cad techniques for rf electromagnetics

8/7/2019 CAD TECHNIQUES FOR RF ELECTROMAGNETICS

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CAD TECHNIQUES FOR RF ELECTROMAGNETICS

EXPERIMENT 01, NETWORK ANALYSER

INTRODUCTION:

The main objective of the experiment is to measure the S-parameters. S-parameters

have got an important position in the field of RF Electromagnetics. S-parameters

measurements are complex functions of frequency and are used for high-frequency

measurements, for example microwave design etc. S-parameters are defined and

measured with the ports terminated in characteristic reference impedance. Modern

network analyzers are well suited for measuring S-parameters. Because the networksbeing analyzed are often employed by insertion in a transmission medium with

common characteristic reference impedance, S-parameters have the additional

advantage that they relate directly to commonly specified performance parameters

such as insertion gain and return loss. S-parameters can be easily measured using an

s-parameter test set. S-Parameters are the reflection and transmission coefficient of

waves, normalized to the incident wave. They describe the input/output behaviour of a

device under linear conditions at microwave frequencies. S-parameters are measured

based on properly terminated transmission lines (and not open/short Circuit

conditions).

Network analyzers have become one of the most important measurement tools for

characterizing the performance of high-frequency components and devices.

We used Hewlett Packard HP8720 Network Analyser to measure the S-parameters for

some simple devices. Beside this tool we used one another important tool, which is

coaxial cable with small SMA connectors. It should be remember that these cables

cannot be correctly mated unless tightened by a spanner (but not over tightened),

although hand tight is not good.

THEORY

RESULT


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1. Amplitude response for matched load

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 5E+ 09 1E +10 1.5E +1

0

2E+10 2.5E+1

0

Series1

Series2

DB

HZ

2. Amplitude open circuit

-5

-4

-3

-2

-1

0

1

2

3

4

0 5E +09 1 E+ 10 1.5E+ 1

0

2E+10 2.5E+1

0

Series1

Series2

db

hz

3. Phase open circuit


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-2.50E+02

-2.00E+02

-1.50E+02

-1.00E+02

-5.00E+01

0.00E+00

5.00E+01

1.00E+02

1.50E+02

2.00E+02

2.50E+02

0 5E+0

9

1E+1

0

2E+1

0

2E+1

0

3E+1

0

Series1

Series2

dg

HZ

4. Phase matched load (106)

-6.00E+01

-4.00E+01

-2.00E+01

0.00E+00

2.00E+01

4.00E+01

6.00E+01

8.00E+01

1.00E+02

1.20E+02

1.40E+02

1.60E+02

0 5E+0

9

1E+1

0

2E+1

0

2E+1

0

3E+1

0

Series1

Series2

HZ

DG

5. Amplitude response RF cable 107


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Amplitude Response

-30

-25

-20

-15

-10

-5

0

0 5E +09 1E+ 10 1.5E +1

0

2E+10 2.5E+1

0

f(Hz)

db dB

6. Forward Amplitude Response S11 jpg 00

7. Forward phase response S21 text109


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Forward Phase Response S21

-40

-30

-20

-10

0

0 5E +09 1E+ 10 1.5E+1

0

2E+10 2.5E+1

0

f(Hz)

dg dB

8. Reverse Amplitude Response S12

Reverse Amplitude Response S12

-40

-30

-20

-10

0

0 5E+ 09 1E+10 1.5E+ 1

0

2E+10 2.5E+1

0

Hz

db dB

9. Reverse phase response S22

Reverse Phase Response S22

-60

-50

-40

-30

-20

-10

0

0 5E+09 1E+10 2E+10 2E+10 3E+10

Hz

dg dB


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PART TWO

REFLECTION AND TRANSMISSION TEST SET

TRANSMISSION MEASUREMENT

In this section, we will investigate the transmission properties of a microwave

waveguide device. This is would be important in the design of microwave system to

ensure that the device operates correctly.

1. Attenuator at 0 dB, attenuation is 2.044 dB, Frequency 10GHz

Value of attenuation at 10 GHz

-14

-12

-10

-8

-6

-4

-2

0

2

0 5000000000 1E+10 1.5E+10

Hz

dB dB

2. Attenuator 10 dB, Attenuation is 10.97dB, Frequency 10GHz

Value of attenuation at 10 GHz

-25

-20

-15

-10

-5

0

0 5000000000 1E+10 1.5E+10

Hz

dB dB

3. Attenuator 20 dB, Attenuation is 28.00, at 10GHz


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Value of Attenuation at 10 GHz

-50

-40

-30

-20

-10

0

0 5E+09 1E+10 1.5E+10

Hz

dB dB

.

4. Attenuator at 0 db and phase shifter range is set to 0 at 10 GHz frequencies theresponse would be 2.2030 dB

5. Attenuator at 0 dB, phase shift range is set to 5, frequency 10 GHz the response

would be 1.1080


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6. Attenuator at 0 dB, phase shift range is set to 10 dB, frequency at 10 GHz the

response would be 1.7070


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response would be 12.220 dB


response would be 11.992 dB


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response would be 11.697dB


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12. Attenuator at 20 dB, phase shift range is set to 5 dB, frequency at 10 GHz theresponse would be 27.006dB


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