| 摘要 |
<p>In the present invention, first and second antenna elements are selected for an antenna apparatus with a switching apparatus so that the first and the second antenna elements are brought into connection with an unbalanced transmission line via a balancing-unbalancing transmission line or only the first antenna element is brought into connection with the unbalanced transmission line, and then, the unbalanced transmission line supplies via a balanced-to-unbalanced transformation apparatus the first and the second antenna elements with power so as to operate as an antenna, and thereby, at this time balanced-to-unbalanced transformation action of the balanced-to-unbalanced transformation apparatus prevents the leakage current from flowing from the first or the second antenna element to the unbalanced transmission line, and prevents the ground member onto which this unbalanced transmission line is grounded from operating as an antenna so that deterioration of antenna characteristics in the vicinity of a human body can be sizably reduced, and thus an antenna device and portable radio set which can sizably reduce deterioration of communication quality can be realized. <IMAGE> <IMAGE></p> |
