A Dual-Band Dual-Sense Circularly Polarized Microstrip Antenna Array with A Small Frequency Ratio

Abstract

A low-profile dual-band dual-sense circularly polarized microstrip patch antenna (MPA) array is presented. For the element design, a non-radiative $\lambda$/2 resonator is coupled with one of the orthogonal modes of the square patch, and an additional mode is introduced. Another mode of the patch is kept unchanged. The dual-band, dual-sense circularly-polarized radiation is realized by the three modes. Finally, a 2*2 array is designed, full-wave simulated, fabricated, and measured. The simulation results are in good agreement with the measure results. Right-handed circular polarization (RHCP) is achieved at 2.95 GHz, and left-handed CP at 3.07 GHz, achieving a small frequency ratio of 1.041.