LOOP ANTENNA WITH REFLECTION PLATE

摘要

PROBLEM TO BE SOLVED: To provide a loop antenna with a reflection plate which effectively controls a back lobe without increasing the size of the reflection plate. SOLUTION: The loop antenna with the reflection plate is provided with an annulus portion 31, a feeding portion connected to the annulus portion 31 and the reflection plate 40 arranged with a space from the annulus portion 31. The annulus portion 31 is provided with a descending portion 37 which approaches a voltage maximum point closer toward the reflection plate direction than toward a current maximum point direction. The loop antenna realizes control of the back lobe without making an input impedance characteristic become a narrow band by approaching a part of the loop antenna rather than an entire of the loop antenna closer to the reflection plate 40. It results in no need of estimating an increase in strength of a mounting structure body for the antenna because the reflection plate itself does not need to be increased in its size. COPYRIGHT: (C)2004,JPO