A multi-sector beam antenna consisting of directional beam antennas and a beam selecting switch is effective for a terminal antenna of a broadband wireless access system and several antennas of this type have been used in the commercial services. In order to increase the channel capacity, higher frequencies such as Ku band, Ka band and millimeter waves are used or studied for the systems. In these high frequencies, the insertion loss of the beam selecting switch becomes large, therefore the antenna performances degrade. In this paper, a new type of the multi-sector antenna which has a distributed implicit RF switch is proposed for reducing insertion loss of the switch. The distributed implicit RF switch is composed of a Yagi-Uda antenna and diode switches in parasitic elements. Numerical calculations have been carried out to ensure the feasibility of the proposed antenna.