<1.4:1 to 3 GHz |
<1.95:1 to 8 GHz |
Max RF Power |
25 W to 4 GHz |
10 W at 3 GHz |
4 W at 8 GHz |
Operating Time |
50 microseconds |
3 milliseconds |
50 microseconds |
Life Expectancy |
3 billion operations |
10 million operations |
Indefinite |
Hot Switching |
NO |
Better tolerance |
Some tolerance |
Price per channel normalized to EMR |
1.3 |
1 |
1.9 |
*Figures are for typical Pickering PXI switches for each technology.
To meet the increased requirements from our high-volume semiconductor customers, we recently joined forces with Menlo Microsystems—a technology company that specializes in developing advanced MEMS technology for a variety of applications—to help advance our PXI & PXIe MEMS-based RF multiplexer product line. Menlo Micro has been at the forefront of perfecting electrical switching in a MEMS environment, making it one of the first companies to achieve this feat and a natural fit with our mission at Pickering to meet the demand from our high-volume semiconductor customers. This partnership has led to the creation of our MEMS product family, which offers several advantages vital to our customers’ success. Unlike traditional electro-mechanical relays (EMRs), the MEMS-based modules we developed using Menlo Micro’s Ideal Switch® offer excellent RF characteristics up to 4 GHz and an operational life exceeding 3 billion operations, a significant improvement over the maximum 10 million operations typically offered by EMR-based solutions.
Menlo Micro Case Study: When cycles matter: Upgrade existing EMR PXI RF multiplexer solution
MEMS switching technology is a game-changer for high-volume RF & microwave customers. By offering speed, durability, reduced testing costs, and low insertion loss, MEMS switches have become an invaluable asset in the field. Understanding their limitations and benefits is crucial for selecting the right technology to meet your testing requirements while achieving the perfect balance of precision and efficiency.