To provide high gain/wide band performance not to fluctuate the radiation center of radio wave even at the time of wide band usage.
A surface radiation type antenna has a rectangular frame-shaped antenna element 3, for which the ratio of length between a short side 1 and a long side 2 is set from 1:2 to 1:6 and the length of the long side 2 is almost set to be 1/2 as long as a wavelength to be used or set equal with the wavelength to be used, and is provided with totally two pairs of power feeding points 4, 4, 4 and 4, two by two on the respective long sides 2 and 2, at the positions almost from 1/3 to 1/8 of a full length from both ends on the respective long sides 2 and 2. Then, the antenna element 3 is cylindrically formed so that the respective long sides 2 can form the outer edges of upper and lower terminal parts and the height equal with the short side 1 can be provided.
F II C KK
Tadaaki Matsuda