Variable beam tilt microstrip array for 5 GHz wireless access system

This paper presents a variable beam tilt array using electromagnetically coupled patch elements. Two antenna elements are excited with the phase difference of 90/spl deg/ and the spacing is adjusted around quarter wavelength to change the beam tilt. The antenna element is coupled electromagnetically to the feeding stub, which is easy to move for variable beam tilt. Numerical simulation shows the beam tilt angle is adjusted from 30 to 60/spl deg/. This variable beam tilt is effective in changing the coverage area of indoor base station antennas for 5 GHz wireless access systems.