RF MEMS devices. Prof. Dr. Wajiha Shah. OUTLINE. Use of RF MEMS devices in wireless and satellite communication system. 1. MEMS variable capacitor (tuning range : 280%) 2. MEMS tunable inductor 3. MEMS multiport switch (using range : > 20GHz). Introduction (1).
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RF MEMS devices
Prof. Dr. Wajiha Shah
1. MEMS variable capacitor (tuning range : 280%)
2. MEMS tunable inductor
3. MEMS multiport switch (using range : > 20GHz)
1. can reduce the size, weight, power consumption and
2. promise superior performance.
3. can be built with low cost, mass producibility and
4. new functionality and system capability.
Fig. 1 illustrates a schematic diagram.
Fig. 1 A schematic diagram of the proposed capacitor
Two structural layers, three sacrificial layers, and two
insulating layers of Nitride.
(a) (b) (c) (d)
(e) (f) (g) (h)
a SEM picture
of the proposed
Fig. 3 An SEM picture of the fabricated variable capacitor
At 1GHz, the achievable tuning of the proposed
capacitor is found to be 280%.
Fig. 4 Measured capacitance vs. frequency at different DC voltage
circuits to circumvent, construct filter for frequency agile applications
use of mutual inductance and 100% tuning range
advantage : wider bandwidth, more design flexibility
Fig. 5 A MEMS Tunable Inductor chip
1. lower plate : poly1 air gap (0.75㎛)
upper plate : poly2
2. C : 2.05pF, Area : 210*270㎛2
1. Mechanical-type (coaxial & waveguide)
2. Semiconductor-type (PIN diode & FET)
coplanar series switch,
consisting of three actuating
attached to a 50Ω coplanar
transmission line, while the
other end is suspended on top of another 50Ω transmission coplanar line to form a series-type contact switch.
Fig. 6 The proposed MEMS SP3T switch
fabricated on a 254㎛ thick
of the switch, the beams are
narrowed at the tip and the
contact is performed only
by small tips at the end of
Fig. 7 The fabrication process of the SP3T
T h e e n d