10-12-2012, 03:22 PM
RF MEMS SATELLITE SWITCH MATRICES
RF MEMS SATELLITE.pptx (Size: 539.78 KB / Downloads: 37)
Micro electromechanical systems
Miniaturized mechanical and electromechanical elements.
micro fabrication.
Dimension-1micron to millimeters.
WHY MEMS IN SATELLITE COMMUNICATION….?
Potential of replacing RF components in satellite.
Reduce the size, weight, and power consumption.
Superior performance.
Provide system redundancy.
MEMS AND CONVENTIONAL TECHNOLOGY
RF switches used- mechanical and semi conductor switches.
Mechanical switches-low insertion loss, large off state isolation,linear,high power handling. But bulky,heavy,slow.
Semiconductor-faster , small in size and weight . They have more loss ,power consumption , intermodulation.
MEMS offer advantages of both.
SWITCHING TIME
Switching time depends on mechanical response of the actuating beams
Also depends on biasing line and materials .
Materials used are chromium and phosphorous doped hydrogenated amorphous silicon .
In selecting the material a tradeoff exists between switching speed and rf performance
MEMS C -SWITCH
transfer switch.
based on micro strip technology
uses dielectric based cantilever beams.
.5dB insertion loss up to 25GHZ.
Suitable for integration in large redundancy switch matrices.
MEMS R- SWITCH
Three operational states.
Reduces number of building blocks in switch matrices.
Simplifies the overall topology.
Excellent RF performance.
.4dB insertion loss,25 dB return loss,25 dB isolation at 3.7-4.2GHz.
L-SHAPED SWITCH MATRIX
To overcome the disadvantage of cross bar switch it is used.
It can be easily expanded.
It gives small variation in both insertion loss and phase shift as switching state is varied.
CONCLUSION
Switch matrices-RF MEMS technology in modern satellite payloads.
RF MEMS switches can be integrated in the form of various matrix topologies.
System redundancy can be improved