| 摘要 |
PURPOSE:To make a strip line stable in propagation characteristics by a method wherein a power source ground pattern and a signal line pattern are made to overlap each other forming a certain angle with each other, and the patterns are kept constant in an overlap area rate. CONSTITUTION:A power source ground pattern 1 is provided making an angle alphaof 45 deg. with a signal line 3, the lateral side (a) and the longitudinal side (b) of the pattern 1 are equal to each other, and the width (c) of the pattern 1 and the length (a) of the side of the pattern 1 are so set as to satisfy a formula, 0<c<b/2. When the width (d) of a clearance 2, the width (c) of the pattern 1, and the length (b) of the pattern 1 are set to satisfy a formula, d=b-2c, and the overlap area rate of the GND pattern 1 with the signal line pattern 3 is constant and as much as 2c/b of the total area of the signal line pattern 3 independent of the width and the position of the signal line pattern 3. Even in case of a signal line 4, the same result can be obtained. Therefore, the signal lines 3 and 4 can be lessened in dispersion of distributed capacity, and a multilayer wiring board of this design can be made stable in characteristic impedance and propagation delay time independent of the width and the position of the signal line patterns. |
