| 摘要 |
PROBLEM TO BE SOLVED: To provide the coupled line directional coupler which is small in size and has proper reflection characteristics. SOLUTION: At both ends of a coupling line 28, a coupling line 29a, whose electrical length is 1/4 wavelength at a design frequency is constructed, and the coupling factor at both ends is not 0 but is set to a specified value. Since the distance between inner conductors can be reduced and a total length of a coupling line is shortened by 1/4 of the wavelength, in comparison with when the coupling factor is 0, when only a tapered coupling line is used, the effect of miniaturization of the coupler exists. Since the line does not change by a large amount in its shape at the end of the coupling line, high accuracy design in the frequency band becomes possible. In addition, at the tapered coupling line part, there are no discontinuity part between coupling lines such as multiply coupled line, and consequently, proper reflection characteristics can be obtained as the effect. COPYRIGHT: (C)2005,JPO&NCIPI
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