To provide a thin plane antenna which suppresses a decrease in radiation efficiency.
A top-surface antenna element 14 formed symmetrically about a feed portion 16 is provided on a top surface 12a of a substrate 12. The surface antenna element 14 is formed of copper foil in a meander line shape having a width W (e.g. 0.5 mm) and a size L1 (e.g. 100 mm)L2 (e.g. 20 mm), and connected to a feeder through the feed portion 16. On the rear surface 12b of the substrate 12, a rear-surface antenna element 18 having the same shape as the top-surface antenna element 14 is provided symmetrically with the top-surface antenna element 14 via the substrate 12. The top-surface antenna element 14 and the rear-surface antenna element 18 are connected together at nearby end portions thereof through vias 20 and 22, and supplied with electric power through the feed portion 16, so that similar currents flow to the top-surface antenna element 14 and rear-surface antenna element 18.
HONJO KAZUHIKO
SAITO AKIRA
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda