Wide-Band SIW Cavity-Backed Circular Polarized Array Antennas with Sequential Rotation Technique<bold> </bold>

A circularly-polarized (CP) array antenna based on the substrate integrated waveguide (SIW) technology is proposed. The 2x2 linearly polarized SIW sub-arrays with 90 degrees sequential rotation are employed as the radiating elements on the top layer. The sequential rotation technique is introduced to design SIW corporate-feed network on the bottom layer to realize wideband circular polarized characteristic. The network and the radiating elements of the array are both designed on close SIW structure with low cost printed circuit board (PCB) technology. The simulated results show that, the proposed 4x4 array has a large axial ratio (AR) bandwidth of 14% from 18.3 GHz to 21.1 GHz with a gain above 13 dBi.<bold> </bold>