RF MEMS: a brief history and future trends
In this thoroughly comprehensive interview, Dr. Hyman shares his expertise and insight, and offers intriguing predictions about the future potential of RF MEMS devices.
MEMS Investor Journal: Why is there a need for RF MEMS? Why are MEMS devices for RF applications better than existing non-MEMS devices?
Dr. Dan Hyman: Developing RF circuits and subsystems requires a series of engineering trade-offs that are limited by the technology you are using. This is true at the device, component, and circuit level, and this is a part of RF engineering life that has been true for many decades. This is "easy" to deal with for single-mode systems like an old-fashioned cell phone, or modern Bluetooth circuit, but this gets harder and harder to do as frequencies get higher, data bandwidth gets larger, and, most of all, when multiple broadband signals have be handled in the same device. This is a defining trend in the wireless industry, and one that is taxing the limits of conventional technologies and "old-school" radio architectures. Wireless engineers inthe broadband, multi-standard world need a better way of doing things, and better technologies that can easily handle these widely varying signals. Enter RF MEMS.
Essentially, RF MEMS devices offer "best of breed" in a host of performance and usage parameters out of all possible technologies you would reasonably consider to be your alternatives in a very wide variety of RF applications. The most widely recognized advantages are low loss, high isolation, near-perfect linearity, and unbelievably large instantaneous bandwidth that conventional mechanical and semiconductor technologies simply can't even compete with. On top of this are a host of usage parameters like cost, size, speed, ruggedness, reliability, repeatability, and lifetime, that each range from fantastic to poor depending specifically on what you are comparing them to and depending on whether or not a customer values that particular specification. A good RF MEMS Ohmic relay, for example, has fantastic repeatability and ruggedness compared to any semiconductor technology, and has a good (or great) price, size, speed, reliability, and lifetime compared to any conventional mechanical technology.