Logarithmic periodic antenna and processing method of log periodic antenna

摘要

PROBLEM TO BE SOLVED: To provide a logarithmic period type antenna capable of sharpening directivity without changing the length of the antenna while maintaining good VSWR characteristics.SOLUTION: A first logarithmic period antenna element part 21a and a second logarithmic period antenna element part 21b are disposed with the rear end sides thereof opened at a prescribed angle on the basis of the tip end sides where elements are shorter, and a H plane half value width is narrowed to obtain sharp directivity. Power feeding parts 23a, 23b are provided at the inner sides of the tip parts of arms 22a, 22b of the logarithmic period antenna element parts 21a, 21b respectively. The power feeding parts 23a, 23b are made to face each other with an almost fixed interval kept between, and each of them has a prescribed length. When the logarithmic period antenna element parts 21a, 21b are disposed with the rear end sides thereof opened, since a mutual distance becomes wider and VSWR characteristics are deteriorated, the power feeding parts 23a, 23b are provided so as to supplement the space part between the logarithmic period antenna element parts 21a, 21b, and the interval therebetween, the length thereof and the like are adjusted.