| 摘要 |
PURPOSE:To match the characteristic impedance without changing the width of a transmission line by combining materials different in dielectric constants so as to satisfy a specific condition. CONSTITUTION:A transmission line 1 is arranged on the upper face of a dielectric substrate 2 and an earth line 3 is arranged on the lower face to form a micro strip line element. The substrate 2 consists of parta 2a in both ends of the substrate where input/output ends 1a having length L1 of the transmission line 1 are arranged, a part 2c in the center of the substrate where a low- impedance line 1c is arranged, and parts 2b which are between parts 2a and 2c and have transformer parts 1b arranged. Materials different in dielectric constants are used in parts 2a, 2b, and 2c respectively, and they are so combined that Z1>Z2>Z3 and Z2=(Z1XZ3)<1/2> are satisfied where Z1 is the characteristic impedance in input/output ends and Z3 is the characteristic impedance in transformer parts. Thus, the characteristic impedance is matched with the same width as the line of a prescribed characteristic impedance, and the element is miniaturized. |
