Agilent Technologies Agilent 4396B User Manual

Page 102

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S-P

arameters

Measurement

S-parameters

S

11

and

S

22

are

no

di erent

from

the

measurements

made

in

the

previous

section.

S

11

is

the

complex

re ection

coecient

of

the

DUT's

input.

S

22

is

the

complex

re ection

coecient

of

the

DUT's

output.

In

both

cases

,

all

unused

ports

must

be

properly

terminated.

T

o

display

the

trace

on

the

polar

chart,

press

4

F

ormat

5

N

NNNNNNNNNNNNNNNN

POLAR

.

The

results

of

a

typical

S

11

measurement

is

shown

in

Figure

5-15.

Each

point

on

the

polar

trace

corresponds

to

a

particular

value

of

both

magnitude

and

phase

.

P

olar

Chart

Shows

Magnitude

and

Phase

Magnitude

The

center

of

the

circle

represents

a

re ection

coecient

0

of

0,

that

is

,

a

perfect

match

or

no

re ected

signal.

The

outermost

circumference

of

the

scale

represents

a

0

=

1.00,

or

100

%

re ection.

Phase

The

3

o'clock

position

corresponds

to

zero

phase

angle

,

that

is

,

the

re ected

signal

is

at

the

same

phase

as

the

incident

signal.

Phase

di erences

of

90,

180,

and

270

degrees

correspond

to

the

12,

9,

and

6

o'clock

positions

on

the

polar

display

,

respectively

.

Figure

5-15.

S

11

on

P

olar

Chart

Data

Readout

Using

the

Marker

Press

4

Ma

rk

er

5

and

use

the

knob

to

position

the

marker

at

any

desired

point

on

the

trace

.

Then

read

the

frequency

,

magnitude

,

and

phase

in

the

upper

right

hand

corner

of

the

display

.

Or

,

enter

the

frequency

of

interest

from

the

data

entry

key

pad

to

read

the

magnitude

and

phase

at

that

point.

T

o

read

the

marker

data

in

logarithmic

,

linear

,

real/imaginary

,

impedance

(R+jX),

admittance

(G+jB),

or

SWR/phase

formats

,

press

4

Utilit

y

5

N

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

SMTH/POLAR

MENU

and

select

the

desired

format.

5-16

Network

Measurement

Examples

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