• English
    • Norsk
  • English 
    • English
    • Norsk
  • Administration
View Item 
  •   Home
  • Det matematisk-naturvitenskapelige fakultet
  • Institutt for informatikk
  • Institutt for informatikk
  • View Item
  •   Home
  • Det matematisk-naturvitenskapelige fakultet
  • Institutt for informatikk
  • Institutt for informatikk
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Out-of-plane CMOS-MEMS variable capacitor

Kjelgård, Kristian Gjertsen
Master thesis
View/Open
kjelgard.pdf (4.157Mb)
Year
2009
Permanent link
http://urn.nb.no/URN:NBN:no-22656

Metadata
Show metadata
Appears in the following Collection
  • Institutt for informatikk [3603]
Abstract
To be able to create small integrated wireless radio front ends, variable

capacitors that can be monolithically integrated on the same chip as the

electronic circuits are needed. Today’s radio front ends are based on solidstate

diode varactors which suffer from poor tuning range and phase noise

and do not meet the requirements for a fully integrated wide band radio

front end. In this thesis we will look at possibilities for implementation of

a monolithic integrated MEMS varactor.

A post-CMOS-MEMS process is used to manufacture the structures. The

post-process is a combination of anisotropic RIE dry etch steps and an

isotropic release step, which makes monlithic integration simple and low

cost. The actuation mechanism is based on an out of the plane curled

cantilever beam. Initial curling of the structure as a result of residual

stress in the CMOS layers of the chip is utilized to initially levitate

the actuator over the chip plane. To actuate the varactor combs, the

actuator is heated with a joule-heating element placed under the structure.

When the the actuator is heated to the in-plane alignment temperature,

maximum capacitance is obtatined. Simulations and analytic models are

used to predict the performance of the actuator and varactor. The analytic

models presented and developed make development of out of plane curled

varactors more efficient and simpler than with FEM simulations only. The

complete varactor design was included in a test circuit sent to production

in November 2008.

Simulations and models yield good results for tuning range and Qualityfactor.

The tuning range is predicted to be between 240 % and 325 % and

the Q-factor is calculated to be 30@1.5GHz. The tuning voltage required

for operation of the varactor is within 8 V and the varactor does not suffer

from pull-in, which is the case for electrostatic based varactors.
 
Responsible for this website 
University of Oslo Library


Contact Us 
duo-hjelp@ub.uio.no


Privacy policy
 

 

For students / employeesSubmit master thesisAccess to restricted material

Browse

All of DUOCommunities & CollectionsBy Issue DateAuthorsTitlesThis CollectionBy Issue DateAuthorsTitles

For library staff

Login
RSS Feeds
 
Responsible for this website 
University of Oslo Library


Contact Us 
duo-hjelp@ub.uio.no


Privacy policy