Filter
Top Products
Intel
®
820E Chipset
R
180 Design Guide
Figure 98. Microstrip (a) and Stripline (b) Cross Section for 28 Ω
ΩΩ
Ω Trace
G
G
4.5 mils
2.1 mils
6 mils
18 mils
10 mils
S
a) Microstrip cross section for 28-
Ω
trace
b) Stripline cross section for 28-
Ω
trace
G
G
5 mils
1.2 mils
5 mils
13.5 mils
6 mils
S
7 mils
1.2 mils
1.2 mils
x-section_28trace
Note: Do not forget ground floods and stitching.
5.1.6. Impedance Calculation Tools
3D field solvers, such as those by HP, Ansoft, Sonnet, and Polar, are most accurate when calculating the
impedance. Z calculators based on equations (zcalc) also are fairly accurate. The differences are listed in
the following table.
Table 62. 3D Field Solver vs. ZCALC
#1 #2 #3 #4 #5 #6
H 4.5 4.5 4.2 4.8 4.5 4.5
W 18 18 18 18 17 19
W1 18.1 18.1 18.1 18.1 17.1 19.1
T 1.4 2.8 1.4 1.4 1.4 1.4
εr 4.5 4.5 4.5 4.5 4.5 4.5
Z0 (3D) 29.0 28.4 27.6 30.4 30.2 27.9
Z0 (zcalc) 29.1 28.7 27.7 30.4 30.2 28.0