Abstract: Disclosed is an electric/magnetic microstrip antenna 17a, 17b, 17c, 17d, 17e, 17f, 17g, and 17h. An electric/magnetic antenna 17a includes a ground plate 11a. A first dielectric substrate 12a, a patch radiator 13a, a second dielectric substrate 14a, parallel plates 15a, 15b are sequentially stacked on the ground plate 11a. The ground plate 11a and the patch radiator 13a have the same width(W1) and the parallel plates 15a and 15b are formed by folding up both ends of the ground plate 11a such that the size of the electric/magnetic microstrip antenna is reduced while the range of electric lines of force between the patch radiator 13a and the ground plate 11a is not restricted. The outer conductor of a feeder 16a is connected with the ground plate 11a, and the inner conductor of the feeder 16a is connected with the patch radiator 13a through the ground plate 11a.