Beyond CMOS and RF devices, integrated circuits and technologies

RF MEMS Switch

© Fraunhofer ENAS
Measurement results of the scatter parameters of the RF MEMS switches, that represent the insertion loss and the reflection loss in the closed state and the isolation in the open state.

The RF MEMS Switch is a miniaturized RF relay with electrostatic with hermetic encapsulation to implement it in micro wave and mm-wave systems. It is a silicon chip (3 mm x 1.5 mm of size and 0.5 mm thick) with a hermetically sealed cavern containing the movable parts of the actuator and the contacts. A novel design of the contact area and of the RF wires is used to achieve a frequency span of the RF signals between DC and 75 GHz with an insertion loss of less 0.5 dB up to 20 GHz and around 1 dB up to 75 GHz. Since the switch is a MEMS component with metal-metal contacts, a very high linearity with IIP3 > 65 dBm (1 GHz, 0dBm) is provided by the device. The switch on and switch off time is approximately 10 µs respectively. In comparison to RF switches at the market, this type of component needs lower actuation voltage (5 Volt without need of any step up converter) and extremely low actuation current (< 10 nA). The actuation electrodes and the RF signal path are separate from each other, which introduces lower noise from the digital control electronics in comparison to many other RF MEMS switches. A high aspect ratio MEMS technology is used for the fabrication and leads to large actuation electrodes and to high contact force for making and breaking the contacts even by low actuation voltage.

List of application opportunities:

The application fields are ranging from automated test equipment (switch matrix with very high frequency bandwidth, controllable attenuators) over antenna beam steering and agile antennas (controlling of the antenna pattern by phase shift of the feed line signals) to the reconfiguration of the front-end circuits of radio systems (antenna switches, filter reconfiguration).