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Positioning, control, and dynamics of electrostatic actuators for use in optical and RF systems

IP.com Disclosure Number: IPCOM000128042D
Original Publication Date: 1998-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 7 page(s) / 24K

Publishing Venue

Software Patent Institute

Related People

Hung, Elmer S: AUTHOR [+3]

Related Documents

http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-197: URL

Abstract

This thesis describes work on incorporating electrostaticallyactuated microstructures for analog tuning and positioning applications within optical and RF systems. The work focuses on the design, simulation, and optimization of actuators which undergo large-amplitude motion, including ways to overcome the so-called pull-in instability which typically limits the stable travel distance of electrostatic actuators. These techniques are applied to the design and fabrication of: (1) the polychromator, a micromechanical diffraction grating with a thousand analogpositioned mirrors for use in a correlation spectroscopy system, and (2) a tunable capacitance device with a lithographicallyprogrammable capacitance-voltage (C-V) characteristic for use in tunable RF oscillators. With the polychromator,1 cm long electrostatic mirror actuators have achieved over 1.75pm of displacement out of a 2pm gap. Prototype t1inable capacitors fabricated in a non-optimized process exhibit a 25% capacitance tuning range with a linear C-V characteristic and 35V actuation voltage. With an optimized process, simulations show that a 150% capacitive tuning range can be. achieved with 3.3V actuation voltage.

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 This record is the front matter from a document that appears on a server at MIT and is used through permission from MIT. See http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-197 for copyright details and for the full document in image form.

Positioning, Control, and Dynamics of Electrostatic Actuators for Use in Optical and RF systems

by

Elmer S. Hung
S.B., Massachusetts Institute of Technology (1991) S.M., Massachusetts Institute of Technology (1994)

Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY at the Massachusetts Institute of Technology

August 21, 1998 [September, 1998]

SIGNATURE OF author: [[signature omitted]]

Department of Electrical Engineer, and Computer Science

August 21, 1998
CERTIFIED BY: [[SIGNATURE OMITTED]]

Stephen D. Senturia Barton L. Weller Professor of Electrical Engineering Thesis Supervisor ACCEPTED BY: [[SIGNATURE OMITTED]]

Arthur C. Smith Chairman, Department Committee on Graduate Students

ARCHIVES MASSACHUSETTS INSTITUTE OF TECHNOLOGY LIBRARIES

Massachusetts Institute of Technology Page 1 Dec 31, 1998

Page 2 of 7

Positioning, control, and dynamics of electrostatic actuators for use in optical and RF systems

Positioning, Control, and Dynamics of Electrostatic Actuators for Use in Optical and RF Systems

by

Elmer S. Hung

Submitted to the Department of Electrical Engineering and Computer Science on August 21, 1998, in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Electrical Engineering and Computer Science

Abstract

This thesis describes work on incorporating electrostaticallyactuated microstructures for analog tuning and positioning applications within optical and RF systems. The work focuses on the design, simulation, and optimization of actuators which undergo large-amplitude motion, including ways to overcome the so-called pull-in instability which typically limits the stable travel distance of electrostatic actuators. These techniques are applied to the design and fabrication of: (1) the polychromator, a micromechanical diffraction grating with a thousand analogpositioned mirrors for use in a correlation spectroscopy system, and (2) a tunable capacitance device with a lithographicallyprogrammable capacitance-voltage (C-V) characteristic for use in tunable RF oscillators. With the polychromator,1 cm long electrostatic mirror actuators have achieved over 1.75pm of displacement out of a 2pm gap. Prototype t1inable capacitors fabricated in a non-optimized process exhibit a 25% capacitance tuning range with a linear C-V characteristic and 35V actuation voltage. With an optimized process, simulations show that a 150% capacitive tuning range can be. achieved with 3.3V actuation voltage.

The integration of micromechanical devices into complex, mixed technology systems also requires methods for efficiently simulating the dynamics of micromechanical devices. We present work on generating efficient reduced-order macro...