| 摘要 |
PURPOSE:To make the strip line compact and low-priced much more by setting the length of the signal wave coupling part of 1st-3rd strip lines to a length corresponding to the electric 1/4 input signal wave while containing 1st-4th capacitors. CONSTITUTION:By connecting capacitors 31 and 32 to both terminals of a 3rd strip line 30, the length of the line 30 can be made shorter in comparison with the case of connecting no capacitor. Since the length of the intermediate line 30 can be made shorter than a strip line equivalent in the manner of the electric length with a longer physical length at a side couple filter 21, the entire size of the filter 21 can be reduced. When the physical length of the line 30 is shortened, however, the amount of coupling caused by shortening a line adjacent to both side strip lines 24 and 25 is decreased and since the line 30 can be actually formed at a position vertically overlapped to both side lines 24 and 25, however, the amount of coupling can be compensated. |
