RF Devices

Optically Activated MicroSwitch
An example (see photo right) of a simple Si microswitch within a transmission line. The Si microswitch is diced from wafer of high resistivity (r) silicon (r > 6000 W×cm).

Attributes:
The main capabilities of the microswitch may be summarised as follows:

• Fast Switching. Can be a good candidate for applications required switching speed as fast as 10.5 µs.
• Low EMC Issues. Light signal used to operate the microswitch does not interfere with EM waves.
• High Isolation Characteristics. Between 1 – 3 GHz frequency range, the switch gives isolation as high as 23dB.

Potential Applications:
The optically operated switch has many potential markets and this could be used for the following applications:

• RF phase shifter
• Phased array antennas (phase array enabler)
• Switched microstrip filters
• Reconfigurable antennas (Switched/Smart antennas)
• Tunable metamaterials
• Millimetre wave technologies such as cameras and scanners

Application Example: High Impedance Delay Line



Si switches are used to alter and control the propagation constant (ß) of the microwave signal, along the transmission line.

Application Example: Steerable Beam Antennas

S - Band steerable beam antenna, consisting of a phase shifter module.

Ka – Band Beam Steering Antenna