Antenna unit having improved antenna radiation characteristics

摘要

An antenna unit comprises a hollow cylindrical member obtained by forming a flexible insulating film member into a hollow cylinder about a center axis and an antenna pattern composed of a plurality of conductors formed on a peripheral surface of the hollow cylindrical member. The antenna pattern comprises a helical pattern extending helically in a direction of the center axis and a loop pattern connected to an end portion of the helical pattern at an upper end portion of the hollow cylindrical member.