To provide a microstrip array antenna operating in a wide frequency band.
A power supplying strip line 13 and plural radiating antenna elements 14a-14j arranged with prescribed intervals along the sides and non- power supply antenna elements 17a-17j arranged in parallel with each of the radiating antenna elements in a small interval g are formed on a dielectric substrate 12 on whose back face a conductive ground plate 11 is formed. In this case, the radiating antenna elements 14a-14j are respectively provided with a rectangular shape, and length which is integral times as long as about half of radio wavelength in set frequencies, and width with the distribution of width corresponding to distribution related with the position of the set exciting amplitude of each radiating antenna element. The non-power supply antenna elements are respectively provided with a rectangular shape in almost the same type as that of the corresponding radiating antenna element, and length ranging from 0.9 times to 1.1 times as long as the length of the corresponding radiating antenna element, and width in almost the same dimension as the width of the corresponding radiating antenna element.
SAKAKIBARA KUNIO
NISHIKAWA KUNITOSHI
WATANABE TOSHIAKI
SATO KAZUO
