Patent ID: 6690924
Filing Date: 2004-02-10
Classification: H01Q

Abstract:
An apparatus for wireless communications to process an electromagnetic signal having horizontally polarized waves and vertically polarized waves, comprising:a substrate having a first surface and a second surface opposite to said first surface; a microstrip line of a quarter-wavelength formed on said first surface; a contact pad formed on the first surface and connected to said microstrip line; an impedance transformer of the quarter-wavelength formed on said first surface and connected to said contact pad; a ground plane formed on said second surface; a loop antenna of the quarter-wavelength formed on said second surface and connected to said ground plane at one end, said loop antenna having another end overlapped with said microstrip line and spaced from said ground plane; and a monopole antenna of the quarter-wavelength attached to said contact pad, wherein the monopole antenna is directed to an orthogonal orientation with respect to a plane where the loop antenna stands to provide circularized-polarized radiation patterns in an azimuth direction.