RF MEMS switches were first invented and reduced to practice in 1993 as a means of achieving the low RF loss afforded by MEMS and micromachining technology. The use of a capacitive coupling mechanism entirely eliminates issues associated with dry contact, metal-metal ohmic switching. Over the years, investments by government and corporate IR&D have evolved these switches considerably. Presently, capacitive MEMS switches, and MEMS switches in general, provide the lowest loss means for switching and routing RF, microwave, and millimeter-wave signals. Over the past decade processing improvements, material refinements, and RF and mechanical design changes have allowed MEMS capacitive switches to demonstrate ultra-low loss (<0.1>+66 dBm

1. Presented by:-
Jitendra Jangid
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2.  Electrostatic Switch
 Electro Magnetic switch
 Cantilever switch
 Switch using hall effect
 Pizeo-resistivity switch
 Cantilever switch using chemical process
 Optical switch
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3.  Electrostatic switch :
1. large gap of at least 100 micro meter between the electrostatic
plates is required
to prevent arcing during a possible high voltage surge on the
order of 2000 volts
2. Maximum device size of 1mm x 1mm
3. Device withstand 3 Amps current for one second for the contact
part of the relay.
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7.  When Fe is larger than Fm, the electrodes
move closer; the distance between the
electrodes is reduced.
 However when the distance between the 2
electrodes is lesser than 2/3 of the original
gap, the electrode collapses.
 This phenomenon is known as pull-in.
 This phenomenon is commonly used in
g-switch design
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9. It takes large time for switching it required additional reference voltage to
moving effectively
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10.  When voltage is applied to the electrodes, the electrostatic
force acting on the electrodes pulls down the cantilever
beam toward the ground.
 When the beam is pulled away from its equilibrium position,
stresses accumulate in the beam . The stresses form a
resultant force to counterbalance the electrostatic force.
 When the applied voltage is removed, the counter-
balancing force returns the beam back to its normal
position. This force, which is the sum of the stresses in the
beam, is referred to as the restoring force that "restores"
the beam to its original position.
 The shorting bar is a thin layer of gold foil located below the
cantilever beam and moving along with the beam.
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11.  Advantage:
 Good Sensitivity
 Excellent temperature stability
 Integrated electronics enable 0.01A or
smaller resolution
 Limitation:
 Small signal
 Undesired electrostatic actuation
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18.  The piezoresistive effect describes the
changing electrical resistance of a material
due to applied mechanical stress.
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19. Advantage :-
 Large sensitivity of simple resistors
 Very easy to fabricate and low cost.
Limitation:
 Too sensitive to temperature changes
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20.  The Hall effect refers to the potential
difference (Hall voltage) on the opposite sides
of an Electrical conductor through which an
electric current is flowing, created by a
magnetic field applied perpendicular to the
current
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21. Advantage:
 Immune to dust, dirt and water when
appropriately packaged.
Limitation:
 Very low signal level, an amplifier is
required.
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22.  Space division switches
 – 2D MEMS
 – 3D MEMS optical switches
 • Spectral domain processors
 – Wavelength-selective switches
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28. ◦ Low Size
◦ High switching speed
◦ High sensitivity
◦ Low noise
◦ Reduced cost
◦ Batch Processing
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29. Thank you
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