| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-reflection and low-loss line converter. SOLUTION: This line converter converts microstrip line and coplanar lines to each other. On the upper surface of a Teflon (R) substrate 40, the microstrip line 10 and a first coplanar line 30 are formed and a second coplanar line 20 is formed between the lines 10 and 30. The second coplanar line 20 is constituted of a plurality of coplanar lines 21 and 23. The strip conductor 11 of the microstrip line 10 is used as the center conductor of the coplanar line 21, and the center conductor 24 of the coplanar line 23 is narrowed in a tapered state and connected to the center conductor 31 of the first coplanar line 23. By using this constitution, signal propagation modes are gradually changed. Therefore, the loss caused by an abrupt mode change does not occur. In addition, the characteristic impedance of the second coplanar line 20 nearly matches those of the microstrip line 10 and first coplanar line 30 by adjusting the distances between a second grounding conductor 32 and center conductors. Consequently, reflection by the line converter is reduced significantly.
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