EC Lecture 1

8/2/2019 EC Lecture 1

1/18

1

EMC Introduction

Prof. Tzong-Lin Wu

NTUEE

What is EMC

EElectro-MMagnetic CCompatibility

EMC

EMI

EMS

(Interference)

(Susceptibility)

Conducted Emission

Radiated Emission

Radiated Susceptibility

Conducted Susceptibility


2/18

2


3/18

3

NaturalNatural RadiationRadiation BiologicalBiological

Terrestrial Far-Field Man

Atmospheric Plane Wave AnimalSun Near-Field Plants

. Capacitate cross-talk

. Inductive cross-talk

ManMan--MadeMade ConductionConduction ManMan--MadeMade

Broadcast Power distribution Broadcast receivers

Radar Signal distribution Navigation receivers

Fluorescent lights Ground loops Radar receivers

Computing devices Computing devices

Microwave Ovens Biomedical sensors

Noise Propagation Receptor

Source Path


4/18

4

What is EMC

EMI

In 1982 the U.K. lost a destroyer () inthe battle of Falkland Island during the

engagement with Argentinean forces. Thedestroyers radio system for communication

with the UK would not operate properlywhile

the ships anti-missile detection was beingoperated.

What is EMC

EMI

A new version of an automobile hasmicroprocessor-controlled emission and fuel

monitoring system installed. When thecustomer drove down a certain street in thetown, the car would stall. The illegal FM radioin this street cause that.


5/18

5

What is EMC

EMI

FM/AM radio is noisy when the Desktop PC isturned on.

It is forbidden to use the electronic devices,such as wireless phone, notebook, on the

airplane.

What is EMC : Examples

EMS

Walking across a nylon carpet with rubber-soled shoes can cause a build-up of static

charge on the body. When an electronic deviceis touched, an ESDESDoccurred. A protectionsystem for ESD is required.


6/18

6

What is EMC

EMS

In the first nuclear detonation in the mid-1940s,it was discovered that semiconductor devices

that was used to monitor the blast weredestroyed. It is due to the intense EM wave

(EMPEMP) created by the charge separation and

movement within the detonation.

What is EMC

EMS

LightingLightingcarries upwards of 50,000A ofcurrent. The EM fields from this intense current

can couple to electronic systems either bydirect radiation or coupling.


7/18

7

What is EMC ?

Electromagnetic Compatibility (EMC)

LowElectromagnetic Interference (EMI)

Conducted & Radiated

LowElectromagnetic Susceptibility (EMS)

ESD, Surge, Fast Transient

GoodSignal Quality/Integrity (SI)

Why EMC

Healthy reasons:

Microwave oven

GSM for brain tumor Cancer caused by high power line

Safety reasons

Aircraft navigation

Appliance in home


8/18

8

Safety and Health

Why EMC

Wireless comm. reasons

clear spectrum is necessary for WCOM.

For proper and secure data transmission. Wide spectrum usage such as

AM radio in LF, MF and HF range

FM, TV, and mobile phone in VHF

GPS, Digital sound broadcasting in UHF

Satellite communication in Microwave range


9/18

9

Why EMC High-speed trend reason:

288W28.7GHz0.4V222016

251W19.3GHz0.5V322013

218W11.5GHz0.6V452010

190W6.7GHz0.7V652007

160W3.99GHz1.0V902004

130W1.68GHz1.1V1502001

Poweron-chipspeed

Vdd pitch(nm)

Year

*Source: The International Technology Roadmap for Semiconductor (ITRS), 2002

(http://public.itrs.net)

Low voltage High speed High powerconsumption

Why EMC

Edge radiation

Memory Die

GBN coupling to

P/G via of RF IC

Decoupling capacitor

Signal trace

Power via

Ground Via

Ground plane

Power plane

Clock signal

Substrate

Digitalsignal

GBN coupling to

signal via

GBN source

from digital IC

GBN source from through

hole via digital signal

RFICDie

MemoryDie

Digital IC

Die

System on Package (SoP) SOC / SOP reason


10/18

10

Why EMC

Automobiles with electronics

Why EMC difficult to meet? (An example)


11/18

11

Horizontal Polarization

Vertical Polarization

Why ver < hor ?


12/18

12

How EMC

Source

(Emitter)

Transfer

(Coupling)

Path

Receptor

(Receiver)

Suppress the emission at its source

Make the coupling path as inefficient as possible

Make the receptor less susceptible to the emission

Cost: LowCost: Low middlemiddle highhigh

How EMC


13/18

13

How EMC

How EMC


14/18

14

How EMC An example: for PC

Suppress the emission:

Proper layout with EM concept

using component with low edge rate as possible

Reduce coupling path

using shielded enclosure

less susceptible receptor differential pairs

error-correcting code

2) EMC technique include three levels.

First( Basic )

--- After the development of product is completed, we can do all standardEMC tests following the regulations

--- When they can not pass, you can fix the problems by addingcomponents. ( Such as cap, choke )

Second( Middle )--- In the testing phase, by the knowledge of EMC, the EMC problem

can be found and the design can be changed before mass production.

--- at this level, only the subparts can be changed, but the architectureof the system can not be changed.

Third( Advanced )

--- In the design stage, the EMC experience, knowledge, and thesimulation tool are well employed to design the architectureof the system, you know all what if conditions.

this course


15/18


16/18

16

outIinI I( )z

ZL

inV V( )z outV

z=0 z=L z

g. Power loss in Cables

basic transmission line.

+ + +

- - -

Note X is the phasor expression

(complex)

f b

f b

V( ) V V V ( ) V ( )

V V V ( ) V ( )I( )

Z Z Z Z

z j z z j z

z j z z j z

L L L L

z e e e e z z

z z z e e e e

+ + +

+

+ +

= + = +

= =

b 2 2

f

b

reflection coef.

V ( ) V( )

V ( ) V

Z( ) 0 if matched load

V ( ) 0

power delivered :

1P ( ) Re V( )

2

z j z

L CL C

L C

av

z z e e

z

Z z Z Z

Z Z

z

z z

+ = =

= = =

+

=

=

2

*

2

I ( )

if matched load

1 VP ( ) cos where

2

zav Cz z

C

z

z e Z Z

+

= =


17/18

17

cable length

2.1(Teflone)

coaxial cable

r =

2

2

dB 10 10

power loss for cables :P ( 0) P

(cable loss)=P ( ) P

(cable loss) 10 log 20 log 8.686

In general: is due to the loss of conductor

ex :

for cable RG-58U

cable loss=4

Lav in

av out

L

ze

z L

e L e L

f

== =

=

= = =

dB.5100 .ft

SignalSource

50

CZ

Signalmeasurer

exSignal Generator Spectrum Analyzer

equivalent circuit

OCV

SRCZ 50=

inC inR

h. Signal Source Specification

S C inGenerally in industrial standard, R =Z =R =50

for RF instrument


18/18

OCV

SR

LRoutV

L S

Lout OC OC

S L

2 2

out outout

L

Output power displayed on a meter of the signal source in terms of

output power of matched load.

i.e

R R 50

R 1V V V

R R 2

V VP

R 50

Note : It is industrial standard that voltage and

= =

= =+

= =

out out peak.

currents are

1specified in their RMS values and no factor of is

2

then required in power expression.

1i.e. V (V )

2=

+

-

out out

for example a S.G. shows -37dBm output means

V 50 P 3.162m (RMS) 70dB V

Many signal measures such as spectrum analyzers also have

their response specified assume a 50 inp

v = = =

i

in max in

ut impedance to

the instrument.

for example a S.A. shows the maximum input rating of-30dBm=1 W

(V ) 50 P 50( ) 1( W) 7.07mv

= = =i i

Documents

EC Lecture 1