To provide a low profile antenna system acting like a vertically polarized wave antenna with respect to azimuth angles.
The antenna system 1 is provided with: a pair of flat upper and lower plate conductors 2, 3 arranged opposite to each other at a prescribed interval and whose external shapes are almost equal to each other; and a plurality of connection conductors 4 for connecting circumferential parts of a pair of the flat upper and lower plate conductors 2, 3, wherein the upper conductor 2 has a feeding point F, and the lower conductor 3 is connected to ground. For example, a pair of the flat upper and lower plate conductors 2, 3 is formed to be a regular polygon and each connection conductor 4 may be arranged at the corners respectively. Three or more of the connection conductors 4 are arranged nearly at an equal interval along the circumferential direction so as to form three or more of openings 5 of almost the same shape over the entire circumference whose external shape is specified by the circumferential parts of a pair of the flat upper and lower plate conductors 2, 3 and the two connection conductors 4. Each of the openings 5 faces with each other in different directions and the electric field distribution in each opening 5 is similar to that of a slot antenna at power feeding.
Ichiro Suzuki
Hirohiro Ichimura
Kazuo Kobayashi