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elektronika electronics - Electronics Journal - Elektrotehnicki fakultet

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elations (16) and (17) given in the paper [3], where are<br />

U = U<br />

k r k<br />

2T<br />

, 2 2T<br />

r<br />

Z = Z<br />

k<br />

22<br />

k<br />

2T<br />

and .<br />

The obtained voltage vector is<br />

U S 1<br />

U S L<br />

Z S 1<br />

Z S L<br />

U S<br />

1<br />

L<br />

k 1<br />

2 T<br />

[<br />

+<br />

U = U | U<br />

Network<br />

1<br />

1<br />

L<br />

k+<br />

1<br />

2T<br />

, 1m<br />

1<br />

L<br />

ELECTRONICS, VOL. 8, NO.1, MAY 2004. 35<br />

]<br />

k+<br />

1 T<br />

2T<br />

, nL<br />

Network<br />

k<br />

. (22)<br />

1<br />

L<br />

1<br />

m+<br />

1<br />

n −1<br />

L<br />

Network<br />

1<br />

k+ 1<br />

Network<br />

2<br />

k+ 1<br />

st<br />

7. The transmission matrices of the K + 1 network and the<br />

other networks till the end are square matrices of sizes<br />

th<br />

L × L . According to the network junction ( K and<br />

st<br />

K + 1 networks) permutation of rows in the<br />

st<br />

transmission matrices only for the K + 1 network must<br />

be done in the manner shown in the previously given<br />

section. In that way new matrices , , and<br />

DP<br />

are formed.<br />

6. For the other networks in cascade connection till the<br />

outputs of networks 1 and 2 the relations (12) and (13)<br />

are used.<br />

Network<br />

1<br />

k+ K1<br />

Network<br />

2<br />

K<br />

1<br />

Current<br />

sources<br />

Fig.2. One microstrip structure with complex network connections.<br />

AP P B P C<br />

th<br />

st<br />

8. At the junction between the K and K + 1 networks,<br />

because of the increased number of input ports, it is<br />

K<br />

2T<br />

necessary to increase the vector and the matrix<br />

K<br />

Z2T<br />

. According to the network connection given in<br />

Fig.2 the source impedance matrix for the next<br />

K<br />

2T<br />

network is impedance matrix increased as<br />

i<br />

Z<br />

K<br />

2T<br />

K<br />

⎡ ZmL<br />

⎢<br />

⎢<br />

− −<br />

= ⎢ 0<br />

⎢<br />

⎢ − −<br />

⎢ K<br />

⎣ Z Lm<br />

|<br />

|<br />

|<br />

|<br />

|<br />

0<br />

Z<br />

− − −<br />

0<br />

− − −<br />

0<br />

|<br />

|<br />

|<br />

|<br />

|<br />

U<br />

Z<br />

1 � m | m + 1�<br />

n − 1|<br />

n � L<br />

K<br />

mm<br />

− −<br />

− −<br />

Z<br />

0<br />

K<br />

LL<br />

⎤<br />

⎥<br />

⎥<br />

⎥<br />

⎥<br />

⎥<br />

⎥<br />

⎦<br />

1<br />

1<br />

1<br />

�<br />

m<br />

m+<br />

�<br />

n−<br />

n<br />

�<br />

L<br />

st<br />

K + 1<br />

. (23)<br />

The voltage vector of ETS at the<br />

th<br />

K open-ended<br />

network is full vector and it can be increased in the form<br />

i<br />

U<br />

K<br />

2 T<br />

k<br />

k<br />

[ U | 0 | ]<br />

= U<br />

2T<br />

, 1m<br />

2T<br />

, nL<br />

1 � m | m+<br />

1�<br />

n-1<br />

| n � L<br />

T<br />

(24)<br />

st<br />

K + 1<br />

which represents the source vector of the next<br />

network.<br />

K + 1<br />

9. The voltage vector, U , and the impedance matrix,<br />

Z<br />

K+<br />

1<br />

2T<br />

, of ETS for the<br />

2T<br />

st<br />

K + 1 open-ended network are<br />

given by equations (10) and (11), where and<br />

i<br />

W = Z<br />

s<br />

K<br />

2T<br />

.<br />

i<br />

S= U<br />

K<br />

2T<br />

L<br />

1<br />

m + 1<br />

n − 1<br />

L<br />

Network<br />

K+ 1<br />

10. For the further calculation, K + 2 , K + 3,...<br />

, till the<br />

Z<br />

1<br />

L<br />

1<br />

L<br />

ZL<br />

load network L , the relations (12) and (13) can be used<br />

for solving the rest of the networks in cascade<br />

connection.<br />

IV. EXAMPLE<br />

Several examples of microstrip lines with arbitrarily<br />

shaped holes and leaders, which are symmetrically or<br />

asymmetrically placed, are shown in this section, Figs. 3-4,<br />

6-7, 9. They are observed as cascade-connected transmission<br />

lines with different lengths and increased or reduced widths.<br />

The nominal substrate dielectric constant is ε r = 10.<br />

2 ,<br />

the substrate thickness is h = 635 µ m and the strip<br />

thickness is t = 18.<br />

03 µ m .<br />

50Ohm<br />

The lines at the ends (L1) are the leader lines.<br />

Their widths are w 1 = 586.<br />

95 µ m and lengths<br />

d 1 = 800 µ m .<br />

The widths of cascade-connected transmission lines are<br />

w 2 = 2500 µ m , w 3 = 250 µ m , w 4 = 500 µ m ,<br />

w 5 = 750 µ m and w 6 = w7<br />

= 1000 µ m . Their lengths<br />

are d 2 = 310 µ m , d 3 = 1000 µ m , d 4 = 400 µ m ,<br />

d 5 = 500 µ m , d 6 = 300 µ m and d 7 = 1200 µ m .<br />

The result obtained by program FAMIL that is done in<br />

MATLAB is shown in Figs. 5, 8, 10.<br />

Input<br />

ports<br />

L1 L2 L3 L4 L5 L6 L2 L1<br />

50Ω 50 Ω<br />

Fig.3. Example 1 – Line with a hole<br />

and symmetrically placed leader lines.<br />

Output<br />

ports

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