Conical Beam Array Antenna With Polarization Diversity

This study designed a 2×2 circular disc array antenna with omnidirectional radiation pattern and polarization diversity. Each disc element was located above a circular slot fed by an L-shaped strip, in which the switching between two orthogonal linear polarizations (LP) and circular polarization (CP) were realized by controlling two pin diodes. To allow conical beam for all polarization senses, a meticulously designed cross-shaped feeding network is proposed, and besides showing a suffficient 10 dB return loss bandwidth that covers the 2.4 GHz band of WLAN operation, good cross-polarization level (XPL) were measured when the array operated in all available polarization senses.