Electromechanical oscillators

foulgirlsUrban and Civil

Nov 15, 2013 (3 years and 11 months ago)

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Electromechanical oscillators



Alfredo D. Bobadilla



An element of the electrical circuit experiences movement or oscillations.




Notice how the electrical current depends on the capacitor displacement.




In the system shown, the electrical behavior depends on mechanical properties.

What is an electromechanical oscillator (or resonator) ?

Schematic of the gyro’s mechanical structure.

Photograph of mechanical sensor.


The ADXRS gyros include two structures to enable differential sensing

in order to reject environmental shock and vibration.



Acceleration sensors for automobile air bag control



Gyroscopes for automobile driving control



Pressure sensors for blood, tire, etc.

Commercialization of micro electromechanical oscillators

Other applications

100x power reduction

100x size reduction

10x improvement in

spectral eff. & BW

Wireless communication

AFM

AFM images of DNA
-
based nanostructures

165nm

scale bars = 100nm

Mechanical
resonators as
filters in RF
circuits

The carbon
nanotube

electromechanical oscillator

A tunable
nanoscale

resonator

V. Sazonova et al., Nature (2004).



When

a

voltage

is

applied

between

the

tube

and

the

underlying



plate,

electrostatic

force

attracts

the

tube

to

the

plate
.




An

alternating

voltage

sets

up

vibration

as

the

tube

is

alternately


attracted

and

repelled
.




A

static

voltage

applied

at

the

same

time

increases

the

tension

on


the

tube,

changing

its

frequency

of

vibration

just

as

tightening

or


loosening

a

guitar

string

changes

its

pitch
.




The

entire

assembly

of

tube

and

plate

behaves

as

a

transistor,

so



the

tube's

motion

can

be

read

out

by

measuring

the

current

flow
.

The carbon
nanotube

electromechanical oscillator

B. Witkamp et al, Nano Lett., 2006.

J. Chung et al, Langmuir, 2004.

Fabrication process

Dielectrophoretic

assembly

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.
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.
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The carbon
nanotube

electromechanical oscillator

B. Witkamp, M. Poot, and H. S. J. van der Zant, Nano Lett., 2006.

g
g
g
g
C
V
V
C
q





Theoretical framework

Mass spectrometer:

Ultra high surface/volume ratio → excellent surface collection

Ultra small mass → exploit
f
o

sensitivity to mass loading

Massive array → very wide dynamic range


Calorimeter:

Ultra low thermal capacity → exploit
f
o

sensitivity to ∆T

Massive array → extends linearity to very wide dynamic range

Ultra small size → very fine pixel size as IR imager

Performance
improvement at
nanoscale

THANKS!

G2

Rebuttal
:

Nano

electromechanical oscillators

Alfredo Bobadilla

Comment
:

“Did

not

describe

the

theoretical

part

of

the

presentation”

Answer
:

The

theoretical

part

was

explained

during

the

lecture
.

In

essence,

the

“beam

equation”

(classical

mechanics)

is

still

useful

for

analyzing

bending
-
mode

vibrations

in

a

carbon

nanotube

longer

than

~
0
.
5
um
.

Research

work

in

the

nonlinear

regime

and

the

quantum

regime

has

just

began

very

recently
.


Comment
:

“Text

was

small

and

hard

to

locate

on

each

slide”

Answer
:

I’ll

improve

that

next

presentation
.


Comment
:

“current

or

potential

applications

of

such


nano


electromechanical

oscillators

should

have

been

shown”

Answer
:

The

potential

applications

of

nano

electromechanical

oscillators

is

shown

in

the

slides

and

was

described

during

the

lecture
.

It

was

shown

nanotube

resonators

can

be

incorporated

as

the

sensing

element

for

improving

the

performance

in

mass

spectrometry

and

in

calorimetry
.

Nano

electromechanical oscillators


‘Rebuttal’

Alfredo D. Bobadilla

G1

Electro
-
Mechanical Oscillators

Review

Edson

P.
Bellido

Sosa

The presenter describe how a EM oscillator
works and the basic equations that rules its
movement .

He explain how a change in a parameter,
lets say the voltage on the system, can
affect the overall functioning of the device,
and how researcher are taking advantage of
these behavior to fabricate consumer
devices

He has explained the fabrication process
and how a carbon
nanotube

based
oscillator works, and how they can tune
the bending mode vibration by changing
the gate applied voltage and how they
can measure the bending modes using
changes in the conductivity of the carbon
nanotube

A comparison of the carbon
nanotube

oscillator and the current oscillator
used on the industry, in terms of
performance and cost would have
been helpful.


Further research is needed specially in the
large scale integration process since there is no
an high throughput technique to create arrays
of carbon
nanotube

oscillators and other
nano
-
devices.

G3

Review: Electromechanical Oscillators


By Mary
Coan

2/12/2010

Review


Overall the presentation was decent


Described


Current applications of EN oscillators


CNT EM oscillator using various sources and diagrams


Improvements to the performance


Did not describe the theoretical part of the
presentation


Showed many equations with out listing parameters


No physical description of the diagrams

Review


Overall style of the Presentation was lacking


Text was small and hard to locate on each slide


Some of these things may have been
addressed during the actual presentation.
However just looking at the presentation
online I had a hard time understanding what
each slide represented and the contents of
each slide.

G4

Summary and review
‘Electromechanical oscillators’

Diego A Gomez
-
Gualdron

An electromechanical oscillator circuit

The

distance

between

the

plates

of

the

capacitor

varies

with

time
,

therefore

changing

the

capacitance
,

which

in

turn

affect

the

behavior

of

the

circuit

giving

it

an

oscillatory

behavior

Figure .1

Promising application of a nanotube in
a
nanocircuit


A voltage in



generates a charge

in


As a result the nanotube is
pushed downwards.


Bending the nanotube alter the
charge once again, ending up in
oscillatory motion
with a
frequency depending on the
tension forces in the nanotube.

The oscillatory motion of the nanotube, alterates the capacitance in cyclic
-
fashion
analogous to the macroscale circuit in the fig 1.

Nature

431
, 284
-
287 (16 September 2004) | doi:10.1038/nature02905

Additional Review


A number of applications were shown for
electromechanical oscillators. However, I am
not sure if the scale of those examples is in
the nanorange. If so, current or potential
applications of such ‘nano’ electromechanical
oscillators should have been shown.


G5

Review Electromechanical Oscillators

by
Norma Rangel


Electromechanical oscillators

by Alfredo D. Bobadilla


Alfredo show the basic concepts of
electromechanical oscillators , with
examples of how these devices are
being implemented in current
technologies in the market, alternative
applications and a couple of papers
about state of the art
electromechanical oscillators using
nanotubes and origami DNA.


My suggestion for Alfred presentation is
to put more emphasis on the
experimental work than being too deep
on the theoretical framework

G6

Review Electromechanical Oscillators

by
Jung Hwan Woo



Review


Overall, the presentation needs improvements


Improved presentation skill will help deliver the idea
in a more effective manner


The use of larger fonts and images will make it easier
for the audience to better visualize and understand
the concept


A better introduction may attract the audience into
the subject and the presentation.


The pace can be increased to contain more
information. The information on the subject was a bit
too little for a 30
-
minute presentation


Jung Hwan Woo

Application


What NEMS applications are there, which take
advantage of the electromechanical oscillator
other than the carbon
nanotube

application?


What are the advantage of reducing the size
of the device in MEMS/NEMS applications?
Is
there any downside to it?

Jung Hwan Woo