An electronically beam-steerable antenna device comprises a dielectric lens having at least one flat surface, a high frequency dielectric board, a plurality of at least one primary antenna element with at least one transmission line formed on the high frequency dielectric board, and a switching network electrically connected to the said plurality of at least one primary antenna element and at least one transmission line and adapted to apply electric power to the at least one primary antenna element. The switching network is a semiconductor integrated circuit mounted in or on the high frequency dielectric board, and the high frequency dielectric board with the plurality of at least one antenna element and at least one transmission line formed thereon is adjacent to the flat surface of the dielectric lens.The electronically beam steerable antenna device according to the present invention allows for electronic beam steering in a continuous angle sector while increasing radiation efficiency. The antenna device according to the present invention may be used for providing high data rate point-to-point millimeter-wave communications in radio relay station applications.