Pattern reconfigurable techniques for LP and CP antennas with the broadside and conical beams

This paper presents two pattern reconfigurable techniques to realize linear (LP) and circular (CP) broadside and conical-beam switchable radiation patterns from a single antenna. First, a wideband monopolar patch and a L-probe fed patch were organically integrated together to achieve a wideband (2.25 to 2.85 GHz) broadside and conical-beam pattern reconfigurable system that radiates LP radiation. Radiation coverage and wireless channel capacity were improved significantly making the reported LP antenna a good candidate as a ceiling mounted antenna for indoor wireless communications. On the other hand, a circularly-polarized (CP) broadside and conical-beam reconfigurable antenna would be preferred for satellite communications. To realize it, we successfully excited both the TM₁₁ and TM₂₁ modes on a circular patch with an annular slot antenna. A reconfigurable feeding network was designed to provide the correct excitations for these two modes. CP switchable broadside and conical radiated beams were realized within the same overlapping frequency ranges from 2.45 to 2.65 GHz. Both the LP and CP antennas were fabricated and tested. Experimental results show good agreement with their simulated performance characteristics. Very good radiation performance was obtained.