A Wideband Transmitarray Antenna Using Quad-Layer Double Circular Ring Elements

The aim of this study is to investigate of two cases; case1: double square-circular rings (DSCR) and case2: double circular rings (DCR), as the transmitarray unit cell element. The features and capabilities of two proposed elements are obtained at 11.3GHz by full wave analysis using HFSS software. The parametric study shows that the variation of the outer radius of the internal circular ring can be led the most phase variation, for two cases. The simulation and analysis of the quad-layer unit cell, for two proposed elements, achieves 320° and 367° transmission phase range, for better than −3dB transmission magnitude, for case1 and case2 respectively. Therefore, it can be concluded that the quad-layer DCR has the better performance, with respect to the other case, because of full 360° range covering. A $214\times 214$ mm²transmitarray antenna based on the DCR elements has been designed and analyzed. The highest gain is about 23.5dBi at 10GHz with 35% aperture efficiency. The 1-dB gain bandwidth of 13.8% (from 9.39 to 10.79GHz) and 3-dB gain bandwidth of 27.44% (from 8.59 to 11.32GHz) have been achieved in this design.