Enhancing the beamwidth of low profile single-fed microstrip antennas using parasitic elements

In this paper we present a technique to broaden the beamwidth of conventional patch microstrip antennas by using parasitic elements. This technique allows to keep the main advantages of microstrip antennas while increasing their beamwidth. We provide guidelines on how to tune the shape of the pattern from directive patterns to broad beam by tuning a few key parameters. Using this technique, the beamwidth of a regular patch antenna can be increased from the usual 70 degrees up to 200 degrees, and is compatible with linear and circular polarization. The antenna presented as an example in the paper covers the ISM band at 2.4GHz.