Development of a dual band circularly polarized mircostrip patch and semi-hexagonal SIW cavity hybrid antenna

A new low profile dual band circularly polarized hybrid antenna is presented. The proposed antenna consists of a hexagonal resonator cavity based on Half Mode Substrate Integrated Waveguide (HMSIW) and two rectangular microstrip patches with different size to provide multiband operation. The hexagonal HMSIW cavity operates at its fundamental TM010 mode and excites two patches. An inclined slot with appropriate size and position is placed on top of the each patch to obtain circular polarization (CP) with different types. The proposed antenna radiates a right hand CP (RHCP) wave at its first band, while at the other band, it provides left hand CP (LHCP) wave. Antenna structure is numerically evaluated using HFSS, and results including reflection coefficient, axial ratio (AR), and radiation patterns are reported.