Simulations with two or more holes

The simulations with two or more holes were performed with box C. The results of the simulations performed in this section are compared with the results of Section 5.6.3. The sizes of the holes and the distance in between the holes are shown in Table 17.

Also the influence of the distance between the holes is examined.

Table 17:Sizes of two or more holes in box C.

I

^Name

^II

^{Length [m]}

^I

Width [m] [Distance

I

total holes

I

13 0.045 0.001 0.15 2

14 0.15 0.001 0.045 2

113 0.015 0.05 0.001 2

0.045 0.15

113a 0.015 0.05 0.1 2

0.045 0.15

1112 0.17 0.002 0.02 2

1112a 0.17 0.002 0.01 2

1112b 0.17 0.002 0.05 2

1112c 0.17 0.002 0.1 2

1116 0.002 0.17 0.02 2

1116a 0.002 0.17 0.01 2

1116b 0.002 0.17 0.05 2

1116c 0.002 0.17 0.1 2

11113 round 0.045 0.02 2

11113a round 0.045 0.1 2

1113 0.17 0.002 0.02 3

1113a 0.17 0.002 0.01 3

1113b 0.17 0.002 0.1 3

1117 0.002 0.17 0.02 3

1117a 0.002 0.17 0.01 3

1117b 0.002 0.17 0.1 3

1114 0.17 0.002 0.02 4

1114a 0.17 0.002 0.1 4

1118 0.002 0.17 0.02 4

1118a 0.002 0.17 0.1 4

15 0.001 0.045 0.15 4

0.15 0.001 0.045

112 0.05 0.001 0.015 4

0.001 0.015 0.05

114 0.05 0.001 0.015 8

0.001 0.015 0.05 0.001 0.045 0.15 0.15 0.001 0.045

The simulation of hole 13 is compared with hole 11 ofthe previous section. The E-field is shown in Figure 62. Apparently when two slits of hole 11 are made they attenuate each other.

The simulation of hole 14 is compared with hole 12b and hole 1 of the previous section. The E-field is shown in Figure 63. When the length slits of hole one, equal to half the wavelength, are used the fields amplify each other, which results in a higher field.

0.5

Figure 62: Left the far field of the holes 11 and 13, right comparison between the E-field of hole 13 and hole 11.

2

4

Figure 63: Left far field of hole 14 and right the comparison with hole 1 and 12b.

In Figure 64 the simulation of hole 1112 is compared with hole 1111 and the holes lll2a, ll12b and 1112c.

- - - Hole 1111

Figure 64: Left the E-field of hole 1112 and right the comparison with the field of hole 1112a,1112b,1112c and hole 1111.

... 15

~ _... a

"018

-

l;::^~

~

I

²¹

When one slit is exchanged for two slits it results in the increase of the amplitude of the E-field.

There is little difference when little is changed in the distance between the slits. A large distance difference shows a large difference in the far field. The same conclusion can be drawn from the E-field atz= 1 m. When the distance between the holes is divided by 2, the field is smaller and when the distance is enlarged 2.5 times, the field is enlarged too. But when the distance is enlarged 5 times the field is smaller. When the distance between the slits is very large, the field will have little influence on each other. An optimum in the distance can be obtained, between the slits at which two separate fields are added..

The simulations of the comparison of 1116 to 1115, 1116a, 1116b and 11l6c are shown in Figure 65.

Figure 65: right far field of 1116, 1116a, 1116b and 1116 cleft E-field comparison between 1116, 1115, 1116, 1116a, 1116b and 1116c.

2 4

- - - . Bole 1117.

- . - . - . - Bole 1117b - - - Bole 1115 - - - . Bole 1116

-2

,---,---~=______i - - - Bole 1117

-4 0.5

2

... 1.5

~ e

...

~ 1

o

x [m]

o

X [m]

Figure 66: Comparison of hole 1113 and hole 1117.

- - - Bole 1113 - - - . Bole 1113.

- . - . - . - Bole 1113b ' - - - - ' - - - 1 - - " ' - - - 1 - - - Bole 1111

- - - . Bole 1112

The same conclusion as for the interchanged situation, 1112 and such, can be drawn.

There is little difference shown when little is changed in the distance between the slits. A large distance difference shows a large difference in the far field. The same conclusion can be drawn from the E-field atz= 1 m. When the distance between the holes is divided by 2, the field is smaller when the distance is enlarged 2.5 times, the field is enlarged too. But when the distance is enlarged 5 times the field is smaller. When the distance between the slits is very large, the field will have little influence on each other.. An optimum in the distance between the slits can be obtained, at which two separate fields are added.

In Figure 66 the comparison of hole 1113 and 1117 are shown.

x

10-3

When three holes are used the field is enlarged more. When the distances between the three holes are changed in hole 1113, the field is lower whether the distance is enlarged or reduced. For the interchanged situation, hole 1117, the field is enlarged whether the distance is enlarged or reduced.

When in the perpendicular situation, hole 1117, three holes are used the field is in between the fields for two and one holes.

In Figure 67 the comparison of holes 1114 and 1118 is given.

4

Figure 67: Left comparison of hole 1114 and right the comparison of 1118.

-4

2

1 1.5 2.5

When the curves in Figure 67 are examined, the same conclusion as for the holes 1113 and 1117 can be drawn. In Figure 68 the comparison of the holes 11112, 11113 and 1ll13a is shown.

2 4

Figure 68: The E-field atz =1 m for holes 11112, 11113 and 11113a.

When the round hole is replaced with two round holes the field increases. When the distance between the holes is enlarged the field decreases.

Now the situation oftwo different holes with different distances in between will be examined in Figure 69.

4

Figure 69: The comparison of hole 113.

Apparently this E-field is the addition of the two separate holes. When the distance is enlarged 100 times the E-field is reduced.

The simulation has also been performed on hole 111 to compare these results with results where more holes are used as shown in Figure 70. The E-fields are shown in Figure 71.

- ^1----1

Figure 70: Example of one hole and the slits of that hole.

4

Figure 71: The E-field of the holes 15 and 112.

-2

When the hole is large the E-field of the slits is larger than when it is small.

At last the slits of hole 114are compared in Figure 72.

, \ Hole 114

Figure 72: The E-field of hole 114.

Figure 72 is shows the influence of the slits on each other. The largest field shown is the field of the largest hole. When the holes are changed into slits the field decreases as is demonstrated.

5.6.5 Simulations with dipole at other positions

The simulations with the dipole at other positioned were also perfonned on box C.

The far field of hole 1for the dipole at the centre, in the left front comer or right back comer shown in Figure 73.

90 0.02

Figure 73: Far field for hole 1with dipole at other positions.

When the dipole is positioned at other positions than at the centre of the box the far field will be larger and shows another curve. When the dipole is positioned in the left front comer the field will show an increase at the left side ofthe box. For the dipole at the right back comer is shown the field at the right side of the box.

TheE-field at measurement distancez= 1 for hole 1 is shown in Figure 74.

4

_._._.- dipole at tbe rigbtbaelcorner

- - - 1- - - -I - - - -I - -

Figure74:E-fieldof hole 1 atz⁼ 1 m with different dipole positions.

When the dipole is placed at another position the field measured will be lower. The curve is also dependent on the position of the dipole. The E-field ofthe dipole in the left front comer shows in the observationx-planefor an enlargement ofthe field at the left side. TheE-fieldof the dipole in the observationy-plane shows some increase ofthe field at the right, or front side. The same is shown for the dipole at the right back comer position.

This simulation will also has been performed on hole 1111 to compare these results with the case of more holes. In these simulations the distances between the holes will be changed. The E-field of hole 1111 is shown in Figure 75. Except for the field value, which is more or less equal, the same conclusion can be drawn as for hole 1 in Figure 74.

The far field has an interesting property, as is demonstrated in Figure 76. Apparently the field for the dipole position at the left front comer causes a far-field maximum at the back of the box.

When more holes are used theE-field is shown in Figure 77. In this figure the dipole at the centre is called position a, left front is called position b and the dipole at the right back position is called c.

2 4

1 '1 _. _. _. - dipole 8t the rightba,"'orner

, .

' - - - , - - - '

Figure 75: E-field for hole 1111 with dipole at other positions.

~

^•_. _. - dipole 8t the froat right .orner - - - - - dipole 8t the left ba.k.orner

dipole 8t the .entre

240

300

270

e ^[0]

Figure 76: Far field for hole 1111 for different dipole positions.

When the dipole is changed in position it is shown in Figure 77 that more holes show no difference in the E-field.

The influence of the distance between the holes is shown in Figure 78.

When the distance between the hole is enlarged and the dipole is positioned at the centre the E-field becomes smaller, but with the dipole positioned at the left front comer the field is not influenced. Also the field with the dipole at the right back comer position is even increased.

Finally, the round hole is examined. The far field of the dipole at position b shows for hole 11112 something interesting as shown in Figure 79.

xl0

-3

"0

3

Hole 11120.

-

^{~ ---} Hole 11120 b

Figure77:E-fieldof more holes and dipole at other positions.

X

10-3

Figure78:E-field of the difference in distance between holes for different dipole positions.

15

Figure 79: Far field for hole 11112with dipole in left front comer.

The E-fields of the round holes are shown in Figure 80.

Hole 11112 a

Figure 80: E-field for round holes.

The change in position of the dipole shows a reduction of the E-field. A large distance between the holes shows little reduction. The effects of the position of the dipole are the same as for hole 1,i.e., the dipole in the left front comer shows an increment left and the dipole at the right back comer shows an increment at the right in the curve of the E-field.

5.6.6 Simulations with holes at other positions

Apart from the influence on the field with the dipole at other positions the holes at different places in the box should influence the field as well. These simulations are performed on the box C configuration. The holes are changed from the centre to the down right, 2, or upper left, 3, comer.

This is shown in Figure 81.

- -

-Figure 81: Front of box with hole positions.

The far field of the three hole positions and the dipole at the centre are shown in Figure 82.

- - - - - boleinthe right front corner - • _. - • - boleinthe left front corner

90 0.05

12

¹

O. 0

\ ./ - -I - ~'A+''', ./\ ,"U.'!.:l.. ..

15

_"

/ /

_/ ^,A./_\ ~'~~A2"_{.:..1_ IA(:.;;. \./.}ⁱ

/ .,... /' riO 01

~...--

..

~!

I ' I ,.:.. • /' :C

I I ~-'"^{11'\ /'\ \ Ii'}

1 / ' 1

18 - -

^{-+- -\ - -)- .l _1-} 1.\

0

\ \ 11 \ ' - ' , I )

Ii

I >- )-\.,... / ,.

\ / ' '- , 1 , . '

\ /', 1

^'\...1 ~Y

1.--.""

/', ' - I \': i..~'" /"

... t·_·;>, /

30

" 'I...1 - _;:-I "~_\ / ..."

1

-270

e ^[0]

Figure 82: The far field of the different hole positions.

In Figure 82 the far field of the holes at other positions shows an increase of the field. The position of the maximum of theE-field is changed as well.

The E-field in the x-plane atz= 1 m for the different hole positions and different dipole positions is shown in Figure 83.

The E-field in the y-plane atz= 1 m for the different hole positions and different dipole positions is shown in Figure 84. The holes at different positions show the same trend as the results for the dipoles at different positions. The field-maxima are derived at the position of the position of the hole and this maximum has a lower amplitude value. When the dipole position is changed, the field decreases when the dipole is positioned far from the hole and increases when the dipole is

positioned near the hole.

4

Figure 83:E-field in thex-planefor hole 1at different positions left total right the small fields.

xl0

-3

Figure 84:E-field in the y-plane of hole 1at different positions right the smallest fields zoomed in.

This simulation is repeated for more than one hole. When the dipole is positioned at the centre of the box the E-field results for the different positions of the holes is shown in Figure 85.

·3

Figure 85:E-field for more than one hole at other positions.

The field will be even smaller for changed dipole positions in combination ofthe holes at different positions.

The simulation is performed with the round holes. The E-field is shown in Figure 85.

10.

¹

10.

¹

Figure 86:E-field of round hole at different positions.

The conclusion derived from this figure is similar to the conclusion derived from Figure 85.

In document Eindhoven University of Technology MASTER Uncertainties of radiated emission measurements in the near-field region Bargboer, G. (pagina 64-78)