Multiple-Resonator-Based Wideband and Multiband Microstrip Patch Antennas

In this work, the multimode concept and technique for designing a class of microstrip patch antennas (MPAs) under wideband and multiband performances concluded. Firstly, the wideband linearly-polarized (LP) of the MPA could be acquired by reallocating two radiative modes with same polarization closely to each other. After that, as these radiative modes maintain orthogonal radiated fields with the sequential rotation, the bandwidth of the circularly-polarized (CP) MPA could be enhanced effectively. Additionally, when these modes maintain orthogonal radiated fields without the sequential rotation, the dual-polarized CP MPA could be consequently acquired. Most importantly, it keeps a small frequency-ratio. All of these results demonstrate that the multimode design concept of the MPAs could be well employed and applied in the low-profile and single-layer devices.