GW Instek GRF-3300 Series Student Manual - Manual (Page 19)

16 Microstrip Line Filters
3 327
Now we can use the following equations to evaluate the line impedance.
c
i i
i i
c
i
i
y
Z
Z
y
Z
Z
- -
- -
2 ,
,
1 ,
0
1 ,
0


We get:
24 . 49
16 . 82
25 . 48
93 . 111
23
2
12
1
Z
Z
Z
Z
And then we can use CAD tools to find out the real length and width of each
section.
mm w
mm l
mm w
mm l
mm w
mm l
mm w
mm l
35 . 2
22 . 21
867 . 0
02 . 11
43 . 2
189 . 21
3762 . 0
23 . 11
23
23
2
2
12
12
1
1
We still need to consider two issues: one is that the minimum practical distance is
0.5mm, and the other one is the cross section of each line. Therefore, after fine tuning, the
final result becomes as follows.
mm w
mm l
mm w
mm l
mm w
mm l
mm w
mm l
3 . 2
2 . 21
1
7 . 10
3 . 2
2 . 21
8 . 0
7 . 10
23
23
2
2
12
12
2
1