| 摘要 |
PURPOSE:To reduce a change in a characteristic due to variance in a line width by forming part of a dielectric board with a dielectric body whose dielectric constant differs from a prescribed dielectric constant of the board. CONSTITUTION:A filter circuit 13 is formed on a dielectric ceramic board 10. The filter circuit 13 consists of main lines 14a, 14b, 14c and stubs 15-18 whose end is open are formed to the lines 14a, 14b, 14c. Moreover, the ceramic board 10a is a board whose dielectric constant is lower than that of the dielectric ceramic board 10 and a transformer 12 is formed on the base 10a. Through the constitution above, the line width is made thick without changing the characteristic impedance of the transformer 12 by using a dielectric material whose dielectric constant is lower than that of a filter for the transformer whose line width is thin and the characteristic is made stable against the dispersion in the line width in the manufacture of strip lines. |
